Fix class fields when super() is in a default param (#12729)

* Fix class fields when `super()` is in a default param

* Use assertion instead of type cast

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params-complex/input.js

@@ -0,0 +1,6 @@
+class Foo extends Bar {
+  bar = "foo";
+
+  constructor(x = test ? super() : 0) {
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params-complex/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    "proposal-class-properties"
+  ]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params-complex/output.js

@@ -0,0 +1,8 @@
+class Foo extends Bar {
+  constructor(x = test ? (() => {
+    var _temp;
+
+    return _temp = super(), babelHelpers.defineProperty(this, "bar", "foo"), _temp;
+  })() : 0) {}
+
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params-in-arrow/input.js

@@ -0,0 +1,6 @@
+class Foo extends Bar {
+  bar = "foo";
+
+  constructor(x = () => { check(super()) }) {
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params-in-arrow/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    "proposal-class-properties"
+  ]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params-in-arrow/output.js

@@ -0,0 +1,8 @@
+class Foo extends Bar {
+  constructor(x = () => {
+    var _temp;
+
+    check((_temp = super(), babelHelpers.defineProperty(this, "bar", "foo"), _temp));
+  }) {}
+
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params/input.js

@@ -0,0 +1,6 @@
+class Foo extends Bar {
+  bar = "foo";
+
+  constructor(x = super()) {
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    "proposal-class-properties"
+  ]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/public/derived-super-in-default-params/output.js

@@ -0,0 +1,8 @@
+class Foo extends Bar {
+  constructor(x = (() => {
+    var _temp;
+
+    return _temp = super(), babelHelpers.defineProperty(this, "bar", "foo"), _temp;
+  })()) {}
+
+}

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

@@ -95,7 +95,10 @@ export function _containerInsertAfter(this: NodePath, nodes) {
  * expression, ensure that the completion record is correct by pushing the current node.
  */
 
-export function insertAfter(this: NodePath, nodes_: t.Node | t.Node[]) {
+export function insertAfter(
+  this: NodePath,
+  nodes_: t.Node | t.Node[],
+): NodePath[] {
   this._assertUnremoved();
 
   const nodes = this._verifyNodeList(nodes_);
@@ -127,6 +130,17 @@ export function insertAfter(this: NodePath, nodes_: t.Node | t.Node[]) {
     if (this.node) {
       const node = this.node as t.Expression | t.VariableDeclaration;
       let { scope } = this;
+
+      if (scope.path.isPattern()) {
+        t.assertExpression(node);
+
+        this.replaceWith(
+          t.callExpression(t.arrowFunctionExpression([], node), []),
+        );
+        (this.get("callee.body") as NodePath).insertAfter(nodes);
+        return [this];
+      }
+
       // Inserting after the computed key of a method should insert the
       // temporary binding in the method's parent's scope.
       if (parentPath.isMethod({ computed: true, key: node })) {