You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
Copy file name to clipboardExpand all lines: message-index/messages/GHC-97044/index.md
+1-2Lines changed: 1 addition & 2 deletions
Display the source diff
Display the rich diff
Original file line number
Diff line number
Diff line change
@@ -13,12 +13,11 @@ instance Coercible A B where ...
13
13
```
14
14
will lead to this error being reported.
15
15
16
-
The instances for these type classes are automatically created by GHC on as-needed basis.
16
+
The instances for these type classes are automatically created by GHC on an as-needed basis.
17
17
18
18
This restriction applies to the following type classes:
19
19
20
20
-[Coercible](https://hackage.haskell.org/package/base/docs/Data-Coerce.html#t:Coercible) - This class does not have regular instances; instead they are created on-the-fly during type-checking.
21
-
-[HasField](https://hackage.haskell.org/package/base/docs/GHC-Records.html#t:HasField) - This class is used by [OverloadedRecordDot](https://downloads.haskell.org/ghc/latest/docs/users_guide/exts/overloaded_record_dot.html) and related extensions.
22
21
-[Typeable](https://hackage.haskell.org/package/base/docs/Type-Reflection.html#t:Typeable) - Since GHC 7.10, all types automatically have `Typeable` instances derived. This is in contrast to previous releases where Typeable had to be explicitly derived using the DeriveDataTypeable language extension.
23
22
- Type equality classes `~` and `~~` defined in [Data.Type.Equality](https://hackage.haskell.org/package/base/docs/Data-Type-Equality.html)
24
23
-[WithDict](https://hackage.haskell.org/package/base/docs/GHC-Exts.html#t:WithDict) - is used to create dictionaries for classes with a single method. It is used to implement a primitive that we cannot define in Haskell but we can write in Core. Some details can be found in a [Note in GHC library](https://hackage.haskell.org/package/ghc-9.6.1/docs/src/GHC.Tc.Instance.Class.html#line-493)
0 commit comments