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%
% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcBinds]{TcBinds}
\begin{code}
<pre><a name="line-1"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>TcBinds</span> <span class='hs-layout'>(</span> <span class='hs-varid'>tcLocalBinds</span><span class='hs-layout'>,</span> <span class='hs-varid'>tcTopBinds</span><span class='hs-layout'>,</span>
<a name="line-2"></a> <span class='hs-varid'>tcHsBootSigs</span><span class='hs-layout'>,</span> <span class='hs-varid'>tcMonoBinds</span><span class='hs-layout'>,</span> <span class='hs-varid'>tcPolyBinds</span><span class='hs-layout'>,</span>
<a name="line-3"></a> <span class='hs-conid'>TcPragFun</span><span class='hs-layout'>,</span> <span class='hs-varid'>tcPrags</span><span class='hs-layout'>,</span> <span class='hs-varid'>mkPragFun</span><span class='hs-layout'>,</span>
<a name="line-4"></a> <span class='hs-conid'>TcSigInfo</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>TcSigFun</span><span class='hs-layout'>,</span> <span class='hs-varid'>mkTcSigFun</span><span class='hs-layout'>,</span>
<a name="line-5"></a> <span class='hs-varid'>badBootDeclErr</span> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-6"></a>
<a name="line-7"></a><span class='hs-keyword'>import</span> <span class='hs-comment'>{-# SOURCE #-}</span> <span class='hs-conid'>TcMatches</span> <span class='hs-layout'>(</span> <span class='hs-varid'>tcGRHSsPat</span><span class='hs-layout'>,</span> <span class='hs-varid'>tcMatchesFun</span> <span class='hs-layout'>)</span>
<a name="line-8"></a><span class='hs-keyword'>import</span> <span class='hs-comment'>{-# SOURCE #-}</span> <span class='hs-conid'>TcExpr</span> <span class='hs-layout'>(</span> <span class='hs-varid'>tcMonoExpr</span> <span class='hs-layout'>)</span>
<a name="line-9"></a>
<a name="line-10"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>DynFlags</span>
<a name="line-11"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>HsSyn</span>
<a name="line-12"></a>
<a name="line-13"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TcRnMonad</span>
<a name="line-14"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Inst</span>
<a name="line-15"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TcEnv</span>
<a name="line-16"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TcUnify</span>
<a name="line-17"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TcSimplify</span>
<a name="line-18"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TcHsType</span>
<a name="line-19"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TcPat</span>
<a name="line-20"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TcMType</span>
<a name="line-21"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TcType</span>
<a name="line-22"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Coercion</span>
<a name="line-23"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>VarEnv</span>
<a name="line-24"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>TysPrim</span>
<a name="line-25"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Id</span>
<a name="line-26"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Var</span>
<a name="line-27"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Name</span>
<a name="line-28"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>NameSet</span>
<a name="line-29"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>NameEnv</span>
<a name="line-30"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>VarSet</span>
<a name="line-31"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>SrcLoc</span>
<a name="line-32"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Bag</span>
<a name="line-33"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>ErrUtils</span>
<a name="line-34"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Digraph</span>
<a name="line-35"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Maybes</span>
<a name="line-36"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Util</span>
<a name="line-37"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>BasicTypes</span>
<a name="line-38"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Outputable</span>
<a name="line-39"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>FastString</span>
<a name="line-40"></a>
<a name="line-41"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span>
</pre>\end{code}
%************************************************************************
%* *
\subsection{Type-checking bindings}
%* *
%************************************************************************
@tcBindsAndThen@ typechecks a @HsBinds@. The "and then" part is because
it needs to know something about the {\em usage} of the things bound,
so that it can create specialisations of them. So @tcBindsAndThen@
takes a function which, given an extended environment, E, typechecks
the scope of the bindings returning a typechecked thing and (most
important) an LIE. It is this LIE which is then used as the basis for
specialising the things bound.
@tcBindsAndThen@ also takes a "combiner" which glues together the
bindings and the "thing" to make a new "thing".
The real work is done by @tcBindWithSigsAndThen@.
Recursive and non-recursive binds are handled in essentially the same
way: because of uniques there are no scoping issues left. The only
difference is that non-recursive bindings can bind primitive values.
Even for non-recursive binding groups we add typings for each binder
to the LVE for the following reason. When each individual binding is
checked the type of its LHS is unified with that of its RHS; and
type-checking the LHS of course requires that the binder is in scope.
At the top-level the LIE is sure to contain nothing but constant
dictionaries, which we resolve at the module level.
\begin{code}
<pre><a name="line-1"></a><a name="tcTopBinds"></a><span class='hs-definition'>tcTopBinds</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>HsValBinds</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-conid'>TcLclEnv</span><span class='hs-layout'>)</span>
<a name="line-2"></a> <span class='hs-comment'>-- Note: returning the TcLclEnv is more than we really</span>
<a name="line-3"></a> <span class='hs-comment'>-- want. The bit we care about is the local bindings</span>
<a name="line-4"></a> <span class='hs-comment'>-- and the free type variables thereof</span>
<a name="line-5"></a><span class='hs-definition'>tcTopBinds</span> <span class='hs-varid'>binds</span>
<a name="line-6"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-conid'>ValBindsOut</span> <span class='hs-varid'>prs</span> <span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>env</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcValBinds</span> <span class='hs-conid'>TopLevel</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>getLclEnv</span>
<a name="line-7"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>foldr</span> <span class='hs-layout'>(</span><span class='hs-varid'>unionBags</span> <span class='hs-varop'>.</span> <span class='hs-varid'>snd</span><span class='hs-layout'>)</span> <span class='hs-varid'>emptyBag</span> <span class='hs-varid'>prs</span><span class='hs-layout'>,</span> <span class='hs-varid'>env</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-8"></a> <span class='hs-comment'>-- The top level bindings are flattened into a giant </span>
<a name="line-9"></a> <span class='hs-comment'>-- implicitly-mutually-recursive LHsBinds</span>
<a name="line-10"></a>
<a name="line-11"></a><a name="tcHsBootSigs"></a><span class='hs-definition'>tcHsBootSigs</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>HsValBinds</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Id</span><span class='hs-keyglyph'>]</span>
<a name="line-12"></a><span class='hs-comment'>-- A hs-boot file has only one BindGroup, and it only has type</span>
<a name="line-13"></a><span class='hs-comment'>-- signatures in it. The renamer checked all this</span>
<a name="line-14"></a><span class='hs-definition'>tcHsBootSigs</span> <span class='hs-layout'>(</span><span class='hs-conid'>ValBindsOut</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>)</span>
<a name="line-15"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>checkTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-varid'>badBootDeclErr</span>
<a name="line-16"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>addLocM</span> <span class='hs-varid'>tc_boot_sig</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>filter</span> <span class='hs-varid'>isTypeLSig</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-17"></a> <span class='hs-keyword'>where</span>
<a name="line-18"></a> <span class='hs-varid'>tc_boot_sig</span> <span class='hs-layout'>(</span><span class='hs-conid'>TypeSig</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-varid'>ty</span><span class='hs-layout'>)</span>
<a name="line-19"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>sigma_ty</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcHsSigType</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunSigCtxt</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-varid'>ty</span>
<a name="line-20"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkVanillaGlobal</span> <span class='hs-varid'>name</span> <span class='hs-varid'>sigma_ty</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-21"></a> <span class='hs-comment'>-- Notice that we make GlobalIds, not LocalIds</span>
<a name="line-22"></a> <span class='hs-varid'>tc_boot_sig</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pprPanic</span> <span class='hs-str'>"tcHsBootSigs/tc_boot_sig"</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-23"></a><span class='hs-definition'>tcHsBootSigs</span> <span class='hs-varid'>groups</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pprPanic</span> <span class='hs-str'>"tcHsBootSigs"</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>groups</span><span class='hs-layout'>)</span>
<a name="line-24"></a>
<a name="line-25"></a><a name="badBootDeclErr"></a><span class='hs-definition'>badBootDeclErr</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Message</span>
<a name="line-26"></a><span class='hs-definition'>badBootDeclErr</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Illegal declarations in an hs-boot file"</span><span class='hs-layout'>)</span>
<a name="line-27"></a>
<a name="line-28"></a><a name="tcLocalBinds"></a><span class='hs-comment'>------------------------</span>
<a name="line-29"></a><span class='hs-definition'>tcLocalBinds</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>HsLocalBinds</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-varid'>thing</span>
<a name="line-30"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsLocalBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span>
<a name="line-31"></a>
<a name="line-32"></a><span class='hs-definition'>tcLocalBinds</span> <span class='hs-conid'>EmptyLocalBinds</span> <span class='hs-varid'>thing_inside</span>
<a name="line-33"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>thing</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>thing_inside</span>
<a name="line-34"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>EmptyLocalBinds</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-35"></a>
<a name="line-36"></a><span class='hs-definition'>tcLocalBinds</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsValBinds</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-varid'>thing_inside</span>
<a name="line-37"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds'</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcValBinds</span> <span class='hs-conid'>NotTopLevel</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>thing_inside</span>
<a name="line-38"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsValBinds</span> <span class='hs-varid'>binds'</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-39"></a>
<a name="line-40"></a><span class='hs-definition'>tcLocalBinds</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsIPBinds</span> <span class='hs-layout'>(</span><span class='hs-conid'>IPBinds</span> <span class='hs-varid'>ip_binds</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>thing_inside</span>
<a name="line-41"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>thing</span><span class='hs-layout'>,</span> <span class='hs-varid'>lie</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>getLIE</span> <span class='hs-varid'>thing_inside</span>
<a name="line-42"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>avail_ips</span><span class='hs-layout'>,</span> <span class='hs-varid'>ip_binds'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapAndUnzipM</span> <span class='hs-layout'>(</span><span class='hs-varid'>wrapLocSndM</span> <span class='hs-varid'>tc_ip_bind</span><span class='hs-layout'>)</span> <span class='hs-varid'>ip_binds</span>
<a name="line-43"></a>
<a name="line-44"></a> <span class='hs-comment'>-- If the binding binds ?x = E, we must now </span>
<a name="line-45"></a> <span class='hs-comment'>-- discharge any ?x constraints in expr_lie</span>
<a name="line-46"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>dict_binds</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcSimplifyIPs</span> <span class='hs-varid'>avail_ips</span> <span class='hs-varid'>lie</span>
<a name="line-47"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsIPBinds</span> <span class='hs-layout'>(</span><span class='hs-conid'>IPBinds</span> <span class='hs-varid'>ip_binds'</span> <span class='hs-varid'>dict_binds</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-48"></a> <span class='hs-keyword'>where</span>
<a name="line-49"></a> <span class='hs-comment'>-- I wonder if we should do these one at at time</span>
<a name="line-50"></a> <span class='hs-comment'>-- Consider ?x = 4</span>
<a name="line-51"></a> <span class='hs-comment'>-- ?y = ?x + 1</span>
<a name="line-52"></a> <span class='hs-varid'>tc_ip_bind</span> <span class='hs-layout'>(</span><span class='hs-conid'>IPBind</span> <span class='hs-varid'>ip</span> <span class='hs-varid'>expr</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-53"></a> <span class='hs-varid'>ty</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newFlexiTyVarTy</span> <span class='hs-varid'>argTypeKind</span>
<a name="line-54"></a> <span class='hs-layout'>(</span><span class='hs-varid'>ip'</span><span class='hs-layout'>,</span> <span class='hs-varid'>ip_inst</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newIPDict</span> <span class='hs-layout'>(</span><span class='hs-conid'>IPBindOrigin</span> <span class='hs-varid'>ip</span><span class='hs-layout'>)</span> <span class='hs-varid'>ip</span> <span class='hs-varid'>ty</span>
<a name="line-55"></a> <span class='hs-varid'>expr'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcMonoExpr</span> <span class='hs-varid'>expr</span> <span class='hs-varid'>ty</span>
<a name="line-56"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>ip_inst</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-conid'>IPBind</span> <span class='hs-varid'>ip'</span> <span class='hs-varid'>expr'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-57"></a>
<a name="line-58"></a><a name="tcValBinds"></a><span class='hs-comment'>------------------------</span>
<a name="line-59"></a><span class='hs-definition'>tcValBinds</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TopLevelFlag</span>
<a name="line-60"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>HsValBinds</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-varid'>thing</span>
<a name="line-61"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsValBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span>
<a name="line-62"></a>
<a name="line-63"></a><span class='hs-definition'>tcValBinds</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>ValBindsIn</span> <span class='hs-varid'>binds</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyword'>_</span>
<a name="line-64"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pprPanic</span> <span class='hs-str'>"tcValBinds"</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span>
<a name="line-65"></a>
<a name="line-66"></a><span class='hs-definition'>tcValBinds</span> <span class='hs-varid'>top_lvl</span> <span class='hs-layout'>(</span><span class='hs-conid'>ValBindsOut</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>)</span> <span class='hs-varid'>thing_inside</span>
<a name="line-67"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-comment'>-- Typecheck the signature</span>
<a name="line-68"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-layout'>{</span> <span class='hs-varid'>prag_fn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkPragFun</span> <span class='hs-varid'>sigs</span>
<a name="line-69"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>ty_sigs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>filter</span> <span class='hs-varid'>isTypeLSig</span> <span class='hs-varid'>sigs</span>
<a name="line-70"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>sig_fn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkTcSigFun</span> <span class='hs-varid'>ty_sigs</span> <span class='hs-layout'>}</span>
<a name="line-71"></a>
<a name="line-72"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>poly_ids</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>checkNoErrs</span> <span class='hs-layout'>(</span><span class='hs-varid'>mapAndRecoverM</span> <span class='hs-varid'>tcTySig</span> <span class='hs-varid'>ty_sigs</span><span class='hs-layout'>)</span>
<a name="line-73"></a> <span class='hs-comment'>-- No recovery from bad signatures, because the type sigs</span>
<a name="line-74"></a> <span class='hs-comment'>-- may bind type variables, so proceeding without them</span>
<a name="line-75"></a> <span class='hs-comment'>-- can lead to a cascade of errors</span>
<a name="line-76"></a> <span class='hs-comment'>-- ToDo: this means we fall over immediately if any type sig</span>
<a name="line-77"></a> <span class='hs-comment'>-- is wrong, which is over-conservative, see Trac bug #745</span>
<a name="line-78"></a>
<a name="line-79"></a> <span class='hs-comment'>-- Extend the envt right away with all </span>
<a name="line-80"></a> <span class='hs-comment'>-- the Ids declared with type signatures</span>
<a name="line-81"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>poly_rec</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>doptM</span> <span class='hs-conid'>Opt_RelaxedPolyRec</span>
<a name="line-82"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds'</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcExtendIdEnv</span> <span class='hs-varid'>poly_ids</span> <span class='hs-varop'>$</span>
<a name="line-83"></a> <span class='hs-varid'>tcBindGroups</span> <span class='hs-varid'>poly_rec</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span>
<a name="line-84"></a> <span class='hs-varid'>binds</span> <span class='hs-varid'>thing_inside</span>
<a name="line-85"></a>
<a name="line-86"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>ValBindsOut</span> <span class='hs-varid'>binds'</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-87"></a>
<a name="line-88"></a><a name="tcBindGroups"></a><span class='hs-comment'>------------------------</span>
<a name="line-89"></a><span class='hs-definition'>tcBindGroups</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TopLevelFlag</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcPragFun</span>
<a name="line-90"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>RecFlag</span><span class='hs-layout'>,</span> <span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>Name</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-varid'>thing</span>
<a name="line-91"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>RecFlag</span><span class='hs-layout'>,</span> <span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span>
<a name="line-92"></a><span class='hs-comment'>-- Typecheck a whole lot of value bindings,</span>
<a name="line-93"></a><span class='hs-comment'>-- one strongly-connected component at a time</span>
<a name="line-94"></a><span class='hs-comment'>-- Here a "strongly connected component" has the strightforward</span>
<a name="line-95"></a><span class='hs-comment'>-- meaning of a group of bindings that mention each other, </span>
<a name="line-96"></a><span class='hs-comment'>-- ignoring type signatures (that part comes later)</span>
<a name="line-97"></a>
<a name="line-98"></a><span class='hs-definition'>tcBindGroups</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-varid'>thing_inside</span>
<a name="line-99"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>thing</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>thing_inside</span>
<a name="line-100"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-101"></a>
<a name="line-102"></a><span class='hs-definition'>tcBindGroups</span> <span class='hs-varid'>poly_rec</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-layout'>(</span><span class='hs-varid'>group</span> <span class='hs-conop'>:</span> <span class='hs-varid'>groups</span><span class='hs-layout'>)</span> <span class='hs-varid'>thing_inside</span>
