@babel/parser error recovery (#10363)

* Add error recovery support to @babel/parser

* Update @babel/parser tests to always recover from errors

* Update this.raise usage in @babel/parser:

- expression.js
- lval.js
- statement.js
- estree.js
- flow.js
- jsx/index.js
- tokenizer/index.js

* Update @babel/parser fixtures with recovered errors

* Fix tests out of @babel/parser

* Do not use try/catch for control flow

* Update invalid fixtures

* Do not report invalid lhs in toAssignable

* Do not validate function id multiple times

* Dedupe reserved await errors

* Remove duplicate errors about strict reserved bindings

* Remove duplicated error about yield/await inside params

* Don't error twice for methods in object patterns

* Don't report invalid super() twice

* Remove dup error about reserved param for expr arrows

* Remove double escapes in migrated tests

* Dedupe errors about invalid escapes in identifiers

* Remove duplicated error about decorated constructor

* Remove duplicated error about spread in flow class

* Don't throw for invalid super usage

* Don't fail for object decorators with stage 2

* Fix flow inexact type errors

* Fix flow

* Fix errors about escapes in keywords (ref: #10455)

* Update after rebase

* Fix todo

* Remove duplicated error when using += for defaults

* Remove unnecessary throw

* Nit: use ??

packages/babel-core/test/fixtures/parse/output.json

@@ -2,6 +2,7 @@
   "type": "File",
   "start": 0,
   "end": 91,
+  "errors": [],
   "loc": {
     "start": {
       "line": 1,

packages/babel-parser/src/options.js

@@ -21,6 +21,7 @@ export type Options = {
   ranges: boolean,
   tokens: boolean,
   createParenthesizedExpressions: boolean,
+  errorRecovery: boolean,
 };
 
 export const defaultOptions: Options = {
@@ -62,6 +63,9 @@ export const defaultOptions: Options = {
   // Whether to create ParenthesizedExpression AST nodes (if false
   // the parser sets extra.parenthesized on the expression nodes instead).
   createParenthesizedExpressions: false,
+  // When enabled, errors are attached to the AST instead of being directly thrown.
+  // Some errors will still throw, because @babel/parser can't always recover.
+  errorRecovery: false,
 };
 
 // Interpret and default an options object

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

@@ -108,6 +108,7 @@ export default class ExpressionParser extends LValParser {
       this.unexpected();
     }
     expr.comments = this.state.comments;
+    expr.errors = this.state.errors;
     return expr;
   }
 
@@ -786,11 +787,11 @@ export default class ExpressionParser extends LValParser {
     if (node.callee.type === "Import") {
       if (node.arguments.length !== 1) {
         this.raise(node.start, "import() requires exactly one argument");
-      }
+      } else {
-
+        const importArg = node.arguments[0];
-      const importArg = node.arguments[0];
+        if (importArg && importArg.type === "SpreadElement") {
-      if (importArg && importArg.type === "SpreadElement") {
+          this.raise(importArg.start, "... is not allowed in import()");
-        this.raise(importArg.start, "... is not allowed in import()");
+        }
       }
     }
     return this.finishNode(
@@ -903,13 +904,6 @@ export default class ExpressionParser extends LValParser {
 
     switch (this.state.type) {
       case tt._super:
-        if (!this.scope.allowSuper && !this.options.allowSuperOutsideMethod) {
-          this.raise(
-            this.state.start,
-            "super is only allowed in object methods and classes",
-          );
-        }
-
         node = this.startNode();
         this.next();
         if (
@@ -922,6 +916,14 @@ export default class ExpressionParser extends LValParser {
             "super() is only valid inside a class constructor of a subclass. " +
               "Maybe a typo in the method name ('constructor') or not extending another class?",
           );
+        } else if (
+          !this.scope.allowSuper &&
+          !this.options.allowSuperOutsideMethod
+        ) {
+          this.raise(
+            node.start,
+            "super is only allowed in object methods and classes",
+          );
         }
 
