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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/T14000.hs | |
| 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/T14000.hs')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/T14000.hs | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_fail/T14000.hs b/testsuite/tests/typecheck/should_fail/T14000.hs new file mode 100644 index 0000000000..854a78b6ad --- /dev/null +++ b/testsuite/tests/typecheck/should_fail/T14000.hs @@ -0,0 +1,8 @@ +{-# LANGUAGE TypeFamilies #-} +module T14000 where + +class C a where + type T a + c :: a -> T a + +foo = c noSuchThing -- noSuchThing is not in scope |