Avoid adding #__PURE__ annotation to .bind(this)() expressions (#7043)

* Avoid adding #__PURE__ annotation to .bind(this)() expressions

Fixes the #__PURE__ annotation getting added to (async () => {})() IIFEs when the arrow function transform is running with spec: true.

* Return false instead of undefined

* Fix indentation in json files

* Add one more case to the async-iife fixtures

packages/babel-helper-remap-async-to-generator/src/index.js

@@ -68,7 +68,7 @@ export default function(path: NodePath, file: Object, helpers: Object) {
     wrapAwait: helpers.wrapAwait,
   });
 
-  const isIIFE = path.parentPath.isCallExpression({ callee: path.node });
+  const isIIFE = checkIsIIFE(path);
 
   path.node.async = false;
   path.node.generator = true;
@@ -84,4 +84,34 @@ export default function(path: NodePath, file: Object, helpers: Object) {
   if (!isProperty && !isIIFE && path.isExpression()) {
     annotateAsPure(path);
   }
+
+  function checkIsIIFE(path: NodePath) {
+    if (path.parentPath.isCallExpression({ callee: path.node })) {
+      return true;
+    }
+
+    // try to catch calls to Function#bind, as emitted by arrowFunctionToExpression in spec mode
+    // this may also catch .bind(this) written by users, but does it matter? 🤔
+    const { parentPath } = path;
+    if (
+      parentPath.isMemberExpression() &&
+      t.isIdentifier(parentPath.node.property, { name: "bind" })
+    ) {
+      const { parentPath: bindCall } = parentPath;
+
+      // (function () { ... }).bind(this)()
+
+      return (
+        // first, check if the .bind is actually being called
+        bindCall.isCallExpression() &&
+        // and whether its sole argument is 'this'
+        bindCall.node.arguments.length === 1 &&
+        t.isThisExpression(bindCall.node.arguments[0]) &&
+        // and whether the result of the .bind(this) is being called
+        bindCall.parentPath.isCallExpression({ callee: bindCall.node })
+      );
+    }
+
+    return false;
+  }
 }

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-iife-with-regenerator-spec/actual.js

@@ -0,0 +1,4 @@
+(async function() { await 'ok' })();
+(async () => { await 'ok' })();
+(async function notIIFE() { await 'ok' });
+(async () => { await 'not iife' });

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-iife-with-regenerator-spec/expected.js

@@ -0,0 +1,74 @@
+var _this = this;
+
+babelHelpers.asyncToGenerator(
+/*#__PURE__*/
+regeneratorRuntime.mark(function _callee() {
+  return regeneratorRuntime.wrap(function _callee$(_context) {
+    while (1) switch (_context.prev = _context.next) {
+      case 0:
+        _context.next = 2;
+        return 'ok';
+
+      case 2:
+      case "end":
+        return _context.stop();
+    }
+  }, _callee, this);
+}))();
+babelHelpers.asyncToGenerator(
+/*#__PURE__*/
+regeneratorRuntime.mark(function _callee2() {
+  return regeneratorRuntime.wrap(function _callee2$(_context2) {
+    while (1) switch (_context2.prev = _context2.next) {
+      case 0:
+        babelHelpers.newArrowCheck(this, _this);
+        _context2.next = 3;
+        return 'ok';
+
+      case 3:
+      case "end":
+        return _context2.stop();
+    }
+  }, _callee2, this);
+})).bind(this)();
+
+/*#__PURE__*/
+(function () {
+  var _notIIFE = babelHelpers.asyncToGenerator(
+  /*#__PURE__*/
+  regeneratorRuntime.mark(function _callee3() {
+    return regeneratorRuntime.wrap(function _callee3$(_context3) {
+      while (1) switch (_context3.prev = _context3.next) {
+        case 0:
+          _context3.next = 2;
+          return 'ok';
+
+        case 2:
+        case "end":
+          return _context3.stop();
+      }
+    }, _callee3, this);
+  }));
+
+  return function notIIFE() {
+    return _notIIFE.apply(this, arguments);
+  };
+})();
+
+/*#__PURE__*/
+babelHelpers.asyncToGenerator(
+/*#__PURE__*/
+regeneratorRuntime.mark(function _callee4() {
+  return regeneratorRuntime.wrap(function _callee4$(_context4) {
+    while (1) switch (_context4.prev = _context4.next) {
+      case 0:
+        babelHelpers.newArrowCheck(this, _this);
+        _context4.next = 3;
+        return 'not iife';
+
+      case 3:
+      case "end":
+        return _context4.stop();
+    }
+  }, _callee4, this);
+})).bind(this);

