Kill off redundant SigTv check in occurCheckExpand
authorSimon Peyton Jones <simonpj@microsoft.com>
Mon, 16 May 2016 21:08:08 +0000 (22:08 +0100)
committerBen Gamari <ben@smart-cactus.org>
Sun, 2 Oct 2016 01:51:30 +0000 (21:51 -0400)
commit11f9bffb11462f0bed3881e160968bf024466bdc
tree57602cdd38d79ba86c032910f0d13488f7bb9eb1
parentc448d5513d68da7077b2b4d3adadda93120d8504
Kill off redundant SigTv check in occurCheckExpand

This patch simply deletes code, the SigTv check in
occurCheckExpand.  As the new comment says

In the past we also rejected a SigTv matched with a non-tyvar
But it is wrong to reject that for Givens;
and SigTv is in any case handled separately by
   - TcUnify.checkTauTvUpdate (on-the-fly unifier)
   - TcInteract.canSolveByUnification (main constraint solver)

(cherry picked from commit d25cb61a1c2a135a2564143a332f8b2962f134bc)
compiler/typecheck/TcType.hs