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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2014-03-07 16:45:55 +0000 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2014-03-07 16:51:37 +0000 |
| commit | cdac487bcd9928d77738f6e79ead7b9bb4bc00fd (patch) | |
| tree | 76a3750754f317b81987e00a66c4ce188eecf181 /testsuite/tests/typecheck/should_fail/tcfail086.stderr | |
| parent | 3efcb0a7d147e05f86501783144bcd0ad3757e93 (diff) | |
| download | haskell-cdac487bcd9928d77738f6e79ead7b9bb4bc00fd.tar.gz | |
Make -XDeriveFunctor more generous about non-last arguments (Trac #8678)
When deriving Functor, Foldable, Traversable, we need only look at the
way that the last type argument is treated. It's fine for there to
be existentials etc, provided they don't affect the last type argument.
See Note [Check that the type variable is truly universal] in TcDeriv.
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/tcfail086.stderr')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/tcfail086.stderr | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/testsuite/tests/typecheck/should_fail/tcfail086.stderr b/testsuite/tests/typecheck/should_fail/tcfail086.stderr index 65149ef1f9..f88fde164b 100644 --- a/testsuite/tests/typecheck/should_fail/tcfail086.stderr +++ b/testsuite/tests/typecheck/should_fail/tcfail086.stderr @@ -1,6 +1,6 @@ tcfail086.hs:6:38: Can't make a derived instance of ‘Eq Ex’: - Constructor ‘Ex’ must have a Haskell-98 type + Constructor ‘Ex’ has existentials or constraints in its type Possible fix: use a standalone deriving declaration instead In the data declaration for ‘Ex’ |