Fix an ASSERT failure in FamInstEnv
authorsimonpj@microsoft.com <unknown>
Thu, 7 Oct 2010 09:13:27 +0000 (09:13 +0000)
committersimonpj@microsoft.com <unknown>
Thu, 7 Oct 2010 09:13:27 +0000 (09:13 +0000)
commite4b7186c16788b719e0150ac3bc3cc628ea00d64
treec0c7d8d522b990d187f989d3e97135d926224c55
parent2060788524c41ae87ba87276cb59e7cab574fe68
Fix an ASSERT failure in FamInstEnv

I added a lot of comments too, to explain the preconditions;
esp Note [FamInstEnv]
compiler/types/FamInstEnv.lhs