Do not remove bindings when removing assignment expression path (#16131)

* Add failing test

* Fix it

packages/babel-traverse/src/path/removal.ts

@@ -4,6 +4,7 @@ import { hooks } from "./lib/removal-hooks.ts";
 import { getCachedPaths } from "../cache.ts";
 import type NodePath from "./index.ts";
 import { REMOVED, SHOULD_SKIP } from "./index.ts";
+import { getBindingIdentifiers } from "@babel/types";
 
 export function remove(this: NodePath) {
   this._assertUnremoved();
@@ -24,7 +25,7 @@ export function remove(this: NodePath) {
 }
 
 export function _removeFromScope(this: NodePath) {
-  const bindings = this.getBindingIdentifiers();
+  const bindings = getBindingIdentifiers(this.node, false, false, true);
   Object.keys(bindings).forEach(name => this.scope.removeBinding(name));
 }
 

packages/babel-traverse/test/removal.js

@@ -144,4 +144,12 @@ describe("removal", function () {
       expect(ifPath.get("alternate").node).toBeNull();
     });
   });
+
+  it("of AssignmentExpression does not remove binding", function () {
+    const rootPath = getPath("var x; x = 1;");
+    const path = rootPath.get("body.1.expression");
+    path.remove();
+
+    expect(rootPath.scope.hasBinding("x")).toBe(true);
+  });
 });

packages/babel-types/src/retrievers/getBindingIdentifiers.ts

@@ -5,6 +5,8 @@ import {
   isFunctionDeclaration,
   isFunctionExpression,
   isExportAllDeclaration,
+  isAssignmentExpression,
+  isUnaryExpression,
 } from "../validators/generated/index.ts";
 import type * as t from "../index.ts";
 
@@ -14,18 +16,21 @@ function getBindingIdentifiers(
   node: t.Node,
   duplicates: true,
   outerOnly?: boolean,
+  newBindingsOnly?: boolean,
 ): Record<string, Array<t.Identifier>>;
 
 function getBindingIdentifiers(
   node: t.Node,
   duplicates?: false,
   outerOnly?: boolean,
+  newBindingsOnly?: boolean,
 ): Record<string, t.Identifier>;
 
 function getBindingIdentifiers(
   node: t.Node,
   duplicates?: boolean,
   outerOnly?: boolean,
+  newBindingsOnly?: boolean,
 ): Record<string, t.Identifier> | Record<string, Array<t.Identifier>>;
 
 /**
@@ -35,6 +40,7 @@ function getBindingIdentifiers(
   node: t.Node,
   duplicates?: boolean,
   outerOnly?: boolean,
+  newBindingsOnly?: boolean,
 ): Record<string, t.Identifier> | Record<string, Array<t.Identifier>> {
   const search: t.Node[] = [].concat(node);
   const ids = Object.create(null);
@@ -43,6 +49,18 @@ function getBindingIdentifiers(
     const id = search.shift();
     if (!id) continue;
 
+    if (
+      newBindingsOnly &&
+      // These two nodes do not introduce _new_ bindings, but they are included
+      // in getBindingIdentifiers.keys for backwards compatibility.
+      // TODO(@nicolo-ribaudo): Check if we can remove them from .keys in a
+      // backward-compatible way, and if not what we need to do to remove them
+      // in Babel 8.
+      (isAssignmentExpression(id) || isUnaryExpression(id))
+    ) {
+      continue;
+    }
+
     const keys =
       // @ts-expect-error getBindingIdentifiers.keys do not cover all AST types
       getBindingIdentifiers.keys[id.type];