Eta-contraction gives a rather bogus type error message
Consider the following program:
module Main where
type T a = Show a => a
f :: T a -> String
f = show
Compiling this with GHC 6.10.3 and -fglasgow-exts gives:
[1 of 1] Compiling Main ( Test.hs, interpreted )
ghc: panic! (the 'impossible' happened)
(GHC version 6.10.3 for i386-apple-darwin):
TcTyFuns.flattenType: unexpected PredType
Trac metadata
Trac field | Value |
---|---|
Version | 6.10.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | thomas@cs.ru.nl |
Operating system | MacOS X |
Architecture | x86 |