Refactor yield await classification (#12230)
* fix: incomplete ParamKind declaration * refactor: add expression scope handler * test: update test262 allowlist * chore: cleanup * fix: push expression scope for function body * fix: push new expression scope for initializer and static block * test: add more test cases * fix flow error * refactor: remove unecessary expression scope * fix: parameter initializer error should not cross expression scope boundary * chore: cleanup outdated comments * fix: do not record async arrow error on ParameterDeclaration * Update packages/babel-parser/src/util/expression-scope.js Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com> * polish: clear ancestry declaration error on validate Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>
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Huáng Jùnliàng
GitHub
189
packages/babel-parser/src/util/expression-scope.js
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189
packages/babel-parser/src/util/expression-scope.js
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// @flow
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/*:: declare var invariant; */
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/**
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* @module util/expression-scope
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ExpressionScope is used to track declaration errors in these ambiguous patterns:
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- CoverParenthesizedExpressionAndArrowParameterList
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e.g. we don't know if `({ x })` is an parenthesized expression or an
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arrow function parameters until we see an `=>` after `)`.
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- CoverCallExpressionAndAsyncArrowHead
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e.g. we don't know if `async({ x })` is a call expression or an async arrow
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function parameters until we see an `=>` after `)`
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The following declaration errors (@see parser/error-message) will be recorded in
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some expression scopes and thrown later when we know what the ambigous pattern is
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- AwaitBindingIdentifier
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- AwaitExpressionFormalParameter
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- YieldInParameter
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There are four different expression scope
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- Expression
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A general scope that represents program / function body / static block. No errors
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will be recorded nor thrown in this scope.
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- MaybeArrowParameterDeclaration
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A scope that represents ambiguous arrow head e.g. `(x)`. Errors will be recorded
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alongside parent scopes and thrown when `ExpressionScopeHandler#validateAsPattern`
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is called.
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- MaybeAsyncArrowParameterDeclaration
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A scope that represents ambiguous async arrow head e.g. `async(x)`. Errors will
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be recorded alongside parent scopes and thrown when
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`ExpressionScopeHandler#validateAsPattern` is called.
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- ParameterDeclaration
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A scope that represents unambiguous function parameters `function(x)`. Errors
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recorded in this scope will be thrown immediately. No errors will be recorded in
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this scope.
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// @see {@link https://docs.google.com/document/d/1FAvEp9EUK-G8kHfDIEo_385Hs2SUBCYbJ5H-NnLvq8M|V8 Expression Scope design docs}
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*/
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const kExpression = 0,
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kMaybeArrowParameterDeclaration = 1,
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kMaybeAsyncArrowParameterDeclaration = 2,
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kParameterDeclaration = 3;
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type ExpressionScopeType = 0 | 1 | 2 | 3;
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type raiseFunction = (number, string, ...any) => void;
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class ExpressionScope {
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type: ExpressionScopeType;
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constructor(type: ExpressionScopeType = kExpression) {
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this.type = type;
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}
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canBeArrowParameterDeclaration() {
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return (
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this.type === kMaybeAsyncArrowParameterDeclaration ||
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this.type === kMaybeArrowParameterDeclaration
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);
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}
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isCertainlyParameterDeclaration() {
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return this.type === kParameterDeclaration;
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}
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}
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class ArrowHeadParsingScope extends ExpressionScope {
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errors: Map</* pos */ number, /* message */ string> = new Map();
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constructor(type: 1 | 2) {
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super(type);
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}
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recordDeclarationError(pos: number, message: string) {
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this.errors.set(pos, message);
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}
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clearDeclarationError(pos: number) {
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this.errors.delete(pos);
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}
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iterateErrors(iterator: (message: string, pos: number) => void) {
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this.errors.forEach(iterator);
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}
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}
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export default class ExpressionScopeHandler {
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stack: Array<ExpressionScope> = [new ExpressionScope()];
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declare raise: raiseFunction;
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constructor(raise: raiseFunction) {
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this.raise = raise;
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}
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enter(scope: ExpressionScope) {
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this.stack.push(scope);
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}
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exit() {
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this.stack.pop();
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}
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/**
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* Record likely parameter initializer errors
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*
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* When current scope is a ParameterDeclaration, the error will be thrown immediately,
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* otherwise it will be recorded to any ancestry MaybeArrowParameterDeclaration and
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* MaybeAsyncArrowParameterDeclaration scope until an Expression scope is seen.