<a name="line-103"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>group'</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varid'>groups'</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-104"></a> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tc_group</span> <span class='hs-varid'>poly_rec</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-varid'>group</span> <span class='hs-varop'>$</span>
<a name="line-105"></a> <span class='hs-varid'>tcBindGroups</span> <span class='hs-varid'>poly_rec</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-varid'>groups</span> <span class='hs-varid'>thing_inside</span>
<a name="line-106"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>group'</span> <span class='hs-varop'>++</span> <span class='hs-varid'>groups'</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-107"></a>
<a name="line-108"></a><a name="tc_group"></a><span class='hs-comment'>------------------------</span>
<a name="line-109"></a><span class='hs-definition'>tc_group</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TopLevelFlag</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcPragFun</span>
<a name="line-110"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>RecFlag</span><span class='hs-layout'>,</span> <span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>Name</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-varid'>thing</span>
<a name="line-111"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>RecFlag</span><span class='hs-layout'>,</span> <span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span>
<a name="line-112"></a>
<a name="line-113"></a><span class='hs-comment'>-- Typecheck one strongly-connected component of the original program.</span>
<a name="line-114"></a><span class='hs-comment'>-- We get a list of groups back, because there may </span>
<a name="line-115"></a><span class='hs-comment'>-- be specialisations etc as well</span>
<a name="line-116"></a>
<a name="line-117"></a><span class='hs-definition'>tc_group</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-layout'>(</span><span class='hs-conid'>NonRecursive</span><span class='hs-layout'>,</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-varid'>thing_inside</span>
<a name="line-118"></a> <span class='hs-comment'>-- A single non-recursive binding</span>
<a name="line-119"></a> <span class='hs-comment'>-- We want to keep non-recursive things non-recursive</span>
<a name="line-120"></a> <span class='hs-comment'>-- so that we desugar unlifted bindings correctly</span>
<a name="line-121"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds1</span><span class='hs-layout'>,</span> <span class='hs-varid'>lie_binds</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tc_haskell98</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span>
<a name="line-122"></a> <span class='hs-conid'>NonRecursive</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>thing_inside</span>
<a name="line-123"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>NonRecursive</span><span class='hs-layout'>,</span> <span class='hs-varid'>unitBag</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>bagToList</span> <span class='hs-varid'>binds1</span><span class='hs-keyglyph'>]</span>
<a name="line-124"></a> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Recursive</span><span class='hs-layout'>,</span> <span class='hs-varid'>lie_binds</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-comment'>-- TcDictBinds have scrambled dependency order</span>
<a name="line-125"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-126"></a>
<a name="line-127"></a><span class='hs-definition'>tc_group</span> <span class='hs-varid'>poly_rec</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-layout'>(</span><span class='hs-conid'>Recursive</span><span class='hs-layout'>,</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-varid'>thing_inside</span>
<a name="line-128"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>not</span> <span class='hs-varid'>poly_rec</span> <span class='hs-comment'>-- Recursive group, normal Haskell 98 route</span>
<a name="line-129"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds1</span><span class='hs-layout'>,</span> <span class='hs-varid'>lie_binds</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tc_haskell98</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span>
<a name="line-130"></a> <span class='hs-conid'>Recursive</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>thing_inside</span>
<a name="line-131"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Recursive</span><span class='hs-layout'>,</span> <span class='hs-varid'>binds1</span> <span class='hs-varop'>`unionBags`</span> <span class='hs-varid'>lie_binds</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-132"></a>
<a name="line-133"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-comment'>-- Recursive group, with -XRelaxedPolyRec</span>
<a name="line-134"></a> <span class='hs-keyglyph'>=</span> <span class='hs-comment'>-- To maximise polymorphism (with -XRelaxedPolyRec), we do a new </span>
<a name="line-135"></a> <span class='hs-comment'>-- strongly-connected-component analysis, this time omitting </span>
<a name="line-136"></a> <span class='hs-comment'>-- any references to variables with type signatures.</span>
<a name="line-137"></a> <span class='hs-comment'>--</span>
<a name="line-138"></a> <span class='hs-comment'>-- Notice that the bindInsts thing covers *all* the bindings in</span>
<a name="line-139"></a> <span class='hs-comment'>-- the original group at once; an earlier one may use a later one!</span>
<a name="line-140"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>traceTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>text</span> <span class='hs-str'>"tc_group rec"</span> <span class='hs-varop'><+></span> <span class='hs-varid'>pprLHsBinds</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span>
<a name="line-141"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds1</span><span class='hs-layout'>,</span><span class='hs-varid'>lie_binds</span><span class='hs-layout'>,</span><span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>bindLocalInsts</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varop'>$</span>
<a name="line-142"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-varid'>stronglyConnCompFromEdgedVertices</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkEdges</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-143"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Recursive</span><span class='hs-layout'>,</span> <span class='hs-varid'>binds1</span> <span class='hs-varop'>`unionBags`</span> <span class='hs-varid'>lie_binds</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-144"></a> <span class='hs-comment'>-- Rec them all together</span>
<a name="line-145"></a> <span class='hs-keyword'>where</span>
<a name="line-146"></a><span class='hs-comment'>-- go :: SCC (LHsBind Name) -> TcM (LHsBinds TcId, [TcId], thing)</span>
<a name="line-147"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-varid'>scc</span><span class='hs-conop'>:</span><span class='hs-varid'>sccs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds1</span><span class='hs-layout'>,</span> <span class='hs-varid'>ids1</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tc_scc</span> <span class='hs-varid'>scc</span>
<a name="line-148"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds2</span><span class='hs-layout'>,</span> <span class='hs-varid'>ids2</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcExtendIdEnv</span> <span class='hs-varid'>ids1</span> <span class='hs-varop'>$</span> <span class='hs-varid'>go</span> <span class='hs-varid'>sccs</span>
<a name="line-149"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds1</span> <span class='hs-varop'>`unionBags`</span> <span class='hs-varid'>binds2</span><span class='hs-layout'>,</span> <span class='hs-varid'>ids1</span> <span class='hs-varop'>++</span> <span class='hs-varid'>ids2</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-150"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>thing</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>thing_inside</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>emptyBag</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-151"></a>
<a name="line-152"></a> <span class='hs-varid'>tc_scc</span> <span class='hs-layout'>(</span><span class='hs-conid'>AcyclicSCC</span> <span class='hs-varid'>bind</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tc_sub_group</span> <span class='hs-conid'>NonRecursive</span> <span class='hs-layout'>(</span><span class='hs-varid'>unitBag</span> <span class='hs-varid'>bind</span><span class='hs-layout'>)</span>
<a name="line-153"></a> <span class='hs-varid'>tc_scc</span> <span class='hs-layout'>(</span><span class='hs-conid'>CyclicSCC</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tc_sub_group</span> <span class='hs-conid'>Recursive</span> <span class='hs-layout'>(</span><span class='hs-varid'>listToBag</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span>
<a name="line-154"></a>
<a name="line-155"></a> <span class='hs-varid'>tc_sub_group</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tcPolyBinds</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-conid'>Recursive</span>
<a name="line-156"></a>
<a name="line-157"></a><a name="tc_haskell98"></a><span class='hs-definition'>tc_haskell98</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TopLevelFlag</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcPragFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RecFlag</span>
<a name="line-158"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-conid'>TcDictBinds</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-159"></a><span class='hs-definition'>tc_haskell98</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-varid'>rec_flag</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>thing_inside</span>
<a name="line-160"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bindLocalInsts</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varop'>$</span>
<a name="line-161"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds1</span><span class='hs-layout'>,</span> <span class='hs-varid'>ids</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcPolyBinds</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-varid'>rec_flag</span> <span class='hs-varid'>rec_flag</span> <span class='hs-varid'>binds</span>
<a name="line-162"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>thing</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcExtendIdEnv</span> <span class='hs-varid'>ids</span> <span class='hs-varid'>thing_inside</span>
<a name="line-163"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds1</span><span class='hs-layout'>,</span> <span class='hs-varid'>ids</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-164"></a>
<a name="line-165"></a><a name="bindLocalInsts"></a><span class='hs-comment'>------------------------</span>
<a name="line-166"></a><span class='hs-definition'>bindLocalInsts</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TopLevelFlag</span>
<a name="line-167"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcId</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-168"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-conid'>TcDictBinds</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-169"></a><span class='hs-definition'>bindLocalInsts</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>thing_inside</span>
<a name="line-170"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isTopLevel</span> <span class='hs-varid'>top_lvl</span>
<a name="line-171"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>thing_inside</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds</span><span class='hs-layout'>,</span> <span class='hs-varid'>emptyBag</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-172"></a> <span class='hs-comment'>-- For the top level don't bother with all this bindInstsOfLocalFuns stuff. </span>
<a name="line-173"></a> <span class='hs-comment'>-- All the top level things are rec'd together anyway, so it's fine to</span>
<a name="line-174"></a> <span class='hs-comment'>-- leave them to the tcSimplifyTop, and quite a bit faster too</span>
<a name="line-175"></a>
<a name="line-176"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-comment'>-- Nested case</span>
<a name="line-177"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>binds</span><span class='hs-layout'>,</span> <span class='hs-varid'>ids</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>lie</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>getLIE</span> <span class='hs-varid'>thing_inside</span>
<a name="line-178"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>lie_binds</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>bindInstsOfLocalFuns</span> <span class='hs-varid'>lie</span> <span class='hs-varid'>ids</span>
<a name="line-179"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>binds</span><span class='hs-layout'>,</span> <span class='hs-varid'>lie_binds</span><span class='hs-layout'>,</span> <span class='hs-varid'>thing</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-180"></a>
<a name="line-181"></a><a name="mkEdges"></a><span class='hs-comment'>------------------------</span>
<a name="line-182"></a><span class='hs-definition'>mkEdges</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>Name</span>
<a name="line-183"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>LHsBind</span> <span class='hs-conid'>Name</span><span class='hs-layout'>,</span> <span class='hs-conid'>BKey</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>BKey</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-184"></a>
<a name="line-185"></a><a name="BKey"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>BKey</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Int</span> <span class='hs-comment'>-- Just number off the bindings</span>
<a name="line-186"></a>
<a name="line-187"></a><span class='hs-definition'>mkEdges</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>binds</span>
<a name="line-188"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span> <span class='hs-layout'>(</span><span class='hs-varid'>bind</span><span class='hs-layout'>,</span> <span class='hs-varid'>key</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>key</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>nameSetToList</span> <span class='hs-layout'>(</span><span class='hs-varid'>bind_fvs</span> <span class='hs-layout'>(</span><span class='hs-varid'>unLoc</span> <span class='hs-varid'>bind</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-189"></a> <span class='hs-conid'>Just</span> <span class='hs-varid'>key</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>lookupNameEnv</span> <span class='hs-varid'>key_map</span> <span class='hs-varid'>n</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-varid'>no_sig</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-190"></a> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>bind</span><span class='hs-layout'>,</span> <span class='hs-varid'>key</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>keyd_binds</span>
<a name="line-191"></a> <span class='hs-keyglyph'>]</span>
<a name="line-192"></a> <span class='hs-keyword'>where</span>
<a name="line-193"></a> <span class='hs-varid'>no_sig</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-194"></a> <span class='hs-varid'>no_sig</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>isNothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_fn</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span>
<a name="line-195"></a>
<a name="line-196"></a> <span class='hs-varid'>keyd_binds</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bagToList</span> <span class='hs-varid'>binds</span> <span class='hs-varop'>`zip`</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>0</span><span class='hs-keyglyph'>::</span><span class='hs-conid'>BKey</span> <span class='hs-keyglyph'>..</span><span class='hs-keyglyph'>]</span>
<a name="line-197"></a>
<a name="line-198"></a> <span class='hs-varid'>key_map</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>NameEnv</span> <span class='hs-conid'>BKey</span> <span class='hs-comment'>-- Which binding it comes from</span>
<a name="line-199"></a> <span class='hs-varid'>key_map</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkNameEnv</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>bndr</span><span class='hs-layout'>,</span> <span class='hs-varid'>key</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>bind</span><span class='hs-layout'>,</span> <span class='hs-varid'>key</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>keyd_binds</span>
<a name="line-200"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>bndr</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>bindersOfHsBind</span> <span class='hs-varid'>bind</span> <span class='hs-keyglyph'>]</span>
<a name="line-201"></a>
<a name="line-202"></a><a name="bindersOfHsBind"></a><span class='hs-definition'>bindersOfHsBind</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>HsBind</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-203"></a><span class='hs-definition'>bindersOfHsBind</span> <span class='hs-layout'>(</span><span class='hs-conid'>PatBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>pat_lhs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pat</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>collectPatBinders</span> <span class='hs-varid'>pat</span>
<a name="line-204"></a><span class='hs-definition'>bindersOfHsBind</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>fun_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>f</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>f</span><span class='hs-keyglyph'>]</span>
<a name="line-205"></a><span class='hs-definition'>bindersOfHsBind</span> <span class='hs-layout'>(</span><span class='hs-conid'>AbsBinds</span> <span class='hs-layout'>{</span><span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>panic</span> <span class='hs-str'>"bindersOfHsBind AbsBinds"</span>
<a name="line-206"></a><span class='hs-definition'>bindersOfHsBind</span> <span class='hs-layout'>(</span><span class='hs-conid'>VarBind</span> <span class='hs-layout'>{</span><span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>panic</span> <span class='hs-str'>"bindersOfHsBind VarBind"</span>
<a name="line-207"></a>
<a name="line-208"></a><a name="tcPolyBinds"></a><span class='hs-comment'>------------------------</span>
<a name="line-209"></a><span class='hs-definition'>tcPolyBinds</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TopLevelFlag</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcPragFun</span>
<a name="line-210"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RecFlag</span> <span class='hs-comment'>-- Whether the group is really recursive</span>
<a name="line-211"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RecFlag</span> <span class='hs-comment'>-- Whether it's recursive after breaking</span>
<a name="line-212"></a> <span class='hs-comment'>-- dependencies based on type signatures</span>
<a name="line-213"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>Name</span>
<a name="line-214"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcId</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-215"></a>
<a name="line-216"></a><span class='hs-comment'>-- Typechecks a single bunch of bindings all together, </span>
<a name="line-217"></a><span class='hs-comment'>-- and generalises them. The bunch may be only part of a recursive</span>
<a name="line-218"></a><span class='hs-comment'>-- group, because we use type signatures to maximise polymorphism</span>
<a name="line-219"></a><span class='hs-comment'>--</span>
<a name="line-220"></a><span class='hs-comment'>-- Returns a list because the input may be a single non-recursive binding,</span>
<a name="line-221"></a><span class='hs-comment'>-- in which case the dependency order of the resulting bindings is</span>
<a name="line-222"></a><span class='hs-comment'>-- important. </span>
<a name="line-223"></a><span class='hs-comment'>-- </span>
<a name="line-224"></a><span class='hs-comment'>-- Knows nothing about the scope of the bindings</span>
<a name="line-225"></a>
<a name="line-226"></a><span class='hs-definition'>tcPolyBinds</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>prag_fn</span> <span class='hs-varid'>rec_group</span> <span class='hs-varid'>rec_tc</span> <span class='hs-varid'>binds</span>
<a name="line-227"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span>
<a name="line-228"></a> <span class='hs-varid'>bind_list</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bagToList</span> <span class='hs-varid'>binds</span>
<a name="line-229"></a> <span class='hs-varid'>binder_names</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>collectHsBindBinders</span> <span class='hs-varid'>binds</span>
<a name="line-230"></a> <span class='hs-varid'>loc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>getLoc</span> <span class='hs-layout'>(</span><span class='hs-varid'>head</span> <span class='hs-varid'>bind_list</span><span class='hs-layout'>)</span>
<a name="line-231"></a> <span class='hs-comment'>-- TODO: location a bit awkward, but the mbinds have been</span>
