Validate inferred theta. Fixes #8883

This checks that all the required extensions are enabled for the
inferred type signature.

Updates binary and vector submodules.

12 files changed, 38 insertions, 9 deletions

diff --git a/testsuite/tests/indexed-types/should_compile/ColInference6.hs b/testsuite/tests/indexed-types/should_compile/ColInference6.hs
index 9273632e2b..bc15aa1dbf 100644
--- a/testsuite/tests/indexed-types/should_compile/ColInference6.hs
+++ b/testsuite/tests/indexed-types/should_compile/ColInference6.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeFamilies, FlexibleContexts #-}
 
 module ColInference6  where 
 
diff --git a/testsuite/tests/indexed-types/should_compile/IndTypesPerf.hs b/testsuite/tests/indexed-types/should_compile/IndTypesPerf.hs
index 4edcd03988..30c92c3a88 100644
--- a/testsuite/tests/indexed-types/should_compile/IndTypesPerf.hs
+++ b/testsuite/tests/indexed-types/should_compile/IndTypesPerf.hs
@@ -2,6 +2,8 @@
 -- This used lots of memory, and took a long time to compile, with GHC 6.12:
 -- http://www.haskell.org/pipermail/glasgow-haskell-users/2010-May/018835.html
 
+{-# LANGUAGE FlexibleContexts, TypeFamilies #-}
+
 module IndTypesPerf where
 
 import IndTypesPerfMerge
diff --git a/testsuite/tests/indexed-types/should_compile/IndTypesPerfMerge.hs b/testsuite/tests/indexed-types/should_compile/IndTypesPerfMerge.hs
index 18ed35bdc1..dbba60d595 100644
--- a/testsuite/tests/indexed-types/should_compile/IndTypesPerfMerge.hs
+++ b/testsuite/tests/indexed-types/should_compile/IndTypesPerfMerge.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE EmptyDataDecls, TypeFamilies, UndecidableInstances,
              ScopedTypeVariables, OverlappingInstances, TypeOperators,
              FlexibleInstances, NoMonomorphismRestriction,
-             MultiParamTypeClasses #-}
+             MultiParamTypeClasses, FlexibleContexts #-}
 module IndTypesPerfMerge where
 
 data a :* b = a :* b
diff --git a/testsuite/tests/perf/should_run/T2902_A.hs b/testsuite/tests/perf/should_run/T2902_A.hs
index c0939104f3..cb2cec990c 100644
--- a/testsuite/tests/perf/should_run/T2902_A.hs
+++ b/testsuite/tests/perf/should_run/T2902_A.hs
@@ -1,5 +1,5 @@
 
-{-# LANGUAGE UnicodeSyntax #-}
+{-# LANGUAGE UnicodeSyntax, FlexibleContexts #-}
 
 module Main (main) where
 
diff --git a/testsuite/tests/perf/should_run/T2902_B.hs b/testsuite/tests/perf/should_run/T2902_B.hs
index c6558c625b..65cb1a6a90 100644
--- a/testsuite/tests/perf/should_run/T2902_B.hs
+++ b/testsuite/tests/perf/should_run/T2902_B.hs
@@ -1,5 +1,5 @@
 
-{-# LANGUAGE UnicodeSyntax #-}
+{-# LANGUAGE UnicodeSyntax, FlexibleContexts #-}
 
 module Main (main) where
 
diff --git a/testsuite/tests/perf/should_run/T5113.hs b/testsuite/tests/perf/should_run/T5113.hs
index e87bcb6cad..6ad6750aab 100644
--- a/testsuite/tests/perf/should_run/T5113.hs
+++ b/testsuite/tests/perf/should_run/T5113.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE BangPatterns, FlexibleContexts #-}
 module Main where
 
 import Data.Array.Base (unsafeRead, unsafeWrite)
diff --git a/testsuite/tests/rebindable/DoRestrictedM.hs b/testsuite/tests/rebindable/DoRestrictedM.hs
index dea2b1ea03..2e982c1532 100644
--- a/testsuite/tests/rebindable/DoRestrictedM.hs
+++ b/testsuite/tests/rebindable/DoRestrictedM.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE RebindableSyntax, MultiParamTypeClasses,
-             FlexibleInstances #-}
+             FlexibleInstances, FlexibleContexts #-}
 
 -- Tests of the do-notation for the restricted monads
 -- We demonstrate that all ordinary monads are restricted monads,
diff --git a/testsuite/tests/typecheck/should_compile/tc168.hs b/testsuite/tests/typecheck/should_compile/tc168.hs
index 0aa56d169a..bd515331c4 100644
--- a/testsuite/tests/typecheck/should_compile/tc168.hs
+++ b/testsuite/tests/typecheck/should_compile/tc168.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE MultiParamTypeClasses, FlexibleContexts #-}
 
 -- We want to get the type
 --   	g :: forall a b c.  C a (b,c) => a -> b
diff --git a/testsuite/tests/typecheck/should_compile/tc231.hs b/testsuite/tests/typecheck/should_compile/tc231.hs
index 304748994b..a7270ef769 100644
--- a/testsuite/tests/typecheck/should_compile/tc231.hs
+++ b/testsuite/tests/typecheck/should_compile/tc231.hs
@@ -1,5 +1,5 @@
 {-# OPTIONS_GHC -ddump-types #-}
-{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies #-}
+{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleContexts #-}
 
 -- See Trac #1456
 
diff --git a/testsuite/tests/typecheck/should_fail/T8883.hs b/testsuite/tests/typecheck/should_fail/T8883.hs
new file mode 100644
index 0000000000..5b0fc5922c
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T8883.hs
@@ -0,0 +1,20 @@
+{-# LANGUAGE TypeFamilies #-}
+
+-- Trac #8883
+
+module T8883 where
+
+type family PF a :: * -> *
+
+class Regular a where
+  from :: a -> PF a a
+
+-- For fold we infer following type signature:
+--
+-- fold :: (Functor (PF a), Regular a) => (PF a b -> b) -> a -> b
+--
+-- However, this signature requires FlexibleContexts since the first
+-- type-class constraint is not of the form (class type-variable) nor
+-- (class (type-variable type1 type2 ... typen)). Since this extension
+-- is not enabled compilation should fail.
+fold f = f . fmap (fold f) . from
diff --git a/testsuite/tests/typecheck/should_fail/T8883.stderr b/testsuite/tests/typecheck/should_fail/T8883.stderr
new file mode 100644
index 0000000000..0ea136869b
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T8883.stderr
@@ -0,0 +1,7 @@
+
+
+T8883.hs:17:1:
+    Non type-variable argument in the constraint: Functor (PF a)
+    (Use FlexibleContexts to permit this)
+    In the context: (Regular a, Functor (PF a))
+    While checking the inferred type for ‘fold’
diff --git a/testsuite/tests/typecheck/should_fail/tcfail093.hs b/testsuite/tests/typecheck/should_fail/tcfail093.hs
index 9c2d8ea80a..1f2063a1c2 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail093.hs
+++ b/testsuite/tests/typecheck/should_fail/tcfail093.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,
-             FlexibleInstances, UndecidableInstances #-}
+             FlexibleInstances, UndecidableInstances, FlexibleContexts #-}
 -- UndecidableInstances now needed because the Coverage Condition fails
 
 module ShouldFail where