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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2017-07-27 14:52:38 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2017-07-28 09:31:55 +0100 |
| commit | 452755de717fad5d8fbfc6330cb42a3335c8912d (patch) | |
| tree | 9907deeb28850a6f98322b7ef3386828baed4b2a /testsuite/tests/typecheck/should_fail/T8142.stderr | |
| parent | b1317a35770b19838c7f6b07e794bfc61419e889 (diff) | |
| download | haskell-452755de717fad5d8fbfc6330cb42a3335c8912d.tar.gz | |
Do not discard insolubles in implications
Trac #14000 showed up two errors
* In TcRnTypes.dropInsolubles we dropped all implications, which
might contain the very insolubles we wanted to keep. This was
an outright error, and is why the out-of-scope error was actually
lost altogether in Trac #14000
* In TcSimplify.simplifyInfer, if there are definite (insoluble)
errors, it's better to suppress the following ambiguity test,
because the type may be bogus anyway. See TcSimplify
Note [Quantification with errors]. This fix seems a bit clunky,
but it'll do for now.
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/T8142.stderr')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/T8142.stderr | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/testsuite/tests/typecheck/should_fail/T8142.stderr b/testsuite/tests/typecheck/should_fail/T8142.stderr index aec8b3b55c..25d60d1aff 100644 --- a/testsuite/tests/typecheck/should_fail/T8142.stderr +++ b/testsuite/tests/typecheck/should_fail/T8142.stderr @@ -1,16 +1,24 @@ -T8142.hs:6:18: error: - • Couldn't match type ‘Nu g0’ with ‘Nu g’ - Expected type: Nu ((,) a) -> Nu g +T8142.hs:6:10: error: + • Couldn't match type ‘Nu ((,) a0)’ with ‘c -> f c’ + Expected type: (c -> f c) -> c -> f c Actual type: Nu ((,) a0) -> Nu g0 - NB: ‘Nu’ is a type function, and may not be injective - The type variable ‘g0’ is ambiguous - • In the ambiguity check for the inferred type for ‘h’ - To defer the ambiguity check to use sites, enable AllowAmbiguousTypes - When checking the inferred type - h :: forall a (g :: * -> *). Nu ((,) a) -> Nu g + The type variable ‘a0’ is ambiguous + • In the expression: h In an equation for ‘tracer’: tracer = h where h = (\ (_, b) -> ((outI . fmap h) b)) . out + • Relevant bindings include + tracer :: (c -> f c) -> c -> f c (bound at T8142.hs:6:1) + +T8142.hs:6:57: error: + • Couldn't match type ‘Nu ((,) a)’ with ‘g (Nu ((,) a))’ + Expected type: Nu ((,) a) -> (a, g (Nu ((,) a))) + Actual type: Nu ((,) a) -> (a, Nu ((,) a)) + • In the second argument of ‘(.)’, namely ‘out’ + In the expression: (\ (_, b) -> ((outI . fmap h) b)) . out + In an equation for ‘h’: h = (\ (_, b) -> ((outI . fmap h) b)) . out + • Relevant bindings include + h :: Nu ((,) a) -> Nu g (bound at T8142.hs:6:18) |