Parse async do expressions (#13043)

* parse async do expressions

* add test cases

* update test fixtures

* chore: add syntax-async-do-expressions

* generater support

* fix: do not transform async do expressions

* chore: add asyncDoExpressions to missing plugin helpers

* update ast types

* add more test cases

* throw when asyncDoExpressions is enabled but not doExpressions

* avoid add parentheses for async do expressions

* address review comments

* chore: update parser typings

packages/babel-core/src/parser/util/missing-plugin-helper.ts

@@ -1,4 +1,10 @@
 const pluginNameMap = {
+  asyncDoExpressions: {
+    syntax: {
+      name: "@babel/plugin-syntax-async-do-expressions",
+      url: "https://git.io/JYer8",
+    },
+  },
   classProperties: {
     syntax: {
       name: "@babel/plugin-syntax-class-properties",

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

@@ -20,6 +20,10 @@ export function UnaryExpression(this: Printer, node: t.UnaryExpression) {
 }
 
 export function DoExpression(this: Printer, node: t.DoExpression) {
+  if (node.async) {
+    this.word("async");
+    this.space();
+  }
   this.word("do");
   this.space();
   this.print(node.body, node);

packages/babel-generator/src/node/parentheses.ts

@@ -82,7 +82,8 @@ export function DoExpression(
   parent: any,
   printStack: Array<any>,
 ): boolean {
-  return isFirstInStatement(printStack);
+  // `async do` can start an expression statement
+  return !node.async && isFirstInStatement(printStack);
 }
 
 export function Binary(node: any, parent: any): boolean {

packages/babel-generator/test/fixtures/async-do-expressions/basic/input.js

@@ -0,0 +1,5 @@
+async do {
+  1;
+};
+
+(async do {});

packages/babel-generator/test/fixtures/async-do-expressions/basic/output.js

@@ -0,0 +1,4 @@
+async do {
+  1;
+};
+async do {};

packages/babel-generator/test/fixtures/async-do-expressions/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["asyncDoExpressions", "doExpressions"]
+}

packages/babel-generator/test/fixtures/async-do-expressions/retain-lines/input.js

@@ -0,0 +1,3 @@
+/* leading comments
+*/async do
+{ 1 } + 0;

packages/babel-generator/test/fixtures/async-do-expressions/retain-lines/options.json

@@ -0,0 +1,3 @@
+{
+  "retainLines": true
+}

packages/babel-generator/test/fixtures/async-do-expressions/retain-lines/output.js

@@ -0,0 +1,3 @@
+/* leading comments
+*/async do
+{1;} + 0;

