Avoid an indent for labelled loops.

Author: nnethercote

compiler/rustc_ast_pretty/src/pprust/state/expr.rs

@@ -485,12 +485,12 @@ impl<'a> State<'a> {
                 self.print_block_with_attrs(body, attrs, cb, ib);
             }
             ast::ExprKind::Loop(blk, opt_label, _) => {
+                let cb = self.cbox(0);
+                let ib = self.ibox(0);
                 if let Some(label) = opt_label {
                     self.print_ident(label.ident);
                     self.word_space(":");
                 }
-                let cb = self.cbox(0);
-                let ib = self.ibox(0);
                 self.word_nbsp("loop");
                 self.print_block_with_attrs(blk, attrs, cb, ib);
             }

compiler/rustc_hir_pretty/src/lib.rs

@@ -1526,12 +1526,12 @@ impl<'a> State<'a> {
                 self.print_if(test, blk, elseopt);
             }
             hir::ExprKind::Loop(blk, opt_label, _, _) => {
+                let cb = self.cbox(0);
+                let ib = self.ibox(0);
                 if let Some(label) = opt_label {
                     self.print_ident(label.ident);
                     self.word_space(":");
                 }
-                let cb = self.cbox(0);
-                let ib = self.ibox(0);
                 self.word_nbsp("loop");
                 self.print_block(blk, cb, ib);
             }

tests/ui/unpretty/exhaustive.hir.stdout

@@ -189,8 +189,7 @@ mod expressions {
             let _t =
                 match #[lang = "into_iter"](x) {
                     mut iter =>
-                        'a:
-                            loop {
+                        'a: loop {
                             match #[lang = "next"](&mut iter) {
                                 #[lang = "None"] {} => break,
                                 #[lang = "Some"] {  0: _ } => { }