fix: appropriate error message for out of scope label

src/compiler/checker.ts

@@ -51606,6 +51606,25 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         let current: Node = node;
         while (current) {
             if (isFunctionLikeOrClassStaticBlockDeclaration(current)) {
+                if (node.label) {
+                    const functionOrClassLike = current as FunctionLikeDeclaration | ClassStaticBlockDeclaration;
+                    if (functionOrClassLike.body) {
+                        const relatedInfo = forEachChild(functionOrClassLike.body, childNode => {
+                            const labeledStatement = childNode as LabeledStatement;
+                            if (labeledStatement.kind === SyntaxKind.LabeledStatement && labeledStatement.label.escapedText === node.label!.escapedText) {
+                                return createDiagnosticForNode(labeledStatement.label, Diagnostics.Label_defined_here, unescapeLeadingUnderscores(labeledStatement.label.escapedText));
+                            }
+                        });
+
+                        if (relatedInfo) {
+                            const diagnostic = createDiagnosticForNode(node, Diagnostics.Label_0_used_before_declaration, unescapeLeadingUnderscores(node.label.escapedText));
+                            diagnostic.relatedInformation = [relatedInfo];
+                            diagnostics.add(diagnostic);
+                            return true;
+                        }
+                    }
+                }
+
                 return grammarErrorOnNode(node, Diagnostics.Jump_target_cannot_cross_function_boundary);
             }
 

src/compiler/diagnosticMessages.json

@@ -8353,5 +8353,13 @@
     "String literal import and export names are not supported when the '--module' flag is set to 'es2015' or 'es2020'.": {
         "category": "Error",
         "code": 18057
+    },
+    "Label '{0}' used before declaration.": {
+        "category": "Error",
+        "code": 18058
+    },
+    "Label defined here": {
+        "category": "Error",
+        "code": 18059
     }
 }

tests/baselines/reference/breakTarget7.errors.txt

@@ -0,0 +1,12 @@
+breakTarget7.ts(2,5): error TS18058: Label 'target' used before declaration.
+
+
+==== breakTarget7.ts (1 errors) ====
+    function functionContainingBreak() {
+        break target;
+        ~~~~~~~~~~~~~
+!!! error TS18058: Label 'target' used before declaration.
+!!! related TS18059 breakTarget7.ts:3:5: Label defined here
+        target:;
+    }
+

tests/baselines/reference/breakTarget7.js

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/breakTarget7.ts] ////
+
+//// [breakTarget7.ts]
+function functionContainingBreak() {
+    break target;
+    target:;
+}
+
+
+//// [breakTarget7.js]
+function functionContainingBreak() {
+    break target;
+    target: ;
+}

tests/baselines/reference/breakTarget7.symbols

@@ -0,0 +1,10 @@
+//// [tests/cases/compiler/breakTarget7.ts] ////
+
+=== breakTarget7.ts ===
+function functionContainingBreak() {
+>functionContainingBreak : Symbol(functionContainingBreak, Decl(breakTarget7.ts, 0, 0))
+
+    break target;
+    target:;
+}
+

tests/baselines/reference/breakTarget7.types

@@ -0,0 +1,16 @@
+//// [tests/cases/compiler/breakTarget7.ts] ////
+
+=== breakTarget7.ts ===
+function functionContainingBreak() {
+>functionContainingBreak : () => void
+>                        : ^^^^^^^^^^
+
+    break target;
+>target : any
+>       : ^^^
+
+    target:;
+>target : any
+>       : ^^^
+}
+

tests/cases/compiler/breakTarget7.ts

@@ -0,0 +1,5 @@
+// @allowUnusedLabels: true
+function functionContainingBreak() {
+    break target;
+    target:;
+}