Rollup merge of #45877 - mikhail-m1:mir-borrowck-act-on-moved, r=arielb1

restore move out dataflow, add report of move out errors

fix https://github.com/rust-lang/rust/issues/45363
r? @arielb1

src/test/ui/borrowck/borrowck-reinit.rs

@@ -0,0 +1,19 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: -Z borrowck-mir -Z emit-end-regions
+
+fn main() {
+    let mut x = Box::new(0);
+    let _u = x; // error shouldn't note this move
+    x = Box::new(1);
+    drop(x);
+    let _ = (1,x);
+}

src/test/ui/borrowck/borrowck-reinit.stderr

@@ -0,0 +1,20 @@
+error[E0382]: use of moved value: `x` (Ast)
+  --> $DIR/borrowck-reinit.rs:18:16
+   |
+17 |     drop(x);
+   |          - value moved here
+18 |     let _ = (1,x);
+   |                ^ value used here after move
+   |
+   = note: move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
+
+error[E0382]: use of moved value: `x` (Mir)
+  --> $DIR/borrowck-reinit.rs:18:16
+   |
+17 |     drop(x);
+   |          - value moved here
+18 |     let _ = (1,x);
+   |                ^ value use here after move
+
+error: aborting due to 2 previous errors
+