From 63dd253df7f344fed5b643c686b289b6b75842de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hu=C3=A1ng=20J=C3=B9nli=C3=A0ng?= <jlhwung@gmail.com>
Date: Mon, 23 Dec 2019 12:33:21 -0500
Subject: [PATCH] address review comments

---
 packages/babel-traverse/src/path/lib/virtual-types.js | 3 ++-
 packages/babel-traverse/src/scope/index.js            | 4 ++--
 packages/babel-traverse/src/scope/lib/renamer.js      | 3 +--
 packages/babel-traverse/test/scope.js                 | 6 +++---
 packages/babel-types/src/validators/isScope.js        | 2 ++
 5 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/packages/babel-traverse/src/path/lib/virtual-types.js b/packages/babel-traverse/src/path/lib/virtual-types.js
index 97cec0e3af99..d7072d6f6e4a 100644
--- a/packages/babel-traverse/src/path/lib/virtual-types.js
+++ b/packages/babel-traverse/src/path/lib/virtual-types.js
@@ -64,7 +64,8 @@ export const Expression = {
 };
 
 export const Scope = {
-  types: ["Scopable"],
+  // When pattern is inside the function params, it is a scope
+  types: ["Scopable", "Pattern"],
   checkPath(path) {
     return t.isScope(path.node, path.parent);
   },
diff --git a/packages/babel-traverse/src/scope/index.js b/packages/babel-traverse/src/scope/index.js
index d1ebaf15a099..9f9d78667336 100644
--- a/packages/babel-traverse/src/scope/index.js
+++ b/packages/babel-traverse/src/scope/index.js
@@ -902,14 +902,14 @@ export default class Scope {
     do {
       const binding = scope.getOwnBinding(name);
       if (binding) {
-        // When a pattern is a Scope, it is a part of parameter expressions.
+        // Check if a pattern is a part of parameter expressions.
         // 9.2.10.28: The closure created by this expression should not have visibility of
         // declarations in the function body. If the binding is not a `param`-kind,
         // then it must be defined inside the function body, thus it should be skipped
         if (
           previousPath &&
           previousPath.isPattern() &&
-          previousPath.isScope() &&
+          previousPath.parentPath.isFunction() &&
           binding.kind !== "param"
         ) {
           // do nothing
diff --git a/packages/babel-traverse/src/scope/lib/renamer.js b/packages/babel-traverse/src/scope/lib/renamer.js
index 98c16a2e1863..cdfd90819681 100644
--- a/packages/babel-traverse/src/scope/lib/renamer.js
+++ b/packages/babel-traverse/src/scope/lib/renamer.js
@@ -9,9 +9,8 @@ const renameVisitor = {
     }
   },
 
-  "Pattern|Scope"(path, state) {
+  Scope(path, state) {
     if (
-      path.isScope() &&
       !path.scope.bindingIdentifierEquals(
         state.oldName,
         state.binding.identifier,
diff --git a/packages/babel-traverse/test/scope.js b/packages/babel-traverse/test/scope.js
index a40402a2d924..b796dbf682f5 100644
--- a/packages/babel-traverse/test/scope.js
+++ b/packages/babel-traverse/test/scope.js
@@ -73,8 +73,8 @@ describe("scope", () => {
       ).toBe("Identifier");
     });
 
-    describe("function paramater expression", function() {
-      it("should not has visibility of declarations inside function body", () => {
+    describe("function parameter expression", function() {
+      it("should not have visibility of declarations inside function body", () => {
         expect(
           getPath(
             `var a = "outside"; (function foo(b = a) { let a = "inside" })`,
@@ -83,7 +83,7 @@ describe("scope", () => {
             .scope.getBinding("a").path.node.init.value,
         ).toBe("outside");
       });
-      it("should has visibility on paramater bindings", () => {
+      it("should have visibility on parameter bindings", () => {
         expect(
           getPath(`var a = "outside"; (function foo(b = a, a = "inside") {})`)
             .get("body.1.expression.params.0")
diff --git a/packages/babel-types/src/validators/isScope.js b/packages/babel-types/src/validators/isScope.js
index e7ddcb2ce3ef..dfd2f5edd96f 100644
--- a/packages/babel-types/src/validators/isScope.js
+++ b/packages/babel-types/src/validators/isScope.js
@@ -19,6 +19,8 @@ export default function isScope(node: Object, parent: Object): boolean {
     return false;
   }
 
+  // If a Pattern is an immediate descendent of a Function, it must be in the params.
+  // Hence we skipped the parentKey === "params" check
   if (isPattern(node) && isFunction(parent)) {
     return true;
   }