         if (
@@ -929,7 +931,11 @@ export default class ExpressionParser extends LValParser {
           !this.match(tt.bracketL) &&
           !this.match(tt.dot)
         ) {
-          this.unexpected();
+          this.raise(
+            node.start,
+            "super can only be used with function calls (i.e. super()) or " +
+              "in property accesses (i.e. super.prop or super[prop])",
+          );
         }
 
         return this.finishNode(node, "Super");
@@ -1106,15 +1112,16 @@ export default class ExpressionParser extends LValParser {
           }
 
           this.next();
-          if (this.primaryTopicReferenceIsAllowedInCurrentTopicContext()) {
+
-            this.registerTopicReference();
+          if (!this.primaryTopicReferenceIsAllowedInCurrentTopicContext()) {
-            return this.finishNode(node, "PipelinePrimaryTopicReference");
+            this.raise(
-          } else {
-            throw this.raise(
               node.start,
               `Topic reference was used in a lexical context without topic binding`,
             );
           }
+
+          this.registerTopicReference();
+          return this.finishNode(node, "PipelinePrimaryTopicReference");
         }
       }
 
@@ -1199,6 +1206,15 @@ export default class ExpressionParser extends LValParser {
 
     if (this.isContextual("meta")) {
       this.expectPlugin("importMeta");
+
+      if (!this.inModule) {
+        this.raise(
+          id.start,
+          `import.meta may appear only with 'sourceType: "module"'`,
+          { code: "BABEL_PARSER_SOURCETYPE_MODULE_REQUIRED" },
+        );
+      }
+      this.sawUnambiguousESM = true;
     } else if (!this.hasPlugin("importMeta")) {
       this.raise(
         id.start,
@@ -1206,15 +1222,6 @@ export default class ExpressionParser extends LValParser {
       );
     }
 
-    if (!this.inModule) {
-      this.raise(
-        id.start,
-        `import.meta may appear only with 'sourceType: "module"'`,
-        { code: "BABEL_PARSER_SOURCETYPE_MODULE_REQUIRED" },
-      );
-    }
-    this.sawUnambiguousESM = true;
-
     return this.parseMetaProperty(node, id, "meta");
   }
 
@@ -1386,7 +1393,10 @@ export default class ExpressionParser extends LValParser {
 
   parseNew(): N.NewExpression | N.MetaProperty {
     const node = this.startNode();
-    const meta = this.parseIdentifier(true);
+
+    let meta = this.startNode();
+    this.next();
+    meta = this.createIdentifier(meta, "new");
 
     if (this.eat(tt.dot)) {
       const metaProp = this.parseMetaProperty(node, meta, "target");
@@ -1553,12 +1563,12 @@ export default class ExpressionParser extends LValParser {
           this.state.start,
           "Stage 2 decorators disallow object literal property decorators",
         );
-      } else {
+      }
-        // we needn't check if decorators (stage 0) plugin is enabled since it's checked by
+
-        // the call to this.parseDecorator
+      // we needn't check if decorators (stage 0) plugin is enabled since it's checked by
-        while (this.match(tt.at)) {
+      // the call to this.parseDecorator
-          decorators.push(this.parseDecorator());
+      while (this.match(tt.at)) {
-        }
+        decorators.push(this.parseDecorator());
       }
     }
 