packages/babel-parser/ast/spec.md

@@ -1084,6 +1084,7 @@ An expression wrapped by parentheses. By default `@babel/parser` does not create
 interface DoExpression <: Expression {
   type: "DoExpression";
   body: BlockStatement;
+  async: boolean;
 }
 ```
 

packages/babel-parser/src/parser/expression.js

@@ -1033,6 +1033,8 @@ export default class ExpressionParser extends LValParser {
             );
           } else if (this.match(tt.name)) {
             return this.parseAsyncArrowUnaryFunction(id);
+          } else if (this.match(tt._do)) {
+            return this.parseDo(true);
           }
         }
 
@@ -1049,7 +1051,7 @@ export default class ExpressionParser extends LValParser {
       }
 
       case tt._do: {
-        return this.parseDo();
+        return this.parseDo(false);
       }
 
       case tt.regexp: {
@@ -1231,13 +1233,27 @@ export default class ExpressionParser extends LValParser {
   }
 
   // https://github.com/tc39/proposal-do-expressions
-  parseDo(): N.DoExpression {
+  // https://github.com/tc39/proposal-async-do-expressions
+  parseDo(isAsync: boolean): N.DoExpression {
     this.expectPlugin("doExpressions");
+    if (isAsync) {
+      this.expectPlugin("asyncDoExpressions");
+    }
     const node = this.startNode();
+    node.async = isAsync;
     this.next(); // eat `do`
     const oldLabels = this.state.labels;
     this.state.labels = [];
-    node.body = this.parseBlock();
+    if (isAsync) {
+      // AsyncDoExpression :
+      // async [no LineTerminator here] do Block[~Yield, +Await, ~Return]
+      this.prodParam.enter(PARAM_AWAIT);
+      node.body = this.parseBlock();
+      this.prodParam.exit();
+    } else {
+      node.body = this.parseBlock();
+    }
+
     this.state.labels = oldLabels;
     return this.finishNode(node, "DoExpression");
   }

packages/babel-parser/src/plugin-utils.js

@@ -117,6 +117,18 @@ export function validatePlugins(plugins: PluginList) {
         RECORD_AND_TUPLE_SYNTAX_TYPES.map(p => `'${p}'`).join(", "),
     );
   }
+
+  if (
+    hasPlugin(plugins, "asyncDoExpressions") &&
+    !hasPlugin(plugins, "doExpressions")
+  ) {
+    const error = new Error(
+      "'asyncDoExpressions' requires 'doExpressions', please add 'doExpressions' to parser plugins.",
+    );
+    // $FlowIgnore
+    error.missingPlugins = "doExpressions"; // so @babel/core can provide better error message
+    throw error;
+  }
 }
 
 // These plugins are defined using a mixin which extends the parser class.

packages/babel-parser/src/types.js

@@ -402,6 +402,7 @@ export type ArrayExpression = NodeBase & {
 export type DoExpression = NodeBase & {
   type: "DoExpression",
   body: ?BlockStatement,
+  async: boolean,
 };
 
 export type TupleExpression = NodeBase & {

packages/babel-parser/test/fixtures/experimental/_no-plugin/async-do-expressions-with-do-expressions/input.js

@@ -0,0 +1 @@
+(async do {x})

packages/babel-parser/test/fixtures/experimental/_no-plugin/async-do-expressions-with-do-expressions/options.json

@@ -0,0 +1,6 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'asyncDoExpressions' (1:7)",
+  "plugins": [
+    "doExpressions"
+  ]
+}

packages/babel-parser/test/fixtures/experimental/_no-plugin/async-do-expressions/input.js

@@ -0,0 +1 @@
+(async do {x})

packages/babel-parser/test/fixtures/experimental/_no-plugin/async-do-expressions/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'doExpressions' (1:7)",
+  "plugins": []
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/asi-async-and-do-while/input.js

@@ -0,0 +1,5 @@
+async
+do {
+  42
+}
+while (false);

packages/babel-parser/test/fixtures/experimental/async-do-expressions/asi-async-and-do-while/output.json

@@ -0,0 +1,51 @@
+{
+  "type": "File",
+  "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5}},
+        "expression": {
+          "type": "Identifier",
+          "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"async"},
+          "name": "async"
+        }
+      },
+      {
+        "type": "DoWhileStatement",
+        "start":6,"end":32,"loc":{"start":{"line":2,"column":0},"end":{"line":5,"column":14}},
+        "body": {
+          "type": "BlockStatement",
+          "start":9,"end":17,"loc":{"start":{"line":2,"column":3},"end":{"line":4,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":13,"end":15,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":4}},
+              "expression": {
+                "type": "NumericLiteral",
+                "start":13,"end":15,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":4}},
+                "extra": {
+                  "rawValue": 42,
+                  "raw": "42"
+                },
+                "value": 42
+              }
+            }
+          ],
+          "directives": []
+        },
+        "test": {
+          "type": "BooleanLiteral",
+          "start":25,"end":30,"loc":{"start":{"line":5,"column":7},"end":{"line":5,"column":12}},
+          "value": false
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/asi-async-do-and-while/input.js

@@ -0,0 +1,4 @@
+async do {
+  42
+}
+while (false);

packages/babel-parser/test/fixtures/experimental/async-do-expressions/asi-async-do-and-while/output.json

@@ -0,0 +1,55 @@
+{
+  "type": "File",
+  "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "expression": {
+          "type": "DoExpression",
+          "start":6,"end":17,"loc":{"start":{"line":1,"column":6},"end":{"line":3,"column":1}},
+          "async": true,
+          "body": {
+            "type": "BlockStatement",
+            "start":9,"end":17,"loc":{"start":{"line":1,"column":9},"end":{"line":3,"column":1}},
+            "body": [
+              {
+                "type": "ExpressionStatement",
+                "start":13,"end":15,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":4}},
+                "expression": {
+                  "type": "NumericLiteral",
+                  "start":13,"end":15,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":4}},
+                  "extra": {
+                    "rawValue": 42,
+                    "raw": "42"
+                  },
+                  "value": 42
+                }
+              }
+            ],
+            "directives": []
+          }
+        }
+      },
+      {
+        "type": "WhileStatement",
+        "start":18,"end":32,"loc":{"start":{"line":4,"column":0},"end":{"line":4,"column":14}},
+        "test": {
+          "type": "BooleanLiteral",
+          "start":25,"end":30,"loc":{"start":{"line":4,"column":7},"end":{"line":4,"column":12}},
+          "value": false
+        },
+        "body": {
+          "type": "EmptyStatement",
+          "start":31,"end":32,"loc":{"start":{"line":4,"column":13},"end":{"line":4,"column":14}}
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/asi/input.js

@@ -0,0 +1,4 @@
+async
+do {
+  42
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/asi/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token, expected \"while\" (4:1)"
