Malformed expression crashes JS optimizer

./qtquickcompiler -s /tmp/000000.qml /dev/null

1 (anonymous namespace)::optimizeSSA     qv4ssa.cpp          4030 0x59e49c 
2 QV4::IR::Optimizer::run                qv4ssa.cpp          5410 0x5e34a6 
3 QmlC::InstructionSelection::run        isel.cpp            190  0x40fafb 
4 QV4::EvalInstructionSelection::compile qv4isel_p.cpp       82   0x4e2350 
5 compileQmlFile                         qtquickcompiler.cpp 119  0x43a8f8 
6 main                                   main.cpp            462  0x40c04c