<a name="line-232"></a> <span class='hs-comment'>-- dependency analysed and may no longer be adjacent</span>
<a name="line-233"></a> <span class='hs-keyword'>in</span>
<a name="line-234"></a> <span class='hs-comment'>-- SET UP THE MAIN RECOVERY; take advantage of any type sigs</span>
<a name="line-235"></a> <span class='hs-varid'>setSrcSpan</span> <span class='hs-varid'>loc</span> <span class='hs-varop'>$</span>
<a name="line-236"></a> <span class='hs-varid'>recoverM</span> <span class='hs-layout'>(</span><span class='hs-varid'>recoveryCode</span> <span class='hs-varid'>binder_names</span> <span class='hs-varid'>sig_fn</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-237"></a>
<a name="line-238"></a> <span class='hs-layout'>{</span> <span class='hs-varid'>traceTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"------------------------------------------------"</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-239"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>traceTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Bindings for"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>binder_names</span><span class='hs-layout'>)</span>
<a name="line-240"></a>
<a name="line-241"></a> <span class='hs-comment'>-- TYPECHECK THE BINDINGS</span>
<a name="line-242"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>binds'</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_bind_infos</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>lie_req</span><span class='hs-layout'>)</span>
<a name="line-243"></a> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>getLIE</span> <span class='hs-layout'>(</span><span class='hs-varid'>tcMonoBinds</span> <span class='hs-varid'>bind_list</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>rec_tc</span><span class='hs-layout'>)</span>
<a name="line-244"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>traceTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>text</span> <span class='hs-str'>"temp"</span> <span class='hs-varop'><+></span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>binds'</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>lie_req</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-245"></a>
<a name="line-246"></a> <span class='hs-comment'>-- CHECK FOR UNLIFTED BINDINGS</span>
<a name="line-247"></a> <span class='hs-comment'>-- These must be non-recursive etc, and are not generalised</span>
<a name="line-248"></a> <span class='hs-comment'>-- They desugar to a case expression in the end</span>
<a name="line-249"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>zonked_mono_tys</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>zonkTcTypes</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>getMonoType</span> <span class='hs-varid'>mono_bind_infos</span><span class='hs-layout'>)</span>
<a name="line-250"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>is_strict</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>checkStrictBinds</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>rec_group</span> <span class='hs-varid'>binds'</span>
<a name="line-251"></a> <span class='hs-varid'>zonked_mono_tys</span> <span class='hs-varid'>mono_bind_infos</span>
<a name="line-252"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>is_strict</span> <span class='hs-keyword'>then</span>
<a name="line-253"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>extendLIEs</span> <span class='hs-varid'>lie_req</span>
<a name="line-254"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>exports</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>zipWith</span> <span class='hs-varid'>mk_export</span> <span class='hs-varid'>mono_bind_infos</span> <span class='hs-varid'>zonked_mono_tys</span>
<a name="line-255"></a> <span class='hs-varid'>mk_export</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-conid'>Nothing</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-varid'>mono_ty</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-varid'>mkLocalId</span> <span class='hs-varid'>name</span> <span class='hs-varid'>mono_ty</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-256"></a> <span class='hs-varid'>mk_export</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>sig</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_id</span> <span class='hs-varid'>sig</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-257"></a> <span class='hs-comment'>-- ToDo: prags for unlifted bindings</span>
<a name="line-258"></a>
<a name="line-259"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span> <span class='hs-varid'>unitBag</span> <span class='hs-varop'>$</span> <span class='hs-conid'>L</span> <span class='hs-varid'>loc</span> <span class='hs-varop'>$</span> <span class='hs-conid'>AbsBinds</span> <span class='hs-conid'>[]</span> <span class='hs-conid'>[]</span> <span class='hs-varid'>exports</span> <span class='hs-varid'>binds'</span><span class='hs-layout'>,</span>
<a name="line-260"></a> <span class='hs-keyglyph'>[</span><span class='hs-varid'>poly_id</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>exports</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span> <span class='hs-comment'>-- Guaranteed zonked</span>
<a name="line-261"></a>
<a name="line-262"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span> <span class='hs-comment'>-- The normal lifted case: GENERALISE</span>
<a name="line-263"></a> <span class='hs-layout'>{</span> <span class='hs-varid'>dflags</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>getDOpts</span>
<a name="line-264"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>tyvars_to_gen</span><span class='hs-layout'>,</span> <span class='hs-varid'>dicts</span><span class='hs-layout'>,</span> <span class='hs-varid'>dict_binds</span><span class='hs-layout'>)</span>
<a name="line-265"></a> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>addErrCtxt</span> <span class='hs-layout'>(</span><span class='hs-varid'>genCtxt</span> <span class='hs-layout'>(</span><span class='hs-varid'>bndrNames</span> <span class='hs-varid'>mono_bind_infos</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-266"></a> <span class='hs-varid'>generalise</span> <span class='hs-varid'>dflags</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>bind_list</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>mono_bind_infos</span> <span class='hs-varid'>lie_req</span>
<a name="line-267"></a>
<a name="line-268"></a> <span class='hs-comment'>-- BUILD THE POLYMORPHIC RESULT IDs</span>
<a name="line-269"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>dict_vars</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>instToVar</span> <span class='hs-varid'>dicts</span> <span class='hs-comment'>-- May include equality constraints</span>
<a name="line-270"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>exports</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkExport</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>prag_fn</span> <span class='hs-varid'>tyvars_to_gen</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>varType</span> <span class='hs-varid'>dict_vars</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-271"></a> <span class='hs-varid'>mono_bind_infos</span>
<a name="line-272"></a>
<a name="line-273"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>poly_ids</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>poly_id</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>exports</span><span class='hs-keyglyph'>]</span>
<a name="line-274"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>traceTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>text</span> <span class='hs-str'>"binding:"</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-layout'>(</span><span class='hs-varid'>poly_ids</span> <span class='hs-varop'>`zip`</span> <span class='hs-varid'>map</span> <span class='hs-varid'>idType</span> <span class='hs-varid'>poly_ids</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-275"></a>
<a name="line-276"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>abs_bind</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-varid'>loc</span> <span class='hs-varop'>$</span> <span class='hs-conid'>AbsBinds</span> <span class='hs-varid'>tyvars_to_gen</span>
<a name="line-277"></a> <span class='hs-varid'>dict_vars</span> <span class='hs-varid'>exports</span>
<a name="line-278"></a> <span class='hs-layout'>(</span><span class='hs-varid'>dict_binds</span> <span class='hs-varop'>`unionBags`</span> <span class='hs-varid'>binds'</span><span class='hs-layout'>)</span>
<a name="line-279"></a>
<a name="line-280"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>unitBag</span> <span class='hs-varid'>abs_bind</span><span class='hs-layout'>,</span> <span class='hs-varid'>poly_ids</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- poly_ids are guaranteed zonked by mkExport</span>
<a name="line-281"></a> <span class='hs-layout'>}</span> <span class='hs-layout'>}</span>
<a name="line-282"></a>
<a name="line-283"></a>
<a name="line-284"></a><a name="mkExport"></a><span class='hs-comment'>--------------</span>
<a name="line-285"></a><span class='hs-definition'>mkExport</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TopLevelFlag</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcPragFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TyVar</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcType</span><span class='hs-keyglyph'>]</span>
<a name="line-286"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>MonoBindInfo</span>
<a name="line-287"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>TyVar</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-conid'>Id</span><span class='hs-layout'>,</span> <span class='hs-conid'>Id</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LPrag</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-288"></a><span class='hs-comment'>-- mkExport generates exports with </span>
<a name="line-289"></a><span class='hs-comment'>-- zonked type variables, </span>
<a name="line-290"></a><span class='hs-comment'>-- zonked poly_ids</span>
<a name="line-291"></a><span class='hs-comment'>-- The former is just because no further unifications will change</span>
<a name="line-292"></a><span class='hs-comment'>-- the quantified type variables, so we can fix their final form</span>
<a name="line-293"></a><span class='hs-comment'>-- right now.</span>
<a name="line-294"></a><span class='hs-comment'>-- The latter is needed because the poly_ids are used to extend the</span>
<a name="line-295"></a><span class='hs-comment'>-- type environment; see the invariant on TcEnv.tcExtendIdEnv </span>
<a name="line-296"></a>
<a name="line-297"></a><span class='hs-comment'>-- Pre-condition: the inferred_tvs are already zonked</span>
<a name="line-298"></a>
<a name="line-299"></a><span class='hs-definition'>mkExport</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>prag_fn</span> <span class='hs-varid'>inferred_tvs</span> <span class='hs-varid'>dict_tys</span> <span class='hs-layout'>(</span><span class='hs-varid'>poly_name</span><span class='hs-layout'>,</span> <span class='hs-varid'>mb_sig</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span>
<a name="line-300"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>warn_missing_sigs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>doptM</span> <span class='hs-conid'>Opt_WarnMissingSigs</span>
<a name="line-301"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>warn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>isTopLevel</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>warn_missing_sigs</span>
<a name="line-302"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>tvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mk_poly_id</span> <span class='hs-varid'>warn</span> <span class='hs-varid'>mb_sig</span>
<a name="line-303"></a> <span class='hs-comment'>-- poly_id has a zonked type</span>
<a name="line-304"></a>
<a name="line-305"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>prags</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcPrags</span> <span class='hs-varid'>poly_id</span> <span class='hs-layout'>(</span><span class='hs-varid'>prag_fn</span> <span class='hs-varid'>poly_name</span><span class='hs-layout'>)</span>
<a name="line-306"></a> <span class='hs-comment'>-- tcPrags requires a zonked poly_id</span>
<a name="line-307"></a>
<a name="line-308"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>tvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>,</span> <span class='hs-varid'>prags</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-309"></a> <span class='hs-keyword'>where</span>
<a name="line-310"></a> <span class='hs-varid'>poly_ty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkForAllTys</span> <span class='hs-varid'>inferred_tvs</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkFunTys</span> <span class='hs-varid'>dict_tys</span> <span class='hs-layout'>(</span><span class='hs-varid'>idType</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-311"></a>
<a name="line-312"></a> <span class='hs-varid'>mk_poly_id</span> <span class='hs-varid'>warn</span> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>poly_ty'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>zonkTcType</span> <span class='hs-varid'>poly_ty</span>
<a name="line-313"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>missingSigWarn</span> <span class='hs-varid'>warn</span> <span class='hs-varid'>poly_name</span> <span class='hs-varid'>poly_ty'</span>
<a name="line-314"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>inferred_tvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>mkLocalId</span> <span class='hs-varid'>poly_name</span> <span class='hs-varid'>poly_ty'</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-315"></a> <span class='hs-varid'>mk_poly_id</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>tvs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapM</span> <span class='hs-varid'>zonk_tv</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_tvs</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span>
<a name="line-316"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>tvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_id</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-317"></a>
<a name="line-318"></a> <span class='hs-varid'>zonk_tv</span> <span class='hs-varid'>tv</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>ty</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>zonkTcTyVar</span> <span class='hs-varid'>tv</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>tcGetTyVar</span> <span class='hs-str'>"mkExport"</span> <span class='hs-varid'>ty</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-319"></a>
<a name="line-320"></a><a name="TcPragFun"></a><span class='hs-comment'>------------------------</span>
<a name="line-321"></a><a name="TcPragFun"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>TcPragFun</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LSig</span> <span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-322"></a>
<a name="line-323"></a><a name="mkPragFun"></a><span class='hs-definition'>mkPragFun</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LSig</span> <span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcPragFun</span>
<a name="line-324"></a><span class='hs-definition'>mkPragFun</span> <span class='hs-varid'>sigs</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>n</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>lookupNameEnv</span> <span class='hs-varid'>env</span> <span class='hs-varid'>n</span> <span class='hs-varop'>`orElse`</span> <span class='hs-conid'>[]</span>
<a name="line-325"></a> <span class='hs-keyword'>where</span>
<a name="line-326"></a> <span class='hs-varid'>prs</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>expectJust</span> <span class='hs-str'>"mkPragFun"</span> <span class='hs-layout'>(</span><span class='hs-varid'>sigName</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span>
<a name="line-327"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>sig</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>,</span> <span class='hs-varid'>isPragLSig</span> <span class='hs-varid'>sig</span><span class='hs-keyglyph'>]</span>
<a name="line-328"></a> <span class='hs-varid'>env</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldl</span> <span class='hs-varid'>add</span> <span class='hs-varid'>emptyNameEnv</span> <span class='hs-varid'>prs</span>
<a name="line-329"></a> <span class='hs-varid'>add</span> <span class='hs-varid'>env</span> <span class='hs-layout'>(</span><span class='hs-varid'>n</span><span class='hs-layout'>,</span><span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>extendNameEnv_Acc</span> <span class='hs-layout'>(</span><span class='hs-conop'>:</span><span class='hs-layout'>)</span> <span class='hs-varid'>singleton</span> <span class='hs-varid'>env</span> <span class='hs-varid'>n</span> <span class='hs-varid'>p</span>
<a name="line-330"></a>
<a name="line-331"></a><a name="tcPrags"></a><span class='hs-definition'>tcPrags</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Id</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LSig</span> <span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LPrag</span><span class='hs-keyglyph'>]</span>
<a name="line-332"></a><span class='hs-definition'>tcPrags</span> <span class='hs-varid'>poly_id</span> <span class='hs-varid'>prags</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>wrapLocM</span> <span class='hs-varid'>tc_prag</span><span class='hs-layout'>)</span> <span class='hs-varid'>prags</span>
<a name="line-333"></a> <span class='hs-keyword'>where</span>
<a name="line-334"></a> <span class='hs-varid'>tc_prag</span> <span class='hs-varid'>prag</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>addErrCtxt</span> <span class='hs-layout'>(</span><span class='hs-varid'>pragSigCtxt</span> <span class='hs-varid'>prag</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-335"></a> <span class='hs-varid'>tcPrag</span> <span class='hs-varid'>poly_id</span> <span class='hs-varid'>prag</span>
<a name="line-336"></a>
<a name="line-337"></a><a name="pragSigCtxt"></a><span class='hs-definition'>pragSigCtxt</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Sig</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-338"></a><span class='hs-definition'>pragSigCtxt</span> <span class='hs-varid'>prag</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hang</span> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"In the pragma"</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-num'>2</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>prag</span><span class='hs-layout'>)</span>
<a name="line-339"></a>
<a name="line-340"></a><a name="tcPrag"></a><span class='hs-definition'>tcPrag</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcId</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Sig</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-conid'>Prag</span>
<a name="line-341"></a><span class='hs-comment'>-- Pre-condition: the poly_id is zonked</span>
<a name="line-342"></a><span class='hs-comment'>-- Reason: required by tcSubExp</span>
<a name="line-343"></a><span class='hs-comment'>-- Most of the work of specialisation is done by </span>
<a name="line-344"></a><span class='hs-comment'>-- the desugarer, guided by the SpecPrag</span>
<a name="line-345"></a><span class='hs-definition'>tcPrag</span> <span class='hs-varid'>poly_id</span> <span class='hs-layout'>(</span><span class='hs-conid'>SpecSig</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>hs_ty</span> <span class='hs-varid'>inl</span><span class='hs-layout'>)</span>
<a name="line-346"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>idName</span> <span class='hs-varid'>poly_id</span>
<a name="line-347"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>spec_ty</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcHsSigType</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunSigCtxt</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-varid'>hs_ty</span>
<a name="line-348"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>co_fn</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcSubExp</span> <span class='hs-layout'>(</span><span class='hs-conid'>SpecPragOrigin</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>idType</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>)</span> <span class='hs-varid'>spec_ty</span>
<a name="line-349"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>SpecPrag</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkHsWrap</span> <span class='hs-varid'>co_fn</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsVar</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>spec_ty</span> <span class='hs-varid'>inl</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-350"></a><span class='hs-definition'>tcPrag</span> <span class='hs-varid'>poly_id</span> <span class='hs-layout'>(</span><span class='hs-conid'>SpecInstSig</span> <span class='hs-varid'>hs_ty</span><span class='hs-layout'>)</span>
<a name="line-351"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>idName</span> <span class='hs-varid'>poly_id</span>
