Remove a zonkTcTyVarToTyVar
authorSimon Peyton Jones <simonpj@microsoft.com>
Thu, 25 Oct 2018 07:50:59 +0000 (08:50 +0100)
committerSimon Peyton Jones <simonpj@microsoft.com>
Thu, 25 Oct 2018 08:10:00 +0000 (09:10 +0100)
commit29978ef1f834d77dc31bf7054590d526d068df7e
tree12d2e981b97096693fce3732bdbf874d1cf8d1ec
parent232b0cb35c1f731be66a032a4deee87bc47db3c9
Remove a zonkTcTyVarToTyVar

This patch fixes Trac #15778 by removing a zonkTcTyVarToTyVar
from tcHsSigType.

Nww that a pattern-bound type variable can refer to a type, it's
obvoiusly wrong to expect it to be a TyVar!  Moreover, that zonk
is entirely unnecessary.

I added a new Note [Type variables in the type environment]
in TcRnTypes
compiler/typecheck/TcHsType.hs
compiler/typecheck/TcRnTypes.hs
testsuite/tests/typecheck/should_compile/T15778.hs [new file with mode: 0644]
testsuite/tests/typecheck/should_compile/all.T