From c4f6a7a06f9ec4b3203da1a372159f4807d13b08 Mon Sep 17 00:00:00 2001
From: Ben Newman <ben@benjamn.com>
Date: Mon, 11 Sep 2017 11:16:14 -0400
Subject: [PATCH] Add failing test case for object rest after array rest, and
 fix it. (#6213)

* Add failing test case for object rest after array rest.

Discovered while upgrading https://github.com/meteor/babel to Babel 7.

The error is:

  1) babel-plugin-transform-object-rest-spread/object rest with array rest:
     TypeError: /Users/ben/dev/babel/packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/actual.js: Property id of VariableDeclarator expected node to be of a type ["LVal"] but instead got null
      at Object.validate (packages/babel-types/lib/definitions/index.js:73:13)
      at validate (packages/babel-types/lib/index.js:460:9)
      at Object.builder (packages/babel-types/lib/index.js:428:7)
      at Object.RestElement (packages/babel-plugin-transform-object-rest-spread/lib/index.js:157:41)
      at NodePath._call (packages/babel-traverse/lib/path/context.js:53:20)
      at NodePath.call (packages/babel-traverse/lib/path/context.js:40:17)
      at NodePath.visit (packages/babel-traverse/lib/path/context.js:84:12)
      ...

* Fix object rest following array rest. (#6213)

* Avoid treating array ...rest elements as object ...rest properties.

* Also avoid treating ...rest parameters as object ...rest properties.

Returning early if the parent was an ArrayPattern was not quite enough,
since a RestElement can appear as a parameter in a Function as well.

* Move RestElement parent check earlier in visitor method.
---
 .../src/index.js                              | 19 +++++++++++++++----
 .../object-rest/with-array-rest/actual.js     |  8 ++++++++
 .../object-rest/with-array-rest/expected.js   |  9 +++++++++
 3 files changed, 32 insertions(+), 4 deletions(-)
 create mode 100644 packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/actual.js
 create mode 100644 packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/expected.js

diff --git a/packages/babel-plugin-transform-object-rest-spread/src/index.js b/packages/babel-plugin-transform-object-rest-spread/src/index.js
index c96358fed1..a33cff0217 100644
--- a/packages/babel-plugin-transform-object-rest-spread/src/index.js
+++ b/packages/babel-plugin-transform-object-rest-spread/src/index.js
@@ -65,9 +65,11 @@ export default function({ types: t }) {
 
   //expects path to an object pattern
   function createObjectSpread(path, file, objRef) {
-    const last = path.get("properties").pop(); // note: popping does not mean removal from path
+    const props = path.get("properties");
+    const last = props[props.length - 1];
+    t.assertRestElement(last.node);
     const restElement = t.clone(last.node);
-    last.remove(); // remove restElement
+    last.remove();
 
     const impureComputedPropertyDeclarators = replaceImpureComputedKeys(path);
     const { keys, allLiteral } = extractNormalizedKeys(path);
@@ -144,6 +146,13 @@ export default function({ types: t }) {
         path.get("id").traverse(
           {
             RestElement(path) {
+              if (!path.parentPath.isObjectPattern()) {
+                // Return early if the parent is not an ObjectPattern, but
+                // (for example) an ArrayPattern or Function, because that
+                // means this RestElement is an not an object property.
+                return;
+              }
+
               if (
                 // skip single-property case, e.g.
                 // const { ...x } = foo();
@@ -197,6 +206,8 @@ export default function({ types: t }) {
                 callExpression,
               ] = createObjectSpread(objectPatternPath, file, ref);
 
+              t.assertIdentifier(argument);
+
               insertionPath.insertBefore(impureComputedPropertyDeclarators);
 
               insertionPath.insertAfter(
@@ -205,8 +216,8 @@ export default function({ types: t }) {
 
               insertionPath = insertionPath.getSibling(insertionPath.key + 1);
 
-              if (path.parentPath.node.properties.length === 0) {
-                path
+              if (objectPatternPath.node.properties.length === 0) {
+                objectPatternPath
                   .findParent(
                     path =>
                       path.isObjectProperty() || path.isVariableDeclarator(),
diff --git a/packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/actual.js b/packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/actual.js
new file mode 100644
index 0000000000..acbe7b35fb
--- /dev/null
+++ b/packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/actual.js
@@ -0,0 +1,8 @@
+let {
+  a: [b, ...arrayRest],
+  c = function(...functionRest){},
+  ...objectRest
+} = {
+  a: [1, 2, 3, 4],
+  d: "oyez"
+};
diff --git a/packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/expected.js b/packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/expected.js
new file mode 100644
index 0000000000..743129f1bb
--- /dev/null
+++ b/packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/with-array-rest/expected.js
@@ -0,0 +1,9 @@
+let _a$d = {
+  a: [1, 2, 3, 4],
+  d: "oyez"
+},
+    {
+  a: [b, ...arrayRest],
+  c = function (...functionRest) {}
+} = _a$d,
+    objectRest = babelHelpers.objectWithoutProperties(_a$d, ["a", "c"]);