<a name="line-352"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>tyvars</span><span class='hs-layout'>,</span> <span class='hs-varid'>theta</span><span class='hs-layout'>,</span> <span class='hs-varid'>tau</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcHsInstHead</span> <span class='hs-varid'>hs_ty</span>
<a name="line-353"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>spec_ty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkSigmaTy</span> <span class='hs-varid'>tyvars</span> <span class='hs-varid'>theta</span> <span class='hs-varid'>tau</span>
<a name="line-354"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>co_fn</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcSubExp</span> <span class='hs-layout'>(</span><span class='hs-conid'>SpecPragOrigin</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>idType</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>)</span> <span class='hs-varid'>spec_ty</span>
<a name="line-355"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>SpecPrag</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkHsWrap</span> <span class='hs-varid'>co_fn</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsVar</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>spec_ty</span> <span class='hs-varid'>defaultInlineSpec</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-356"></a>
<a name="line-357"></a><span class='hs-definition'>tcPrag</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>InlineSig</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>inl</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>InlinePrag</span> <span class='hs-varid'>inl</span><span class='hs-layout'>)</span>
<a name="line-358"></a><span class='hs-definition'>tcPrag</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>sig</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pprPanic</span> <span class='hs-str'>"tcPrag"</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span>
<a name="line-359"></a>
<a name="line-360"></a>
<a name="line-361"></a><a name="recoveryCode"></a><span class='hs-comment'>--------------</span>
<a name="line-362"></a><span class='hs-comment'>-- If typechecking the binds fails, then return with each</span>
<a name="line-363"></a><span class='hs-comment'>-- signature-less binder given type (forall a.a), to minimise </span>
<a name="line-364"></a><span class='hs-comment'>-- subsequent error messages</span>
<a name="line-365"></a><span class='hs-definition'>recoveryCode</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-366"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Id</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-367"></a><span class='hs-definition'>recoveryCode</span> <span class='hs-varid'>binder_names</span> <span class='hs-varid'>sig_fn</span>
<a name="line-368"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>traceTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>text</span> <span class='hs-str'>"tcBindsWithSigs: error recovery"</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>binder_names</span><span class='hs-layout'>)</span>
<a name="line-369"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>poly_ids</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapM</span> <span class='hs-varid'>mk_dummy</span> <span class='hs-varid'>binder_names</span>
<a name="line-370"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>emptyBag</span><span class='hs-layout'>,</span> <span class='hs-varid'>poly_ids</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-371"></a> <span class='hs-keyword'>where</span>
<a name="line-372"></a> <span class='hs-varid'>mk_dummy</span> <span class='hs-varid'>name</span>
<a name="line-373"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isJust</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_fn</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tcLookupId</span> <span class='hs-varid'>name</span> <span class='hs-comment'>-- Had signature; look it up</span>
<a name="line-374"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkLocalId</span> <span class='hs-varid'>name</span> <span class='hs-varid'>forall_a_a</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- No signature</span>
<a name="line-375"></a>
<a name="line-376"></a><a name="forall_a_a"></a><span class='hs-definition'>forall_a_a</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcType</span>
<a name="line-377"></a><span class='hs-definition'>forall_a_a</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkForAllTy</span> <span class='hs-varid'>alphaTyVar</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkTyVarTy</span> <span class='hs-varid'>alphaTyVar</span><span class='hs-layout'>)</span>
<a name="line-378"></a>
<a name="line-379"></a>
<a name="line-380"></a><span class='hs-comment'>-- Check that non-overloaded unlifted bindings are</span>
<a name="line-381"></a><span class='hs-comment'>-- a) non-recursive,</span>
<a name="line-382"></a><span class='hs-comment'>-- b) not top level, </span>
<a name="line-383"></a><span class='hs-comment'>-- c) not a multiple-binding group (more or less implied by (a))</span>
<a name="line-384"></a>
<a name="line-385"></a><a name="checkStrictBinds"></a><span class='hs-definition'>checkStrictBinds</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TopLevelFlag</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RecFlag</span>
<a name="line-386"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcType</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>MonoBindInfo</span><span class='hs-keyglyph'>]</span>
<a name="line-387"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-conid'>Bool</span>
<a name="line-388"></a><span class='hs-definition'>checkStrictBinds</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>rec_group</span> <span class='hs-varid'>mbind</span> <span class='hs-varid'>mono_tys</span> <span class='hs-varid'>infos</span>
<a name="line-389"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>unlifted</span> <span class='hs-varop'>||</span> <span class='hs-varid'>bang_pat</span>
<a name="line-390"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>checkTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>isNotTopLevel</span> <span class='hs-varid'>top_lvl</span><span class='hs-layout'>)</span>
<a name="line-391"></a> <span class='hs-layout'>(</span><span class='hs-varid'>strictBindErr</span> <span class='hs-str'>"Top-level"</span> <span class='hs-varid'>unlifted</span> <span class='hs-varid'>mbind</span><span class='hs-layout'>)</span>
<a name="line-392"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>checkTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>isNonRec</span> <span class='hs-varid'>rec_group</span><span class='hs-layout'>)</span>
<a name="line-393"></a> <span class='hs-layout'>(</span><span class='hs-varid'>strictBindErr</span> <span class='hs-str'>"Recursive"</span> <span class='hs-varid'>unlifted</span> <span class='hs-varid'>mbind</span><span class='hs-layout'>)</span>
<a name="line-394"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>checkTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>isSingletonBag</span> <span class='hs-varid'>mbind</span><span class='hs-layout'>)</span>
<a name="line-395"></a> <span class='hs-layout'>(</span><span class='hs-varid'>strictBindErr</span> <span class='hs-str'>"Multiple"</span> <span class='hs-varid'>unlifted</span> <span class='hs-varid'>mbind</span><span class='hs-layout'>)</span>
<a name="line-396"></a> <span class='hs-comment'>-- This should be a checkTc, not a warnTc, but as of GHC 6.11</span>
<a name="line-397"></a> <span class='hs-comment'>-- the versions of alex and happy available have non-conforming</span>
<a name="line-398"></a> <span class='hs-comment'>-- templates, so the GHC build fails if it's an error:</span>
<a name="line-399"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>warnUnlifted</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>doptM</span> <span class='hs-conid'>Opt_WarnLazyUnliftedBindings</span>
<a name="line-400"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>warnTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>warnUnlifted</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>not</span> <span class='hs-varid'>bang_pat</span><span class='hs-layout'>)</span>
<a name="line-401"></a> <span class='hs-layout'>(</span><span class='hs-varid'>unliftedMustBeBang</span> <span class='hs-varid'>mbind</span><span class='hs-layout'>)</span>
<a name="line-402"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>mapM_</span> <span class='hs-varid'>check_sig</span> <span class='hs-varid'>infos</span>
<a name="line-403"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span> <span class='hs-layout'>}</span>
<a name="line-404"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span>
<a name="line-405"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-406"></a> <span class='hs-keyword'>where</span>
<a name="line-407"></a> <span class='hs-varid'>unlifted</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>any</span> <span class='hs-varid'>isUnLiftedType</span> <span class='hs-varid'>mono_tys</span>
<a name="line-408"></a> <span class='hs-varid'>bang_pat</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>anyBag</span> <span class='hs-layout'>(</span><span class='hs-varid'>isBangHsBind</span> <span class='hs-varop'>.</span> <span class='hs-varid'>unLoc</span><span class='hs-layout'>)</span> <span class='hs-varid'>mbind</span>
<a name="line-409"></a> <span class='hs-varid'>check_sig</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>sig</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>checkTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_tvs</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>null</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_theta</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-410"></a> <span class='hs-layout'>(</span><span class='hs-varid'>badStrictSig</span> <span class='hs-varid'>unlifted</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span>
<a name="line-411"></a> <span class='hs-varid'>check_sig</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-412"></a>
<a name="line-413"></a><a name="unliftedMustBeBang"></a><span class='hs-definition'>unliftedMustBeBang</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>LHsBindsLR</span> <span class='hs-conid'>Var</span> <span class='hs-conid'>Var</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-414"></a><span class='hs-definition'>unliftedMustBeBang</span> <span class='hs-varid'>mbind</span>
<a name="line-415"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hang</span> <span class='hs-layout'>(</span><span class='hs-varid'>text</span> <span class='hs-str'>"Bindings containing unlifted types must use an outermost bang pattern:"</span><span class='hs-layout'>)</span>
<a name="line-416"></a> <span class='hs-num'>4</span> <span class='hs-layout'>(</span><span class='hs-varid'>pprLHsBinds</span> <span class='hs-varid'>mbind</span><span class='hs-layout'>)</span>
<a name="line-417"></a> <span class='hs-varop'>$$</span> <span class='hs-varid'>text</span> <span class='hs-str'>"*** This will be an error in GHC 6.14! Fix your code now!"</span>
<a name="line-418"></a>
<a name="line-419"></a><a name="strictBindErr"></a><span class='hs-definition'>strictBindErr</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>LHsBindsLR</span> <span class='hs-conid'>Var</span> <span class='hs-conid'>Var</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-420"></a><span class='hs-definition'>strictBindErr</span> <span class='hs-varid'>flavour</span> <span class='hs-varid'>unlifted</span> <span class='hs-varid'>mbind</span>
<a name="line-421"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hang</span> <span class='hs-layout'>(</span><span class='hs-varid'>text</span> <span class='hs-varid'>flavour</span> <span class='hs-varop'><+></span> <span class='hs-varid'>msg</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"aren't allowed:"</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-422"></a> <span class='hs-num'>4</span> <span class='hs-layout'>(</span><span class='hs-varid'>pprLHsBinds</span> <span class='hs-varid'>mbind</span><span class='hs-layout'>)</span>
<a name="line-423"></a> <span class='hs-keyword'>where</span>
<a name="line-424"></a> <span class='hs-varid'>msg</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>unlifted</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"bindings for unlifted types"</span><span class='hs-layout'>)</span>
<a name="line-425"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"bang-pattern bindings"</span><span class='hs-layout'>)</span>
<a name="line-426"></a>
<a name="line-427"></a><a name="badStrictSig"></a><span class='hs-definition'>badStrictSig</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigInfo</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-428"></a><span class='hs-definition'>badStrictSig</span> <span class='hs-varid'>unlifted</span> <span class='hs-varid'>sig</span>
<a name="line-429"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hang</span> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Illegal polymorphic signature in"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>msg</span><span class='hs-layout'>)</span>
<a name="line-430"></a> <span class='hs-num'>4</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span>
<a name="line-431"></a> <span class='hs-keyword'>where</span>
<a name="line-432"></a> <span class='hs-varid'>msg</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>unlifted</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"an unlifted binding"</span><span class='hs-layout'>)</span>
<a name="line-433"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"a bang-pattern binding"</span><span class='hs-layout'>)</span>
</pre>\end{code}
%************************************************************************
%* *
\subsection{tcMonoBind}
%* *
%************************************************************************
@tcMonoBinds@ deals with a perhaps-recursive group of HsBinds.
The signatures have been dealt with already.
\begin{code}
<pre><a name="line-1"></a><a name="tcMonoBinds"></a><span class='hs-definition'>tcMonoBinds</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LHsBind</span> <span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-2"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigFun</span>
<a name="line-3"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RecFlag</span> <span class='hs-comment'>-- Whether the binding is recursive for typechecking purposes</span>
<a name="line-4"></a> <span class='hs-comment'>-- i.e. the binders are mentioned in their RHSs, and</span>
<a name="line-5"></a> <span class='hs-comment'>-- we are not resuced by a type signature</span>
<a name="line-6"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>LHsBinds</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>MonoBindInfo</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-7"></a>
<a name="line-8"></a><span class='hs-definition'>tcMonoBinds</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>L</span> <span class='hs-varid'>b_loc</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>fun_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-varid'>nm_loc</span> <span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_infix</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>inf</span><span class='hs-layout'>,</span>
<a name="line-9"></a> <span class='hs-varid'>fun_matches</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>matches</span><span class='hs-layout'>,</span> <span class='hs-varid'>bind_fvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fvs</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-10"></a> <span class='hs-varid'>sig_fn</span> <span class='hs-comment'>-- Single function binding,</span>
<a name="line-11"></a> <span class='hs-conid'>NonRecursive</span> <span class='hs-comment'>-- binder isn't mentioned in RHS,</span>
<a name="line-12"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>name</span> <span class='hs-comment'>-- ...with no type signature</span>
<a name="line-13"></a> <span class='hs-keyglyph'>=</span> <span class='hs-comment'>-- In this very special case we infer the type of the</span>
<a name="line-14"></a> <span class='hs-comment'>-- right hand side first (it may have a higher-rank type)</span>
<a name="line-15"></a> <span class='hs-comment'>-- and *then* make the monomorphic Id for the LHS</span>
<a name="line-16"></a> <span class='hs-comment'>-- e.g. f = \(x::forall a. a->a) -> <body></span>
<a name="line-17"></a> <span class='hs-comment'>-- We want to infer a higher-rank type for f</span>
<a name="line-18"></a> <span class='hs-varid'>setSrcSpan</span> <span class='hs-varid'>b_loc</span> <span class='hs-varop'>$</span>
<a name="line-19"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>co_fn</span><span class='hs-layout'>,</span> <span class='hs-varid'>matches'</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>rhs_ty</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcInfer</span> <span class='hs-layout'>(</span><span class='hs-varid'>tcMatchesFun</span> <span class='hs-varid'>name</span> <span class='hs-varid'>inf</span> <span class='hs-varid'>matches</span><span class='hs-layout'>)</span>
<a name="line-20"></a>
<a name="line-21"></a> <span class='hs-comment'>-- Check for an unboxed tuple type</span>
<a name="line-22"></a> <span class='hs-comment'>-- f = (# True, False #)</span>
<a name="line-23"></a> <span class='hs-comment'>-- Zonk first just in case it's hidden inside a meta type variable</span>
<a name="line-24"></a> <span class='hs-comment'>-- (This shows up as a (more obscure) kind error </span>
<a name="line-25"></a> <span class='hs-comment'>-- in the 'otherwise' case of tcMonoBinds.)</span>
<a name="line-26"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>zonked_rhs_ty</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>zonkTcType</span> <span class='hs-varid'>rhs_ty</span>
<a name="line-27"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>checkTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>isUnboxedTupleType</span> <span class='hs-varid'>zonked_rhs_ty</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-28"></a> <span class='hs-layout'>(</span><span class='hs-varid'>unboxedTupleErr</span> <span class='hs-varid'>name</span> <span class='hs-varid'>zonked_rhs_ty</span><span class='hs-layout'>)</span>
<a name="line-29"></a>
<a name="line-30"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>mono_name</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newLocalName</span> <span class='hs-varid'>name</span>
<a name="line-31"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>mono_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkLocalId</span> <span class='hs-varid'>mono_name</span> <span class='hs-varid'>zonked_rhs_ty</span>
<a name="line-32"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>unitBag</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-varid'>b_loc</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>fun_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-varid'>nm_loc</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_infix</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>inf</span><span class='hs-layout'>,</span>
<a name="line-33"></a> <span class='hs-varid'>fun_matches</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>matches'</span><span class='hs-layout'>,</span> <span class='hs-varid'>bind_fvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fvs</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-varid'>fun_co_fn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>co_fn</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_tick</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-35"></a> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-conid'>Nothing</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-36"></a>
<a name="line-37"></a><span class='hs-definition'>tcMonoBinds</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>L</span> <span class='hs-varid'>b_loc</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>fun_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-varid'>nm_loc</span> <span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_infix</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>inf</span><span class='hs-layout'>,</span>
<a name="line-38"></a> <span class='hs-varid'>fun_matches</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>matches</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-39"></a> <span class='hs-varid'>sig_fn</span> <span class='hs-comment'>-- Single function binding</span>
<a name="line-40"></a> <span class='hs-keyword'>_</span>
<a name="line-41"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>scoped_tvs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>name</span> <span class='hs-comment'>-- ...with a type signature</span>
<a name="line-42"></a> <span class='hs-keyglyph'>=</span> <span class='hs-comment'>-- When we have a single function binding, with a type signature</span>
<a name="line-43"></a> <span class='hs-comment'>-- we can (a) use genuine, rigid skolem constants for the type variables</span>
<a name="line-44"></a> <span class='hs-comment'>-- (b) bring (rigid) scoped type variables into scope</span>
<a name="line-45"></a> <span class='hs-varid'>setSrcSpan</span> <span class='hs-varid'>b_loc</span> <span class='hs-varop'>$</span>
