c++: Fix error recovery ICE [PR112365]

check_field_decls for DECL_C_BIT_FIELD FIELD_DECLs with error_mark_node
TREE_TYPE continues early and doesn't call check_bitfield_decl which would
either set DECL_BIT_FIELD, or clear DECL_C_BIT_FIELD.  So, the following
testcase ICEs after emitting tons of errors, because
SET_DECL_FIELD_CXX_ZERO_WIDTH_BIT_FIELD asserts DECL_BIT_FIELD.

The patch skips that for FIELD_DECLs with error_mark_node, another
option would be to check DECL_BIT_FIELD in addition to DECL_C_BIT_FIELD.

2023-11-16  Jakub Jelinek  <jakub@redhat.com>

	PR c++/112365
	* class.cc (layout_class_type): Don't
	SET_DECL_FIELD_CXX_ZERO_WIDTH_BIT_FIELD on FIELD_DECLs with
	error_mark_node type.

	* g++.dg/cpp0x/pr112365.C: New test.

diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc
index 9d4d95f85bf750e6aa69f2e1cfb536db302f15cf..4766b7cf832c665bec59752433972435988a2255 100644 (file)
--- a/gcc/cp/class.cc
+++ b/gcc/cp/class.cc
@@ -6962,7 +6962,8 @@ layout_class_type (tree t, tree *virtuals_p)
             check_bitfield_decl eventually sets DECL_SIZE (field)
             to that width.  */
          && (DECL_SIZE (field) == NULL_TREE
-             || integer_zerop (DECL_SIZE (field))))
+             || integer_zerop (DECL_SIZE (field)))
+         && TREE_TYPE (field) != error_mark_node)
        SET_DECL_FIELD_CXX_ZERO_WIDTH_BIT_FIELD (field, 1);
       check_non_pod_aggregate (field);
     }

diff --git a/gcc/testsuite/g++.dg/cpp0x/pr112365.C b/gcc/testsuite/g++.dg/cpp0x/pr112365.C
new file mode 100644 (file)
index 0000000..23409cb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/pr112365.C
@@ -0,0 +1,8 @@
+// PR c++/112365
+// { dg-do compile { target c++11 } }
+// { dg-excess-errors "" }
+
+template <typename> struct A;
+template <typename T> A <T> foo (T;
+template <typename T> struct A { constexpr A : T {} }
+struct { bar ( { foo (this)