Auto merge of #45200 - mikhail-m1:match-with-false-edges, r=nikomatsakis

MIR-borrowck: add false edges to match arms

basic fix for https://github.com/rust-lang/rust/issues/45043, should be modified with #45184

src/test/compile-fail/borrowck/borrowck-match-already-borrowed.rs

@@ -0,0 +1,25 @@
+// 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.
+
+// revisions: ast mir
+//[mir]compile-flags: -Z emit-end-regions -Z borrowck-mir
+
+fn main() {
+    let mut x = 1;
+    let _x = &mut x;
+    let _ = match x {
+        x => x + 1, //[ast]~ ERROR E0503
+                    //[mir]~^ ERROR (Mir) [E0503]
+                    //[mir]~| ERROR (Ast) [E0503]
+        y => y + 2, //[ast]~ ERROR [E0503]
+                    //[mir]~^ ERROR (Mir) [E0503]
+                    //[mir]~| ERROR (Ast) [E0503]
+    };
+}