<a name="line-46"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>tc_sig</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcInstSig</span> <span class='hs-conid'>True</span> <span class='hs-varid'>name</span>
<a name="line-47"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>mono_name</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newLocalName</span> <span class='hs-varid'>name</span>
<a name="line-48"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>mono_ty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sig_tau</span> <span class='hs-varid'>tc_sig</span>
<a name="line-49"></a> <span class='hs-varid'>mono_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkLocalId</span> <span class='hs-varid'>mono_name</span> <span class='hs-varid'>mono_ty</span>
<a name="line-50"></a> <span class='hs-varid'>rhs_tvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>mkTyVarTy</span> <span class='hs-varid'>tv</span><span class='hs-layout'>)</span>
<a name="line-51"></a> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>tv</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>scoped_tvs</span> <span class='hs-varop'>`zip`</span> <span class='hs-varid'>sig_tvs</span> <span class='hs-varid'>tc_sig</span> <span class='hs-keyglyph'>]</span>
<a name="line-52"></a> <span class='hs-comment'>-- See Note [More instantiated than scoped]</span>
<a name="line-53"></a> <span class='hs-comment'>-- Note that the scoped_tvs and the (sig_tvs sig) </span>
<a name="line-54"></a> <span class='hs-comment'>-- may have different Names. That's quite ok.</span>
<a name="line-55"></a>
<a name="line-56"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>traceTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>text</span> <span class='hs-str'>"tcMoonBinds"</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>scoped_tvs</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>tc_sig</span><span class='hs-layout'>)</span>
<a name="line-57"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>co_fn</span><span class='hs-layout'>,</span> <span class='hs-varid'>matches'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcExtendTyVarEnv2</span> <span class='hs-varid'>rhs_tvs</span> <span class='hs-varop'>$</span>
<a name="line-58"></a> <span class='hs-varid'>tcMatchesFun</span> <span class='hs-varid'>mono_name</span> <span class='hs-varid'>inf</span> <span class='hs-varid'>matches</span> <span class='hs-varid'>mono_ty</span>
<a name="line-59"></a> <span class='hs-comment'>-- Note that "mono_ty" might actually be a polymorphic type,</span>
<a name="line-60"></a> <span class='hs-comment'>-- if the original function had a signature like</span>
<a name="line-61"></a> <span class='hs-comment'>-- forall a. Eq a => forall b. Ord b => ....</span>
<a name="line-62"></a> <span class='hs-comment'>-- But that's ok: tcMatchesFun can deal with that</span>
<a name="line-63"></a> <span class='hs-comment'>-- It happens, too! See Note [Polymorphic methods] in TcClassDcl.</span>
<a name="line-64"></a>
<a name="line-65"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>fun_bind'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>FunBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>fun_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-varid'>nm_loc</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>,</span>
<a name="line-66"></a> <span class='hs-varid'>fun_infix</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>inf</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_matches</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>matches'</span><span class='hs-layout'>,</span>
<a name="line-67"></a> <span class='hs-varid'>bind_fvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>placeHolderNames</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_co_fn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>co_fn</span><span class='hs-layout'>,</span>
<a name="line-68"></a> <span class='hs-varid'>fun_tick</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>}</span>
<a name="line-69"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>unitBag</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-varid'>b_loc</span> <span class='hs-varid'>fun_bind'</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-70"></a> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>tc_sig</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-71"></a>
<a name="line-72"></a><span class='hs-definition'>tcMonoBinds</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>sig_fn</span> <span class='hs-keyword'>_</span>
<a name="line-73"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>tc_binds</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>wrapLocM</span> <span class='hs-layout'>(</span><span class='hs-varid'>tcLhs</span> <span class='hs-varid'>sig_fn</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>binds</span>
<a name="line-74"></a>
<a name="line-75"></a> <span class='hs-comment'>-- Bring the monomorphic Ids, into scope for the RHSs</span>
<a name="line-76"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>mono_info</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>getMonoBindInfo</span> <span class='hs-varid'>tc_binds</span>
<a name="line-77"></a> <span class='hs-varid'>rhs_id_env</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span><span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-conid'>Nothing</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mono_info</span><span class='hs-keyglyph'>]</span>
<a name="line-78"></a> <span class='hs-comment'>-- A monomorphic binding for each term variable that lacks </span>
<a name="line-79"></a> <span class='hs-comment'>-- a type sig. (Ones with a sig are already in scope.)</span>
<a name="line-80"></a>
<a name="line-81"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>binds'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcExtendIdEnv2</span> <span class='hs-varid'>rhs_id_env</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-82"></a> <span class='hs-varid'>traceTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>text</span> <span class='hs-str'>"tcMonoBinds"</span> <span class='hs-varop'><+></span> <span class='hs-varid'>vcat</span> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>n</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>id</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-layout'>(</span><span class='hs-varid'>idType</span> <span class='hs-varid'>id</span><span class='hs-layout'>)</span>
<a name="line-83"></a> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>n</span><span class='hs-layout'>,</span><span class='hs-varid'>id</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>rhs_id_env</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-84"></a> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>wrapLocM</span> <span class='hs-varid'>tcRhs</span><span class='hs-layout'>)</span> <span class='hs-varid'>tc_binds</span>
<a name="line-85"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>listToBag</span> <span class='hs-varid'>binds'</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_info</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-86"></a>
<a name="line-87"></a><span class='hs-comment'>------------------------</span>
<a name="line-88"></a><span class='hs-comment'>-- tcLhs typechecks the LHS of the bindings, to construct the environment in which</span>
<a name="line-89"></a><span class='hs-comment'>-- we typecheck the RHSs. Basically what we are doing is this: for each binder:</span>
<a name="line-90"></a><span class='hs-comment'>-- if there's a signature for it, use the instantiated signature type</span>
<a name="line-91"></a><span class='hs-comment'>-- otherwise invent a type variable</span>
<a name="line-92"></a><span class='hs-comment'>-- You see that quite directly in the FunBind case.</span>
<a name="line-93"></a><span class='hs-comment'>-- </span>
<a name="line-94"></a><span class='hs-comment'>-- But there's a complication for pattern bindings:</span>
<a name="line-95"></a><span class='hs-comment'>-- data T = MkT (forall a. a->a)</span>
<a name="line-96"></a><span class='hs-comment'>-- MkT f = e</span>
<a name="line-97"></a><span class='hs-comment'>-- Here we can guess a type variable for the entire LHS (which will be refined to T)</span>
<a name="line-98"></a><span class='hs-comment'>-- but we want to get (f::forall a. a->a) as the RHS environment.</span>
<a name="line-99"></a><span class='hs-comment'>-- The simplest way to do this is to typecheck the pattern, and then look up the</span>
<a name="line-100"></a><span class='hs-comment'>-- bound mono-ids. Then we want to retain the typechecked pattern to avoid re-doing</span>
<a name="line-101"></a><span class='hs-comment'>-- it; hence the TcMonoBind data type in which the LHS is done but the RHS isn't</span>
<a name="line-102"></a>
<a name="line-103"></a><a name="TcMonoBind"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>TcMonoBind</span> <span class='hs-comment'>-- Half completed; LHS done, RHS not done</span>
<a name="line-104"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>TcFunBind</span> <span class='hs-conid'>MonoBindInfo</span> <span class='hs-layout'>(</span><span class='hs-conid'>Located</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>)</span> <span class='hs-conid'>Bool</span> <span class='hs-layout'>(</span><span class='hs-conid'>MatchGroup</span> <span class='hs-conid'>Name</span><span class='hs-layout'>)</span>
<a name="line-105"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>TcPatBind</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>MonoBindInfo</span><span class='hs-keyglyph'>]</span> <span class='hs-layout'>(</span><span class='hs-conid'>LPat</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>GRHSs</span> <span class='hs-conid'>Name</span><span class='hs-layout'>)</span> <span class='hs-conid'>TcSigmaType</span>
<a name="line-106"></a>
<a name="line-107"></a><a name="MonoBindInfo"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>MonoBindInfo</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>Name</span><span class='hs-layout'>,</span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>TcSigInfo</span><span class='hs-layout'>,</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>)</span>
<a name="line-108"></a> <span class='hs-comment'>-- Type signature (if any), and</span>
<a name="line-109"></a> <span class='hs-comment'>-- the monomorphic bound things</span>
<a name="line-110"></a>
<a name="line-111"></a><a name="bndrNames"></a><span class='hs-definition'>bndrNames</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>MonoBindInfo</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-112"></a><span class='hs-definition'>bndrNames</span> <span class='hs-varid'>mbi</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>n</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>n</span><span class='hs-layout'>,</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span><span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mbi</span><span class='hs-keyglyph'>]</span>
<a name="line-113"></a>
<a name="line-114"></a><a name="getMonoType"></a><span class='hs-definition'>getMonoType</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonoBindInfo</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcTauType</span>
<a name="line-115"></a><span class='hs-definition'>getMonoType</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span><span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>idType</span> <span class='hs-varid'>mono_id</span>
<a name="line-116"></a>
<a name="line-117"></a><a name="tcLhs"></a><span class='hs-definition'>tcLhs</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>HsBind</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-conid'>TcMonoBind</span>
<a name="line-118"></a><span class='hs-definition'>tcLhs</span> <span class='hs-varid'>sig_fn</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>fun_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-varid'>nm_loc</span> <span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_infix</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>inf</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_matches</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>matches</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-119"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>mb_sig</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcInstSig_maybe</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>name</span>
<a name="line-120"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>mono_name</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newLocalName</span> <span class='hs-varid'>name</span>
<a name="line-121"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>mono_ty</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mk_mono_ty</span> <span class='hs-varid'>mb_sig</span>
<a name="line-122"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>mono_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkLocalId</span> <span class='hs-varid'>mono_name</span> <span class='hs-varid'>mono_ty</span>
<a name="line-123"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcFunBind</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>mb_sig</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-varid'>nm_loc</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-varid'>inf</span> <span class='hs-varid'>matches</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-124"></a> <span class='hs-keyword'>where</span>
<a name="line-125"></a> <span class='hs-varid'>mk_mono_ty</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_tau</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span>
<a name="line-126"></a> <span class='hs-varid'>mk_mono_ty</span> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>newFlexiTyVarTy</span> <span class='hs-varid'>argTypeKind</span>
<a name="line-127"></a>
<a name="line-128"></a><span class='hs-definition'>tcLhs</span> <span class='hs-varid'>sig_fn</span> <span class='hs-layout'>(</span><span class='hs-conid'>PatBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>pat_lhs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pat</span><span class='hs-layout'>,</span> <span class='hs-varid'>pat_rhs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>grhss</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-129"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>mb_sigs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>tcInstSig_maybe</span> <span class='hs-varid'>sig_fn</span><span class='hs-layout'>)</span> <span class='hs-varid'>names</span>
<a name="line-130"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>mono_pat_binds</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>doptM</span> <span class='hs-conid'>Opt_MonoPatBinds</span>
<a name="line-131"></a> <span class='hs-comment'>-- With -XMonoPatBinds, we do no generalisation of pattern bindings</span>
<a name="line-132"></a> <span class='hs-comment'>-- But the signature can still be polymoprhic!</span>
<a name="line-133"></a> <span class='hs-comment'>-- data T = MkT (forall a. a->a)</span>
<a name="line-134"></a> <span class='hs-comment'>-- x :: forall a. a->a</span>
<a name="line-135"></a> <span class='hs-comment'>-- MkT x = <rhs></span>
<a name="line-136"></a> <span class='hs-comment'>-- The function get_sig_ty decides whether the pattern-bound variables</span>
<a name="line-137"></a> <span class='hs-comment'>-- should have exactly the type in the type signature (-XMonoPatBinds), </span>
<a name="line-138"></a> <span class='hs-comment'>-- or the instantiated version (-XMonoPatBinds)</span>
<a name="line-139"></a>
<a name="line-140"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>nm_sig_prs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>names</span> <span class='hs-varop'>`zip`</span> <span class='hs-varid'>mb_sigs</span>
<a name="line-141"></a> <span class='hs-varid'>get_sig_ty</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>mono_pat_binds</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>idType</span> <span class='hs-varop'>.</span> <span class='hs-varid'>sig_id</span>
<a name="line-142"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sig_tau</span>
<a name="line-143"></a> <span class='hs-varid'>tau_sig_env</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkNameEnv</span> <span class='hs-keyglyph'>[</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>get_sig_ty</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span>
<a name="line-144"></a> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>nm_sig_prs</span><span class='hs-keyglyph'>]</span>
<a name="line-145"></a> <span class='hs-varid'>sig_tau_fn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lookupNameEnv</span> <span class='hs-varid'>tau_sig_env</span>
<a name="line-146"></a>
<a name="line-147"></a> <span class='hs-varid'>tc_pat</span> <span class='hs-varid'>exp_ty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tcLetPat</span> <span class='hs-varid'>sig_tau_fn</span> <span class='hs-varid'>pat</span> <span class='hs-varid'>exp_ty</span> <span class='hs-varop'>$</span>
<a name="line-148"></a> <span class='hs-varid'>mapM</span> <span class='hs-varid'>lookup_info</span> <span class='hs-varid'>nm_sig_prs</span>
<a name="line-149"></a>
<a name="line-150"></a> <span class='hs-comment'>-- After typechecking the pattern, look up the binder</span>
<a name="line-151"></a> <span class='hs-comment'>-- names, which the pattern has brought into scope.</span>
<a name="line-152"></a> <span class='hs-varid'>lookup_info</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Name</span><span class='hs-layout'>,</span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>TcSigInfo</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-conid'>MonoBindInfo</span>
<a name="line-153"></a> <span class='hs-varid'>lookup_info</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>mb_sig</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>mono_id</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcLookupId</span> <span class='hs-varid'>name</span>
<a name="line-154"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>mb_sig</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-155"></a>
<a name="line-156"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>pat'</span><span class='hs-layout'>,</span> <span class='hs-varid'>infos</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>pat_ty</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>addErrCtxt</span> <span class='hs-layout'>(</span><span class='hs-varid'>patMonoBindsCtxt</span> <span class='hs-varid'>pat</span> <span class='hs-varid'>grhss</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-157"></a> <span class='hs-varid'>tcInfer</span> <span class='hs-varid'>tc_pat</span>
<a name="line-158"></a>
<a name="line-159"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcPatBind</span> <span class='hs-varid'>infos</span> <span class='hs-varid'>pat'</span> <span class='hs-varid'>grhss</span> <span class='hs-varid'>pat_ty</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-160"></a> <span class='hs-keyword'>where</span>
<a name="line-161"></a> <span class='hs-varid'>names</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>collectPatBinders</span> <span class='hs-varid'>pat</span>
<a name="line-162"></a>
<a name="line-163"></a>
<a name="line-164"></a><span class='hs-definition'>tcLhs</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>other_bind</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pprPanic</span> <span class='hs-str'>"tcLhs"</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>other_bind</span><span class='hs-layout'>)</span>
<a name="line-165"></a> <span class='hs-comment'>-- AbsBind, VarBind impossible</span>
<a name="line-166"></a>
<a name="line-167"></a><a name="tcRhs"></a><span class='hs-comment'>-------------------</span>
<a name="line-168"></a><span class='hs-definition'>tcRhs</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcMonoBind</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>HsBind</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>)</span>
<a name="line-169"></a><span class='hs-comment'>-- When we are doing pattern bindings, or multiple function bindings at a time</span>
<a name="line-170"></a><span class='hs-comment'>-- we *don't* bring any scoped type variables into scope</span>
<a name="line-171"></a><span class='hs-comment'>-- Wny not? They are not completely rigid.</span>
<a name="line-172"></a><span class='hs-comment'>-- That's why we have the special case for a single FunBind in tcMonoBinds</span>
<a name="line-173"></a><span class='hs-definition'>tcRhs</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcFunBind</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span><span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-varid'>fun'</span> <span class='hs-varid'>inf</span> <span class='hs-varid'>matches</span><span class='hs-layout'>)</span>
<a name="line-174"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-layout'>(</span><span class='hs-varid'>co_fn</span><span class='hs-layout'>,</span> <span class='hs-varid'>matches'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcMatchesFun</span> <span class='hs-layout'>(</span><span class='hs-varid'>idName</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-varid'>inf</span>
