Kill varSetElems in injImproveEqns
authorBartosz Nitka <niteria@gmail.com>
Thu, 28 Apr 2016 12:40:39 +0000 (05:40 -0700)
committerBartosz Nitka <niteria@gmail.com>
Thu, 28 Apr 2016 12:50:35 +0000 (05:50 -0700)
commit82538f65f48f370764691264c3c71b975fd43e16
tree83b51c36847ddff57ab25e2fc67e7a757e1dee02
parentfa3ba060cdc7f469e7f5c4f7503fadfe99937c90
Kill varSetElems in injImproveEqns

We want to remove varSetElems at the source level because it
might be a source of nondeterminism. I don't think it introduces
nondeterminism here, but it's easy to do the same thing
deterministically for the same price.

instFlexiTcS :: [TKVar] -> TcS (TCvSubst, [TcType])
instFlexiTcS currently gives the range of the produced substitution
as the second element of the tuple, but it's not used anywhere
right now. If it started to be used in the code I'm modifying
it would cause nondeterminism problems.

Test Plan: ./validate

Reviewers: austin, goldfire, bgamari, simonmar, simonpj

Reviewed By: simonpj

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2149

GHC Trac Issues: #4012
compiler/typecheck/TcInteract.hs