Document -fwarn-unrecognised-pragmas; fixes trac #3031

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

diff --git a/docs/users_guide/using.xml b/docs/users_guide/using.xml
index 439fb58..20bb687 100644 (file)
--- a/docs/users_guide/using.xml
+++ b/docs/users_guide/using.xml
@@ -46,26 +46,25 @@ ghc [argument...]
 
       <para>Sometimes it is useful to make the connection between a
       source file and the command-line options it requires quite
-      tight. For instance, if a Haskell source file uses GHC
-      extensions, it will always need to be compiled with the
-      <option>-fglasgow-exts</option> option.  Rather than maintaining
+      tight. For instance, if a Haskell source file deliberately
+       uses name shadowing, it should be compiled with  the
+      <option>-fno-warn-name-shadowing</option> option.  Rather than maintaining
       the list of per-file options in a <filename>Makefile</filename>,
       it is possible to do this directly in the source file using the
       <literal>OPTIONS_GHC</literal> pragma <indexterm><primary>OPTIONS_GHC
       pragma</primary></indexterm>:</para>
 
 <programlisting>
-{-# OPTIONS_GHC -fglasgow-exts #-}
+{-# OPTIONS_GHC -fno-warn-name-shadowing #-}
 module X where
 ...
 </programlisting>
       
-      <para><literal>OPTIONS_GHC</literal> pragmas are only looked for at
-      the top of your source files, upto the first
-      (non-literate,non-empty) line not containing
-      <literal>OPTIONS_GHC</literal>. Multiple <literal>OPTIONS_GHC</literal>
-      pragmas are recognised.  Do not put comments before, or on the same line
-       as, the <literal>OPTIONS_GHC</literal> pragma.</para>
+      <para><literal>OPTIONS_GHC</literal> is a <emphasis>file-header pragma</emphasis>
+      (see <xref linkend="pragmas"/>).</para>
+
+      <para>Only <emphasis>dynamic</emphasis> flags can be used in an <literal>OPTIONS_GHC</literal> pragma
+      (see <xref linkend="static-dynamic-flags"/>).</para>
 
       <para>Note that your command shell does not
       get to the source file options, they are just included literally
@@ -919,6 +918,23 @@ ghc -c Foo.hs</screen>
     <variablelist>
 
       <varlistentry>
+       <term><option>-fwarn-unrecognised-pragmas</option>:</term>
+       <listitem>
+         <indexterm><primary><option>-fwarn-unrecognised-pragmas</option></primary>
+         </indexterm>
+         <indexterm><primary>warnings</primary></indexterm>
+         <indexterm><primary>pragmas</primary></indexterm>
+         <para>Causes a warning to be emitted when a
+         pragma that GHC doesn't recognise is used. As well as pragmas
+      that GHC itself uses, GHC also recognises pragmas known to be used
+      by other tools, e.g. <literal>OPTIONS_HUGS</literal> and
+      <literal>DERIVE</literal>.</para>
+
+         <para>This option is on by default.</para>
+       </listitem>
+      </varlistentry>
+
+      <varlistentry>
        <term><option>-fwarn-warnings-deprecations</option>:</term>
        <listitem>
          <indexterm><primary><option>-fwarn-warnings-deprecations</option></primary>