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/conditional-statement/input.js

@@ -0,0 +1,5 @@
+let x = async do {
+  if (foo()) { f() }
+  else if (bar()) { g() }
+  else { h() }
+};

packages/babel-parser/test/fixtures/experimental/async-do-expressions/conditional-statement/output.json

@@ -0,0 +1,132 @@
+{
+  "type": "File",
+  "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start":4,"end":82,"loc":{"start":{"line":1,"column":4},"end":{"line":5,"column":1}},
+            "id": {
+              "type": "Identifier",
+              "start":4,"end":5,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":5},"identifierName":"x"},
+              "name": "x"
+            },
+            "init": {
+              "type": "DoExpression",
+              "start":14,"end":82,"loc":{"start":{"line":1,"column":14},"end":{"line":5,"column":1}},
+              "async": true,
+              "body": {
+                "type": "BlockStatement",
+                "start":17,"end":82,"loc":{"start":{"line":1,"column":17},"end":{"line":5,"column":1}},
+                "body": [
+                  {
+                    "type": "IfStatement",
+                    "start":21,"end":80,"loc":{"start":{"line":2,"column":2},"end":{"line":4,"column":14}},
+                    "test": {
+                      "type": "CallExpression",
+                      "start":25,"end":30,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":11}},
+                      "callee": {
+                        "type": "Identifier",
+                        "start":25,"end":28,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":9},"identifierName":"foo"},
+                        "name": "foo"
+                      },
+                      "arguments": []
+                    },
+                    "consequent": {
+                      "type": "BlockStatement",
+                      "start":32,"end":39,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":20}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":34,"end":37,"loc":{"start":{"line":2,"column":15},"end":{"line":2,"column":18}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":34,"end":37,"loc":{"start":{"line":2,"column":15},"end":{"line":2,"column":18}},
+                            "callee": {
+                              "type": "Identifier",
+                              "start":34,"end":35,"loc":{"start":{"line":2,"column":15},"end":{"line":2,"column":16},"identifierName":"f"},
+                              "name": "f"
+                            },
+                            "arguments": []
+                          }
+                        }
+                      ],
+                      "directives": []
+                    },
+                    "alternate": {
+                      "type": "IfStatement",
+                      "start":47,"end":80,"loc":{"start":{"line":3,"column":7},"end":{"line":4,"column":14}},
+                      "test": {
+                        "type": "CallExpression",
+                        "start":51,"end":56,"loc":{"start":{"line":3,"column":11},"end":{"line":3,"column":16}},
+                        "callee": {
+                          "type": "Identifier",
+                          "start":51,"end":54,"loc":{"start":{"line":3,"column":11},"end":{"line":3,"column":14},"identifierName":"bar"},
+                          "name": "bar"
+                        },
+                        "arguments": []
+                      },
+                      "consequent": {
+                        "type": "BlockStatement",
+                        "start":58,"end":65,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25}},
+                        "body": [
+                          {
+                            "type": "ExpressionStatement",
+                            "start":60,"end":63,"loc":{"start":{"line":3,"column":20},"end":{"line":3,"column":23}},
+                            "expression": {
+                              "type": "CallExpression",
+                              "start":60,"end":63,"loc":{"start":{"line":3,"column":20},"end":{"line":3,"column":23}},
+                              "callee": {
+                                "type": "Identifier",
+                                "start":60,"end":61,"loc":{"start":{"line":3,"column":20},"end":{"line":3,"column":21},"identifierName":"g"},
+                                "name": "g"
+                              },
+                              "arguments": []
+                            }
+                          }
+                        ],
+                        "directives": []
+                      },
+                      "alternate": {
+                        "type": "BlockStatement",
+                        "start":73,"end":80,"loc":{"start":{"line":4,"column":7},"end":{"line":4,"column":14}},
+                        "body": [
+                          {
+                            "type": "ExpressionStatement",
+                            "start":75,"end":78,"loc":{"start":{"line":4,"column":9},"end":{"line":4,"column":12}},
+                            "expression": {
+                              "type": "CallExpression",
+                              "start":75,"end":78,"loc":{"start":{"line":4,"column":9},"end":{"line":4,"column":12}},
+                              "callee": {
+                                "type": "Identifier",
+                                "start":75,"end":76,"loc":{"start":{"line":4,"column":9},"end":{"line":4,"column":10},"identifierName":"h"},
+                                "name": "h"
+                              },
+                              "arguments": []
+                            }
+                          }
+                        ],
+                        "directives": []
+                      }
+                    }
+                  }
+                ],
+                "directives": []
+              }
+            }
+          }
+        ],
+        "kind": "let"
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/expression-statement/input.js

@@ -0,0 +1,3 @@
+async do {
+  await 42
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/expression-statement/output.json

@@ -0,0 +1,46 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "expression": {
+          "type": "DoExpression",
+          "start":6,"end":23,"loc":{"start":{"line":1,"column":6},"end":{"line":3,"column":1}},
+          "async": true,
+          "body": {
+            "type": "BlockStatement",
+            "start":9,"end":23,"loc":{"start":{"line":1,"column":9},"end":{"line":3,"column":1}},
+            "body": [
+              {
+                "type": "ExpressionStatement",
+                "start":13,"end":21,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":10}},
+                "expression": {
