Compile-time crash with sources with non-representable unicode characters

The following file causes GHC to crash, if compiled in the "C" locale.

$ LC_ALL=C ghc unicode.hs
[1 of 1] Compiling Foo              ( unicode.hs, unicode.o )

unicode.hs:2:1:
    Warning: Pattern match(es) are overlapped
             In an equation for `<stderr>: hPutChar: invalid argument (invalid character)

unicode.hs:

module Foo where
δ x = 3
δ x = 4

Trac metadata

Trac field	Value
Version	7.4.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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