@@ -1933,7 +1943,7 @@ export default class ExpressionParser extends LValParser {
 
     if (isExpression) {
       node.body = this.parseMaybeAssign();
-      this.checkParams(node, false, allowExpression);
+      this.checkParams(node, false, allowExpression, false);
     } else {
       const nonSimple = !this.isSimpleParamList(node.params);
       if (!oldStrict || nonSimple) {
@@ -1967,6 +1977,7 @@ export default class ExpressionParser extends LValParser {
         node,
         !oldStrict && !useStrict && !allowExpression && !isMethod && !nonSimple,
         allowExpression,
+        !oldStrict && useStrict,
       );
       node.body = this.parseBlock(true, false);
       this.state.labels = oldLabels;
@@ -1975,7 +1986,14 @@ export default class ExpressionParser extends LValParser {
     this.state.inParameters = oldInParameters;
     // Ensure the function name isn't a forbidden identifier in strict mode, e.g. 'eval'
     if (this.state.strict && node.id) {
-      this.checkLVal(node.id, BIND_OUTSIDE, undefined, "function name");
+      this.checkLVal(
+        node.id,
+        BIND_OUTSIDE,
+        undefined,
+        "function name",
+        undefined,
+        !oldStrict && useStrict,
+      );
     }
     this.state.strict = oldStrict;
   }
@@ -1994,6 +2012,7 @@ export default class ExpressionParser extends LValParser {
     allowDuplicates: boolean,
     // eslint-disable-next-line no-unused-vars
     isArrowFunction: ?boolean,
+    strictModeChanged?: boolean = true,
   ): void {
     // $FlowIssue
     const nameHash: {} = Object.create(null);
@@ -2003,6 +2022,8 @@ export default class ExpressionParser extends LValParser {
         BIND_VAR,
         allowDuplicates ? null : nameHash,
         "function parameter list",
+        undefined,
+        strictModeChanged,
       );
     }
   }
@@ -2084,6 +2105,8 @@ export default class ExpressionParser extends LValParser {
   // Parse the next token as an identifier. If `liberal` is true (used
   // when parsing properties), it will also convert keywords into
   // identifiers.
+  // This shouldn't be used to parse the keywords of meta properties, since they
+  // are not identifiers and cannot contain escape sequences.
 
   parseIdentifier(liberal?: boolean): N.Identifier {
     const node = this.startNode();
@@ -2104,11 +2127,6 @@ export default class ExpressionParser extends LValParser {
 
     if (this.match(tt.name)) {
       name = this.state.value;
-
-      // An escaped identifier whose value is the same as a keyword
-      if (!liberal && this.state.containsEsc && isKeyword(name)) {
-        this.raise(this.state.pos, `Escape sequence in keyword ${name}`);
-      }
     } else if (this.state.type.keyword) {
       name = this.state.type.keyword;
 
@@ -2128,7 +2146,11 @@ export default class ExpressionParser extends LValParser {
       throw this.unexpected();
     }
 
-    if (!liberal) {
+    if (liberal) {
+      // If the current token is not used as a keyword, set its type to "tt.name".
+      // This will prevent this.next() from throwing about unexpected escapes.
+      this.state.type = tt.name;
+    } else {
       this.checkReservedWord(
         name,
         this.state.start,
@@ -2153,6 +2175,7 @@ export default class ExpressionParser extends LValParser {
         startLoc,
         "Can not use 'yield' as identifier inside a generator",
       );
+      return;
     }
 
     if (word === "await") {
@@ -2161,7 +2184,9 @@ export default class ExpressionParser extends LValParser {
           startLoc,
           "Can not use 'await' as identifier inside an async function",
         );
-      } else if (
+        return;
+      }
+      if (
         this.state.awaitPos === -1 &&
         (this.state.maybeInArrowParameters || this.isAwaitAllowed())
       ) {
@@ -2174,9 +2199,11 @@ export default class ExpressionParser extends LValParser {
         startLoc,
         "'arguments' is not allowed in class field initializer",
       );
+      return;
     }
     if (checkKeywords && isKeyword(word)) {
       this.raise(startLoc, `Unexpected keyword '${word}'`);
+      return;
     }
 
     const reservedTest = !this.state.strict
@@ -2191,8 +2218,9 @@ export default class ExpressionParser extends LValParser {
           startLoc,
           "Can not use keyword 'await' outside an async function",
         );
+      } else {
+        this.raise(startLoc, `Unexpected reserved word '${word}'`);
       }
-      this.raise(startLoc, `Unexpected reserved word '${word}'`);
     }
   }
 
