Eta-expansion of a left-section
If I say
x = seq (True `undefined`) ()
what should I get when evaluating x
?
According to my understanding of the Haskell Report, I should get ()
. And according to my understanding of GHC's source code (in GHC.Tc.Gen.Expr
), I should get ()
. But I get an exception.
Why?
NB: -XPostfixOperators
is off. If it were on, the exception would be expected.
Spun off from https://github.com/ghc-proposals/ghc-proposals/pull/275#issuecomment-624282022