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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/users_guide/9.6.1-notes.rst | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/docs/users_guide/9.6.1-notes.rst b/docs/users_guide/9.6.1-notes.rst index f66ba9e06a..54f4a3fed2 100644 --- a/docs/users_guide/9.6.1-notes.rst +++ b/docs/users_guide/9.6.1-notes.rst @@ -68,6 +68,16 @@ Language :extension:`TypeData`. This extension permits ``type data`` declarations as a more fine-grained alternative to :extension:`DataKinds`. +- GHC now does a better job of solving constraints in the presence of multiple + matching quantified constraints. For example, if we want to solve + ``C a b Int`` and we have matching quantified constraints: :: + + forall x y z. (Ord x, Enum y, Num z) => C x y z + forall u v. (Enum v, Eq u) => C u v Int + + Then GHC will use the second quantified constraint to solve ``C a b Int``, + as it has a strictly weaker precondition. + Compiler ~~~~~~~~ |