+                  "type": "AwaitExpression",
+                  "start":13,"end":21,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":10}},
+                  "argument": {
+                    "type": "NumericLiteral",
+                    "start":19,"end":21,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":10}},
+                    "extra": {
+                      "rawValue": 42,
+                      "raw": "42"
+                    },
+                    "value": 42
+                  }
+                }
+              }
+            ],
+            "directives": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/invalid-break/input.js

@@ -0,0 +1,8 @@
+function iter() {
+  switch(1) {
+    default:
+      var x = async do {
+        break;
+      }
+  }
+};

packages/babel-parser/test/fixtures/experimental/async-do-expressions/invalid-break/output.json

@@ -0,0 +1,94 @@
+{
+  "type": "File",
+  "start":0,"end":99,"loc":{"start":{"line":1,"column":0},"end":{"line":8,"column":2}},
+  "errors": [
+    "SyntaxError: Unsyntactic break (5:8)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":99,"loc":{"start":{"line":1,"column":0},"end":{"line":8,"column":2}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":98,"loc":{"start":{"line":1,"column":0},"end":{"line":8,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":13,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":13},"identifierName":"iter"},
+          "name": "iter"
+        },
+        "generator": false,
+        "async": false,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":16,"end":98,"loc":{"start":{"line":1,"column":16},"end":{"line":8,"column":1}},
+          "body": [
+            {
+              "type": "SwitchStatement",
+              "start":20,"end":96,"loc":{"start":{"line":2,"column":2},"end":{"line":7,"column":3}},
+              "discriminant": {
+                "type": "NumericLiteral",
+                "start":27,"end":28,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":10}},
+                "extra": {
+                  "rawValue": 1,
+                  "raw": "1"
+                },
+                "value": 1
+              },
+              "cases": [
+                {
+                  "type": "SwitchCase",
+                  "start":36,"end":92,"loc":{"start":{"line":3,"column":4},"end":{"line":6,"column":7}},
+                  "consequent": [
+                    {
+                      "type": "VariableDeclaration",
+                      "start":51,"end":92,"loc":{"start":{"line":4,"column":6},"end":{"line":6,"column":7}},
+                      "declarations": [
+                        {
+                          "type": "VariableDeclarator",
+                          "start":55,"end":92,"loc":{"start":{"line":4,"column":10},"end":{"line":6,"column":7}},
+                          "id": {
+                            "type": "Identifier",
+                            "start":55,"end":56,"loc":{"start":{"line":4,"column":10},"end":{"line":4,"column":11},"identifierName":"x"},
+                            "name": "x"
+                          },
+                          "init": {
+                            "type": "DoExpression",
+                            "start":65,"end":92,"loc":{"start":{"line":4,"column":20},"end":{"line":6,"column":7}},
+                            "async": true,
+                            "body": {
+                              "type": "BlockStatement",
+                              "start":68,"end":92,"loc":{"start":{"line":4,"column":23},"end":{"line":6,"column":7}},
+                              "body": [
+                                {
+                                  "type": "BreakStatement",
+                                  "start":78,"end":84,"loc":{"start":{"line":5,"column":8},"end":{"line":5,"column":14}},
+                                  "label": null
+                                }
+                              ],
+                              "directives": []
+                            }
+                          }
+                        }
+                      ],
+                      "kind": "var"
+                    }
+                  ],
+                  "test": null
+                }
+              ]
+            }
+          ],
+          "directives": []
+        }
+      },
+      {
+        "type": "EmptyStatement",
+        "start":98,"end":99,"loc":{"start":{"line":8,"column":1},"end":{"line":8,"column":2}}
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/invalid-generators/input.js

@@ -0,0 +1,5 @@
+async function *iter() {
+  await async do {
+    yield 1;
+  }
+};

packages/babel-parser/test/fixtures/experimental/async-do-expressions/invalid-generators/output.json

@@ -0,0 +1,81 @@
+{
+  "type": "File",
+  "start":0,"end":63,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+  "errors": [
+    "SyntaxError: Missing semicolon (3:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":63,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":16,"end":20,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":20},"identifierName":"iter"},
+          "name": "iter"
+        },
+        "generator": true,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":23,"end":62,"loc":{"start":{"line":1,"column":23},"end":{"line":5,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":27,"end":60,"loc":{"start":{"line":2,"column":2},"end":{"line":4,"column":3}},
+              "expression": {
+                "type": "AwaitExpression",
+                "start":27,"end":60,"loc":{"start":{"line":2,"column":2},"end":{"line":4,"column":3}},
+                "argument": {
+                  "type": "DoExpression",
+                  "start":39,"end":60,"loc":{"start":{"line":2,"column":14},"end":{"line":4,"column":3}},
+                  "async": true,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":42,"end":60,"loc":{"start":{"line":2,"column":17},"end":{"line":4,"column":3}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":48,"end":53,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":9}},
+                        "expression": {
+                          "type": "Identifier",
+                          "start":48,"end":53,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":9},"identifierName":"yield"},
+                          "name": "yield"
+                        }
+                      },
+                      {
+                        "type": "ExpressionStatement",
+                        "start":54,"end":56,"loc":{"start":{"line":3,"column":10},"end":{"line":3,"column":12}},
+                        "expression": {
+                          "type": "NumericLiteral",
+                          "start":54,"end":55,"loc":{"start":{"line":3,"column":10},"end":{"line":3,"column":11}},
+                          "extra": {
+                            "rawValue": 1,
