Correctly transpile when cross-param refs with obj rest (#11326)

* Transform initializers with ids in rest elements

Fix issue 11281. Transform parameters with default initializers that
have ids that are also in a parameter with a rest element.
Before, these parameters were not transformed.

* Add plugin-transform-parameters as dependency

* Remove outdated comment

* Use set instead of array for paramsWithRestElement

* Skip when encounter "Scope"

Previously, f({...R}, f = R => R) would be incorrectly transformed.

* Pass in loose mode option instead of false

* Address review and re-organize tests

Checking the RHS of an assignment pattern/checking the parent of
an identifier node fails on cases like "({...R}, a = f(R))" or
"({...R}, {[R.key]: a = 42})".

Also refactor tests by removing unecessary tests and
separating "should transform" from "should not transform" tests.

packages/babel-plugin-transform-parameters/src/index.js

@@ -1,6 +1,7 @@
 import { declare } from "@babel/helper-plugin-utils";
 import convertFunctionParams from "./params";
 import convertFunctionRest from "./rest";
+export { convertFunctionParams };
 
 export default declare((api, options) => {
   api.assertVersion(7);

packages/babel-plugin-transform-parameters/src/params.js

@@ -41,7 +41,13 @@ const iifeVisitor = {
     path.skip(),
 };
 
-export default function convertFunctionParams(path, loose) {
+// last 2 parameters are optional -- they are used by proposal-object-rest-spread/src/index.js
+export default function convertFunctionParams(
+  path,
+  loose,
+  shouldTransformParam,
+  replaceRestElement,
+) {
   const params = path.get("params");
 
   const isSimpleParameterList = params.every(param => param.isIdentifier());
@@ -108,6 +114,14 @@ export default function convertFunctionParams(path, loose) {
   for (let i = 0; i < params.length; i++) {
     const param = params[i];
 
+    if (shouldTransformParam && !shouldTransformParam(i)) {
+      continue;
+    }
+    const transformedRestNodes = [];
+    if (replaceRestElement) {
+      replaceRestElement(param.parentPath, param, transformedRestNodes);
+    }
+
     const paramIsAssignmentPattern = param.isAssignmentPattern();
     if (paramIsAssignmentPattern && (loose || node.kind === "set")) {
       const left = param.get("left");
@@ -164,6 +178,12 @@ export default function convertFunctionParams(path, loose) {
 
       param.replaceWith(t.cloneNode(uid));
     }
+
+    if (transformedRestNodes) {
+      for (const transformedNode of transformedRestNodes) {
+        body.push(transformedNode);
+      }
+    }
   }
 
   // we need to cut off all trailing parameters