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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2017-05-19 10:50:35 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2017-05-19 10:54:55 +0100 |
| commit | 433b80dec1cfef787fc1327a9eada1791b11c12e (patch) | |
| tree | 786621c3d42147db996738242d2c5492f8e0068e /testsuite/tests/gadt | |
| parent | 7b52525ecb2a09b21e7e5393f45a72ed1dfa3bc8 (diff) | |
| download | haskell-433b80dec1cfef787fc1327a9eada1791b11c12e.tar.gz | |
Ensure that insolubles are fully rewritten
I was alerted to this by Trac #12468 and #11325. We were treating
insolubles (and "hole" constraints are treated as insoluble)
inconsistently. In some places we were carefully rewriting them
e.g. Note [Make sure that insolubles are fully rewritten] in
TcCanonical. But in TcSimplify we weren't feeding them into
the solver.
As a result, "hole" constraints were not being rewritten, which
some users found confusing, and I think rightly so.
This patch also fixes a bug in TcSMonad.emitInsoluble, in which two
different "hole" constriants could be treated (bogusly) as duplicates,
thereby losing one.
Diffstat (limited to 'testsuite/tests/gadt')
| -rw-r--r-- | testsuite/tests/gadt/T12468.hs | 9 | ||||
| -rw-r--r-- | testsuite/tests/gadt/T12468.stderr | 6 | ||||
| -rw-r--r-- | testsuite/tests/gadt/all.T | 1 |
3 files changed, 16 insertions, 0 deletions
diff --git a/testsuite/tests/gadt/T12468.hs b/testsuite/tests/gadt/T12468.hs new file mode 100644 index 0000000000..a147c09fa6 --- /dev/null +++ b/testsuite/tests/gadt/T12468.hs @@ -0,0 +1,9 @@ +{-# LANGUAGE GADTs #-} + +module T12468 where + +data T a where + I :: T Int + +f :: T a -> a +f I = _ diff --git a/testsuite/tests/gadt/T12468.stderr b/testsuite/tests/gadt/T12468.stderr new file mode 100644 index 0000000000..729b5c45b0 --- /dev/null +++ b/testsuite/tests/gadt/T12468.stderr @@ -0,0 +1,6 @@ + +T12468.hs:9:7: error: + • Found hole: _ :: Int + • In the expression: _ + In an equation for ‘f’: f I = _ + • Relevant bindings include f :: T a -> a (bound at T12468.hs:9:1) diff --git a/testsuite/tests/gadt/all.T b/testsuite/tests/gadt/all.T index d29fa8e4b0..877943b0c5 100644 --- a/testsuite/tests/gadt/all.T +++ b/testsuite/tests/gadt/all.T @@ -112,3 +112,4 @@ test('T7974', normal, compile, ['']) test('T7558', normal, compile_fail, ['']) test('T9096', normal, compile, ['']) test('T9380', normal, compile_and_run, ['']) +test('T12468', normal, compile_fail, ['']) |