+                            "raw": "1"
+                          },
+                          "value": 1
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      },
+      {
+        "type": "EmptyStatement",
+        "start":62,"end":63,"loc":{"start":{"line":5,"column":1},"end":{"line":5,"column":2}}
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/invalid-return/input.js

@@ -0,0 +1,5 @@
+function iter() {
+  return async do {
+    return 1;
+  }
+};

packages/babel-parser/test/fixtures/experimental/async-do-expressions/invalid-return/output.json

@@ -0,0 +1,68 @@
+{
+  "type": "File",
+  "start":0,"end":58,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+  "errors": [
+    "SyntaxError: 'return' outside of function (3:4)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":58,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":57,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":13,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":13},"identifierName":"iter"},
+          "name": "iter"
+        },
+        "generator": false,
+        "async": false,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":16,"end":57,"loc":{"start":{"line":1,"column":16},"end":{"line":5,"column":1}},
+          "body": [
+            {
+              "type": "ReturnStatement",
+              "start":20,"end":55,"loc":{"start":{"line":2,"column":2},"end":{"line":4,"column":3}},
+              "argument": {
+                "type": "DoExpression",
+                "start":33,"end":55,"loc":{"start":{"line":2,"column":15},"end":{"line":4,"column":3}},
+                "async": true,
+                "body": {
+                  "type": "BlockStatement",
+                  "start":36,"end":55,"loc":{"start":{"line":2,"column":18},"end":{"line":4,"column":3}},
+                  "body": [
+                    {
+                      "type": "ReturnStatement",
+                      "start":42,"end":51,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":13}},
+                      "argument": {
+                        "type": "NumericLiteral",
+                        "start":49,"end":50,"loc":{"start":{"line":3,"column":11},"end":{"line":3,"column":12}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    }
+                  ],
+                  "directives": []
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      },
+      {
+        "type": "EmptyStatement",
+        "start":57,"end":58,"loc":{"start":{"line":5,"column":1},"end":{"line":5,"column":2}}
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["doExpressions", "asyncDoExpressions"]
+}

packages/babel-parser/test/fixtures/experimental/async-do-expressions/scoping-variable/input.js

@@ -0,0 +1,4 @@
+let x = async do {
+  let tmp = f();
+  tmp * tmp + 1
+};

packages/babel-parser/test/fixtures/experimental/async-do-expressions/scoping-variable/output.json

@@ -0,0 +1,100 @@
+{
+  "type": "File",
+  "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":2}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":2}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":2}},
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start":4,"end":53,"loc":{"start":{"line":1,"column":4},"end":{"line":4,"column":1}},
+            "id": {
+              "type": "Identifier",
+              "start":4,"end":5,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":5},"identifierName":"x"},
+              "name": "x"
+            },
+            "init": {
+              "type": "DoExpression",
+              "start":14,"end":53,"loc":{"start":{"line":1,"column":14},"end":{"line":4,"column":1}},
+              "async": true,
+              "body": {
+                "type": "BlockStatement",
+                "start":17,"end":53,"loc":{"start":{"line":1,"column":17},"end":{"line":4,"column":1}},
+                "body": [
+                  {
+                    "type": "VariableDeclaration",
+                    "start":21,"end":35,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":16}},
+                    "declarations": [
+                      {
+                        "type": "VariableDeclarator",
+                        "start":25,"end":34,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":15}},
+                        "id": {
+                          "type": "Identifier",
+                          "start":25,"end":28,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":9},"identifierName":"tmp"},
+                          "name": "tmp"
+                        },
+                        "init": {
+                          "type": "CallExpression",
+                          "start":31,"end":34,"loc":{"start":{"line":2,"column":12},"end":{"line":2,"column":15}},
+                          "callee": {
+                            "type": "Identifier",
+                            "start":31,"end":32,"loc":{"start":{"line":2,"column":12},"end":{"line":2,"column":13},"identifierName":"f"},
+                            "name": "f"
+                          },
+                          "arguments": []
+                        }
+                      }
+                    ],
+                    "kind": "let"
+                  },
+                  {
+                    "type": "ExpressionStatement",
+                    "start":38,"end":51,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":15}},
+                    "expression": {
+                      "type": "BinaryExpression",
+                      "start":38,"end":51,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":15}},
+                      "left": {
+                        "type": "BinaryExpression",
+                        "start":38,"end":47,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":11}},
+                        "left": {
+                          "type": "Identifier",
+                          "start":38,"end":41,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":5},"identifierName":"tmp"},
+                          "name": "tmp"
+                        },
+                        "operator": "*",
+                        "right": {
+                          "type": "Identifier",
+                          "start":44,"end":47,"loc":{"start":{"line":3,"column":8},"end":{"line":3,"column":11},"identifierName":"tmp"},
+                          "name": "tmp"
+                        }
+                      },
+                      "operator": "+",
+                      "right": {
+                        "type": "NumericLiteral",
+                        "start":50,"end":51,"loc":{"start":{"line":3,"column":14},"end":{"line":3,"column":15}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    }
+                  }
+                ],
+                "directives": []
+              }
+            }
+          }
+        ],
+        "kind": "let"
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/do-expressions/conditional-statement/output.json

