c++: aggregate prvalue as for range [PR106230]

Since my PR94041 work on temporary lifetime in aggregate initialization, we
end up calling build_vec_init to initialize the reference-extended temporary
for the artificial __for_range variable.  And build_vec_init uses
finish_for_stmt to implement its loop.  That function assumes that if
__for_range is in current_binding_level, we're finishing a range-for, and we
should fix up the variable as it goes out of scope.  But when called from
build_vec_init we aren't finishing a range-for, and do_poplevel doesn't
remove the variable from scope because stmts_are_full_exprs_p is false.  So
let's check that here as well, and leave the DECL_NAME alone.

	PR c++/106230

gcc/cp/ChangeLog:

	* semantics.cc (finish_for_stmt): Check stmts_are_full_exprs_p.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/range-for38.C: New test.

gcc/cp/semantics.cc

@@ -1398,6 +1398,11 @@ finish_for_stmt (tree for_stmt)
 
   add_stmt (do_poplevel (scope));
 
+  /* If we're being called from build_vec_init, don't mess with the names of
+     the variables for an enclosing range-for.  */
+  if (!stmts_are_full_exprs_p ())
+    return;
+
   for (int i = 0; i < 3; i++)
     if (range_for_decl[i])
       DECL_NAME (range_for_decl[i])

gcc/testsuite/g++.dg/cpp0x/range-for38.C

@@ -0,0 +1,16 @@
+// PR c++/106230
+// { dg-do compile { target c++11 } }
+
+struct A {
+  A();
+  operator int();
+};
+template <int N> struct array {
+  A elts[N];
+  A *begin();
+  A *end();
+};
+void fn() {
+  for (int i : array<4>{})
+    ;
+}