patch applied (ghc): Fix a deriving bug,
arising from recent refactoring
Simon Peyton Jones
simonpj at microsoft.com
Wed Feb 21 11:54:11 EST 2007
Wed Feb 21 04:47:39 PST 2007 simonpj at microsoft.com
* 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.
M ./compiler/typecheck/TcDeriv.lhs +20
M ./compiler/typecheck/TcSimplify.lhs -28 +4
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