diff options
Diffstat (limited to 'docs/users_guide/glasgow_exts.rst')
| -rw-r--r-- | docs/users_guide/glasgow_exts.rst | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/docs/users_guide/glasgow_exts.rst b/docs/users_guide/glasgow_exts.rst index 0ec5bd4f1c..e77a7c0243 100644 --- a/docs/users_guide/glasgow_exts.rst +++ b/docs/users_guide/glasgow_exts.rst @@ -2237,6 +2237,15 @@ Here are the details: will have its type variables ordered as ``m, a, b, c``. +- If any of the variables depend on other variables (that is, if some + of the variables are *kind* variables), the variables are reordered + so that kind variables come before type variables, preserving the + left-to-right order as much as possible. That is, GHC performs a + stable topological sort on the variables. + + For example: if we have ``bar :: Proxy (a :: (j, k)) -> b``, then + the variables are ordered ``j``, ``k``, ``a``, ``b``. + - Class methods' type arguments include the class type variables, followed by any variables an individual method is polymorphic in. So, ``class Monad m where return :: a -> m a`` means |