@@ -22,6 +22,7 @@
             "init": {
               "type": "DoExpression",
               "start":8,"end":76,"loc":{"start":{"line":1,"column":8},"end":{"line":5,"column":1}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":11,"end":76,"loc":{"start":{"line":1,"column":11},"end":{"line":5,"column":1}},

packages/babel-parser/test/fixtures/experimental/do-expressions/scoping-variable/output.json

@@ -22,6 +22,7 @@
             "init": {
               "type": "DoExpression",
               "start":8,"end":47,"loc":{"start":{"line":1,"column":8},"end":{"line":4,"column":1}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":11,"end":47,"loc":{"start":{"line":1,"column":11},"end":{"line":4,"column":1}},

packages/babel-parser/test/fixtures/experimental/do-expressions/with-jsx/output.json

@@ -28,6 +28,10 @@
               "argument": {
                 "type": "JSXElement",
                 "start":32,"end":216,"loc":{"start":{"line":3,"column":4},"end":{"line":14,"column":10}},
+                "extra": {
+                  "parenthesized": true,
+                  "parenStart": 26
+                },
                 "openingElement": {
                   "type": "JSXOpeningElement",
                   "start":32,"end":37,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":9}},
@@ -90,6 +94,7 @@
                     "expression": {
                       "type": "DoExpression",
                       "start":69,"end":197,"loc":{"start":{"line":6,"column":8},"end":{"line":12,"column":9}},
+                      "async": false,
                       "body": {
                         "type": "BlockStatement",
                         "start":72,"end":197,"loc":{"start":{"line":6,"column":11},"end":{"line":12,"column":9}},
@@ -173,11 +178,7 @@
                     },
                     "value": "\n    "
                   }
-                ],
+                ]
-                "extra": {
-                  "parenthesized": true,
-                  "parenStart": 26
-                }
               }
             }
           ],

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-error,-topic-style,-unbound-topic,-do-expression,-do-while-loop,-outer-topic-reference-in-loop-body/output.json

@@ -29,6 +29,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":42,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":42}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":42,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":42}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-error,-topic-style,-unbound-topic,-do-expression,-for-await-of-loop,-outer-topic-reference-in-loop-body/output.json

@@ -44,6 +44,7 @@
                   "expression": {
                     "type": "DoExpression",
                     "start":34,"end":75,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":52}},
+                    "async": false,
                     "body": {
                       "type": "BlockStatement",
                       "start":37,"end":75,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":52}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-error,-topic-style,-unbound-topic,-do-expression,-for-classic-loop,-outer-topic-reference-in-loop-body/output.json

@@ -29,6 +29,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":49,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":49}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":49,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":49}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-error,-topic-style,-unbound-topic,-do-expression,-for-in-loop,-outer-topic-reference-in-loop-body/output.json

@@ -29,6 +29,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":36,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":36}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":36,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":36}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-error,-topic-style,-unbound-topic,-do-expression,-for-of-loop,-outer-topic-reference-in-loop-body/output.json

@@ -29,6 +29,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":38,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":38}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":38,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":38}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-error,-topic-style,-unbound-topic,-do-expression,-try-statement,-outer-topic-reference-in-catch-clause/output.json

@@ -28,6 +28,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":78,"loc":{"start":{"line":1,"column":9},"end":{"line":4,"column":1}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":78,"loc":{"start":{"line":1,"column":12},"end":{"line":4,"column":1}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-error,-topic-style,-unbound-topic,-do-expression,-while-loop,-outer-topic-reference-in-loop-body/output.json

@@ -29,6 +29,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":38,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":38}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":38,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":38}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-error,-topic-style,-unbound-topic,-do-expression,-with-statement,-outer-topic-reference-in-with-body/output.json

@@ -29,6 +29,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":28,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":28}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":28,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":28}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-do-while-loop,-outer-topic-reference-in-loop-head/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":41,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":41}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":41,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":41}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-for-await-of-loop,-outer-topic-reference-in-loop-head/output.json

@@ -40,6 +40,7 @@
                   "expression": {
                     "type": "DoExpression",
                     "start":34,"end":68,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":45}},
+                    "async": false,
                     "body": {
                       "type": "BlockStatement",
