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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/deriving | |
| 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/deriving')
| -rw-r--r-- | testsuite/tests/deriving/should_compile/T8678.hs | 12 | ||||
| -rw-r--r-- | testsuite/tests/deriving/should_compile/all.T | 3 | ||||
| -rw-r--r-- | testsuite/tests/deriving/should_fail/T3101.stderr | 2 |
3 files changed, 15 insertions, 2 deletions
diff --git a/testsuite/tests/deriving/should_compile/T8678.hs b/testsuite/tests/deriving/should_compile/T8678.hs new file mode 100644 index 0000000000..655f530b5b --- /dev/null +++ b/testsuite/tests/deriving/should_compile/T8678.hs @@ -0,0 +1,12 @@ +{-# LANGUAGE DataKinds, DeriveFunctor, FlexibleInstances, GADTs, KindSignatures, StandaloneDeriving #-} +module T8678 where + +data {- kind -} Nat = Z | S Nat + +-- GADT in parameter other than the last +data NonStandard :: Nat -> * -> * -> * where + Standard :: a -> NonStandard (S n) a b + Non :: NonStandard n a b -> b -> NonStandard (S n) a b + +deriving instance (Show a, Show b) => Show (NonStandard n a b) +deriving instance Functor (NonStandard n a) diff --git a/testsuite/tests/deriving/should_compile/all.T b/testsuite/tests/deriving/should_compile/all.T index 8620c36dc5..5d9c7337f1 100644 --- a/testsuite/tests/deriving/should_compile/all.T +++ b/testsuite/tests/deriving/should_compile/all.T @@ -44,4 +44,5 @@ test('AutoDeriveTypeable', normal, compile, ['']) test('T8138', reqlib('primitive'), compile, ['-O2']) test('T8631', normal, compile, ['']) test('T8758', extra_clean(['T8758a.o', 'T8758a.hi']), multimod_compile, ['T8758a', '-v0']) -test('T8851', expect_broken(8851), compile, [''])
\ No newline at end of file +test('T8851', expect_broken(8851), compile, ['']) +test('T8678', normal, compile, ['']) diff --git a/testsuite/tests/deriving/should_fail/T3101.stderr b/testsuite/tests/deriving/should_fail/T3101.stderr index 58069283dc..7c976178c4 100644 --- a/testsuite/tests/deriving/should_fail/T3101.stderr +++ b/testsuite/tests/deriving/should_fail/T3101.stderr @@ -1,6 +1,6 @@ T3101.hs:9:12: Can't make a derived instance of ‘Show Boom’: - Constructor ‘Boom’ must have a Haskell-98 type + Constructor ‘Boom’ has a higher-rank type Possible fix: use a standalone deriving declaration instead In the data declaration for ‘Boom’ |