Changes between Version 193 and Version 194 of TypeFunctionsStatus

Timestamp:

09/05/07 04:08:23 (6 years ago)

Author:

chak

Comment:

--

TypeFunctionsStatus

@@ -6 +6 @@
  0. #1651; fixed the panic, remains the bogus missing instance error
  0. Check that the restrictions on equality constraints in instance and class contexts are enforced.  We should have tests for that in the testsuite.  Document the exact restrictions on the Haskell wiki tutorial page. '''[Tom is working at this.]'''
+ 0. To fix `Simple8`:
+   * Fix tcLookupFamInst to gracefully handle this case.  (This requires some care to not violate assumptions made by other  clients of this function, as it is also used for data families,  but I see no fundamental problem.)
+* Issue a warning if there are two identical instances (as per  Roman's suggestion).
  0. `boxySplitTyConApp` and friends must be able to deal with `orig_ty`s that have outermost type family applications; i.e., they need to try to normalise and possibly have to defer.  They also need to defer on skolems.  Consequently, they also need to return a coercion.  This , in particular, affects the treatment of literal lists, parallel arrays, and tuples in`TcExpr.tcExpr` is fishy.
  0. Can't we now allow non-left-linear declarations; e.g., `instance type F a a = ..`?