[commit: ghc] wip/users-guide-kind-inference: User's Guide: remove outdated info on kind inference (3086222)

git at git.haskell.org git at git.haskell.org
Fri Feb 22 15:22:03 UTC 2019


Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/users-guide-kind-inference
Link       : http://ghc.haskell.org/trac/ghc/changeset/308622279b7f5c03e1af0199c48bb65ab3e72af5/ghc

>---------------------------------------------------------------

commit 308622279b7f5c03e1af0199c48bb65ab3e72af5
Author: Vladislav Zavialov <vlad.z.4096 at gmail.com>
Date:   Fri Feb 22 15:49:20 2019 +0300

    User's Guide: remove outdated info on kind inference
    
    We no longer put class variables in front,
    see "Taming the Kind Inference Monster"
    
    (also fix some markup issues)


>---------------------------------------------------------------

308622279b7f5c03e1af0199c48bb65ab3e72af5
 docs/users_guide/glasgow_exts.rst | 40 +++++++++------------------------------
 1 file changed, 9 insertions(+), 31 deletions(-)

diff --git a/docs/users_guide/glasgow_exts.rst b/docs/users_guide/glasgow_exts.rst
index c3090b0..978ae4e 100644
--- a/docs/users_guide/glasgow_exts.rst
+++ b/docs/users_guide/glasgow_exts.rst
@@ -8881,18 +8881,18 @@ using kind signatures: ::
 
 The general principle is this:
 
--  *When there is a right-hand side, GHC infers the most polymorphic
-   kind consistent with the right-hand side.* Examples: ordinary data
+-  When there is a right-hand side, GHC infers the most polymorphic
+   kind consistent with the right-hand side. Examples: ordinary data
    type and GADT declarations, class declarations. In the case of a
    class declaration the role of "right hand side" is played by the
    class method signatures.
 
--  *When there is no right hand side, GHC defaults argument and result
-   kinds to ``Type``, except when directed otherwise by a kind signature*.
+-  When there is no right hand side, GHC defaults argument and result
+   kinds to ``Type``, except when directed otherwise by a kind signature.
    Examples: data and open type family declarations.
 
 This rule has occasionally-surprising consequences (see
-:ghc-ticket:`10132`. ::
+:ghc-ticket:`10132`). ::
 
     class C a where    -- Class declarations are generalised
                        -- so C :: forall k. k -> Constraint
@@ -8956,28 +8956,6 @@ is implicitly declared in ``c``\'s kind. Thus, according to our general
 principle, ``b`` must come *before* ``k``. However, ``b`` *depends on*
 ``k``. We thus reject ``T2`` with a suitable error message.
 
-In keeping with the way that class methods list their class variables
-first, associated types also list class variables before others. This
-means that the inferred variables from the class come before the
-specified variables from the class, which come before other implicitly
-bound variables. Here is an example::
-
-  class C (a :: k) b where
-    type F (c :: j) (d :: Proxy m) a b
-
-We infer these kinds::
-
-  C :: forall {k2 :: Type} (k :: Type). k -> k2 -> Constraint
-  F :: forall {k2 :: Type} (k :: Type)
-              {k3 :: Type} (j :: Type) (m :: k3).
-	      j -> Proxy m -> k -> k2 -> Type
-
-The "general principle" described here is meant to make all this more
-predictable for users. It would not be hard to extend GHC to relax
-this principle. If you should want a change here, consider writing
-a `proposal <https://github.com/ghc-proposals/ghc-proposals/>`_ to
-do so.
-
 .. index::
    single: CUSK
    single: complete user-supplied kind signature
@@ -9411,8 +9389,8 @@ Here are the key definitions, all available from ``GHC.Exts``: ::
   data RuntimeRep = LiftedRep     -- for things like `Int`
                   | UnliftedRep   -- for things like `Array#`
                   | IntRep        -- for `Int#`
-		  | TupleRep [RuntimeRep]  -- unboxed tuples, indexed by the representations of the elements
-		  | SumRep [RuntimeRep]    -- unboxed sums, indexed by the representations of the disjuncts
+                  | TupleRep [RuntimeRep]  -- unboxed tuples, indexed by the representations of the elements
+                  | SumRep [RuntimeRep]    -- unboxed sums, indexed by the representations of the disjuncts
                   | ...
 
   type Type = TYPE LiftedRep    -- Type is just an ordinary type synonym
@@ -10797,11 +10775,11 @@ application. This isn't true, however! Be sure to use :ghci-cmd:`:type +v`
 if you want the most accurate information with respect to visible type
 application properties.
 
-.. _ScopedSort:
-
 .. index::
    single: ScopedSort
 
+.. _ScopedSort:
+
 Ordering of specified variables
 -------------------------------
 



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