Closed
Description
Repro (copy of necessary parts of libcore/cell.rs): https://play.rust-lang.org/?gist=41cc5138c7765666a646bbcb09748ff3&version=stable
Notice the second statement in bb1: _4 = discriminant(_2); _2 is of type usize on which you are not allowed to the discriminant. _4 isn't used anywhere. This has been detected while fixing miri.
fn <impl at src/main.rs:11:1: 22:2>::new(_1: &std::cell::Cell<usize>) -> std::option::Option<BorrowRef> {
let mut _0: std::option::Option<BorrowRef>; // return place
scope 1 {
let _5: usize; // "b" in scope 1 at src/main.rs:16:13: 16:14
}
let mut _2: usize;
let mut _3: &std::cell::Cell<usize>;
let mut _4: u8;
let mut _6: ();
let mut _7: &std::cell::Cell<usize>;
let mut _8: usize;
let mut _9: usize;
let mut _10: (usize, bool);
let mut _11: BorrowRef;
let mut _12: &std::cell::Cell<usize>;
bb0: {
StorageLive(_2); // bb0[0]: scope 0 at src/main.rs:14:15: 14:27
StorageLive(_3); // bb0[1]: scope 0 at src/main.rs:14:15: 14:21
_3 = _1; // bb0[2]: scope 0 at src/main.rs:14:15: 14:21
_2 = const <std::cell::Cell<T>>::get(move _3) -> bb1; // bb0[3]: scope 0 at src/main.rs:14:15: 14:27
// ty::Const
// └ ty: for<'r> fn(&'r std::cell::Cell<usize>) -> usize {<std::cell::Cell<T>><usize>::get}
// └ val: Function(DefId(2/0:1406 ~ core[3d52]::cell[0]::{{impl}}[0]::get[0]), Slice([usize]))
// mir::Constant
// └ span: src/main.rs:14:15: 14:27
// └ ty: for<'r> fn(&'r std::cell::Cell<usize>) -> usize {<std::cell::Cell<T>><usize>::get}
// └ literal: const <std::cell::Cell<T>>::get
}
bb1: {
StorageDead(_3); // bb1[0]: scope 0 at src/main.rs:14:27: 14:27
_4 = discriminant(_2); // bb1[1]: scope 0 at src/main.rs:14:9: 20:10
switchInt(_2) -> [18446744073709551615usize: bb2, otherwise: bb3]; // bb1[2]: scope 0 at src/main.rs:15:13: 15:20
}
bb2: {
_0 = std::option::Option<BorrowRef>::None; // bb2[0]: scope 0 at src/main.rs:15:24: 15:28
goto -> bb4; // bb2[1]: scope 0 at src/main.rs:14:9: 20:10
}
bb3: {
StorageLive(_5); // bb3[0]: scope 0 at src/main.rs:16:13: 16:14
_5 = _2; // bb3[1]: scope 0 at src/main.rs:16:13: 16:14
StorageLive(_7); // bb3[2]: scope 1 at src/main.rs:17:17: 17:23
_7 = _1; // bb3[3]: scope 1 at src/main.rs:17:17: 17:23
StorageLive(_8); // bb3[4]: scope 1 at src/main.rs:17:28: 17:33
StorageLive(_9); // bb3[5]: scope 1 at src/main.rs:17:28: 17:29
_9 = _5; // bb3[6]: scope 1 at src/main.rs:17:28: 17:29
_10 = CheckedAdd(move _9, const 1usize); // bb3[7]: scope 1 at src/main.rs:17:28: 17:33
// ty::Const
// └ ty: usize
// └ val: Integral(Usize(Us64(1)))
// mir::Constant
// └ span: src/main.rs:17:32: 17:33
// └ ty: usize
// └ literal: const 1usize
assert(!move (_10.1: bool), "attempt to add with overflow") -> bb5; // bb3[8]: scope 1 at src/main.rs:17:28: 17:33
}
bb4: {
StorageDead(_5); // bb4[0]: scope 0 at src/main.rs:20:10: 20:10
StorageDead(_2); // bb4[1]: scope 0 at src/main.rs:21:6: 21:6
return; // bb4[2]: scope 0 at src/main.rs:21:6: 21:6
}
bb5: {
_8 = move (_10.0: usize); // bb5[0]: scope 1 at src/main.rs:17:28: 17:33
StorageDead(_9); // bb5[1]: scope 1 at src/main.rs:17:33: 17:33
_6 = const <std::cell::Cell<T>>::set(move _7, move _8) -> bb6; // bb5[2]: scope 1 at src/main.rs:17:17: 17:34
// ty::Const
// └ ty: for<'r> fn(&'r std::cell::Cell<usize>, usize) {<std::cell::Cell<T>><usize>::set}
// └ val: Function(DefId(2/0:1430 ~ core[3d52]::cell[0]::{{impl}}[10]::set[0]), Slice([usize]))
// mir::Constant
// └ span: src/main.rs:17:17: 17:34
// └ ty: for<'r> fn(&'r std::cell::Cell<usize>, usize) {<std::cell::Cell<T>><usize>::set}
// └ literal: const <std::cell::Cell<T>>::set
}
bb6: {
StorageDead(_8); // bb6[0]: scope 1 at src/main.rs:17:34: 17:34
StorageDead(_7); // bb6[1]: scope 1 at src/main.rs:17:34: 17:34
StorageLive(_11); // bb6[2]: scope 1 at src/main.rs:18:22: 18:50
StorageLive(_12); // bb6[3]: scope 1 at src/main.rs:18:42: 18:48
_12 = _1; // bb6[4]: scope 1 at src/main.rs:18:42: 18:48
_11 = BorrowRef { borrow: move _12 }; // bb6[5]: scope 1 at src/main.rs:18:22: 18:50
StorageDead(_12); // bb6[6]: scope 1 at src/main.rs:18:50: 18:50
_0 = std::option::Option<BorrowRef>::Some(move _11,); // bb6[7]: scope 1 at src/main.rs:18:17: 18:51
StorageDead(_11); // bb6[8]: scope 1 at src/main.rs:18:51: 18:51
goto -> bb4; // bb6[9]: scope 0 at src/main.rs:14:9: 20:10
}
}