===================================================================
@@ -9210,6 +9210,12 @@ grokdeclarator (const cp_declarator *dec
error ("const %qs cannot be declared %<mutable%>", name);
storage_class = sc_none;
}
+ else if (TREE_CODE (type) == REFERENCE_TYPE)
+ {
+ permerror (input_location, "reference %qs cannot be declared "
+ "%<mutable%>", name);
+ storage_class = sc_none;
+ }
}
/* If this is declaring a typedef name, return a TYPE_DECL. */
===================================================================
@@ -0,0 +1,5 @@
+/* { dg-do compile } */
+
+class X {
+ mutable int &q; /* { dg-error "cannot be declared 'mutable'" } */
+};
===================================================================
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-fpermissive" } */
+
+class X {
+ mutable int &q; /* { dg-warning "cannot be declared 'mutable'" } */
+};
This is a slightly modified version of the patch attached to PR33558 which was posted to gcc-patches but apparently never reviewed. I don't know if the author of the original patch, Giovanni, has a copyright assignment but I think the change is obvious and I hope is sufficiently small to not need an assignment. I was in the process of making the same change when I found his patch on the PR and copied the wording of his diagnostic and testcase. Sun CC and g++ both incorrectly accept mutable references, so it might not be uncommon in the wild (I found a use in some production code yesterday.) This version of the patch allows mutable on reference members when -fpermissive is used, giving old code a transition path. I'll add a note to changes.html if this is approved. tested x86_64-linux, OK for trunk? cp/ChangeLog entry: 2010-12-18 Giovanni Funchal <gafunchal@gmail.com> Jonathan Wakely <jwakely.gcc@gmail.com> PR c++/33558 * decl.c (grokdeclarator): Reject mutable reference members. testsuite/ChangeLog entry: 2010-12-18 Giovanni Funchal <gafunchal@gmail.com> Jonathan Wakely <jwakely.gcc@gmail.com> PR c++/33558 * testsuite/g++.dg/other/pr33558.C: New. * testsuite/g++.dg/other/pr33558-2.C: New.