<a name="line-175"></a> <span class='hs-varid'>matches</span> <span class='hs-layout'>(</span><span class='hs-varid'>idType</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span>
<a name="line-176"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>fun_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fun'</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_infix</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>inf</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_matches</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>matches'</span><span class='hs-layout'>,</span>
<a name="line-177"></a> <span class='hs-varid'>bind_fvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>placeHolderNames</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_co_fn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>co_fn</span><span class='hs-layout'>,</span>
<a name="line-178"></a> <span class='hs-varid'>fun_tick</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-179"></a>
<a name="line-180"></a><span class='hs-definition'>tcRhs</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcPatBind</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>pat'</span> <span class='hs-varid'>grhss</span> <span class='hs-varid'>pat_ty</span><span class='hs-layout'>)</span>
<a name="line-181"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>grhss'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>addErrCtxt</span> <span class='hs-layout'>(</span><span class='hs-varid'>patMonoBindsCtxt</span> <span class='hs-varid'>pat'</span> <span class='hs-varid'>grhss</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-182"></a> <span class='hs-varid'>tcGRHSsPat</span> <span class='hs-varid'>grhss</span> <span class='hs-varid'>pat_ty</span>
<a name="line-183"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>PatBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>pat_lhs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pat'</span><span class='hs-layout'>,</span> <span class='hs-varid'>pat_rhs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>grhss'</span><span class='hs-layout'>,</span> <span class='hs-varid'>pat_rhs_ty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pat_ty</span><span class='hs-layout'>,</span>
<a name="line-184"></a> <span class='hs-varid'>bind_fvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>placeHolderNames</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-185"></a>
<a name="line-186"></a>
<a name="line-187"></a><a name="getMonoBindInfo"></a><span class='hs-comment'>---------------------</span>
<a name="line-188"></a><span class='hs-definition'>getMonoBindInfo</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Located</span> <span class='hs-conid'>TcMonoBind</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>MonoBindInfo</span><span class='hs-keyglyph'>]</span>
<a name="line-189"></a><span class='hs-definition'>getMonoBindInfo</span> <span class='hs-varid'>tc_binds</span>
<a name="line-190"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldr</span> <span class='hs-layout'>(</span><span class='hs-varid'>get_info</span> <span class='hs-varop'>.</span> <span class='hs-varid'>unLoc</span><span class='hs-layout'>)</span> <span class='hs-conid'>[]</span> <span class='hs-varid'>tc_binds</span>
<a name="line-191"></a> <span class='hs-keyword'>where</span>
<a name="line-192"></a> <span class='hs-varid'>get_info</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcFunBind</span> <span class='hs-varid'>info</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>rest</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>info</span> <span class='hs-conop'>:</span> <span class='hs-varid'>rest</span>
<a name="line-193"></a> <span class='hs-varid'>get_info</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcPatBind</span> <span class='hs-varid'>infos</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>rest</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>infos</span> <span class='hs-varop'>++</span> <span class='hs-varid'>rest</span>
</pre>\end{code}
%************************************************************************
%* *
Generalisation
%* *
%************************************************************************
\begin{code}
<pre><a name="line-1"></a><a name="generalise"></a><span class='hs-definition'>generalise</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>DynFlags</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TopLevelFlag</span>
<a name="line-2"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LHsBind</span> <span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigFun</span>
<a name="line-3"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>MonoBindInfo</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Inst</span><span class='hs-keyglyph'>]</span>
<a name="line-4"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>TyVar</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Inst</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-conid'>TcDictBinds</span><span class='hs-layout'>)</span>
<a name="line-5"></a><span class='hs-comment'>-- The returned [TyVar] are all ready to quantify</span>
<a name="line-6"></a>
<a name="line-7"></a><span class='hs-definition'>generalise</span> <span class='hs-varid'>dflags</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>bind_list</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>mono_infos</span> <span class='hs-varid'>lie_req</span>
<a name="line-8"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isMonoGroup</span> <span class='hs-varid'>dflags</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>bind_list</span> <span class='hs-varid'>sigs</span>
<a name="line-9"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>extendLIEs</span> <span class='hs-varid'>lie_req</span>
<a name="line-10"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-varid'>emptyBag</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-11"></a>
<a name="line-12"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isRestrictedGroup</span> <span class='hs-varid'>dflags</span> <span class='hs-varid'>bind_list</span> <span class='hs-varid'>sig_fn</span> <span class='hs-comment'>-- RESTRICTED CASE</span>
<a name="line-13"></a> <span class='hs-keyglyph'>=</span> <span class='hs-comment'>-- Check signature contexts are empty </span>
<a name="line-14"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>checkTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>all</span> <span class='hs-varid'>is_mono_sig</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>)</span>
<a name="line-15"></a> <span class='hs-layout'>(</span><span class='hs-varid'>restrictedBindCtxtErr</span> <span class='hs-varid'>bndrs</span><span class='hs-layout'>)</span>
<a name="line-16"></a>
<a name="line-17"></a> <span class='hs-comment'>-- Now simplify with exactly that set of tyvars</span>
<a name="line-18"></a> <span class='hs-comment'>-- We have to squash those Methods</span>
<a name="line-19"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>qtvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcSimplifyRestricted</span> <span class='hs-varid'>doc</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>bndrs</span>
<a name="line-20"></a> <span class='hs-varid'>tau_tvs</span> <span class='hs-varid'>lie_req</span>
<a name="line-21"></a>
<a name="line-22"></a> <span class='hs-comment'>-- Check that signature type variables are OK</span>
<a name="line-23"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>final_qtvs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>checkSigsTyVars</span> <span class='hs-varid'>qtvs</span> <span class='hs-varid'>sigs</span>
<a name="line-24"></a>
<a name="line-25"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>final_qtvs</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-26"></a>
<a name="line-27"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>null</span> <span class='hs-varid'>sigs</span> <span class='hs-comment'>-- UNRESTRICTED CASE, NO TYPE SIGS</span>
<a name="line-28"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tcSimplifyInfer</span> <span class='hs-varid'>doc</span> <span class='hs-varid'>tau_tvs</span> <span class='hs-varid'>lie_req</span>
<a name="line-29"></a>
<a name="line-30"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-comment'>-- UNRESTRICTED CASE, WITH TYPE SIGS</span>
<a name="line-31"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>sig_lie</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>unifyCtxts</span> <span class='hs-varid'>sigs</span> <span class='hs-comment'>-- sigs is non-empty; sig_lie is zonked</span>
<a name="line-32"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-comment'>-- The "sig_avails" is the stuff available. We get that from</span>
<a name="line-33"></a> <span class='hs-comment'>-- the context of the type signature, BUT ALSO the lie_avail</span>
<a name="line-34"></a> <span class='hs-comment'>-- so that polymorphic recursion works right (see Note [Polymorphic recursion])</span>
<a name="line-35"></a> <span class='hs-varid'>local_meths</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>mkMethInst</span> <span class='hs-varid'>sig</span> <span class='hs-varid'>mono_id</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>sig</span><span class='hs-layout'>,</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mono_infos</span><span class='hs-keyglyph'>]</span>
<a name="line-36"></a> <span class='hs-varid'>sig_avails</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sig_lie</span> <span class='hs-varop'>++</span> <span class='hs-varid'>local_meths</span>
<a name="line-37"></a> <span class='hs-varid'>loc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sig_loc</span> <span class='hs-layout'>(</span><span class='hs-varid'>head</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>)</span>
<a name="line-38"></a>
<a name="line-39"></a> <span class='hs-comment'>-- Check that the needed dicts can be</span>
<a name="line-40"></a> <span class='hs-comment'>-- expressed in terms of the signature ones</span>
<a name="line-41"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>qtvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcSimplifyInferCheck</span> <span class='hs-varid'>loc</span> <span class='hs-varid'>tau_tvs</span> <span class='hs-varid'>sig_avails</span> <span class='hs-varid'>lie_req</span>
<a name="line-42"></a>
<a name="line-43"></a> <span class='hs-comment'>-- Check that signature type variables are OK</span>
<a name="line-44"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>final_qtvs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>checkSigsTyVars</span> <span class='hs-varid'>qtvs</span> <span class='hs-varid'>sigs</span>
<a name="line-45"></a>
<a name="line-46"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>final_qtvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_lie</span><span class='hs-layout'>,</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-47"></a> <span class='hs-keyword'>where</span>
<a name="line-48"></a> <span class='hs-varid'>bndrs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bndrNames</span> <span class='hs-varid'>mono_infos</span>
<a name="line-49"></a> <span class='hs-varid'>sigs</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>sig</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>sig</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mono_infos</span><span class='hs-keyglyph'>]</span>
<a name="line-50"></a> <span class='hs-varid'>get_tvs</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isTopLevel</span> <span class='hs-varid'>top_lvl</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tyVarsOfType</span> <span class='hs-comment'>-- See Note [Silly type synonym] in TcType</span>
<a name="line-51"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>exactTyVarsOfType</span>
<a name="line-52"></a> <span class='hs-varid'>tau_tvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldr</span> <span class='hs-layout'>(</span><span class='hs-varid'>unionVarSet</span> <span class='hs-varop'>.</span> <span class='hs-varid'>get_tvs</span> <span class='hs-varop'>.</span> <span class='hs-varid'>getMonoType</span><span class='hs-layout'>)</span> <span class='hs-varid'>emptyVarSet</span> <span class='hs-varid'>mono_infos</span>
<a name="line-53"></a> <span class='hs-varid'>is_mono_sig</span> <span class='hs-varid'>sig</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>null</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_theta</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span>
<a name="line-54"></a> <span class='hs-varid'>doc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"type signature(s) for"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>pprBinders</span> <span class='hs-varid'>bndrs</span>
<a name="line-55"></a>
<a name="line-56"></a> <span class='hs-varid'>mkMethInst</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcSigInfo</span> <span class='hs-layout'>{</span> <span class='hs-varid'>sig_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_tvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tvs</span><span class='hs-layout'>,</span>
<a name="line-57"></a> <span class='hs-varid'>sig_theta</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>theta</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_loc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loc</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-varid'>mono_id</span>
<a name="line-58"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Method</span> <span class='hs-layout'>{</span><span class='hs-varid'>tci_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mono_id</span><span class='hs-layout'>,</span> <span class='hs-varid'>tci_oid</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>,</span> <span class='hs-varid'>tci_tys</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkTyVarTys</span> <span class='hs-varid'>tvs</span><span class='hs-layout'>,</span>
<a name="line-59"></a> <span class='hs-varid'>tci_theta</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>theta</span><span class='hs-layout'>,</span> <span class='hs-varid'>tci_loc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loc</span><span class='hs-layout'>}</span>
</pre>\end{code}
unifyCtxts checks that all the signature contexts are the same
The type signatures on a mutually-recursive group of definitions
must all have the same context (or none).
The trick here is that all the signatures should have the same
context, and we want to share type variables for that context, so that
all the right hand sides agree a common vocabulary for their type
constraints
We unify them because, with polymorphic recursion, their types
might not otherwise be related. This is a rather subtle issue.
\begin{code}
<pre><a name="line-1"></a><a name="unifyCtxts"></a><span class='hs-definition'>unifyCtxts</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcSigInfo</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Inst</span><span class='hs-keyglyph'>]</span>
<a name="line-2"></a><span class='hs-comment'>-- Post-condition: the returned Insts are full zonked</span>
<a name="line-3"></a><span class='hs-definition'>unifyCtxts</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>panic</span> <span class='hs-str'>"unifyCtxts []"</span>
<a name="line-4"></a><span class='hs-definition'>unifyCtxts</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig1</span> <span class='hs-conop'>:</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- Argument is always non-empty</span>
<a name="line-5"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>traceTc</span> <span class='hs-varop'>$</span> <span class='hs-varid'>text</span> <span class='hs-str'>"unifyCtxts"</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig1</span> <span class='hs-conop'>:</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>)</span>
<a name="line-6"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>mapM_</span> <span class='hs-varid'>unify_ctxt</span> <span class='hs-varid'>sigs</span>
<a name="line-7"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>theta</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>zonkTcThetaType</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_theta</span> <span class='hs-varid'>sig1</span><span class='hs-layout'>)</span>
<a name="line-8"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>newDictBndrs</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_loc</span> <span class='hs-varid'>sig1</span><span class='hs-layout'>)</span> <span class='hs-varid'>theta</span> <span class='hs-layout'>}</span>
<a name="line-9"></a> <span class='hs-keyword'>where</span>
<a name="line-10"></a> <span class='hs-varid'>theta1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sig_theta</span> <span class='hs-varid'>sig1</span>
<a name="line-11"></a> <span class='hs-varid'>unify_ctxt</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcSigInfo</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-conid'>()</span>
<a name="line-12"></a> <span class='hs-varid'>unify_ctxt</span> <span class='hs-varid'>sig</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>TcSigInfo</span> <span class='hs-layout'>{</span> <span class='hs-varid'>sig_theta</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>theta</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-13"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>setSrcSpan</span> <span class='hs-layout'>(</span><span class='hs-varid'>instLocSpan</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_loc</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-14"></a> <span class='hs-varid'>addErrCtxt</span> <span class='hs-layout'>(</span><span class='hs-varid'>sigContextsCtxt</span> <span class='hs-varid'>sig1</span> <span class='hs-varid'>sig</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-15"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>cois</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>unifyTheta</span> <span class='hs-varid'>theta1</span> <span class='hs-varid'>theta</span>
<a name="line-16"></a> <span class='hs-layout'>;</span> <span class='hs-comment'>-- Check whether all coercions are identity coercions</span>
<a name="line-17"></a> <span class='hs-comment'>-- That can happen if we have, say</span>
<a name="line-18"></a> <span class='hs-comment'>-- f :: C [a] => ...</span>
<a name="line-19"></a> <span class='hs-comment'>-- g :: C (F a) => ...</span>
<a name="line-20"></a> <span class='hs-comment'>-- where F is a type function and (F a ~ [a])</span>
<a name="line-21"></a> <span class='hs-comment'>-- Then unification might succeed with a coercion. But it's much</span>
<a name="line-22"></a> <span class='hs-comment'>-- much simpler to require that such signatures have identical contexts</span>
<a name="line-23"></a> <span class='hs-varid'>checkTc</span> <span class='hs-layout'>(</span><span class='hs-varid'>all</span> <span class='hs-varid'>isIdentityCoI</span> <span class='hs-varid'>cois</span><span class='hs-layout'>)</span>
<a name="line-24"></a> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Mutually dependent functions have syntactically distinct contexts"</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-25"></a> <span class='hs-layout'>}</span>
<a name="line-26"></a>
<a name="line-27"></a><a name="checkSigsTyVars"></a><span class='hs-definition'>checkSigsTyVars</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcTyVar</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcSigInfo</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcTyVar</span><span class='hs-keyglyph'>]</span>
<a name="line-28"></a><span class='hs-definition'>checkSigsTyVars</span> <span class='hs-varid'>qtvs</span> <span class='hs-varid'>sigs</span>
<a name="line-29"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>gbl_tvs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcGetGlobalTyVars</span>
<a name="line-30"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>sig_tvs_s</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>check_sig</span> <span class='hs-varid'>gbl_tvs</span><span class='hs-layout'>)</span> <span class='hs-varid'>sigs</span>
<a name="line-31"></a>
<a name="line-32"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-comment'>-- Sigh. Make sure that all the tyvars in the type sigs</span>
<a name="line-33"></a> <span class='hs-comment'>-- appear in the returned ty var list, which is what we are</span>
<a name="line-34"></a> <span class='hs-comment'>-- going to generalise over. Reason: we occasionally get</span>
<a name="line-35"></a> <span class='hs-comment'>-- silly types like</span>
<a name="line-36"></a> <span class='hs-comment'>-- type T a = () -> ()</span>
<a name="line-37"></a> <span class='hs-comment'>-- f :: T a</span>
<a name="line-38"></a> <span class='hs-comment'>-- f () = ()</span>
<a name="line-39"></a> <span class='hs-comment'>-- Here, 'a' won't appear in qtvs, so we have to add it</span>
<a name="line-40"></a> <span class='hs-varid'>sig_tvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldl</span> <span class='hs-varid'>extendVarSetList</span> <span class='hs-varid'>emptyVarSet</span> <span class='hs-varid'>sig_tvs_s</span>
<a name="line-41"></a> <span class='hs-varid'>all_tvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>varSetElems</span> <span class='hs-layout'>(</span><span class='hs-varid'>extendVarSetList</span> <span class='hs-varid'>sig_tvs</span> <span class='hs-varid'>qtvs</span><span class='hs-layout'>)</span>
