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| author | RyanGlScott <ryan.gl.scott@gmail.com> | 2016-05-11 15:57:24 +0200 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2016-05-12 15:39:30 +0200 |
| commit | e53f2180e89652c72e51ffa614c56294ba67cf37 (patch) | |
| tree | d55760338985aebb5c3ba879e32b0ec9d825b6de /testsuite | |
| parent | c079de3c43704ea88f592e441389e520313e30ad (diff) | |
| download | haskell-e53f2180e89652c72e51ffa614c56294ba67cf37.tar.gz | |
Fix deriveTyData's kind unification when two kind variables are unified
When `deriveTyData` attempts to unify two kind variables (which can
happen if both the typeclass and the datatype are poly-kinded), it
mistakenly adds an extra mapping to its substitution which causes the
unification to fail when applying the substitution. This can be
prevented by checking both the domain and the range of the original
substitution to see which kind variables shouldn't be put into the
domain of the substitution. A more in-depth explanation is included in
`Note [Unification of two kind variables in deriving]`.
Fixes #11837.
Test Plan: ./validate
Reviewers: simonpj, hvr, goldfire, niteria, austin, bgamari
Reviewed By: bgamari
Subscribers: niteria, thomie
Differential Revision: https://phabricator.haskell.org/D2117
GHC Trac Issues: #11837
Diffstat (limited to 'testsuite')
| -rw-r--r-- | testsuite/tests/deriving/should_compile/T11837.hs | 9 | ||||
| -rw-r--r-- | testsuite/tests/deriving/should_compile/all.T | 1 |
2 files changed, 10 insertions, 0 deletions
diff --git a/testsuite/tests/deriving/should_compile/T11837.hs b/testsuite/tests/deriving/should_compile/T11837.hs new file mode 100644 index 0000000000..917f9cb5cb --- /dev/null +++ b/testsuite/tests/deriving/should_compile/T11837.hs @@ -0,0 +1,9 @@ +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE PolyKinds #-} +module T11837 where + +class Category (cat :: k -> k -> *) where + catId :: cat a a + catComp :: cat b c -> cat a b -> cat a c + +newtype T (c :: k -> k -> *) a b = MkT (c a b) deriving Category diff --git a/testsuite/tests/deriving/should_compile/all.T b/testsuite/tests/deriving/should_compile/all.T index 07242ec694..9017687b07 100644 --- a/testsuite/tests/deriving/should_compile/all.T +++ b/testsuite/tests/deriving/should_compile/all.T @@ -70,3 +70,4 @@ test('T11732a', normal, compile, ['']) test('T11732b', normal, compile, ['']) test('T11732c', normal, compile, ['']) test('T11833', normal, compile, ['']) +test('T11837', normal, compile, ['']) |