[Ada] Handling of deferred references with nested prefixed calls

[Arnaud Charlet]

When handling deferred references, if an actual that is the prefix of an
enclosing prefixed call has been rewritten, we must use Nkind and Sloc to
identify the corresponding formal. The First_Named_Actual of the enclosing
call may be meaningless after the surrounding expansion.

No simple example available.

Tested on x86_64-pc-linux-gnu, committed on trunk

2014-05-21  Ed Schonberg  <schonb...@adacore.com>

        * sem_util.adb (Find_Actual): If an actual that is the prefix
        of an enclosing prefixed call has been rewritten, use Nkind
        and Sloc to identify the corresponding formal, when handling
        deferred references.


Index: sem_util.adb
===================================================================
--- sem_util.adb        (revision 210687)
+++ sem_util.adb        (working copy)
@@ -5518,6 +5518,16 @@
          while Present (Formal) and then Present (Actual) loop
             if Actual = N then
                return;
+
+            --  An actual that is the prefix in a prefixed call may have
+            --  been rewritten in the call, after the deferred reference
+            --  was collected. Check if sloc and kinds match.
+
+            elsif Sloc (Actual) = Sloc (N)
+              and then Nkind (Actual) = Nkind (N)
+            then
+               return;
+
             else
                Actual := Next_Actual (Actual);
                Formal := Next_Formal (Formal);