                       "start":37,"end":68,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":45}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-for-classic-loop,-outer-topic-reference-in-loop-head/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":59,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":59}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":59,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":59}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-for-in-loop,-outer-topic-reference-in-loop-head/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":31,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":31}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":31,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":31}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-for-of-loop,-outer-topic-reference-in-loop-head/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":31,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":31}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":31,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":31}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-identity/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":18,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":18}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":18,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":18}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-if-statement,-outer-topic-reference-in-else-body/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":46,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":46}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":46,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":46}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-if-statement,-outer-topic-reference-in-else-if-body/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":38,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":38}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":38,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":38}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-if-statement,-outer-topic-reference-in-if-body/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":27,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":27}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":27,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":27}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-if-statement,-outer-topic-reference-in-if-head/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":33,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":33}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":33,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":33}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-switch-statement,-outer-topic-reference-in-switch-body/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":94,"loc":{"start":{"line":1,"column":9},"end":{"line":7,"column":1}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":94,"loc":{"start":{"line":1,"column":12},"end":{"line":7,"column":1}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-switch-statement,-outer-topic-reference-in-switch-head/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":83,"loc":{"start":{"line":1,"column":9},"end":{"line":7,"column":1}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":83,"loc":{"start":{"line":1,"column":12},"end":{"line":7,"column":1}},

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-try-statement,-outer-topic-reference-in-finally-clause-with-catch-and-finally/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":117,"loc":{"start":{"line":1,"column":9},"end":{"line":5,"column":1}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":117,"loc":{"start":{"line":1,"column":12},"end":{"line":5,"column":1}},
@@ -50,12 +51,12 @@
                                 "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
                                 "name": "JSON"
                               },
+                              "computed": false,
                               "property": {
                                 "type": "Identifier",
                                 "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
                                 "name": "parse"
-                              },
+                              }
-                              "computed": false
                             },
                             "arguments": [
                               {
@@ -95,12 +96,12 @@
                                   "start":64,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
                                   "name": "console"
                                 },
+                                "computed": false,
                                 "property": {
                                   "type": "Identifier",
                                   "start":72,"end":77,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
                                   "name": "error"
-                                },
+                                }
-                                "computed": false
                               },
                               "arguments": [
                                 {

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-try-statement,-outer-topic-reference-in-try-clause-with-catch-and-finally/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":109,"loc":{"start":{"line":1,"column":9},"end":{"line":5,"column":1}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":109,"loc":{"start":{"line":1,"column":12},"end":{"line":5,"column":1}},
@@ -50,12 +51,12 @@
                                 "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
                                 "name": "JSON"
                               },
+                              "computed": false,
                               "property": {
                                 "type": "Identifier",
                                 "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
                                 "name": "parse"
-                              },
+                              }
-                              "computed": false
                             },
                             "arguments": [
                               {
@@ -94,12 +95,12 @@
                                   "start":57,"end":64,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
                                   "name": "console"
                                 },
+                                "computed": false,
                                 "property": {
                                   "type": "Identifier",
                                   "start":65,"end":70,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
                                   "name": "error"
-                                },
+                                }
-                                "computed": false
                               },
                               "arguments": [
                                 {

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-try-statement,-outer-topic-reference-in-try-clause-with-catch/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":82,"loc":{"start":{"line":1,"column":9},"end":{"line":4,"column":1}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":82,"loc":{"start":{"line":1,"column":12},"end":{"line":4,"column":1}},
@@ -50,12 +51,12 @@
