add thir print test

Author: folkertdev

compiler/rustc_mir_build/src/thir/print.rs

@@ -320,7 +320,7 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
                 print_indented!(self, ")", depth_lvl);
             }
             LoopMatch { state, region_scope, match_span, arms } => {
-                print_indented!(self, "LoopMatch (", depth_lvl);
+                print_indented!(self, "LoopMatch {", depth_lvl);
                 print_indented!(self, "state:", depth_lvl + 1);
                 self.print_expr(*state, depth_lvl + 2);
                 print_indented!(self, format!("region_scope: {:?}", region_scope), depth_lvl + 1);

tests/ui/thir-print/thir-tree-loop-match.rs

@@ -0,0 +1,22 @@
+//@ check-pass
+//@ compile-flags: -Zunpretty=thir-tree
+
+#![allow(incomplete_features)]
+#![feature(loop_match)]
+
+fn boolean(mut state: bool) -> bool {
+    #[loop_match]
+    loop {
+        state = 'blk: {
+            match state {
+                true => {
+                    #[const_continue]
+                    break 'blk false;
+                }
+                false => return state,
+            }
+        }
+    }
+}
+
+fn main() {}