cvs commit: fptools/ghc/compiler/iface TcIface.lhs
Simon Peyton Jones
simonpj at microsoft.com
Wed Jun 14 07:46:15 EDT 2006
simonpj 2006/06/14 04:46:15 PDT
Modified files: (Branch: ghc-6-4-branch)
Fix a nasty GADT bug
Consider typechecking an interface decl like this:
f (x::T a) (y::a) = case x of
C -> case y of ...
Matching on 'x' refines 'y' to a data type. tcIfaceExpr of IfaceCase
expects 'y' to have a data type, but if we don't refine the envt it'll
just have the type 'a'.
Solution: refine the envt, as is done in the simplifier. Sigh.
System FC is better!
Revision Changes Path
18.104.22.168 +24 -8 fptools/ghc/compiler/iface/TcIface.lhs
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