qml: compiler generates unreachable byte code

function f() { return; let a = 1; }

=== Bytecode for "f" strict mode false register count 8 implicit return false
       5       0: 0e                       LoadUndefined 
               1: 02                       Ret 
       7       2: 0e                       LoadUndefined // This shouldn't be here
               3: 02                       Ret  // This shouldn't be here

    function f() {
        for (x in a) { return; }
    }

=== Bytecode for "f" strict mode false register count 9 implicit return false
       5       0: 2e 00                    LoadQmlContextPropertyLookup 0
               2: d6 00                    GetIterator 0
               4: 18 07                    StoreReg r1
               6: 16 07                    LoadReg r1
               8: d8 08 09                 IteratorNext r2, 20
              11: 16 08                    LoadReg r2
              13: 30 05                    StoreNameSloppy 5
              15: 0e                       LoadUndefined 
              16: 02                       Ret 
              17: 56                       CheckException // why do we do stuff after a Ret?
              18: 4c f2                    Jump 6.             // never executed
       6      20: 16 06                    LoadReg r0 // never executed
              22: 02                       Ret // never executed