format label break

Author: csmoe

src/expr.rs

@@ -119,7 +119,7 @@ pub fn format_expr(
         | ast::ExprKind::WhileLet(..) => to_control_flow(expr, expr_type)
             .and_then(|control_flow| control_flow.rewrite(context, shape)),
         // FIXME(topecongiro): Handle label on a block (#2722).
-        ast::ExprKind::Block(ref block, _) => {
+        ast::ExprKind::Block(ref block, opt_label) => {
             match expr_type {
                 ExprType::Statement => {
                     if is_unsafe_block(block) {
@@ -131,9 +131,11 @@ pub fn format_expr(
                         rw
                     } else {
                         let prefix = block_prefix(context, block, shape)?;
+                        let label_string = rewrite_label(opt_label);
+
                         rewrite_block_with_visitor(
                             context,
-                            &prefix,
+                            &format!("{} {}", &prefix, &label_string),
                             block,
                             Some(&expr.attrs),
                             shape,

tests/source/label_break.rs

@@ -0,0 +1,16 @@
+// format with label break value.
+fn main() {
+
+'empty_block: {}
+
+let result = 'block: {
+    if foo() {
+        // comment
+        break 'block 1;
+    }
+    if bar() { /* comment */
+        break 'block      2;
+    }
+    3
+};
+}

tests/target/label_break.rs

@@ -0,0 +1,16 @@
+// format with label break value.
+fn main() {
+    {}
+
+    let result = {
+        if foo() {
+            // comment
+            break 'block 1;
+        }
+        if bar() {
+            /* comment */
+            break 'block 2;
+        }
+        3
+    };
+}