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-iife-with-regenerator-spec/options.json

@@ -0,0 +1,8 @@
+{
+	"plugins": [
+		["transform-arrow-functions", { "spec": true }],
+		"transform-regenerator",
+		"transform-async-to-generator",
+		"external-helpers"
+	]
+}

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-iife-with-regenerator/actual.js

@@ -0,0 +1,4 @@
+(async function() { await 'ok' })();
+(async () => { await 'ok' })();
+(async function notIIFE() { await 'ok' });
+(async () => { await 'not iife' });

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-iife-with-regenerator/expected.js

@@ -0,0 +1,70 @@
+babelHelpers.asyncToGenerator(
+/*#__PURE__*/
+regeneratorRuntime.mark(function _callee() {
+  return regeneratorRuntime.wrap(function _callee$(_context) {
+    while (1) switch (_context.prev = _context.next) {
+      case 0:
+        _context.next = 2;
+        return 'ok';
+
+      case 2:
+      case "end":
+        return _context.stop();
+    }
+  }, _callee, this);
+}))();
+babelHelpers.asyncToGenerator(
+/*#__PURE__*/
+regeneratorRuntime.mark(function _callee2() {
+  return regeneratorRuntime.wrap(function _callee2$(_context2) {
+    while (1) switch (_context2.prev = _context2.next) {
+      case 0:
+        _context2.next = 2;
+        return 'ok';
+
+      case 2:
+      case "end":
+        return _context2.stop();
+    }
+  }, _callee2, this);
+}))();
+
+/*#__PURE__*/
+(function () {
+  var _notIIFE = babelHelpers.asyncToGenerator(
+  /*#__PURE__*/
+  regeneratorRuntime.mark(function _callee3() {
+    return regeneratorRuntime.wrap(function _callee3$(_context3) {
+      while (1) switch (_context3.prev = _context3.next) {
+        case 0:
+          _context3.next = 2;
+          return 'ok';
+
+        case 2:
+        case "end":
+          return _context3.stop();
+      }
+    }, _callee3, this);
+  }));
+
+  return function notIIFE() {
+    return _notIIFE.apply(this, arguments);
+  };
+})();
+
+/*#__PURE__*/
+babelHelpers.asyncToGenerator(
+/*#__PURE__*/
+regeneratorRuntime.mark(function _callee4() {
+  return regeneratorRuntime.wrap(function _callee4$(_context4) {
+    while (1) switch (_context4.prev = _context4.next) {
+      case 0:
+        _context4.next = 2;
+        return 'not iife';
+
+      case 2:
+      case "end":
+        return _context4.stop();
+    }
+  }, _callee4, this);
+}));

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-iife-with-regenerator/options.json

@@ -0,0 +1,8 @@
+{
+	"plugins": [
+		"transform-arrow-functions",
+		"transform-regenerator",
+		"transform-async-to-generator",
+		"external-helpers"
+	]
+}

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-iife/actual.js

@@ -1,3 +1,4 @@
 (async function() { await 'ok' })();
 (async () => { await 'ok' })();
 (async function notIIFE() { await 'ok' });
+(async () => { await 'not iife' });

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-iife/expected.js

@@ -15,3 +15,8 @@ babelHelpers.asyncToGenerator(function* () {
     return _notIIFE.apply(this, arguments);
   };
 })();
+
+/*#__PURE__*/
+babelHelpers.asyncToGenerator(function* () {
+  yield 'not iife';
+});