Ensure StorageDead is created even if variable initialization fails

Fixes #49232

Author: manuels

src/librustc_mir/build/matches/mod.rs

@@ -188,9 +188,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     self.user_assert_ty(block, ty, var, irrefutable_pat.span);
                 }
 
-                unpack!(block = self.into(&place, block, initializer));
                 self.schedule_drop_for_binding(var, irrefutable_pat.span, OutsideGuard);
-                block.unit()
+                self.into(&place, block, initializer)
             }
             _ => {
                 let place = unpack!(block = self.as_place(block, initializer));

src/test/mir-opt/issue-49232.rs

@@ -0,0 +1,66 @@
+// Copyright 2017 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 identify_regions -Z emit-end-regions
+// ignore-tidy-linelength
+
+// We must mark a variable whose initialization fails due to an
+// abort statement as StorageDead.
+
+fn main() {
+    loop {
+        let beacon = {
+            match true {
+                false => 4,
+                true => break,
+            }
+        };
+        drop(&beacon);
+    }
+}
+
+// END RUST SOURCE
+// START rustc.main.mir_map.0.mir
+//    ...
+//    scope 1 {
+//        let _2: i32;
+//    }
+//    ...
+//    bb3: {
+//        StorageLive(_2);
+//        StorageLive(_3);
+//        _3 = const true;
+//        EndRegion('3s);
+//        _4 = discriminant(_3);
+//        switchInt(_3) -> [false: bb11, otherwise: bb10];
+//    }
+//    ...
+//    bb22: {
+//        EndRegion('20_0rs);
+//        StorageDead(_2);
+//        goto -> bb23;
+//    }
+//    ...
+//    bb28: {
+//        EndRegion('18s);
+//        StorageDead(_7);
+//        EndRegion('19s);
+//        EndRegion('19ds);
+//        _1 = ();
+//        EndRegion('20_0rs);
+//        StorageDead(_2);
+//        EndRegion('20s);
+//        EndRegion('20ds);
+//        goto -> bb1;
+//    }
+//    bb29: {
+//        return;
+//    }
+// END rustc.main.mir_map.0.mir