The following invalid testcase triggers an ICE since GCC 4.1.0 (when objective-c++ was introduced):
==================== Class<> c; ==================== bug.mm:1: error: expected identifier before '>' token bug.mm:1: internal compiler error: tree check: expected identifier_node, have error_mark in lookup_and_install_protocols, at objc/objc-act.c:1438 Please submit a full bug report, [etc.] Posting a patch soon. -- Summary: ICE with invalid protocol Product: gcc Version: 4.2.0 Status: UNCONFIRMED Keywords: ice-on-invalid-code, error-recovery, monitored Severity: normal Priority: P3 Component: objc++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: reichelt at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28434