class C { var data: int; ghost var gdata: int; ghost method Init_ModifyNothing() { } ghost method Init_ModifyThis() modifies this; { data := 6; // error: assignment to a non-ghost field gdata := 7; } ghost method Init_ModifyStuff(c: C) modifies this, c; { } method NonGhostMethod() { print "hello\n"; } } method M0(IS: set) { parallel (i | 0 <= i < 20) { i := i + 1; // error: not allowed to assign to bound variable } var k := 0; parallel (i | 0 <= i < 20) { k := k + i; // error: not allowed to assign to local k, since k is not declared inside parallel block } parallel (i | 0 <= i < 20) ensures true; { var x := i; x := x + 1; } ghost var y; var z; parallel (i | 0 <= i) ensures true; { var x := i; x := x + 1; y := 18; // (this statement is not allowed, since y is declared outside the parallel, but that check happens only if the first resolution pass of the parallel statement passes, which it doesn't in this case because of the next line) z := 20; // error: assigning to a non-ghost variable inside a ghost parallel block } parallel (i | 0 <= i) ensures true; { ghost var x := i; x := x + 1; // cool } var ia := new int[20]; parallel (i | 0 <= i < 20) { ia[i] := choose IS; // error: set choose not allowed } var ca := new C[20]; parallel (i | 0 <= i < 20) { ca[i] := new C; // error: new allocation not allowed } parallel (i | 0 <= i < 20) ensures true; { var c := new C; // allowed var d := new C.Init_ModifyNothing(); var e := new C.Init_ModifyThis(); var f := new C.Init_ModifyStuff(e); c.Init_ModifyStuff(d); c.NonGhostMethod(); // error: only allowed to call ghost methods (because of possible 'print' statements, sigh) } } method M1() { parallel (i | 0 <= i < 20) { assert i < 100; if (i == 17) { break; } // error: nothing to break out of } parallel (i | 0 <= i < 20) ensures true; { if (i == 8) { return; } // error: return not allowed inside parallel block } var m := 0; label OutsideLoop: while (m < 20) { parallel (i | 0 <= i < 20) { if (i == 17) { break; } // error: not allowed to break out of loop that sits outside parallel if (i == 8) { break break; } // error: ditto (also: attempt to break too far) if (i == 9) { break OutsideLoop; } // error: ditto } m := m + 1; } parallel (i | 0 <= i < 20) { var j := 0; while (j < i) { if (j == 6) { break; } // fine if (j % 7 == 4) { break break; } // error: attempt to break out too far if (j % 7 == 4) { break OutsideLoop; } // error: attempt to break to place not in enclosing scope j := j + 1; } } } method M2() { var a := new int[100]; parallel (x | 0 <= x < 100) { a[x] :| assume a[x] > 0; // error: not allowed to update heap location in a parallel statement with an assume } }