Fix Trac #2518: add hs-boot files as an infelicty

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

diff --git a/docs/users_guide/bugs.xml b/docs/users_guide/bugs.xml
index c0c4bdb..4d79d24 100644 (file)
--- a/docs/users_guide/bugs.xml
+++ b/docs/users_guide/bugs.xml
@@ -98,14 +98,28 @@ main = do args <- getArgs
 
       <para>GHC's typechecker makes all pattern bindings monomorphic
       by default; this behaviour can be disabled with
-      <option>-fno-mono-pat-binds</option>.  See <xref
+      <option>-XNoMonoPatBinds</option>.  See <xref
       linkend="options-language" />.</para>
     </sect3>
       
       <sect3 id="infelicities-Modules">
        <title>Module system and interface files</title>
        
-       <para>None known.</para>
+       <para>GHC requires the use of <literal>hs-boot</literal>
+         files to cut the recursive loops among mutually recursive modules
+         as described in <xref linkend="mutual-recursion"/>.  This more of an infelicity
+           than a bug: the Haskell Report says 
+         (<ulink url="http://haskell.org/onlinereport/modules.html#sect5.7">Section 5.7</ulink>) "Depending on the Haskell
+       implementation used, separate compilation of mutually
+       recursive modules may require that imported modules contain
+       additional information so that they may be referenced before
+       they are compiled. Explicit type signatures for all exported
+       values may be necessary to deal with mutual recursion. The
+       precise details of separate compilation are not defined by
+       this Report."
+
+       </para>
+
     </sect3>
 
     <sect3 id="infelicities-numbers">
@@ -344,7 +358,7 @@ checking for duplicates.  The reason for this is efficiency, pure and simple.
         the problem would impose an extra overhead on every
         compilation.  So the bug remains un-fixed.  There is more
         background in <ulink
-        url="http://research.microsoft.com/~simonpj/Papers/inlining">
+        url="http://research.microsoft.com/~simonpj/Papers/inlining/">
         Secrets of the GHC inliner</ulink>.</para>
       </listitem>