@@ -2206,9 +2234,6 @@ export default class ExpressionParser extends LValParser {
   // Parses await expression inside async function.
 
   parseAwait(): N.AwaitExpression {
-    if (this.state.awaitPos === -1) {
-      this.state.awaitPos = this.state.start;
-    }
     const node = this.startNode();
 
     this.next();
@@ -2218,8 +2243,10 @@ export default class ExpressionParser extends LValParser {
         node.start,
         "await is not allowed in async function parameters",
       );
+    } else if (this.state.awaitPos === -1) {
+      this.state.awaitPos = node.start;
     }
-    if (this.match(tt.star)) {
+    if (this.eat(tt.star)) {
       this.raise(
         node.start,
         "await* has been removed from the async functions proposal. Use Promise.all() instead.",
@@ -2259,13 +2286,12 @@ export default class ExpressionParser extends LValParser {
   // Parses yield expression inside generator.
 
   parseYield(noIn?: ?boolean): N.YieldExpression {
-    if (this.state.yieldPos === -1) {
-      this.state.yieldPos = this.state.start;
-    }
     const node = this.startNode();
 
     if (this.state.inParameters) {
       this.raise(node.start, "yield is not allowed in generator parameters");
+    } else if (this.state.yieldPos === -1) {
+      this.state.yieldPos = node.start;
     }
 
     this.next();
@@ -2291,7 +2317,7 @@ export default class ExpressionParser extends LValParser {
       if (left.type === "SequenceExpression") {
         // Ensure that the pipeline head is not a comma-delimited
         // sequence expression.
-        throw this.raise(
+        this.raise(
           leftStartPos,
           `Pipeline head should not be a comma-separated sequence expression`,
         );
@@ -2336,7 +2362,7 @@ export default class ExpressionParser extends LValParser {
       pipelineStyle === "PipelineTopicExpression" &&
       childExpression.type === "SequenceExpression"
     ) {
-      throw this.raise(
+      this.raise(
         startPos,
         `Pipeline body may not be a comma-separated sequence expression`,
       );
@@ -2362,7 +2388,7 @@ export default class ExpressionParser extends LValParser {
         break;
       case "PipelineTopicExpression":
         if (!this.topicReferenceWasUsedInCurrentTopicContext()) {
-          throw this.raise(
+          this.raise(
             startPos,
             `Pipeline is in topic style but does not use topic reference`,
           );
@@ -2370,7 +2396,9 @@ export default class ExpressionParser extends LValParser {
         bodyNode.expression = childExpression;
         break;
       default:
-        throw this.raise(startPos, `Unknown pipeline style ${pipelineStyle}`);
+        throw new Error(
+          `Internal @babel/parser error: Unknown pipeline style (${pipelineStyle})`,
+        );
     }
     return this.finishNode(bodyNode, pipelineStyle);
   }

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

@@ -39,7 +39,10 @@ export default class Parser extends StatementParser {
     const file = this.startNode();
     const program = this.startNode();
     this.nextToken();
-    return this.parseTopLevel(file, program);
+    file.errors = null;
+    this.parseTopLevel(file, program);
+    file.errors = this.state.errors;
+    return file;
   }
 }
 

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

@@ -10,6 +10,8 @@ import CommentsParser from "./comments";
 // message.
 
 export default class LocationParser extends CommentsParser {
+  +isLookahead: boolean;
+
   getLocationForPosition(pos: number): Position {
     let loc;
     if (pos === this.state.start) loc = this.state.startLoc;
@@ -31,7 +33,7 @@ export default class LocationParser extends CommentsParser {
       missingPluginNames?: Array<string>,
       code?: string,
     } = {},
-  ): empty {
+  ): Error | empty {
     const loc = this.getLocationForPosition(pos);
 
     message += ` (${loc.line}:${loc.column})`;
@@ -47,6 +49,12 @@ export default class LocationParser extends CommentsParser {
     if (code !== undefined) {
       err.code = code;
     }
-    throw err;
+
+    if (this.options.errorRecovery) {
+      if (!this.isLookahead) this.state.errors.push(err);
+      return err;
+    } else {
+      throw err;
+    }
   }
 }

