tools: move eslint from tools to tools/node_modules

This is required because we need to add the babel-eslint dependency
and it has to be able to resolve "eslint".
babel-eslint is required to support future ES features such as async
iterators and import.meta.

Refs: https://github.com/nodejs/node/pull/17755
PR-URL: https://github.com/nodejs/node/pull/17820
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/tools/node_modules/eslint/lib/rules/no-func-assign.js b/tools/node_modules/eslint/lib/rules/no-func-assign.js
new file mode 100644
index 0000000000..ea86365b29
--- /dev/null
+++ b/tools/node_modules/eslint/lib/rules/no-func-assign.js
@@ -0,0 +1,63 @@
+/**
+ * @fileoverview Rule to flag use of function declaration identifiers as variables.
+ * @author Ian Christian Myers
+ */
+
+"use strict";
+
+const astUtils = require("../ast-utils");
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow reassigning `function` declarations",
+            category: "Possible Errors",
+            recommended: true
+        },
+
+        schema: []
+    },
+
+    create(context) {
+
+        /**
+         * Reports a reference if is non initializer and writable.
+         * @param {References} references - Collection of reference to check.
+         * @returns {void}
+         */
+        function checkReference(references) {
+            astUtils.getModifyingReferences(references).forEach(reference => {
+                context.report({ node: reference.identifier, message: "'{{name}}' is a function.", data: { name: reference.identifier.name } });
+            });
+        }
+
+        /**
+         * Finds and reports references that are non initializer and writable.
+         * @param {Variable} variable - A variable to check.
+         * @returns {void}
+         */
+        function checkVariable(variable) {
+            if (variable.defs[0].type === "FunctionName") {
+                checkReference(variable.references);
+            }
+        }
+
+        /**
+         * Checks parameters of a given function node.
+         * @param {ASTNode} node - A function node to check.
+         * @returns {void}
+         */
+        function checkForFunction(node) {
+            context.getDeclaredVariables(node).forEach(checkVariable);
+        }
+
+        return {
+            FunctionDeclaration: checkForFunction,
+            FunctionExpression: checkForFunction
+        };
+    }
+};