Fix a deriving bug, arising from recent refactoring
authorsimonpj@microsoft.com <unknown>
Wed, 21 Feb 2007 12:47:39 +0000 (12:47 +0000)
committersimonpj@microsoft.com <unknown>
Wed, 21 Feb 2007 12:47:39 +0000 (12:47 +0000)
commit66f73ee4d4130b98d35ec26bba073b2197724011
treeafe87a3f8065723f19dacaa7f753f11fdc99fc26
parent041c35e5d9f3aefab6908b4c776a3fd8242720ab
Fix a deriving bug, arising from recent refactoring

This one is a hangover from something I did a month or two ago, but
didn't get quite right.  tcSimplifyDefault should not check for no-instances;
instead the checkValidInstance in TcDeriv does so.

Conal's DeepArrow needs this fix.  Test is drv015.
compiler/typecheck/TcDeriv.lhs
compiler/typecheck/TcSimplify.lhs