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

@@ -15,7 +15,10 @@ import type {
   SpreadElement,
 } from "../types";
 import type { Pos, Position } from "../util/location";
-import { isStrictBindReservedWord } from "../util/identifier";
+import {
+  isStrictBindOnlyReservedWord,
+  isStrictBindReservedWord,
+} from "../util/identifier";
 import { NodeUtils } from "./node";
 import { type BindingTypes, BIND_NONE } from "../util/scopeflags";
 
@@ -37,6 +40,8 @@ export default class LValParser extends NodeUtils {
 
   // Convert existing expression atom to assignable pattern
   // if possible.
+  // NOTE: There is a corresponding "isAssignable" method in flow.js.
+  // When this one is updated, please check if also that one needs to be updated.
 
   toAssignable(
     node: Node,
@@ -96,15 +101,16 @@ export default class LValParser extends NodeUtils {
           break;
 
         case "AssignmentExpression":
-          if (node.operator === "=") {
+          if (node.operator !== "=") {
-            node.type = "AssignmentPattern";
-            delete node.operator;
-          } else {
             this.raise(
               node.left.end,
               "Only '=' operator can be used for specifying default value.",
             );
           }
+
+          node.type = "AssignmentPattern";
+          delete node.operator;
+          this.toAssignable(node.left, isBinding, contextDescription);
           break;
 
         case "ParenthesizedExpression":
@@ -118,14 +124,9 @@ export default class LValParser extends NodeUtils {
         case "MemberExpression":
           if (!isBinding) break;
 
-        default: {
+        default:
-          const message =
+        // We don't know how to deal with this node. It will
-            "Invalid left-hand side" +
+        // be reported by a later call to checkLVal
-            (contextDescription
-              ? " in " + contextDescription
-              : /* istanbul ignore next */ "expression");
-          this.raise(node.start, message);
-        }
       }
     }
     return node;
@@ -349,12 +350,18 @@ export default class LValParser extends NodeUtils {
     checkClashes: ?{ [key: string]: boolean },
     contextDescription: string,
     disallowLetBinding?: boolean,
+    strictModeChanged?: boolean = false,
   ): void {
     switch (expr.type) {
       case "Identifier":
         if (
           this.state.strict &&
-          isStrictBindReservedWord(expr.name, this.inModule)
+          // "Global" reserved words have already been checked by parseIdentifier,
+          // unless they have been found in the id or parameters of a strict-mode
+          // function in a sloppy context.
+          (strictModeChanged
+            ? isStrictBindReservedWord(expr.name, this.inModule)
+            : isStrictBindOnlyReservedWord(expr.name))
         ) {
           this.raise(
             expr.start,
@@ -404,6 +411,11 @@ export default class LValParser extends NodeUtils {
       case "ObjectPattern":
         for (let prop of expr.properties) {
           if (prop.type === "ObjectProperty") prop = prop.value;
+          // If we find here an ObjectMethod, it's because this was originally
+          // an ObjectExpression which has then been converted.
+          // toAssignable already reported this error with a nicer message.
+          else if (prop.type === "ObjectMethod") continue;
+
           this.checkLVal(
             prop,
             bindingType,
@@ -489,7 +501,7 @@ export default class LValParser extends NodeUtils {
   }
 
   raiseRestNotLast(pos: number) {
-    this.raise(pos, `Rest element must be last element`);
+    throw this.raise(pos, `Rest element must be last element`);
   }
 
