X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=docs%2Fusers_guide%2Fglasgow_exts.xml;h=8bca4857c5840fd55b658d0215077c8c94b2516d;hb=7e03b5b7cfd72c651444856fe83b429da0734ec2;hp=0c3b07cb6c50d9e3bda756061f9b75083a8cc85a;hpb=f94f26a7cb7bb7005b88f50c4383a761fc18718d;p=ghc-hetmet.git

diff --git a/docs/users_guide/glasgow_exts.xml b/docs/users_guide/glasgow_exts.xml
index 0c3b07c..8bca485 100644
--- a/docs/users_guide/glasgow_exts.xml
+++ b/docs/users_guide/glasgow_exts.xml
@@ -4226,6 +4226,14 @@ Tim Sheard is going to expand it.)
 	    (It would make sense to do so, but it's hard to implement.)
    </para></listitem>
 
+   <listitem><para>
+   Furthermore, you can only run a function at compile time if it is imported
+   from another module <emphasis>that is not part of a mutually-recursive group of modules
+   that includes the module currently being compiled</emphasis>.  For example, when compiling module A,
+   you can only run Template Haskell functions imported from B if B does not import A (directly or indirectly).
+   The reason should be clear: to run B we must compile and run A, but we are currently type-checking A.
+   </para></listitem>
+
     <listitem><para>
 	    The flag <literal>-ddump-splices</literal> shows the expansion of all top-level splices as they happen.
    </para></listitem>