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| author | Richard Eisenberg <rae@cs.brynmawr.edu> | 2018-11-01 18:03:21 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2018-11-02 11:00:36 -0400 |
| commit | 41f0f6c2f571ea05c49f9f6ed64beebdc5a9f9fc (patch) | |
| tree | dfe05f6c60bb0743d274cc355f28effb5c30dfde | |
| parent | 7a439e7b13f350e1ac6163f1bfa60e30924dbeea (diff) | |
| download | haskell-41f0f6c2f571ea05c49f9f6ed64beebdc5a9f9fc.tar.gz | |
Don't lint erroneous programs.ghc-8.6.2-release
newFamInst lints its types. This is good. But it's not so good
when there have been errors and thus recovery tycons are about.
So we now don't.
Fixes #15796.
Test case: typecheck/should_fail/T15796
(cherry picked from commit 1f72a1c81368e34387aac38c0b1c59521cec58ec)
| -rw-r--r-- | compiler/typecheck/FamInst.hs | 7 | ||||
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/T15796.hs | 8 | ||||
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/T15796.stderr | 6 | ||||
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/all.T | 1 |
4 files changed, 20 insertions, 2 deletions
diff --git a/compiler/typecheck/FamInst.hs b/compiler/typecheck/FamInst.hs index 00602ecba5..eff33e3210 100644 --- a/compiler/typecheck/FamInst.hs +++ b/compiler/typecheck/FamInst.hs @@ -150,7 +150,7 @@ See #9562. -- It is defined here to avoid a dependency from FamInstEnv on the monad -- code. -newFamInst :: FamFlavor -> CoAxiom Unbranched -> TcRnIf gbl lcl FamInst +newFamInst :: FamFlavor -> CoAxiom Unbranched -> TcM FamInst -- Freshen the type variables of the FamInst branches newFamInst flavor axiom@(CoAxiom { co_ax_tc = fam_tc }) = ASSERT2( tyCoVarsOfTypes lhs `subVarSet` tcv_set, text "lhs" <+> pp_ax ) @@ -162,7 +162,10 @@ newFamInst flavor axiom@(CoAxiom { co_ax_tc = fam_tc }) ; let lhs' = substTys subst lhs rhs' = substTy subst rhs tcvs' = tvs' ++ cvs' - ; when (gopt Opt_DoCoreLinting dflags) $ + ; ifErrsM (return ()) $ -- Don't lint when there are errors, because + -- errors might mean TcTyCons. + -- See Note [Recover from validity error] in TcTyClsDecls + when (gopt Opt_DoCoreLinting dflags) $ -- Check that the types involved in this instance are well formed. -- Do /not/ expand type synonyms, for the reasons discussed in -- Note [Linting type synonym applications]. diff --git a/testsuite/tests/typecheck/should_fail/T15796.hs b/testsuite/tests/typecheck/should_fail/T15796.hs new file mode 100644 index 0000000000..450064d4cc --- /dev/null +++ b/testsuite/tests/typecheck/should_fail/T15796.hs @@ -0,0 +1,8 @@ +{-# LANGUAGE GADTs #-} +{-# LANGUAGE TypeFamilies #-} +module Bug where + +newtype N a where + MkN :: Show a => a -> N a +type family T a +type instance T (N a) = N a diff --git a/testsuite/tests/typecheck/should_fail/T15796.stderr b/testsuite/tests/typecheck/should_fail/T15796.stderr new file mode 100644 index 0000000000..3aa7ae8d65 --- /dev/null +++ b/testsuite/tests/typecheck/should_fail/T15796.stderr @@ -0,0 +1,6 @@ + +T15796.hs:6:3: error: + • A newtype constructor cannot have a context in its type + MkN :: forall a. Show a => a -> N a + • In the definition of data constructor ‘MkN’ + In the newtype declaration for ‘N’ diff --git a/testsuite/tests/typecheck/should_fail/all.T b/testsuite/tests/typecheck/should_fail/all.T index e12aba6362..1b635cf614 100644 --- a/testsuite/tests/typecheck/should_fail/all.T +++ b/testsuite/tests/typecheck/should_fail/all.T @@ -477,3 +477,4 @@ test('T15067', normal, compile_fail, ['']) test('T15361', normal, compile_fail, ['']) test('T15527', normal, compile_fail, ['']) test('T15767', normal, compile_fail, ['']) +test('T15796', normal, compile_fail, ['']) |