1 files changed, 82 insertions, 0 deletions
diff --git a/tests/ui/hygiene/hygienic-labels-in-let.rs b/tests/ui/hygiene/hygienic-labels-in-let.rs
new file mode 100644
index 000000000..8cf66f31a
--- /dev/null
+++ b/tests/ui/hygiene/hygienic-labels-in-let.rs
@@ -0,0 +1,82 @@
+// run-pass
+#![allow(unreachable_code)]
+#![allow(unused_labels)]
+
+// Test that labels injected by macros do not break hygiene.  This
+// checks cases where the macros invocations are under the rhs of a
+// let statement.
+
+// Issue #24278: The label/lifetime shadowing checker from #24162
+// conservatively ignores hygiene, and thus issues warnings that are
+// both true- and false-positives for this test.
+
+macro_rules! loop_x {
+    ($e: expr) => {
+        // $e shouldn't be able to interact with this 'x
+        'x: loop {
+            $e
+        }
+    };
+}
+
+macro_rules! while_true {
+    ($e: expr) => {
+        // $e shouldn't be able to interact with this 'x
+        'x: while 1 + 1 == 2 {
+            $e
+        }
+    };
+}
+
+macro_rules! run_once {
+    ($e: expr) => {
+        // ditto
+        'x: for _ in 0..1 {
+            $e
+        }
+    };
+}
+
+pub fn main() {
+    let mut i = 0;
+
+    let j: isize = {
+        'x: loop {
+            // this 'x should refer to the outer loop, lexically
+            loop_x!(break 'x);
+            i += 1;
+        }
+        i + 1
+    };
+    assert_eq!(j, 1);
+
+    let k: isize = {
+        'x: for _ in 0..1 {
+            // ditto
+            loop_x!(break 'x);
+            i += 1;
+        }
+        i + 1
+    };
+    assert_eq!(k, 1);
+
+    let l: isize = {
+        'x: for _ in 0..1 {
+            // ditto
+            while_true!(break 'x);
+            i += 1;
+        }
+        i + 1
+    };
+    assert_eq!(l, 1);
+
+    let n: isize = {
+        'x: for _ in 0..1 {
+            // ditto
+            run_once!(continue 'x);
+            i += 1;
+        }
+        i + 1
+    };
+    assert_eq!(n, 1);
+}