invoke.texi: Update -Waliasing description.

* invoke.texi:  Update -Waliasing description.

Co-Authored-By: Steven G. Kargl <kargls@comcast.net>

From-SVN: r98418

gcc/fortran/ChangeLog

+2005-04-19  Arnaud Desitter  <arnaud.desitter@ouce.ox.ac.uk>
+            Steven G. Kargl  <kargls@comcast.net>
+
+	* invoke.texi: Update -Waliasing description
+
 2005-04-19  Francois-Xavier Coudert  <coudert@clipper.ens.fr>
 
 	PR fortran/16861

gcc/fortran/invoke.texi

@@ -329,12 +329,22 @@ This currently includes @option{-Wunused-labels}, @option{-Waliasing},
 @cindex options, -Waliasing
 @item -Waliasing
 @cindex aliasing
-Warn about possible aliasing of dummy arguments. The following example
-will trigger the warning as it would be illegal to @code{bar} to
-modify either parameter.
+Warn about possible aliasing of dummy arguments. Specifically, it warns
+if the same actual argument is associated with a dummy argument with
+@code{intent(in)} and a dummy argument with @code{intent(out)} in a call
+with an explicit interface.
+
+The following example will trigger the warning.
 @smallexample
-  INTEGER A
-  CALL BAR(A,A)
+  interface
+    subroutine bar(a,b)
+      integer, intent(in) :: a
+      integer, intent(out) :: b
+    end subroutine
+  end interface
+  integer :: a
+
+  call bar(a,a)
 @end smallexample