The following invalid code snippet crashes the C++ frontend: =================================================== struct A;
A foo() { A a; return a; } =================================================== bug.cc: In function 'A foo()': bug.cc:7: error: return type 'struct A' is incomplete bug.cc:9: error: aggregate 'A a' has incomplete type and cannot be defined bug.cc:10: internal compiler error: tree check: expected class 'type', have 'exceptional' (error_mark) in check_return_expr, at cp/typeck.c:6296 Please submit a full bug report, [etc.] The bug is present since gcc 3.4.0. Looks like it was introduced with the new parser: : Search converges between 2002-12-14-trunk (#159) and 2002-12-29-trunk (#160). -- Summary: [3.4/4.0 regression] ICE when returning undefined type Product: gcc Version: 4.0.0 Status: UNCONFIRMED Keywords: ice-on-invalid-code, error-recovery, monitored Severity: normal Priority: P2 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: reichelt at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18545