<a name="line-42"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>all_tvs</span> <span class='hs-layout'>}</span>
<a name="line-43"></a> <span class='hs-keyword'>where</span>
<a name="line-44"></a> <span class='hs-varid'>check_sig</span> <span class='hs-varid'>gbl_tvs</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcSigInfo</span> <span class='hs-layout'>{</span><span class='hs-varid'>sig_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_tvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tvs</span><span class='hs-layout'>,</span>
<a name="line-45"></a> <span class='hs-varid'>sig_theta</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>theta</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_tau</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tau</span><span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-46"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>addErrCtxt</span> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"In the type signature for"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>quotes</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>id</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-47"></a> <span class='hs-varid'>addErrCtxtM</span> <span class='hs-layout'>(</span><span class='hs-varid'>sigCtxt</span> <span class='hs-varid'>id</span> <span class='hs-varid'>tvs</span> <span class='hs-varid'>theta</span> <span class='hs-varid'>tau</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-48"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>tvs'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>checkDistinctTyVars</span> <span class='hs-varid'>tvs</span>
<a name="line-49"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>when</span> <span class='hs-layout'>(</span><span class='hs-varid'>any</span> <span class='hs-layout'>(</span><span class='hs-varop'>`elemVarSet`</span> <span class='hs-varid'>gbl_tvs</span><span class='hs-layout'>)</span> <span class='hs-varid'>tvs'</span><span class='hs-layout'>)</span>
<a name="line-50"></a> <span class='hs-layout'>(</span><span class='hs-varid'>bleatEscapedTvs</span> <span class='hs-varid'>gbl_tvs</span> <span class='hs-varid'>tvs</span> <span class='hs-varid'>tvs'</span><span class='hs-layout'>)</span>
<a name="line-51"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>tvs'</span> <span class='hs-layout'>}</span>
<a name="line-52"></a>
<a name="line-53"></a><a name="checkDistinctTyVars"></a><span class='hs-definition'>checkDistinctTyVars</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcTyVar</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcTyVar</span><span class='hs-keyglyph'>]</span>
<a name="line-54"></a><span class='hs-comment'>-- (checkDistinctTyVars tvs) checks that the tvs from one type signature</span>
<a name="line-55"></a><span class='hs-comment'>-- are still all type variables, and all distinct from each other. </span>
<a name="line-56"></a><span class='hs-comment'>-- It returns a zonked set of type variables.</span>
<a name="line-57"></a><span class='hs-comment'>-- For example, if the type sig is</span>
<a name="line-58"></a><span class='hs-comment'>-- f :: forall a b. a -> b -> b</span>
<a name="line-59"></a><span class='hs-comment'>-- we want to check that 'a' and 'b' haven't </span>
<a name="line-60"></a><span class='hs-comment'>-- (a) been unified with a non-tyvar type</span>
<a name="line-61"></a><span class='hs-comment'>-- (b) been unified with each other (all distinct)</span>
<a name="line-62"></a>
<a name="line-63"></a><span class='hs-definition'>checkDistinctTyVars</span> <span class='hs-varid'>sig_tvs</span>
<a name="line-64"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>zonked_tvs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapM</span> <span class='hs-varid'>zonkSigTyVar</span> <span class='hs-varid'>sig_tvs</span>
<a name="line-65"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>foldlM_</span> <span class='hs-varid'>check_dup</span> <span class='hs-varid'>emptyVarEnv</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_tvs</span> <span class='hs-varop'>`zip`</span> <span class='hs-varid'>zonked_tvs</span><span class='hs-layout'>)</span>
<a name="line-66"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>zonked_tvs</span> <span class='hs-layout'>}</span>
<a name="line-67"></a> <span class='hs-keyword'>where</span>
<a name="line-68"></a> <span class='hs-varid'>check_dup</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TyVarEnv</span> <span class='hs-conid'>TcTyVar</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>TcTyVar</span><span class='hs-layout'>,</span> <span class='hs-conid'>TcTyVar</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>TyVarEnv</span> <span class='hs-conid'>TcTyVar</span><span class='hs-layout'>)</span>
<a name="line-69"></a> <span class='hs-comment'>-- The TyVarEnv maps each zonked type variable back to its</span>
<a name="line-70"></a> <span class='hs-comment'>-- corresponding user-written signature type variable</span>
<a name="line-71"></a> <span class='hs-varid'>check_dup</span> <span class='hs-varid'>acc</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_tv</span><span class='hs-layout'>,</span> <span class='hs-varid'>zonked_tv</span><span class='hs-layout'>)</span>
<a name="line-72"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>lookupVarEnv</span> <span class='hs-varid'>acc</span> <span class='hs-varid'>zonked_tv</span> <span class='hs-keyword'>of</span>
<a name="line-73"></a> <span class='hs-conid'>Just</span> <span class='hs-varid'>sig_tv'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>bomb_out</span> <span class='hs-varid'>sig_tv</span> <span class='hs-varid'>sig_tv'</span>
<a name="line-74"></a>
<a name="line-75"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>extendVarEnv</span> <span class='hs-varid'>acc</span> <span class='hs-varid'>zonked_tv</span> <span class='hs-varid'>sig_tv</span><span class='hs-layout'>)</span>
<a name="line-76"></a>
<a name="line-77"></a> <span class='hs-varid'>bomb_out</span> <span class='hs-varid'>sig_tv1</span> <span class='hs-varid'>sig_tv2</span>
<a name="line-78"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>env0</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcInitTidyEnv</span>
<a name="line-79"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>env1</span><span class='hs-layout'>,</span> <span class='hs-varid'>tidy_tv1</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tidyOpenTyVar</span> <span class='hs-varid'>env0</span> <span class='hs-varid'>sig_tv1</span>
<a name="line-80"></a> <span class='hs-layout'>(</span><span class='hs-varid'>env2</span><span class='hs-layout'>,</span> <span class='hs-varid'>tidy_tv2</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tidyOpenTyVar</span> <span class='hs-varid'>env1</span> <span class='hs-varid'>sig_tv2</span>
<a name="line-81"></a> <span class='hs-varid'>msg</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Quantified type variable"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>quotes</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>tidy_tv1</span><span class='hs-layout'>)</span>
<a name="line-82"></a> <span class='hs-varop'><+></span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"is unified with another quantified type variable"</span><span class='hs-layout'>)</span>
<a name="line-83"></a> <span class='hs-varop'><+></span> <span class='hs-varid'>quotes</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>tidy_tv2</span><span class='hs-layout'>)</span>
<a name="line-84"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>failWithTcM</span> <span class='hs-layout'>(</span><span class='hs-varid'>env2</span><span class='hs-layout'>,</span> <span class='hs-varid'>msg</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
</pre>\end{code}
@getTyVarsToGen@ decides what type variables to generalise over.
For a "restricted group" -- see the monomorphism restriction
for a definition -- we bind no dictionaries, and
remove from tyvars_to_gen any constrained type variables
*Don't* simplify dicts at this point, because we aren't going
to generalise over these dicts. By the time we do simplify them
we may well know more. For example (this actually came up)
f :: Array Int Int
f x = array ... xs where xs = [1,2,3,4,5]
We don't want to generate lots of (fromInt Int 1), (fromInt Int 2)
stuff. If we simplify only at the f-binding (not the xs-binding)
we'll know that the literals are all Ints, and we can just produce
Int literals!
Find all the type variables involved in overloading, the
"constrained_tyvars". These are the ones we *aren't* going to
generalise. We must be careful about doing this:
(a) If we fail to generalise a tyvar which is not actually
constrained, then it will never, ever get bound, and lands
up printed out in interface files! Notorious example:
instance Eq a => Eq (Foo a b) where ..
Here, b is not constrained, even though it looks as if it is.
Another, more common, example is when there's a Method inst in
the LIE, whose type might very well involve non-overloaded
type variables.
[NOTE: Jan 2001: I don't understand the problem here so I'm doing
the simple thing instead]
(b) On the other hand, we mustn't generalise tyvars which are constrained,
because we are going to pass on out the unmodified LIE, with those
tyvars in it. They won't be in scope if we've generalised them.
So we are careful, and do a complete simplification just to find the
constrained tyvars. We don't use any of the results, except to
find which tyvars are constrained.
Note [Polymorphic recursion]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The game plan for polymorphic recursion in the code above is
* Bind any variable for which we have a type signature
to an Id with a polymorphic type. Then when type-checking
the RHSs we'll make a full polymorphic call.
This fine, but if you aren't a bit careful you end up with a horrendous
amount of partial application and (worse) a huge space leak. For example:
f :: Eq a => [a] -> [a]
f xs = ...f...
If we don't take care, after typechecking we get
f = /\a -> \d::Eq a -> let f' = f a d
in
\ys:[a] -> ...f'...
Notice the the stupid construction of (f a d), which is of course
identical to the function we're executing. In this case, the
polymorphic recursion isn't being used (but that's a very common case).
This can lead to a massive space leak, from the following top-level defn
(post-typechecking)
ff :: [Int] -> [Int]
ff = f Int dEqInt
Now (f dEqInt) evaluates to a lambda that has f' as a free variable; but
f' is another thunk which evaluates to the same thing... and you end
up with a chain of identical values all hung onto by the CAF ff.
ff = f Int dEqInt
= let f' = f Int dEqInt in \ys. ...f'...
= let f' = let f' = f Int dEqInt in \ys. ...f'...
in \ys. ...f'...
Etc.
NOTE: a bit of arity anaysis would push the (f a d) inside the (\ys...),
which would make the space leak go away in this case
Solution: when typechecking the RHSs we always have in hand the
*monomorphic* Ids for each binding. So we just need to make sure that
if (Method f a d) shows up in the constraints emerging from (...f...)
we just use the monomorphic Id. We achieve this by adding monomorphic Ids
to the "givens" when simplifying constraints. That's what the "lies_avail"
is doing.
Then we get
f = /\a -> \d::Eq a -> letrec
fm = \ys:[a] -> ...fm...
in
fm
%************************************************************************
%* *
Signatures
%* *
%************************************************************************
Type signatures are tricky. See Note [Signature skolems] in TcType
@tcSigs@ checks the signatures for validity, and returns a list of
{\em freshly-instantiated} signatures. That is, the types are already
split up, and have fresh type variables installed. All non-type-signature
"RenamedSigs" are ignored.
The @TcSigInfo@ contains @TcTypes@ because they are unified with
the variable's type, and after that checked to see whether they've
been instantiated.
Note [Scoped tyvars]
~~~~~~~~~~~~~~~~~~~~
The -XScopedTypeVariables flag brings lexically-scoped type variables
into scope for any explicitly forall-quantified type variables:
f :: forall a. a -> a
f x = e
Then 'a' is in scope inside 'e'.
However, we do *not* support this
- For pattern bindings e.g
f :: forall a. a->a
(f,g) = e
- For multiple function bindings, unless Opt_RelaxedPolyRec is on
f :: forall a. a -> a
f = g
g :: forall b. b -> b
g = ...f...
Reason: we use mutable variables for 'a' and 'b', since they may
unify to each other, and that means the scoped type variable would
not stand for a completely rigid variable.
Currently, we simply make Opt_ScopedTypeVariables imply Opt_RelaxedPolyRec
Note [More instantiated than scoped]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There may be more instantiated type variables than lexically-scoped
ones. For example:
type T a = forall b. b -> (a,b)
f :: forall c. T c
Here, the signature for f will have one scoped type variable, c,
but two instantiated type variables, c' and b'.
We assume that the scoped ones are at the *front* of sig_tvs,
and remember the names from the original HsForAllTy in the TcSigFun.
\begin{code}
<pre><a name="line-1"></a><a name="TcSigFun"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-comment'>-- Maps a let-binder to the list of</span>
<a name="line-2"></a> <span class='hs-comment'>-- type variables brought into scope</span>
<a name="line-3"></a> <span class='hs-comment'>-- by its type signature.</span>
<a name="line-4"></a> <span class='hs-comment'>-- Nothing => no type signature</span>
<a name="line-5"></a>
<a name="line-6"></a><a name="mkTcSigFun"></a><span class='hs-definition'>mkTcSigFun</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LSig</span> <span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigFun</span>
<a name="line-7"></a><span class='hs-comment'>-- Search for a particular type signature</span>
<a name="line-8"></a><span class='hs-comment'>-- Precondition: the sigs are all type sigs</span>
<a name="line-9"></a><span class='hs-comment'>-- Precondition: no duplicates</span>
<a name="line-10"></a><span class='hs-definition'>mkTcSigFun</span> <span class='hs-varid'>sigs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lookupNameEnv</span> <span class='hs-varid'>env</span>
<a name="line-11"></a> <span class='hs-keyword'>where</span>
<a name="line-12"></a> <span class='hs-varid'>env</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkNameEnv</span> <span class='hs-layout'>(</span><span class='hs-varid'>mapCatMaybes</span> <span class='hs-varid'>mk_pair</span> <span class='hs-varid'>sigs</span><span class='hs-layout'>)</span>
<a name="line-13"></a> <span class='hs-varid'>mk_pair</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>TypeSig</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-varid'>lhs_ty</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>hsExplicitTvs</span> <span class='hs-varid'>lhs_ty</span><span class='hs-layout'>)</span>
<a name="line-14"></a> <span class='hs-varid'>mk_pair</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdSig</span> <span class='hs-varid'>id</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>idName</span> <span class='hs-varid'>id</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-15"></a> <span class='hs-varid'>mk_pair</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-16"></a> <span class='hs-comment'>-- The scoped names are the ones explicitly mentioned</span>
<a name="line-17"></a> <span class='hs-comment'>-- in the HsForAll. (There may be more in sigma_ty, because</span>
<a name="line-18"></a> <span class='hs-comment'>-- of nested type synonyms. See Note [More instantiated than scoped].)</span>
<a name="line-19"></a> <span class='hs-comment'>-- See Note [Only scoped tyvars are in the TyVarEnv]</span>
<a name="line-20"></a>
<a name="line-21"></a><a name="TcSigInfo"></a><span class='hs-comment'>---------------</span>
<a name="line-22"></a><a name="TcSigInfo"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>TcSigInfo</span>
<a name="line-23"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>TcSigInfo</span> <span class='hs-layout'>{</span>
<a name="line-24"></a> <span class='hs-varid'>sig_id</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcId</span><span class='hs-layout'>,</span> <span class='hs-comment'>-- *Polymorphic* binder for this value...</span>
<a name="line-25"></a>
<a name="line-26"></a> <span class='hs-varid'>sig_tvs</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcTyVar</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-comment'>-- Instantiated type variables</span>
<a name="line-27"></a> <span class='hs-comment'>-- See Note [Instantiate sig]</span>
<a name="line-28"></a>
<a name="line-29"></a> <span class='hs-varid'>sig_theta</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcThetaType</span><span class='hs-layout'>,</span> <span class='hs-comment'>-- Instantiated theta</span>
<a name="line-30"></a> <span class='hs-varid'>sig_tau</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcTauType</span><span class='hs-layout'>,</span> <span class='hs-comment'>-- Instantiated tau</span>
<a name="line-31"></a> <span class='hs-varid'>sig_loc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>InstLoc</span> <span class='hs-comment'>-- The location of the signature</span>
<a name="line-32"></a> <span class='hs-layout'>}</span>
<a name="line-33"></a>
<a name="line-34"></a>
<a name="line-35"></a><span class='hs-comment'>-- Note [Only scoped tyvars are in the TyVarEnv]</span>
<a name="line-36"></a><span class='hs-comment'>-- We are careful to keep only the *lexically scoped* type variables in</span>
<a name="line-37"></a><span class='hs-comment'>-- the type environment. Why? After all, the renamer has ensured</span>
<a name="line-38"></a><span class='hs-comment'>-- that only legal occurrences occur, so we could put all type variables</span>
<a name="line-39"></a><span class='hs-comment'>-- into the type env.</span>
<a name="line-40"></a><span class='hs-comment'>--</span>
<a name="line-41"></a><span class='hs-comment'>-- But we want to check that two distinct lexically scoped type variables</span>
<a name="line-42"></a><span class='hs-comment'>-- do not map to the same internal type variable. So we need to know which</span>
<a name="line-43"></a><span class='hs-comment'>-- the lexically-scoped ones are... and at the moment we do that by putting</span>
<a name="line-44"></a><span class='hs-comment'>-- only the lexically scoped ones into the environment.</span>
<a name="line-45"></a>
<a name="line-46"></a>
<a name="line-47"></a><span class='hs-comment'>-- Note [Instantiate sig]</span>
<a name="line-48"></a><span class='hs-comment'>-- It's vital to instantiate a type signature with fresh variables.</span>
<a name="line-49"></a><span class='hs-comment'>-- For example:</span>
<a name="line-50"></a><span class='hs-comment'>-- type S = forall a. a->a</span>
<a name="line-51"></a><span class='hs-comment'>-- f,g :: S</span>
<a name="line-52"></a><span class='hs-comment'>-- f = ...</span>
<a name="line-53"></a><span class='hs-comment'>-- g = ...</span>
<a name="line-54"></a><span class='hs-comment'>-- Here, we must use distinct type variables when checking f,g's right hand sides.</span>
<a name="line-55"></a><span class='hs-comment'>-- (Instantiation is only necessary because of type synonyms. Otherwise,</span>
<a name="line-56"></a><span class='hs-comment'>-- it's all cool; each signature has distinct type variables from the renamer.)</span>
<a name="line-57"></a>
<a name="line-58"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Outputable</span> <span class='hs-conid'>TcSigInfo</span> <span class='hs-keyword'>where</span>
<a name="line-59"></a> <span class='hs-varid'>ppr</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcSigInfo</span> <span class='hs-layout'>{</span> <span class='hs-varid'>sig_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_tvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tyvars</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_theta</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>theta</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_tau</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tau</span><span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-60"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>id</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"::"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>tyvars</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>theta</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"=>"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>tau</span>
</pre>\end{code}
\begin{code}
<pre><a name="line-1"></a><a name="tcTySig"></a><span class='hs-definition'>tcTySig</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>LSig</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-conid'>TcId</span>
<a name="line-2"></a><span class='hs-definition'>tcTySig</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-varid'>span</span> <span class='hs-layout'>(</span><span class='hs-conid'>TypeSig</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-varid'>ty</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-3"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>setSrcSpan</span> <span class='hs-varid'>span</span> <span class='hs-varop'>$</span>