   raiseTrailingCommaAfterRest(pos: number) {

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

@@ -203,7 +203,7 @@ export default class StatementParser extends ExpressionParser {
       case tt._var:
         kind = kind || this.state.value;
         if (context && kind !== "var") {
-          this.unexpected(
+          this.raise(
             this.state.start,
             "Lexical declaration cannot appear in a single-statement context",
           );
@@ -269,8 +269,8 @@ export default class StatementParser extends ExpressionParser {
       default: {
         if (this.isAsyncFunction()) {
           if (context) {
-            this.unexpected(
+            this.raise(
-              null,
+              this.state.start,
               "Async functions can only be declared at the top level or inside a block",
             );
           }
@@ -351,7 +351,7 @@ export default class StatementParser extends ExpressionParser {
         );
       }
     } else if (!this.canHaveLeadingDecorator()) {
-      this.raise(
+      throw this.raise(
         this.state.start,
         "Leading decorators must be attached to a class declaration",
       );
@@ -1036,7 +1036,7 @@ export default class StatementParser extends ExpressionParser {
     this.initFunction(node, isAsync);
 
     if (this.match(tt.star) && isHangingStatement) {
-      this.unexpected(
+      this.raise(
         this.state.start,
         "Generators can only be declared at the top level or inside a block",
       );
@@ -1077,10 +1077,10 @@ export default class StatementParser extends ExpressionParser {
     this.scope.exit();
 
     if (isStatement && !isHangingStatement) {
-      // We need to validate this _after_ parsing the function body
+      // We need to register this _after_ parsing the function body
       // because of TypeScript body-less function declarations,
       // which shouldn't be added to the scope.
-      this.checkFunctionStatementId(node);
+      this.registerFunctionStatementId(node);
     }
 
     this.state.maybeInArrowParameters = oldMaybeInArrowParameters;
@@ -1111,22 +1111,21 @@ export default class StatementParser extends ExpressionParser {
     this.checkYieldAwaitInDefaultParams();
   }
 
-  checkFunctionStatementId(node: N.Function): void {
+  registerFunctionStatementId(node: N.Function): void {
     if (!node.id) return;
 
     // If it is a regular function declaration in sloppy mode, then it is
     // subject to Annex B semantics (BIND_FUNCTION). Otherwise, the binding
     // mode depends on properties of the current scope (see
     // treatFunctionsAsVar).
-    this.checkLVal(
+    this.scope.declareName(
-      node.id,
+      node.id.name,
       this.state.strict || node.generator || node.async
         ? this.scope.treatFunctionsAsVar
           ? BIND_VAR
           : BIND_LEXICAL
         : BIND_FUNCTION,
-      null,
+      node.id.start,
-      "function name",
     );
   }
 
@@ -1191,7 +1190,7 @@ export default class StatementParser extends ExpressionParser {
       while (!this.eat(tt.braceR)) {
         if (this.eat(tt.semi)) {
           if (decorators.length > 0) {
-            this.raise(
+            throw this.raise(
               this.state.lastTokEnd,
               "Decorators must not be followed by a semicolon",
             );
@@ -1229,7 +1228,7 @@ export default class StatementParser extends ExpressionParser {
     });
 
     if (decorators.length) {
-      this.raise(
+      throw this.raise(
         this.state.start,
         "You have trailing decorators with no method",
       );
@@ -1362,13 +1361,6 @@ export default class StatementParser extends ExpressionParser {
       if (isConstructor) {
         publicMethod.kind = "constructor";
 
