Do not generate given kind-equalities (fix Trac #8566)
authorSimon Peyton Jones <simonpj@microsoft.com>
Tue, 10 Dec 2013 17:49:18 +0000 (17:49 +0000)
committerSimon Peyton Jones <simonpj@microsoft.com>
Tue, 10 Dec 2013 17:50:12 +0000 (17:50 +0000)
commit755823126f4f58b74f2bb783dc683197273f3474
tree29f191ee1cb359cab0812bbf15af9d234a9e479d
parent289ecda3d4bd3073b37cfdcccce02ad53962ea0d
Do not generate given kind-equalities (fix Trac #8566)

This is a long-standing bug.  We were generating a Given
equality between kind variables, and (at least until we support
kind coercions) we can't do that.

The fix is to drop such Given equalities entirely. That may
mean we can't prove some things, but that's fair enough -- the
current proof language can't express such proofs.

See Note [Do not create Given kind equalities] in TcSMonad
compiler/typecheck/TcCanonical.lhs
compiler/typecheck/TcInteract.lhs
compiler/typecheck/TcSMonad.lhs