<a name="line-4"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>sigma_ty</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcHsSigType</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunSigCtxt</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span> <span class='hs-varid'>ty</span>
<a name="line-5"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkLocalId</span> <span class='hs-varid'>name</span> <span class='hs-varid'>sigma_ty</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-6"></a><span class='hs-definition'>tcTySig</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdSig</span> <span class='hs-varid'>id</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-7"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>id</span>
<a name="line-8"></a><span class='hs-definition'>tcTySig</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pprPanic</span> <span class='hs-str'>"tcTySig"</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-9"></a>
<a name="line-10"></a><a name="tcInstSig_maybe"></a><span class='hs-comment'>-------------------</span>
<a name="line-11"></a><span class='hs-definition'>tcInstSig_maybe</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-conid'>TcSigInfo</span><span class='hs-layout'>)</span>
<a name="line-12"></a><span class='hs-comment'>-- Instantiate with *meta* type variables; </span>
<a name="line-13"></a><span class='hs-comment'>-- this signature is part of a multi-signature group</span>
<a name="line-14"></a><span class='hs-definition'>tcInstSig_maybe</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>name</span>
<a name="line-15"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>sig_fn</span> <span class='hs-varid'>name</span> <span class='hs-keyword'>of</span>
<a name="line-16"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>Nothing</span>
<a name="line-17"></a> <span class='hs-conid'>Just</span> <span class='hs-sel'>_scoped_tvs</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>tc_sig</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcInstSig</span> <span class='hs-conid'>False</span> <span class='hs-varid'>name</span>
<a name="line-18"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>tc_sig</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-19"></a> <span class='hs-comment'>-- NB: the _scoped_tvs may be non-empty, but we can </span>
<a name="line-20"></a> <span class='hs-comment'>-- just ignore them. See Note [Scoped tyvars].</span>
<a name="line-21"></a>
<a name="line-22"></a><a name="tcInstSig"></a><span class='hs-definition'>tcInstSig</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-conid'>TcSigInfo</span>
<a name="line-23"></a><span class='hs-comment'>-- Instantiate the signature, with either skolems or meta-type variables</span>
<a name="line-24"></a><span class='hs-comment'>-- depending on the use_skols boolean. This variable is set True</span>
<a name="line-25"></a><span class='hs-comment'>-- when we are typechecking a single function binding; and False for</span>
<a name="line-26"></a><span class='hs-comment'>-- pattern bindings and a group of several function bindings.</span>
<a name="line-27"></a><span class='hs-comment'>-- Reason: in the latter cases, the "skolems" can be unified together, </span>
<a name="line-28"></a><span class='hs-comment'>-- so they aren't properly rigid in the type-refinement sense.</span>
<a name="line-29"></a><span class='hs-comment'>-- NB: unless we are doing H98, each function with a sig will be done</span>
<a name="line-30"></a><span class='hs-comment'>-- separately, even if it's mutually recursive, so use_skols will be True</span>
<a name="line-31"></a><span class='hs-comment'>--</span>
<a name="line-32"></a><span class='hs-comment'>-- We always instantiate with fresh uniques,</span>
<a name="line-33"></a><span class='hs-comment'>-- although we keep the same print-name</span>
<a name="line-34"></a><span class='hs-comment'>-- </span>
<a name="line-35"></a><span class='hs-comment'>-- type T = forall a. [a] -> [a]</span>
<a name="line-36"></a><span class='hs-comment'>-- f :: T; </span>
<a name="line-37"></a><span class='hs-comment'>-- f = g where { g :: T; g = <rhs> }</span>
<a name="line-38"></a><span class='hs-comment'>--</span>
<a name="line-39"></a><span class='hs-comment'>-- We must not use the same 'a' from the defn of T at both places!!</span>
<a name="line-40"></a>
<a name="line-41"></a><span class='hs-definition'>tcInstSig</span> <span class='hs-varid'>use_skols</span> <span class='hs-varid'>name</span>
<a name="line-42"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>poly_id</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcLookupId</span> <span class='hs-varid'>name</span> <span class='hs-comment'>-- Cannot fail; the poly ids are put into </span>
<a name="line-43"></a> <span class='hs-comment'>-- scope when starting the binding group</span>
<a name="line-44"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>skol_info</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>SigSkol</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunSigCtxt</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span>
<a name="line-45"></a> <span class='hs-layout'>;</span> <span class='hs-layout'>(</span><span class='hs-varid'>tvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>theta</span><span class='hs-layout'>,</span> <span class='hs-varid'>tau</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcInstSigType</span> <span class='hs-varid'>use_skols</span> <span class='hs-varid'>skol_info</span> <span class='hs-layout'>(</span><span class='hs-varid'>idType</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>)</span>
<a name="line-46"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>loc</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>getInstLoc</span> <span class='hs-layout'>(</span><span class='hs-conid'>SigOrigin</span> <span class='hs-varid'>skol_info</span><span class='hs-layout'>)</span>
<a name="line-47"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>TcSigInfo</span> <span class='hs-layout'>{</span> <span class='hs-varid'>sig_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>poly_id</span><span class='hs-layout'>,</span>
<a name="line-48"></a> <span class='hs-varid'>sig_tvs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tvs</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_theta</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>theta</span><span class='hs-layout'>,</span> <span class='hs-varid'>sig_tau</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tau</span><span class='hs-layout'>,</span>
<a name="line-49"></a> <span class='hs-varid'>sig_loc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loc</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-50"></a>
<a name="line-51"></a><a name="isMonoGroup"></a><span class='hs-comment'>-------------------</span>
<a name="line-52"></a><span class='hs-definition'>isMonoGroup</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>DynFlags</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TopLevelFlag</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LHsBind</span> <span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-53"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TcSigInfo</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-54"></a><span class='hs-comment'>-- No generalisation at all</span>
<a name="line-55"></a><span class='hs-definition'>isMonoGroup</span> <span class='hs-varid'>dflags</span> <span class='hs-varid'>top_lvl</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>sigs</span>
<a name="line-56"></a> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>dopt</span> <span class='hs-conid'>Opt_MonoPatBinds</span> <span class='hs-varid'>dflags</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>any</span> <span class='hs-varid'>is_pat_bind</span> <span class='hs-varid'>binds</span><span class='hs-layout'>)</span>
<a name="line-57"></a> <span class='hs-varop'>||</span> <span class='hs-layout'>(</span><span class='hs-varid'>dopt</span> <span class='hs-conid'>Opt_MonoLocalBinds</span> <span class='hs-varid'>dflags</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>null</span> <span class='hs-varid'>sigs</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>isTopLevel</span> <span class='hs-varid'>top_lvl</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-58"></a> <span class='hs-keyword'>where</span>
<a name="line-59"></a> <span class='hs-varid'>is_pat_bind</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>PatBind</span> <span class='hs-layout'>{</span><span class='hs-layout'>}</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-60"></a> <span class='hs-varid'>is_pat_bind</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-61"></a>
<a name="line-62"></a><a name="isRestrictedGroup"></a><span class='hs-comment'>-------------------</span>
<a name="line-63"></a><span class='hs-definition'>isRestrictedGroup</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>DynFlags</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>LHsBind</span> <span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigFun</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-64"></a><span class='hs-definition'>isRestrictedGroup</span> <span class='hs-varid'>dflags</span> <span class='hs-varid'>binds</span> <span class='hs-varid'>sig_fn</span>
<a name="line-65"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mono_restriction</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>not</span> <span class='hs-varid'>all_unrestricted</span>
<a name="line-66"></a> <span class='hs-keyword'>where</span>
<a name="line-67"></a> <span class='hs-varid'>mono_restriction</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>dopt</span> <span class='hs-conid'>Opt_MonomorphismRestriction</span> <span class='hs-varid'>dflags</span>
<a name="line-68"></a> <span class='hs-varid'>all_unrestricted</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>all</span> <span class='hs-layout'>(</span><span class='hs-varid'>unrestricted</span> <span class='hs-varop'>.</span> <span class='hs-varid'>unLoc</span><span class='hs-layout'>)</span> <span class='hs-varid'>binds</span>
<a name="line-69"></a> <span class='hs-varid'>has_sig</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>isJust</span> <span class='hs-layout'>(</span><span class='hs-varid'>sig_fn</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span>
<a name="line-70"></a>
<a name="line-71"></a> <span class='hs-varid'>unrestricted</span> <span class='hs-layout'>(</span><span class='hs-conid'>PatBind</span> <span class='hs-layout'>{</span><span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-72"></a> <span class='hs-varid'>unrestricted</span> <span class='hs-layout'>(</span><span class='hs-conid'>VarBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>var_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>v</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>has_sig</span> <span class='hs-varid'>v</span>
<a name="line-73"></a> <span class='hs-varid'>unrestricted</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunBind</span> <span class='hs-layout'>{</span> <span class='hs-varid'>fun_id</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>v</span><span class='hs-layout'>,</span> <span class='hs-varid'>fun_matches</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>matches</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unrestricted_match</span> <span class='hs-varid'>matches</span>
<a name="line-74"></a> <span class='hs-varop'>||</span> <span class='hs-varid'>has_sig</span> <span class='hs-layout'>(</span><span class='hs-varid'>unLoc</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span>
<a name="line-75"></a> <span class='hs-varid'>unrestricted</span> <span class='hs-layout'>(</span><span class='hs-conid'>AbsBinds</span> <span class='hs-layout'>{</span><span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-76"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>panic</span> <span class='hs-str'>"isRestrictedGroup/unrestricted AbsBinds"</span>
<a name="line-77"></a>
<a name="line-78"></a> <span class='hs-varid'>unrestricted_match</span> <span class='hs-layout'>(</span><span class='hs-conid'>MatchGroup</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>Match</span> <span class='hs-conid'>[]</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-conop'>:</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-79"></a> <span class='hs-comment'>-- No args => like a pattern binding</span>
<a name="line-80"></a> <span class='hs-varid'>unrestricted_match</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-81"></a> <span class='hs-comment'>-- Some args => a function binding</span>
</pre>\end{code}
%************************************************************************
%* *
\subsection[TcBinds-errors]{Error contexts and messages}
%* *
%************************************************************************
\begin{code}
<pre><a name="line-1"></a><a name="patMonoBindsCtxt"></a><span class='hs-comment'>-- This one is called on LHS, when pat and grhss are both Name </span>
<a name="line-2"></a><span class='hs-comment'>-- and on RHS, when pat is TcId and grhss is still Name</span>
<a name="line-3"></a><span class='hs-definition'>patMonoBindsCtxt</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>OutputableBndr</span> <span class='hs-varid'>id</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>LPat</span> <span class='hs-varid'>id</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>GRHSs</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-4"></a><span class='hs-definition'>patMonoBindsCtxt</span> <span class='hs-varid'>pat</span> <span class='hs-varid'>grhss</span>
<a name="line-5"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hang</span> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"In a pattern binding:"</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-num'>4</span> <span class='hs-layout'>(</span><span class='hs-varid'>pprPatBind</span> <span class='hs-varid'>pat</span> <span class='hs-varid'>grhss</span><span class='hs-layout'>)</span>
<a name="line-6"></a>
<a name="line-7"></a><a name="sigContextsCtxt"></a><span class='hs-comment'>-----------------------------------------------</span>
<a name="line-8"></a><span class='hs-definition'>sigContextsCtxt</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>TcSigInfo</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcSigInfo</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-9"></a><span class='hs-definition'>sigContextsCtxt</span> <span class='hs-varid'>sig1</span> <span class='hs-varid'>sig2</span>
<a name="line-10"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vcat</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"When matching the contexts of the signatures for"</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-11"></a> <span class='hs-varid'>nest</span> <span class='hs-num'>2</span> <span class='hs-layout'>(</span><span class='hs-varid'>vcat</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>id1</span> <span class='hs-varop'><+></span> <span class='hs-varid'>dcolon</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-layout'>(</span><span class='hs-varid'>idType</span> <span class='hs-varid'>id1</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-12"></a> <span class='hs-varid'>ppr</span> <span class='hs-varid'>id2</span> <span class='hs-varop'><+></span> <span class='hs-varid'>dcolon</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-layout'>(</span><span class='hs-varid'>idType</span> <span class='hs-varid'>id2</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-13"></a> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"The signature contexts in a mutually recursive group should all be identical"</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-14"></a> <span class='hs-keyword'>where</span>
<a name="line-15"></a> <span class='hs-varid'>id1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sig_id</span> <span class='hs-varid'>sig1</span>
<a name="line-16"></a> <span class='hs-varid'>id2</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sig_id</span> <span class='hs-varid'>sig2</span>
<a name="line-17"></a>
<a name="line-18"></a>
<a name="line-19"></a><a name="unboxedTupleErr"></a><span class='hs-comment'>-----------------------------------------------</span>
<a name="line-20"></a><span class='hs-definition'>unboxedTupleErr</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Type</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-21"></a><span class='hs-definition'>unboxedTupleErr</span> <span class='hs-varid'>name</span> <span class='hs-varid'>ty</span>
<a name="line-22"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hang</span> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Illegal binding of unboxed tuple"</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-23"></a> <span class='hs-num'>4</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>name</span> <span class='hs-varop'><+></span> <span class='hs-varid'>dcolon</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>ty</span><span class='hs-layout'>)</span>
<a name="line-24"></a>
<a name="line-25"></a><a name="restrictedBindCtxtErr"></a><span class='hs-comment'>-----------------------------------------------</span>
<a name="line-26"></a><span class='hs-definition'>restrictedBindCtxtErr</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-27"></a><span class='hs-definition'>restrictedBindCtxtErr</span> <span class='hs-varid'>binder_names</span>
<a name="line-28"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hang</span> <span class='hs-layout'>(</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Illegal overloaded type signature(s)"</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-29"></a> <span class='hs-num'>4</span> <span class='hs-layout'>(</span><span class='hs-varid'>vcat</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"in a binding group for"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>pprBinders</span> <span class='hs-varid'>binder_names</span><span class='hs-layout'>,</span>
<a name="line-30"></a> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"that falls under the monomorphism restriction"</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-31"></a>
<a name="line-32"></a><a name="genCtxt"></a><span class='hs-definition'>genCtxt</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SDoc</span>
<a name="line-33"></a><span class='hs-definition'>genCtxt</span> <span class='hs-varid'>binder_names</span>
<a name="line-34"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"When generalising the type(s) for"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>pprBinders</span> <span class='hs-varid'>binder_names</span>
<a name="line-35"></a>
<a name="line-36"></a><a name="missingSigWarn"></a><span class='hs-definition'>missingSigWarn</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Type</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>TcM</span> <span class='hs-conid'>()</span>
<a name="line-37"></a><span class='hs-definition'>missingSigWarn</span> <span class='hs-conid'>False</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-38"></a><span class='hs-definition'>missingSigWarn</span> <span class='hs-conid'>True</span> <span class='hs-varid'>name</span> <span class='hs-varid'>ty</span>
<a name="line-39"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>env0</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tcInitTidyEnv</span>
<a name="line-40"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>env1</span><span class='hs-layout'>,</span> <span class='hs-varid'>tidy_ty</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tidyOpenType</span> <span class='hs-varid'>env0</span> <span class='hs-varid'>ty</span>
<a name="line-41"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>addWarnTcM</span> <span class='hs-layout'>(</span><span class='hs-varid'>env1</span><span class='hs-layout'>,</span> <span class='hs-varid'>mk_msg</span> <span class='hs-varid'>tidy_ty</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-42"></a> <span class='hs-keyword'>where</span>
<a name="line-43"></a> <span class='hs-varid'>mk_msg</span> <span class='hs-varid'>ty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vcat</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Definition but no type signature for"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>quotes</span> <span class='hs-layout'>(</span><span class='hs-varid'>ppr</span> <span class='hs-varid'>name</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-44"></a> <span class='hs-varid'>sep</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>ptext</span> <span class='hs-layout'>(</span><span class='hs-varid'>sLit</span> <span class='hs-str'>"Inferred type:"</span><span class='hs-layout'>)</span> <span class='hs-varop'><+></span> <span class='hs-varid'>pprHsVar</span> <span class='hs-varid'>name</span> <span class='hs-varop'><+></span> <span class='hs-varid'>dcolon</span> <span class='hs-varop'><+></span> <span class='hs-varid'>ppr</span> <span class='hs-varid'>ty</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span>
</pre>\end{code}
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