Deriving Eq on bottom types breaks reflexivity of (==)
Related to #4220 (closed) and #4302 (closed).
{-# LANGUAGE EmptyDataDecls, StandaloneDeriving #-}
data Z
deriving instance Eq Z
g :: Z
g = g
main :: IO ()
main = print (g == g)
Observed output ((==)
not reflexive anymore?):
False
Expected output (this is what TcGenDeriv.mkRdrFunBind
does for Show
etc.):
"*** Exception: Void (==)
Trac metadata
Trac field | Value |
---|---|
Version | 7.0.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |