<entry><option>-XNoScopedTypeVariables</option></entry>
</row>
<row>
+ <entry><option>-XMonoLocalBinds</option></entry>
+ <entry>Enable <link linkend="mono-local-binds">do not generalise local bindings</link>.
+ </entry>
+ <entry>dynamic</entry>
+ <entry><option>-XNoMonoLocalBinds</option></entry>
+ </row>
+ <row>
<entry><option>-XTemplateHaskell</option></entry>
<entry>Enable <link linkend="template-haskell">Template Haskell</link>.
No longer implied by <option>-fglasgow-exts</option>.</entry>
</para>
</sect2>
+<sect2 id="mono-local-binds">
+<title>Monomorphic local bindings</title>
+<para>
+We are actively thinking of simplifying GHC's type system, by <emphasis>not generalising local bindings</emphasis>.
+The rationale is described in the paper
+<ulink url="http://research.microsoft.com/~simonpj/papers/constraints/index.htm">Let should not be generalised</ulink>.
+</para>
+<para>
+The experimental new behaviour is enabled by the flag <option>-XMonoLocalBinds</option>. The effect is
+that local (that is, non-top-level) bindings without a type signature are not generalised at all. You can
+think of it as an extreme (but much more predictable) version of the Monomorphism Restriction.
+If you supply a type signature, then the flag has no effect.
+</para>
+</sect2>
+
</sect1>
<!-- ==================== End of type system extensions ================= -->