1 files changed, 106 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/no-unused-labels.js b/tools/node_modules/eslint/lib/rules/no-unused-labels.js
new file mode 100644
index 0000000000..bcd3cfdc47
--- /dev/null
+++ b/tools/node_modules/eslint/lib/rules/no-unused-labels.js
@@ -0,0 +1,106 @@
+/**
+ * @fileoverview Rule to disallow unused labels.
+ * @author Toru Nagashima
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow unused labels",
+            category: "Best Practices",
+            recommended: true
+        },
+
+        schema: [],
+
+        fixable: "code"
+    },
+
+    create(context) {
+        const sourceCode = context.getSourceCode();
+        let scopeInfo = null;
+
+        /**
+         * Adds a scope info to the stack.
+         *
+         * @param {ASTNode} node - A node to add. This is a LabeledStatement.
+         * @returns {void}
+         */
+        function enterLabeledScope(node) {
+            scopeInfo = {
+                label: node.label.name,
+                used: false,
+                upper: scopeInfo
+            };
+        }
+
+        /**
+         * Removes the top of the stack.
+         * At the same time, this reports the label if it's never used.
+         *
+         * @param {ASTNode} node - A node to report. This is a LabeledStatement.
+         * @returns {void}
+         */
+        function exitLabeledScope(node) {
+            if (!scopeInfo.used) {
+                context.report({
+                    node: node.label,
+                    message: "'{{name}}:' is defined but never used.",
+                    data: node.label,
+                    fix(fixer) {
+
+                        /*
+                         * Only perform a fix if there are no comments between the label and the body. This will be the case
+                         * when there is exactly one token/comment (the ":") between the label and the body.
+                         */
+                        if (sourceCode.getTokenAfter(node.label, { includeComments: true }) ===
+                                sourceCode.getTokenBefore(node.body, { includeComments: true })) {
+                            return fixer.removeRange([node.range[0], node.body.range[0]]);
+                        }
+
+                        return null;
+                    }
+                });
+            }
+
+            scopeInfo = scopeInfo.upper;
+        }
+
+        /**
+         * Marks the label of a given node as used.
+         *
+         * @param {ASTNode} node - A node to mark. This is a BreakStatement or
+         *      ContinueStatement.
+         * @returns {void}
+         */
+        function markAsUsed(node) {
+            if (!node.label) {
+                return;
+            }
+
+            const label = node.label.name;
+            let info = scopeInfo;
+
+            while (info) {
+                if (info.label === label) {
+                    info.used = true;
+                    break;
+                }
+                info = info.upper;
+            }
+        }
+
+        return {
+            LabeledStatement: enterLabeledScope,
+            "LabeledStatement:exit": exitLabeledScope,
+            BreakStatement: markAsUsed,
+            ContinueStatement: markAsUsed
+        };
+    }
+};