[commit: ghc] master: Mention new solver for -XTypeNats in release notes. (769bfc7)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/769bfc7332a89e8f022e3c1b9f5ba3a2a13f88c6/ghc

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

commit 769bfc7332a89e8f022e3c1b9f5ba3a2a13f88c6
Author: Austin Seipp <austin at well-typed.com>
Date:   Sun Sep 15 16:06:30 2013 -0500

    Mention new solver for -XTypeNats in release notes.
    
    Signed-off-by: Austin Seipp <austin at well-typed.com>


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

769bfc7332a89e8f022e3c1b9f5ba3a2a13f88c6
 docs/users_guide/7.8.1-notes.xml |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/docs/users_guide/7.8.1-notes.xml b/docs/users_guide/7.8.1-notes.xml
index 3d045bc..40b48d1 100644
--- a/docs/users_guide/7.8.1-notes.xml
+++ b/docs/users_guide/7.8.1-notes.xml
@@ -30,6 +30,26 @@
 
         <listitem>
             <para>
+                GHC can now perform simple evaluation of type-level
+                natural numbers, when using the
+                <literal>TypeNats</literal> extension. For example,
+                given a type-level constraint such as <literal>(x + 3)
+                ~ 5</literal>, GHC is able to infer that
+                <literal>x</literal> is 2. Similarly, GHC can now
+                understand type-level identities such as <literal>x +
+                0 ~ x</literal>.
+           </para>
+
+            <para>
+                Note that the solving of these equations is only used
+                to resolve unification variables - it does not
+                generate new facts in the type checker. This is
+                similar to how functional dependencies work.
+           </para>
+       </listitem>
+
+        <listitem>
+            <para>
                 It is now possible to declare a 'closed' <literal>type
                 family</literal> when using the
                 <literal>TypeFamilies</literal> extension. A closed