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author | Simon Peyton Jones <simonpj@microsoft.com> | 2017-10-11 16:17:41 +0100 |
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committer | Ben Gamari <ben@smart-cactus.org> | 2017-11-06 18:20:07 -0500 |
commit | a05d71a73048df005c924f023607005a327e2adf (patch) | |
tree | 30362c61f76c5952e867deb4d58b7efef7e78537 | |
parent | 913ffc0cbc8f76f4bba88e8faea5e9b3ffd4677d (diff) | |
download | haskell-a05d71a73048df005c924f023607005a327e2adf.tar.gz |
Add a missing zonk in TcDerivInfer.simplifyDeriv
I'm astonished that anything worked without this!
Fixes Trac #14339
(cherry picked from commit 13fdca3d174ff15ac347c5db78370f457a3013ee)
-rw-r--r-- | compiler/typecheck/TcDerivInfer.hs | 2 | ||||
-rw-r--r-- | testsuite/tests/deriving/should_compile/T14339.hs | 17 | ||||
-rw-r--r-- | testsuite/tests/deriving/should_compile/all.T | 1 |
3 files changed, 20 insertions, 0 deletions
diff --git a/compiler/typecheck/TcDerivInfer.hs b/compiler/typecheck/TcDerivInfer.hs index 93dcf4383c..bbd054cb93 100644 --- a/compiler/typecheck/TcDerivInfer.hs +++ b/compiler/typecheck/TcDerivInfer.hs @@ -622,6 +622,8 @@ simplifyDeriv pred tvs thetas -- Simplify the constraints ; solved_implics <- runTcSDeriveds $ solveWantedsAndDrop $ unionsWC wanteds + -- It's not yet zonked! Obviously zonk it before peering at it + ; solved_implics <- zonkWC solved_implics -- See [STEP DAC HOIST] -- Split the resulting constraints into bad and good constraints, diff --git a/testsuite/tests/deriving/should_compile/T14339.hs b/testsuite/tests/deriving/should_compile/T14339.hs new file mode 100644 index 0000000000..e2521f2de0 --- /dev/null +++ b/testsuite/tests/deriving/should_compile/T14339.hs @@ -0,0 +1,17 @@ +{-# LANGUAGE DataKinds #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE UndecidableInstances #-} +module Bug where + +import GHC.TypeLits + +newtype Baz = Baz Foo + deriving Bar + +newtype Foo = Foo Int + +class Bar a where + bar :: a + +instance (TypeError (Text "Boo")) => Bar Foo where + bar = undefined diff --git a/testsuite/tests/deriving/should_compile/all.T b/testsuite/tests/deriving/should_compile/all.T index 5f94f9d7e4..86648d3edf 100644 --- a/testsuite/tests/deriving/should_compile/all.T +++ b/testsuite/tests/deriving/should_compile/all.T @@ -89,3 +89,4 @@ test('T13272', normal, compile, ['']) test('T13272a', normal, compile, ['']) test('T13297', normal, compile, ['']) test('T14331', normal, compile, ['']) +test('T14339', normal, compile, ['']) |