-        if (publicMethod.decorators) {
-          this.raise(
-            publicMethod.start,
-            "You can't attach decorators to a class constructor",
-          );
-        }
-
         // TypeScript allows multiple overloaded constructor declarations.
         if (state.hadConstructor && !this.hasPlugin("typescript")) {
           this.raise(key.start, "Duplicate constructor in the same class");
@@ -1797,7 +1789,7 @@ export default class StatementParser extends ExpressionParser {
         this.hasPlugin("decorators") &&
         this.getPluginOption("decorators", "decoratorsBeforeExport")
       ) {
-        this.unexpected(
+        this.raise(
           this.state.start,
           "Decorators must be placed *before* the 'export' keyword." +
             " You can set the 'decoratorsBeforeExport' option to false to use" +
@@ -1807,7 +1799,7 @@ export default class StatementParser extends ExpressionParser {
       this.parseDecorators(false);
       return this.parseClass(expr, true, true);
     } else if (this.match(tt._const) || this.match(tt._var) || this.isLet()) {
-      return this.raise(
+      throw this.raise(
         this.state.start,
         "Only expressions, functions or classes are allowed as the `default` export.",
       );
@@ -1977,7 +1969,7 @@ export default class StatementParser extends ExpressionParser {
     name: string,
   ): void {
     if (this.state.exportedIdentifiers.indexOf(name) > -1) {
-      throw this.raise(
+      this.raise(
         node.start,
         name === "default"
           ? "Only one default export allowed per module."
@@ -2098,8 +2090,8 @@ export default class StatementParser extends ExpressionParser {
       } else {
         // Detect an attempt to deep destructure
         if (this.eat(tt.colon)) {
-          this.unexpected(
+          throw this.raise(
-            null,
+            this.state.start,
             "ES2015 named imports do not destructure. " +
               "Use another statement for destructuring after the import.",
           );

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

@@ -2,6 +2,7 @@
 
 import { types as tt, type TokenType } from "../tokenizer/types";
 import Tokenizer from "../tokenizer";
+import State from "../tokenizer/state";
 import type { Node } from "../types";
 import { lineBreak, skipWhiteSpace } from "../util/whitespace";
 import { isIdentifierChar } from "../util/identifier";
@@ -9,6 +10,14 @@ import * as charCodes from "charcodes";
 
 const literal = /^('|")((?:\\?.)*?)\1/;
 
+type TryParse<Node, Error, Thrown, Aborted, FailState> = {
+  node: Node,
+  error: Error,
+  thrown: Thrown,
+  aborted: Aborted,
+  failState: FailState,
+};
+
 // ## Parser utilities
 
 export default class UtilParser extends Tokenizer {
@@ -215,4 +224,58 @@ export default class UtilParser extends Tokenizer {
 
     return false;
   }
+
+  // tryParse will clone parser state.
+  // It is expensive and should be used with cautions
+  tryParse<T: Node | $ReadOnlyArray<Node>>(
+    fn: (abort: (node?: T) => empty) => T,
+    oldState: State = this.state.clone(),
+  ):
+    | TryParse<T, null, false, false, null>
+    | TryParse<T | null, SyntaxError, boolean, false, State>
+    | TryParse<T | null, null, false, true, State> {
+    const abortSignal: { node: T | null } = { node: null };
+    try {
+      const node = fn((node = null) => {
+        abortSignal.node = node;
+        throw abortSignal;
+      });
+      if (this.state.errors.length > oldState.errors.length) {
+        const failState = this.state;
+        this.state = oldState;
+        return {
+          node,
+          error: (failState.errors[oldState.errors.length]: SyntaxError),
+          thrown: false,
+          aborted: false,
+          failState,
+        };
+      }
+
+      return {
+        node,
+        error: null,
+        thrown: false,
+        aborted: false,
+        failState: null,
+      };
+    } catch (error) {
+      const failState = this.state;
+      this.state = oldState;
+      if (error instanceof SyntaxError) {
+        return { node: null, error, thrown: true, aborted: false, failState };
+      }
+      if (error === abortSignal) {
+        return {
+          node: abortSignal.node,
+          error: null,
+          thrown: false,
+          aborted: true,
+          failState,
+        };
+      }
+
+      throw error;
+    }
+  }
 }

