Auto merge of #68170 - wesleywiser:stop_const_prop_ref_taking, r=oli-obk

Turn off const propagation of ref taking

Fixes #67529
Fixes #67640
Fixes #67641
Fixes #67862

r? @oli-obk

src/test/mir-opt/const_prop/ref_deref_project.rs

@@ -1,5 +1,5 @@
 fn main() {
-    *(&(4, 5).1);
+    *(&(4, 5).1); // This does not currently propagate (#67862)
 }
 
 // END RUST SOURCE
@@ -35,7 +35,7 @@ fn main() {
 //     ...
 //     _4 = const main::promoted[0];
 //     _2 = &((*_4).1: i32);
-//     _1 = const 5i32;
+//     _1 = (*_2);
 //     ...
 // }
 // END rustc.main.ConstProp.after.mir

src/test/ui/consts/issue-67529.rs

@@ -0,0 +1,11 @@
+// compile-flags: -Z mir-opt-level=2
+// run-pass
+
+struct Baz<T: ?Sized> {
+    a: T
+}
+
+fn main() {
+    let d : Baz<[i32; 4]> = Baz { a: [1,2,3,4] };
+    assert_eq!([1, 2, 3, 4], d.a);
+}

src/test/ui/consts/issue-67640.rs

@@ -0,0 +1,24 @@
+// compile-flags: -Z mir-opt-level=3
+// run-pass
+
+struct X {
+    x: isize
+}
+
+fn f1(a: &mut X, b: &mut isize, c: isize) -> isize {
+    let r = a.x + *b + c;
+    a.x = 0;
+    *b = 10;
+    return r;
+}
+
+fn f2<F>(a: isize, f: F) -> isize where F: FnOnce(isize) { f(1); return a; }
+
+pub fn main() {
+    let mut a = X {x: 1};
+    let mut b = 2;
+    let c = 3;
+    assert_eq!(f1(&mut a, &mut b, c), 6);
+    assert_eq!(a.x, 0);
+    assert_eq!(f2(a.x, |_| a.x = 50), 0);
+}

src/test/ui/consts/issue-67641.rs

@@ -0,0 +1,24 @@
+// compile-flags: -Z mir-opt-level=2
+// run-pass
+
+use std::cell::Cell;
+
+#[derive(Debug)]
+struct B<'a> {
+    a: [Cell<Option<&'a B<'a>>>; 2]
+}
+
+impl<'a> B<'a> {
+    fn new() -> B<'a> {
+        B { a: [Cell::new(None), Cell::new(None)] }
+    }
+}
+
+fn f() {
+    let b2 = B::new();
+    b2.a[0].set(Some(&b2));
+}
+
+fn main() {
+    f();
+}

src/test/ui/consts/issue-67862.rs

@@ -0,0 +1,18 @@
+// compile-flags: -Z mir-opt-level=2
+// run-pass
+
+fn e220() -> (i64, i64) {
+    #[inline(never)]
+    fn get_displacement() -> [i64; 2] {
+        [139776, 963904]
+    }
+
+    let res = get_displacement();
+    match (&res[0], &res[1]) {
+        (arg0, arg1) => (*arg0, *arg1),
+    }
+}
+
+fn main() {
+    assert_eq!(e220(), (139776, 963904));
+}