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| author | Richard Eisenberg <rae@richarde.dev> | 2019-12-11 15:58:56 +0000 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2020-01-12 21:29:27 -0500 |
| commit | 350e2b78788d47255d27489dfc62d664498b5de4 (patch) | |
| tree | 50f2f1982c9f120e6b8aac1970579d34333cd16a /docs | |
| parent | 9129210f7e9937c1065330295f06524661575839 (diff) | |
| download | haskell-350e2b78788d47255d27489dfc62d664498b5de4.tar.gz | |
Don't zap to Any; error instead
This changes GHC's treatment of so-called Naughty Quantification
Candidates to issue errors, instead of zapping to Any.
Close #16775.
No new test cases, because existing ones cover this well.
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/users_guide/8.12.1-notes.rst | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/docs/users_guide/8.12.1-notes.rst b/docs/users_guide/8.12.1-notes.rst index 70bb901b07..5cd7131fac 100644 --- a/docs/users_guide/8.12.1-notes.rst +++ b/docs/users_guide/8.12.1-notes.rst @@ -18,6 +18,12 @@ Full details Language ~~~~~~~~ +* In obscure scenarios, GHC now rejects programs it previously accepted, but + with unhelpful types. For example, if (with ``-XPartialTypeSignatures``) you + were to write ``x :: forall (f :: forall a (b :: a -> Type). b _). f _``, GHC previously + would have accepted ``x``, but its type would have involved the mysterious ``Any`` + internal type family. Now, GHC rejects, explaining the situation. + Compiler ~~~~~~~~ |