add test

Author: BoxyUwU

crates/bevy_ecs_compile_fail_tests/tests/ui/entity_ref_mut_lifetime_safety.rs

@@ -0,0 +1,64 @@
+use bevy_ecs::prelude::*;
+
+#[derive(Component, Eq, PartialEq, Debug)]
+struct A(Box<usize>);
+
+#[derive(Component)]
+struct B;
+
+fn main() {
+    let mut world = World::default();
+    let e = world.spawn().insert(A(Box::new(10_usize))).id();
+
+    let mut e_mut = world.entity_mut(e);
+
+    {
+        let gotten: &A = e_mut.get::<A>().unwrap();
+        let gotten2: A = e_mut.remove::<A>().unwrap();
+        assert_eq!(gotten, &gotten2); // oops UB
+    }
+
+    e_mut.insert(A(Box::new(12_usize)));
+
+    {
+        let mut gotten: Mut<A> = e_mut.get_mut::<A>().unwrap();
+        let mut gotten2: A = e_mut.remove::<A>().unwrap();
+        assert_eq!(&mut *gotten, &mut gotten2); // oops UB
+    }
+
+    e_mut.insert(A(Box::new(14_usize)));
+
+    {
+        let gotten: &A = e_mut.get::<A>().unwrap();
+        e_mut.despawn();
+        assert_eq!(gotten, &A(Box::new(14_usize))); // oops UB
+    }
+
+    let e = world.spawn().insert(A(Box::new(16_usize))).id();
+    let mut e_mut = world.entity_mut(e);
+
+    {
+        let gotten: &A = e_mut.get::<A>().unwrap();
+        let gotten_mut: Mut<A> = e_mut.get_mut::<A>().unwrap();
+        assert_eq!(gotten, &*gotten_mut); // oops UB
+    }
+
+    {
+        let gotten_mut: Mut<A> = e_mut.get_mut::<A>().unwrap();
+        let gotten: &A = e_mut.get::<A>().unwrap();
+        assert_eq!(gotten, &*gotten_mut); // oops UB
+    }
+
+    {
+        let gotten: &A = e_mut.get::<A>().unwrap();
+        e_mut.insert::<B>(B);
+        assert_eq!(gotten, &A(Box::new(16_usize))); // oops UB
+        e_mut.remove::<B>();
+    }
+
+    {
+        let mut gotten_mut: Mut<A> = e_mut.get_mut::<A>().unwrap();
+        e_mut.insert::<B>(B);
+        assert_eq!(&mut *gotten_mut, &mut A(Box::new(16_usize))); // oops UB
+    }
+}

crates/bevy_ecs_compile_fail_tests/tests/ui/entity_ref_mut_lifetime_safety.stderr

@@ -0,0 +1,69 @@
+error[E0502]: cannot borrow `e_mut` as mutable because it is also borrowed as immutable
+  --> tests/ui/entity_ref_mut_lifetime_safety.rs:17:26
+   |
+16 |         let gotten: &A = e_mut.get::<A>().unwrap();
+   |                          ---------------- immutable borrow occurs here
+17 |         let gotten2: A = e_mut.remove::<A>().unwrap();
+   |                          ^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
+18 |         assert_eq!(gotten, &gotten2); // oops UB
+   |         ---------------------------- immutable borrow later used here
+
+error[E0499]: cannot borrow `e_mut` as mutable more than once at a time
+  --> tests/ui/entity_ref_mut_lifetime_safety.rs:25:30
+   |
+24 |         let mut gotten: Mut<A> = e_mut.get_mut::<A>().unwrap();
+   |                                  -------------------- first mutable borrow occurs here
+25 |         let mut gotten2: A = e_mut.remove::<A>().unwrap();
+   |                              ^^^^^^^^^^^^^^^^^^^ second mutable borrow occurs here
+26 |         assert_eq!(&mut *gotten, &mut gotten2); // oops UB
+   |                          ------ first borrow later used here
+
+error[E0505]: cannot move out of `e_mut` because it is borrowed
+  --> tests/ui/entity_ref_mut_lifetime_safety.rs:33:9
+   |
+32 |         let gotten: &A = e_mut.get::<A>().unwrap();
+   |                          ---------------- borrow of `e_mut` occurs here
+33 |         e_mut.despawn();
+   |         ^^^^^ move out of `e_mut` occurs here
+34 |         assert_eq!(gotten, &A(Box::new(14_usize))); // oops UB
+   |         ------------------------------------------ borrow later used here
+
+error[E0502]: cannot borrow `e_mut` as mutable because it is also borrowed as immutable
+  --> tests/ui/entity_ref_mut_lifetime_safety.rs:42:34
+   |
+41 |         let gotten: &A = e_mut.get::<A>().unwrap();
+   |                          ---------------- immutable borrow occurs here
+42 |         let gotten_mut: Mut<A> = e_mut.get_mut::<A>().unwrap();
+   |                                  ^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
+43 |         assert_eq!(gotten, &*gotten_mut); // oops UB
+   |         -------------------------------- immutable borrow later used here
+
+error[E0502]: cannot borrow `e_mut` as immutable because it is also borrowed as mutable
+  --> tests/ui/entity_ref_mut_lifetime_safety.rs:48:26
+   |
+47 |         let gotten_mut: Mut<A> = e_mut.get_mut::<A>().unwrap();
+   |                                  -------------------- mutable borrow occurs here
+48 |         let gotten: &A = e_mut.get::<A>().unwrap();
+   |                          ^^^^^^^^^^^^^^^^ immutable borrow occurs here
+49 |         assert_eq!(gotten, &*gotten_mut); // oops UB
+   |                              ---------- mutable borrow later used here
+
+error[E0502]: cannot borrow `e_mut` as mutable because it is also borrowed as immutable
+  --> tests/ui/entity_ref_mut_lifetime_safety.rs:54:9
+   |
+53 |         let gotten: &A = e_mut.get::<A>().unwrap();
+   |                          ---------------- immutable borrow occurs here
+54 |         e_mut.insert::<B>(B);
+   |         ^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
+55 |         assert_eq!(gotten, &A(Box::new(16_usize))); // oops UB
+   |         ------------------------------------------ immutable borrow later used here
+
+error[E0499]: cannot borrow `e_mut` as mutable more than once at a time
+  --> tests/ui/entity_ref_mut_lifetime_safety.rs:61:9
+   |
+60 |         let mut gotten_mut: Mut<A> = e_mut.get_mut::<A>().unwrap();
+   |                                      -------------------- first mutable borrow occurs here
+61 |         e_mut.insert::<B>(B);
+   |         ^^^^^^^^^^^^^^^^^^^^ second mutable borrow occurs here
+62 |         assert_eq!(&mut *gotten_mut, &mut A(Box::new(16_usize))); // oops UB
+   |                          ---------- first borrow later used here