[C++ PATCH] c++/92450 - ICE with invalid nested name specifier.

[Marek Polacek]

The newly added diagnostic causes an ICE because the new grokdeclarator call
returned error_mark_node and DECL_SOURCE_LOCATION crashes on that.  So don't
attempt to print the new diagnostic if we've encountered something not
resembling a bit-field.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2019-11-18  Marek Polacek  <pola...@redhat.com>

        PR c++/92450 - ICE with invalid nested name specifier.
        * parser.c (cp_parser_member_declaration): Bail out for invalid code.

        * g++.dg/parse/crash71.C: New test.

diff --git gcc/cp/parser.c gcc/cp/parser.c
index c473e7fd92f..caed6946977 100644
--- gcc/cp/parser.c
+++ gcc/cp/parser.c
@@ -25052,6 +25052,9 @@ cp_parser_member_declaration (cp_parser* parser)
                  tree d = grokdeclarator (declarator, &decl_specifiers,
                                           BITFIELD, /*initialized=*/false,
                                           &attributes);
+                 /* Hopelessly invalid code, give up.  */
+                 if (error_operand_p (d))
+                   goto out;
                  error_at (DECL_SOURCE_LOCATION (d),
                            "bit-field %qD has non-integral type %qT",
                            d, TREE_TYPE (d));
diff --git gcc/testsuite/g++.dg/parse/crash71.C 
gcc/testsuite/g++.dg/parse/crash71.C
new file mode 100644
index 00000000000..13f484801fe
--- /dev/null
+++ gcc/testsuite/g++.dg/parse/crash71.C
@@ -0,0 +1,11 @@
+// PR c++/92450 - ICE with invalid nested name specifier.
+
+typedef int C2;
+struct B1 {
+  struct B2 {
+  };
+};
+
+struct S6g {
+  C2 : B1:B2; // { dg-error "" }
+};