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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2018-06-25 17:42:57 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2018-06-26 12:09:36 +0100 |
| commit | 261dd83cacec71edd551e9c581d05285c9ea3226 (patch) | |
| tree | 325b904128148fa6f865403b70f4c6e84ac54335 /testsuite/tests/quantified-constraints/all.T | |
| parent | e53c113dcfeca9ee957722ede3d8b6a2c4c751a1 (diff) | |
| download | haskell-261dd83cacec71edd551e9c581d05285c9ea3226.tar.gz | |
Fix TcLevel manipulation in TcDerivInfer.simplifyDeriv
The level numbers we were getting simply didn't obey the
invariant (ImplicInv) in TcType
Note [TcLevel and untouchable type variables]
That leads to chaos. Easy to fix. I improved the documentation.
I also added an assertion in TcSimplify that checks that
level numbers go up by 1 as we dive inside implications, so
that we catch the problem at source rather than than through
its obscure consequences.
That in turn showed up that TcRules was also generating
constraints that didn't obey (ImplicInv), so I fixed that too.
I have no idea what consequences were lurking behing that
bug, but anyway now it's fixed. Hooray.
Diffstat (limited to 'testsuite/tests/quantified-constraints/all.T')
| -rw-r--r-- | testsuite/tests/quantified-constraints/all.T | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/testsuite/tests/quantified-constraints/all.T b/testsuite/tests/quantified-constraints/all.T index 5f8547b5a8..65e636744f 100644 --- a/testsuite/tests/quantified-constraints/all.T +++ b/testsuite/tests/quantified-constraints/all.T @@ -13,3 +13,4 @@ test('T15231', normal, compile_fail, ['']) test('T15290', normal, compile, ['']) test('T15290a', normal, compile_fail, ['']) +test('T15290b', normal, compile_fail, ['']) |