From d562848268e02d6cf342598551bc663fcd4ff341 Mon Sep 17 00:00:00 2001
From: Michael Howell <michael@notriddle.com>
Date: Sat, 28 Aug 2021 17:28:39 -0700
Subject: [PATCH] fix(rustc_parse): incorrect span information for macro block
 expr

Old error output:

   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
help: wrap this expression in parentheses
   |
4  |             break '_l $f(;)
   |                         ^ ^

New error output:

   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
help: wrap this expression in parentheses
   |
4  |             break '_l ($f);
   |                       ^  ^
---
 compiler/rustc_parse/src/parser/expr.rs |  2 +-
 src/test/ui/parser/issue-87812.rs       | 13 +++++++++++++
 src/test/ui/parser/issue-87812.stderr   | 22 ++++++++++++++++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/parser/issue-87812.rs
 create mode 100644 src/test/ui/parser/issue-87812.stderr

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 326c8f81ffb..bb7e44b18d2 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -50,7 +50,7 @@ macro_rules! maybe_whole_expr {
                     let block = block.clone();
                     $p.bump();
                     return Ok($p.mk_expr(
-                        $p.token.span,
+                        $p.prev_token.span,
                         ExprKind::Block(block, None),
                         AttrVec::new(),
                     ));
diff --git a/src/test/ui/parser/issue-87812.rs b/src/test/ui/parser/issue-87812.rs
new file mode 100644
index 00000000000..0ba87b99544
--- /dev/null
+++ b/src/test/ui/parser/issue-87812.rs
@@ -0,0 +1,13 @@
+#![deny(break_with_label_and_loop)]
+
+macro_rules! foo {
+    ( $f:block ) => {
+        '_l: loop {
+            break '_l $f; //~ERROR
+        }
+    };
+}
+
+fn main() {
+    let x = foo!({ 3 });
+}
diff --git a/src/test/ui/parser/issue-87812.stderr b/src/test/ui/parser/issue-87812.stderr
new file mode 100644
index 00000000000..d61ee23a50b
--- /dev/null
+++ b/src/test/ui/parser/issue-87812.stderr
@@ -0,0 +1,22 @@
+error: this labeled break expression is easy to confuse with an unlabeled break with a labeled value expression
+  --> $DIR/issue-87812.rs:6:13
+   |
+LL |             break '_l $f;
+   |             ^^^^^^^^^^^^
+...
+LL |     let x = foo!({ 3 });
+   |             ----------- in this macro invocation
+   |
+note: the lint level is defined here
+  --> $DIR/issue-87812.rs:1:9
+   |
+LL | #![deny(break_with_label_and_loop)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: wrap this expression in parentheses
+   |
+LL |             break '_l ($f);
+   |                       +  +
+
+error: aborting due to previous error
+