Remove await* from babel-generator, add parsing error to babylon - (fixes T6688)

packages/babel-generator/src/generators/expressions.js

@@ -118,7 +118,7 @@ function buildYieldAwait(keyword: string) {
   return function (node: Object) {
     this.push(keyword);
 
-    if (node.delegate || node.all) {
+    if (node.delegate) {
       this.push("*");
     }
 

packages/babel-generator/test/fixtures/types/AwaitExpression/actual.js

@@ -1,7 +1,3 @@
 async function foo() {
   await bar();
 }
-
-async function bar() {
-  await* foo();
-}

packages/babel-generator/test/fixtures/types/AwaitExpression/expected.js

@@ -1,7 +1,3 @@
 async function foo() {
   await bar();
 }
-
-async function bar() {
-  await* foo();
-}

packages/babel-plugin-transform-regenerator/src/visit.js

@@ -247,7 +247,7 @@ let awaitVisitor = {
   },
 
   AwaitExpression: function(path) {
-    // Convert await and await* expressions to yield expressions.
+    // Convert await expressions to yield expressions.
     let argument = path.node.argument;
 
     // Transforming `await x` to `yield regeneratorRuntime.awrap(x)`

packages/babylon/src/parser/expression.js

@@ -968,7 +968,10 @@ pp.parseAwait = function (node) {
   if (this.isLineTerminator()) {
     this.unexpected();
   }
-  node.all = this.eat(tt.star);
+  node.all = false;
+  if (this.match(tt.star)) {
+    this.raise(node.start, "await* has been removed from the async functions proposal. Use Promise.all() instead.")
+  }
   node.argument = this.parseMaybeUnary();
   return this.finishNode(node, "AwaitExpression");
 };

packages/babylon/test/fixtures/experimental/await/illegal-await-star/actual.js

@@ -0,0 +1,3 @@
+async function bar() {
+  await* foo();
+}

packages/babylon/test/fixtures/experimental/await/illegal-await-star/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["asyncFunctions"],
+  "throws": "await* has been removed from the async functions proposal. Use Promise.all() instead. (2:2)"
+}