Make dropDerivedSimples restore [WD] constraints
authorSimon Peyton Jones <simonpj@microsoft.com>
Fri, 9 Dec 2016 17:37:28 +0000 (17:37 +0000)
committerSimon Peyton Jones <simonpj@microsoft.com>
Mon, 12 Dec 2016 11:56:32 +0000 (11:56 +0000)
commitf1036ad80efb9cf80977fa234f8b9c7b23cc6835
tree369296f37578b0a2502123b9b0009dd983a37f61
parent818e027e2db2ac291c44a5e07ae151505f3908b8
Make dropDerivedSimples restore [WD] constraints

I'd forgotten to turn [W] + [D] constraints back into [WD]
in dropDerivedSimples; and that led to Trac #12936.

Fortunately the fix is simple.
compiler/typecheck/TcRnTypes.hs
compiler/utils/Bag.hs
testsuite/tests/typecheck/should_compile/T12936.hs [new file with mode: 0644]
testsuite/tests/typecheck/should_compile/all.T