                                 "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
                                 "name": "JSON"
                               },
+                              "computed": false,
                               "property": {
                                 "type": "Identifier",
                                 "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
                                 "name": "parse"
-                              },
+                              }
-                              "computed": false
                             },
                             "arguments": [
                               {
@@ -94,12 +95,12 @@
                                   "start":57,"end":64,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
                                   "name": "console"
                                 },
+                                "computed": false,
                                 "property": {
                                   "type": "Identifier",
                                   "start":65,"end":70,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
                                   "name": "error"
-                                },
+                                }
-                                "computed": false
                               },
                               "arguments": [
                                 {

packages/babel-parser/test/fixtures/experimental/pipeline-operator/proposal-smart-topic-style,-do-expression,-while-loop,-outer-topic-reference-in-loop-head/output.json

@@ -25,6 +25,7 @@
             "expression": {
               "type": "DoExpression",
               "start":9,"end":37,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":37}},
+              "async": false,
               "body": {
                 "type": "BlockStatement",
                 "start":12,"end":37,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":37}},

packages/babel-parser/typings/babel-parser.d.ts

@@ -108,6 +108,7 @@ export interface ParserOptions {
 }
 
 export type ParserPlugin =
+  | "asyncDoExpressions"
   | "asyncGenerators"
   | "bigInt"
   | "classPrivateMethods"

packages/babel-plugin-proposal-do-expressions/src/index.js

@@ -11,7 +11,12 @@ export default declare(api => {
     visitor: {
       DoExpression: {
         exit(path) {
-          const body = path.node.body.body;
+          const { node } = path;
+          if (node.async) {
+            // Async do expressions are not yet supported
+            return;
+          }
+          const body = node.body.body;
           if (body.length) {
             path.replaceExpressionWithStatements(body);
           } else {

packages/babel-plugin-proposal-do-expressions/test/fixtures/async-do-expressions/basic/input.js

@@ -0,0 +1 @@
+(async do {});

packages/babel-plugin-proposal-do-expressions/test/fixtures/async-do-expressions/basic/output.js

@@ -0,0 +1 @@
+async do {};

packages/babel-plugin-proposal-do-expressions/test/fixtures/async-do-expressions/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["syntax-async-do-expressions", "proposal-do-expressions"]
+}

packages/babel-plugin-syntax-async-do-expressions/.npmignore

@@ -0,0 +1,3 @@
+src
+test
+*.log

packages/babel-plugin-syntax-async-do-expressions/README.md

@@ -0,0 +1,19 @@
+# @babel/plugin-syntax-async-do-expressions
+
+> Allow parsing of async do expressions
+
+See our website [@babel/plugin-syntax-async-do-expressions](https://babel.dev/docs/en/babel-plugin-syntax-async-do-expressions) for more information.
+
+## Install
+
+Using npm:
+
+```sh
+npm install --save-dev @babel/plugin-syntax-async-do-expressions
+```
+
+or using yarn:
+
+```sh
+yarn add @babel/plugin-syntax-async-do-expressions --dev
+```

packages/babel-plugin-syntax-async-do-expressions/package.json

@@ -0,0 +1,31 @@
+{
+  "name": "@babel/plugin-syntax-async-do-expressions",
+  "version": "7.13.0",
+  "description": "Allow parsing of async do expressions",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/babel/babel.git",
+    "directory": "packages/babel-plugin-syntax-async-do-expressions"
+  },
+  "license": "MIT",
+  "publishConfig": {
+    "access": "public"
+  },
+  "main": "./lib/index.js",
+  "exports": {
+    ".": "./lib/index.js"
+  },
+  "keywords": [
+    "babel-plugin"
+  ],
+  "dependencies": {
+    "@babel/helper-plugin-utils": "workspace:^7.12.13"
+  },
+  "peerDependencies": {
+    "@babel/core": "^7.0.0-0"
+  },
+  "devDependencies": {
+    "@babel/core": "workspace:*"
+  },
+  "homepage": "https://babel.dev/docs/en/next/babel-plugin-syntax-async-do-expressions"
+}

packages/babel-plugin-syntax-async-do-expressions/src/index.ts

@@ -0,0 +1,13 @@
+import { declare } from "@babel/helper-plugin-utils";
+
+export default declare(api => {
+  api.assertVersion(7);
+
+  return {
+    name: "syntax-async-do-expressions",
+
+    manipulateOptions(opts, parserOpts) {
+      parserOpts.plugins.push("asyncDoExpressions", "doExpressions");
+    },
+  };
+});

packages/babel-types/src/ast-types/generated/index.ts

@@ -1609,6 +1609,7 @@ export interface Decorator extends BaseNode {
 export interface DoExpression extends BaseNode {
   type: "DoExpression";
   body: BlockStatement;
+  async: boolean;
 }
 
 export interface ExportDefaultSpecifier extends BaseNode {

packages/babel-types/src/builders/generated/index.ts

@@ -1051,7 +1051,10 @@ export function importAttribute(
 export function decorator(expression: t.Expression): t.Decorator {
   return builder("Decorator", ...arguments);
 }
-export function doExpression(body: t.BlockStatement): t.DoExpression {
+export function doExpression(
+  body: t.BlockStatement,
+  async?: boolean,
+): t.DoExpression {
   return builder("DoExpression", ...arguments);
 }
 export function exportDefaultSpecifier(

packages/babel-types/src/definitions/experimental.ts

@@ -188,11 +188,16 @@ defineType("Decorator", {
 
 defineType("DoExpression", {
   visitor: ["body"],
+  builder: ["body", "async"],
   aliases: ["Expression"],
   fields: {
     body: {
       validate: assertNodeType("BlockStatement"),
     },
+    async: {
+      validate: assertValueType("boolean"),
+      default: false,
+    },
   },
 });
 

yarn.lock

@@ -1512,6 +1512,17 @@ __metadata:
   languageName: unknown
   linkType: soft
 
+"@babel/plugin-syntax-async-do-expressions@workspace:packages/babel-plugin-syntax-async-do-expressions":
+  version: 0.0.0-use.local
+  resolution: "@babel/plugin-syntax-async-do-expressions@workspace:packages/babel-plugin-syntax-async-do-expressions"
+  dependencies:
+    "@babel/core": "workspace:*"
+    "@babel/helper-plugin-utils": "workspace:^7.12.13"
+  peerDependencies:
+    "@babel/core": ^7.0.0-0
+  languageName: unknown
+  linkType: soft
+
 "@babel/plugin-syntax-async-generators@npm:^7.8.4":
   version: 7.8.4
   resolution: "@babel/plugin-syntax-async-generators@npm:7.8.4"