Improve documentation for -fwarn-incomplete-patterns

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

diff --git a/docs/users_guide/using.xml b/docs/users_guide/using.xml
index 9d7875a..a4c673c 100644 (file)
--- a/docs/users_guide/using.xml
+++ b/docs/users_guide/using.xml
@@ -1175,6 +1175,21 @@ foreign import "&f" f :: FunPtr t
       </varlistentry>
 
       <varlistentry>
+        <term><option>-fwarn-identities</option>:</term>
+       <listitem>
+          <indexterm><primary><option>-fwarn-identities</option></primary></indexterm>
+          <para>Causes the compiler to emit a warning when a Prelude numeric
+            conversion converts a type T to the same type T; such calls
+            are probably no-ops and can be omitted.  The functions checked for
+            are: <literal>toInteger</literal>,
+            <literal>toRational</literal>,
+            <literal>fromIntegral</literal>,
+            and <literal>realToFrac</literal>.
+          </para>
+       </listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><option>-fwarn-implicit-prelude</option>:</term>
         <listitem>
           <indexterm><primary><option>-fwarn-implicit-prelude</option></primary></indexterm>
@@ -1206,14 +1221,15 @@ foreign import "&amp;f" f :: FunPtr t
          <indexterm><primary>incomplete patterns, warning</primary></indexterm>
          <indexterm><primary>patterns, incomplete</primary></indexterm>
 
-         <para>Similarly for incomplete patterns, the function
-          <function>g</function> below will fail when applied to
+          <para>Similarly for incomplete patterns, the functions
+          <function>g</function> and <function>h</function> below will fail when applied to
           non-empty lists, so the compiler will emit a warning about
           this when <option>-fwarn-incomplete-patterns</option> is
           enabled.</para>
 
 <programlisting>
 g [] = 2
+h = \[] -> 2
 </programlisting>
 
          <para>This option isn't enabled by default because it can be
@@ -1631,31 +1647,6 @@ f "2"    = 2
             <option>-O</option>.</para>
          </listitem>
        </varlistentry>
-
-       <varlistentry>
-         <term>
-            <option>-Ofile &lt;file&gt;</option>:
-            <indexterm><primary>-Ofile &lt;file&gt; option</primary></indexterm>
-            <indexterm><primary>optimising, customised</primary></indexterm>
-          </term>
-         <listitem>
-           <para>(NOTE: not supported since GHC 4.x.  Please ask if
-           you're interested in this.)</para>
-           
-           <para>For those who need <emphasis>absolute</emphasis>
-            control over <emphasis>exactly</emphasis> what options are
-            used (e.g., compiler writers, sometimes :-), a list of
-            options can be put in a file and then slurped in with
-            <option>-Ofile</option>.</para>
-
-           <para>In that file, comments are of the
-            <literal>&num;</literal>-to-end-of-line variety; blank
-            lines and most whitespace is ignored.</para>
-
-           <para>Please ask if you are baffled and would like an
-           example of <option>-Ofile</option>!</para>
-         </listitem>
-       </varlistentry>
       </variablelist>
 
       <para>We don't use a <option>-O*</option> flag for day-to-day