1 files changed, 90 insertions, 0 deletions
diff --git a/tests/ui/loops/label-on-block-suggest-move.rs b/tests/ui/loops/label-on-block-suggest-move.rs
new file mode 100644
index 00000000000..656034cd0e9
--- /dev/null
+++ b/tests/ui/loops/label-on-block-suggest-move.rs
@@ -0,0 +1,90 @@
+// see https://github.com/rust-lang/rust/issues/138585
+#![allow(break_with_label_and_loop)] // doesn't work locally
+
+fn main() {
+    loop 'a: {}
+    //~^ ERROR: block label not supported here
+    //~| HELP: if you meant to label the loop, move this label before the loop
+    while false 'a: {}
+    //~^ ERROR: block label not supported here
+    //~| HELP: if you meant to label the loop, move this label before the loop
+    for i in [0] 'a: {}
+    //~^ ERROR: block label not supported here
+    //~| HELP: if you meant to label the loop, move this label before the loop
+    'a: loop {
+        // first block is parsed as the break expr's value with or without parens
+        while break 'a 'b: {} 'c: {}
+        //~^ ERROR: block label not supported here
+        //~| HELP: if you meant to label the loop, move this label before the loop
+        while break 'a ('b: {}) 'c: {}
+        //~^ ERROR: block label not supported here
+        //~| HELP: if you meant to label the loop, move this label before the loop
+
+        // without the parens, the first block is parsed as the while-loop's body
+        // (see the 'no errors' section)
+        // #[allow(break_with_label_and_loop)] (doesn't work locally)
+        while (break 'a {}) 'c: {}
+        //~^ ERROR: block label not supported here
+        //~| HELP: if you meant to label the loop, move this label before the loop
+    }
+
+    // do not suggest moving the label if there is already a label on the loop
+    'a: loop 'b: {}
+    //~^ ERROR: block label not supported here
+    //~| HELP: remove this block label
+    'a: while false 'b: {}
+    //~^ ERROR: block label not supported here
+    //~| HELP: remove this block label
+    'a: for i in [0] 'b: {}
+    //~^ ERROR: block label not supported here
+    //~| HELP: remove this block label
+    'a: loop {
+        // first block is parsed as the break expr's value with or without parens
+        'd: while break 'a 'b: {} 'c: {}
+        //~^ ERROR: block label not supported here
+        //~| HELP: remove this block label
+        'd: while break 'a ('b: {}) 'c: {}
+        //~^ ERROR: block label not supported here
+        //~| HELP: remove this block label
+
+        // without the parens, the first block is parsed as the while-loop's body
+        // (see the 'no errors' section)
+        // #[allow(break_with_label_and_loop)] (doesn't work locally)
+        'd: while (break 'a {}) 'c: {}
+        //~^ ERROR: block label not supported here
+        //~| HELP: remove this block label
+    }
+
+    // no errors
+    loop { 'a: {} }
+    'a: loop { 'b: {} }
+    while false { 'a: {} }
+    'a: while false { 'b: {} }
+    for i in [0] { 'a: {} }
+    'a: for i in [0] { 'b: {} }
+    'a: {}
+    'a: { 'b: {} }
+    'a: loop {
+        // first block is parsed as the break expr's value if it is a labeled block
+        while break 'a 'b: {} {}
+        'd: while break 'a 'b: {} {}
+        while break 'a ('b: {}) {}
+        'd: while break 'a ('b: {}) {}
+        // first block is parsed as the while-loop's body if it has no label
+        // (the break expr is parsed as having no value),
+        // so the second block is a normal stmt-block, and the label is allowed
+        while break 'a {} 'c: {}
+        while break 'a {} {}
+        'd: while break 'a {} 'c: {}
+        'd: while break 'a {} {}
+    }
+
+    // unrelated errors that should not be affected
+    'a: 'b: {}
+    //~^ ERROR: expected `while`, `for`, `loop` or `{` after a label
+    //~| HELP: consider removing the label
+    loop { while break 'b: {} {} }
+    //~^ ERROR: parentheses are required around this expression to avoid confusion with a labeled break expression
+    //~| HELP: wrap the expression in parentheses
+    //~| ERROR: `break` or `continue` with no label in the condition of a `while` loop [E0590]
+}