Parsing type constraints in GHC 7.4.1
This appears to be a parsing bug, or at least a bad error message, for a *malformed* type constraint:
Given the following malformed program, I get the following output loading it with ghci (GHC 7.4.1):
module Test where
data Foo a = Foo a
-- Malformed!
instance Ord a => Eq a => Show (Foo a) where
show (Foo a) = undefined
$ ghci Test.hs
GHCi, version 7.4.1: http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
[1 of 1] Compiling Test ( Test.hs, interpreted )
*** Exception: compiler/rename/RnSource.lhs:429:14-81: Irrefutable pattern failed for pattern Data.Maybe.Just (inst_tyvars,
_,
SrcLoc.L _ cls,
_)
>
Trac metadata
Trac field | Value |
---|---|
Version | 7.4.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |