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author | Simon Peyton Jones <simonpj@microsoft.com> | 2014-07-15 07:43:55 +0100 |
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committer | Simon Peyton Jones <simonpj@microsoft.com> | 2014-07-15 07:43:55 +0100 |
commit | 9b8ba62991ae22420a0c4486127a3b22ee7f22bd (patch) | |
tree | 69e03640c54a4393efe91a5f184b764692460808 /testsuite/tests/typecheck/should_fail/AssocTyDef02.stderr | |
parent | f692e8e7cde712cc4dce4245d5745063fd8b0626 (diff) | |
download | haskell-9b8ba62991ae22420a0c4486127a3b22ee7f22bd.tar.gz |
Entirely re-jig the handling of default type-family instances (fixes Trac #9063)
In looking at Trac #9063 I decided to re-design the default
instances for associated type synonyms. Previously it was all
jolly complicated, to support generality that no one wanted, and
was arguably undesirable.
Specifically
* The default instance for an associated type can have only
type variables on the LHS. (Not type patterns.)
* There can be at most one default instances declaration for
each associated type.
To achieve this I had to do a surprisingly large amount of refactoring
of HsSyn, specifically to parameterise HsDecls.TyFamEqn over the type
of the LHS patterns.
That change in HsDecls has a (trivial) knock-on effect in Haddock, so
this commit does a submodule update too.
The net result is good though. The code is simpler; the language
specification is simpler. Happy days.
Trac #9263 and #9264 are thereby fixed as well.
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/AssocTyDef02.stderr')
-rw-r--r-- | testsuite/tests/typecheck/should_fail/AssocTyDef02.stderr | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/testsuite/tests/typecheck/should_fail/AssocTyDef02.stderr b/testsuite/tests/typecheck/should_fail/AssocTyDef02.stderr index 9b3ac0e364..b310a79a6f 100644 --- a/testsuite/tests/typecheck/should_fail/AssocTyDef02.stderr +++ b/testsuite/tests/typecheck/should_fail/AssocTyDef02.stderr @@ -1,6 +1,6 @@ -AssocTyDef02.hs:6:10: - Type indexes must match class instance head - Found ‘[b]’ but expected ‘a’ - In the type synonym instance default declaration for ‘Typ’ - In the class declaration for ‘Cls’ +AssocTyDef02.hs:6:14: + Unexpected type ‘[b]’ + In the default declaration for ‘Typ’ + A default declaration should have form + default Typ a = ... |