Commit 769bfc73 authored by Austin Seipp's avatar Austin Seipp
Browse files

Mention new solver for -XTypeNats in release notes.


Signed-off-by: default avatarAustin Seipp <austin@well-typed.com>
parent bb532682
......@@ -28,6 +28,26 @@
</para>
</listitem>
<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
......
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