Fix Trac #1899; missing equality check in typechecker's constraint simplifier
authorsimonpj@microsoft.com <unknown>
Tue, 26 Feb 2008 17:47:43 +0000 (17:47 +0000)
committersimonpj@microsoft.com <unknown>
Tue, 26 Feb 2008 17:47:43 +0000 (17:47 +0000)
commite7577a785b467d1a7f48bef8fc6d934c67a56ba7
tree8c81c784c2123269f9f9f98eefec14d1a3f60026
parent7453eaaf0b690420ef2359f022a1838ad697b441
Fix Trac #1899; missing equality check in typechecker's constraint simplifier

This patch fixes a missing equality check (uifying type variable b=b) in
the new constraint simplifier in TcTyFuns.  As it stands, we were making
'b' point to itself, which subsequently led to an infinite loop when
zonking.  Test is T1899.hs
compiler/typecheck/TcTyFuns.lhs