typecheck: Don't warn about "redundant" TypeError constraints
authorBen Gamari <bgamari.foss@gmail.com>
Thu, 7 Jun 2018 17:40:57 +0000 (13:40 -0400)
committerBen Gamari <ben@smart-cactus.org>
Fri, 8 Jun 2018 00:11:32 +0000 (20:11 -0400)
commitd66ca0111cefcda6620a4c82a932456b3e48874c
tree90708c165979eaa22c286665f85594c1459ab459
parent297879a78cc6ca4c27afb0cc863c8796b60da6e1
typecheck: Don't warn about "redundant" TypeError constraints

Summary: This fixes #15232, where we would warn about `TypeError` constraints being redundant.

Test Plan: Validate

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #15232

Differential Revision: https://phabricator.haskell.org/D4808
compiler/typecheck/TcErrors.hs
testsuite/tests/typecheck/should_compile/all.T