Fix unused-given-constraint bug
authorSimon Peyton Jones <simonpj@microsoft.com>
Tue, 19 Sep 2017 11:37:13 +0000 (12:37 +0100)
committerSimon Peyton Jones <simonpj@microsoft.com>
Tue, 19 Sep 2017 11:38:28 +0000 (12:38 +0100)
commit1db0f4a48e9db5e85782e32f074cc83bbc145cb7
tree9d528ded8ddaaf280d3721d6e6d582e54f6932c6
parenta2f004b68ad4d69fd02be419f7517570baa28a58
Fix unused-given-constraint bug

This bug was shown up by Trac #14237.  It turned out
to be an outright error in TcSimplify.neededEvVars,
easily fixed.

I improved the comments.
compiler/typecheck/TcEvidence.hs
compiler/typecheck/TcSimplify.hs
testsuite/tests/indexed-types/should_compile/T14237.hs [new file with mode: 0644]
testsuite/tests/indexed-types/should_compile/all.T