Mention that generalised list comprehensions are enabled with -XTransformListComp

[ghc-hetmet.git] / docs / users_guide / using.xml

diff --git a/docs/users_guide/using.xml b/docs/users_guide/using.xml
index f769d28..fad30ac 100644 (file)
--- a/docs/users_guide/using.xml
+++ b/docs/users_guide/using.xml
@@ -120,7 +120,7 @@ module X where
        <listitem>
          <para>Most non-mode flags fall into this category.  A dynamic flag
            may be used on the command line, in a
-           <literal>GHC_OPTIONS</literal> pragma in a source file, or set
+           <literal>OPTIONS_GHC</literal> pragma in a source file, or set
            using <literal>:set</literal> in GHCi.</para>
        </listitem>
       </varlistentry>
@@ -1175,6 +1175,11 @@ f foo = foo { x = 6 }
           typographical errors that turn into hard-to-find bugs, e.g.,
           in the inadvertent capture of what would be a recursive call in
           <literal>f = ... let f = id in ... f ...</literal>.</para>
+          <para>The warning is suppressed for names beginning with an underscore.  For example
+          <programlisting>
+             f x = do { _ignore &lt;- this; _ignore &lt;- that; return (the other) }
+          </programlisting>
+         </para>
        </listitem>
       </varlistentry>