Auto merge of #24072 - ebfull:explain_closure_type_err, r=pnkfelix

Also fixed bug calling .note() instead of .help()

See #24036

src/test/compile-fail/issue-24036.rs

@@ -0,0 +1,30 @@
+// 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.
+
+fn closure_to_loc() {
+    let mut x = |c| c + 1;
+    x = |c| c + 1;
+    //~^ ERROR mismatched types
+    //~| NOTE no two closures, even if identical, have the same type
+    //~| HELP consider boxing your closure and/or using it as a trait object
+}
+
+fn closure_from_match() {
+    let x = match 1usize {
+        1 => |c| c + 1,
+        2 => |c| c - 1,
+        _ => |c| c - 1
+    };
+    //~^^^^^ ERROR match arms have incompatible types
+    //~| NOTE no two closures, even if identical, have the same type
+    //~| HELP consider boxing your closure and/or using it as a trait object
+}
+
+fn main() { }