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* @param {number} pos Error position
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* @param {string} message Error message
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* @memberof ExpressionScopeHandler
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*/
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recordParameterInitializerError(pos: number, message: string): void {
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const { stack } = this;
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let i = stack.length - 1;
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let scope: ExpressionScope = stack[i];
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while (!scope.isCertainlyParameterDeclaration()) {
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if (scope.canBeArrowParameterDeclaration()) {
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/*:: invariant(scope instanceof ArrowHeadParsingScope) */
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scope.recordDeclarationError(pos, message);
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} else {
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/*:: invariant(scope.type == kExpression) */
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// Type-Expression is the boundary where initializer error can populate to
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return;
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}
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scope = stack[--i];
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}
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/* eslint-disable @babel/development-internal/dry-error-messages */
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this.raise(pos, message);
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}
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/**
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* Record likely async arrow parameter errors
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*
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* Errors will be recorded to any ancestry MaybeAsyncArrowParameterDeclaration
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* scope until an Expression scope is seen.
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* @param {number} pos
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* @param {string} message
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* @memberof ExpressionScopeHandler
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*/
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recordAsyncArrowParametersError(pos: number, message: string): void {
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const { stack } = this;
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let i = stack.length - 1;
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let scope: ExpressionScope = stack[i];
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while (scope.canBeArrowParameterDeclaration()) {
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if (scope.type === kMaybeAsyncArrowParameterDeclaration) {
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/*:: invariant(scope instanceof ArrowHeadParsingScope) */
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scope.recordDeclarationError(pos, message);
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}
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scope = stack[--i];
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}
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}
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validateAsPattern(): void {
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const { stack } = this;
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const currentScope = stack[stack.length - 1];
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if (!currentScope.canBeArrowParameterDeclaration()) return;
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/*:: invariant(currentScope instanceof ArrowHeadParsingScope) */
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currentScope.iterateErrors((message, pos) => {
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/* eslint-disable @babel/development-internal/dry-error-messages */
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this.raise(pos, message);
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// iterate from parent scope
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let i = stack.length - 2;
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let scope = stack[i];
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while (scope.canBeArrowParameterDeclaration()) {
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/*:: invariant(scope instanceof ArrowHeadParsingScope) */
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scope.clearDeclarationError(pos);
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scope = stack[--i];
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}
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});
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}
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}
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export function newParameterDeclarationScope() {
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return new ExpressionScope(kParameterDeclaration);
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}
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export function newArrowHeadScope() {
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return new ArrowHeadParsingScope(kMaybeArrowParameterDeclaration);
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}
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export function newAsyncArrowScope() {
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return new ArrowHeadParsingScope(kMaybeAsyncArrowParameterDeclaration);
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}
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export function newExpressionScope() {
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return new ExpressionScope();
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}
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@@ -26,7 +26,12 @@ export const PARAM = 0b0000, // Initial Parameter flags
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// 6. parse function body
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// 7. exit current stack
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export type ParamKind = typeof PARAM | typeof PARAM_AWAIT | typeof PARAM_YIELD;
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export type ParamKind =
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| typeof PARAM
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| typeof PARAM_AWAIT
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| typeof PARAM_IN
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| typeof PARAM_RETURN
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| typeof PARAM_YIELD;
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export default class ProductionParameterHandler {
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stacks: Array<ParamKind> = [];
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