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FIX Trac #1935: generate superclass constraints for derived classes
authorsimonpj@microsoft.com <unknown>
Wed, 28 Nov 2007 15:05:41 +0000 (15:05 +0000)
committersimonpj@microsoft.com <unknown>
Wed, 28 Nov 2007 15:05:41 +0000 (15:05 +0000)
commit162ae90572443ca726992ea54f4cbc75658453d3
tree09841929a5930a5e21c227bdb0a1537f1f1eb1e7tree | snapshot
parentb566be3509bacb565acb5fbda67a93967bd99359commit | diff
FIX Trac #1935: generate superclass constraints for derived classes

This bug only reports a problem with phantom types, but actually
there was quite a long-standing and significant omission in the
constraint generation for derived classes.  See
Note [Superclasses of derived instance] in TcDeriv.

The test deriving-1935 tests both cases.
compiler/typecheck/TcDeriv.lhs diff | blob | history
Glasgow Haskell Compiler with heterogeneous metaprogramming (generalized arrows and modal types)