packages/babel-parser/src/plugins/estree.js

@@ -93,9 +93,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         } else {
           this.raise(start, "setter must have exactly one formal parameter");
         }
-      }
+      } else if (
-
+        prop.kind === "set" &&
-      if (prop.kind === "set" && prop.value.params[0].type === "RestElement") {
+        prop.value.params[0].type === "RestElement"
+      ) {
         this.raise(
           start,
           "setter function argument must not be a rest parameter",
@@ -382,12 +383,15 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       isLast: boolean,
     ) {
       if (prop.kind === "get" || prop.kind === "set") {
-        this.raise(
+        throw this.raise(
           prop.key.start,
           "Object pattern can't contain getter or setter",
         );
       } else if (prop.method) {
-        this.raise(prop.key.start, "Object pattern can't contain methods");
+        throw this.raise(
+          prop.key.start,
+          "Object pattern can't contain methods",
+        );
       } else {
         super.toAssignableObjectExpressionProp(prop, isBinding, isLast);
       }

packages/babel-parser/src/plugins/flow.js

@@ -1,5 +1,7 @@
 // @flow
 
+/*:: declare var invariant; */
+
 import type Parser from "../parser";
 import { types as tt, type TokenType } from "../tokenizer/types";
 import * as N from "../types";
@@ -263,7 +265,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           return this.flowParseDeclareModuleExports(node);
         } else {
           if (insideModule) {
-            this.unexpected(
+            this.raise(
               this.state.lastTokStart,
               "`declare module` cannot be used inside another `declare module`",
             );
@@ -313,7 +315,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         if (this.match(tt._import)) {
           this.next();
           if (!this.isContextual("type") && !this.match(tt._typeof)) {
-            this.unexpected(
+            this.raise(
               this.state.lastTokStart,
               "Imports within a `declare module` body must always be `import type` or `import typeof`",
             );
@@ -345,17 +347,17 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       body.forEach(bodyElement => {
         if (isEsModuleType(bodyElement)) {
           if (kind === "CommonJS") {
-            this.unexpected(bodyElement.start, errorMessage);
+            this.raise(bodyElement.start, errorMessage);
           }
           kind = "ES";
         } else if (bodyElement.type === "DeclareModuleExports") {
           if (hasModuleExport) {
-            this.unexpected(
+            this.raise(
               bodyElement.start,
               "Duplicate `declare module.exports` statement",
             );
           }
-          if (kind === "ES") this.unexpected(bodyElement.start, errorMessage);
+          if (kind === "ES") this.raise(bodyElement.start, errorMessage);
           kind = "CommonJS";
           hasModuleExport = true;
         }
@@ -548,8 +550,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
     checkNotUnderscore(word: string) {
       if (word === "_") {
-        throw this.unexpected(
+        this.raise(
-          null,
+          this.state.start,
           "`_` is only allowed as a type argument to call or new",
         );
       }
@@ -632,7 +634,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         node.default = this.flowParseType();
       } else {
         if (requireDefault) {
-          this.unexpected(
+          this.raise(
             nodeStart,
             // eslint-disable-next-line max-len
             "Type parameter declaration needs a default, since a preceding type parameter declaration has a default.",
@@ -878,6 +880,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       while (!this.match(endDelim)) {
         let isStatic = false;
         let protoStart: ?number = null;
+        let inexactStart: ?number = null;
         const node = this.startNode();
 
         if (allowProto && this.isContextual("proto")) {
@@ -950,17 +953,29 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             variance,
             kind,
             allowSpread,
-            allowInexact,
+            allowInexact ?? !exact,
           );
 
           if (propOrInexact === null) {
             inexact = true;
+            inexactStart = this.state.lastTokStart;
           } else {
             nodeStart.properties.push(propOrInexact);
           }
         }
 
         this.flowObjectTypeSemicolon();
+
+        if (
+          inexactStart &&
+          !this.match(tt.braceR) &&
+          !this.match(tt.braceBarR)
+        ) {
+          this.raise(
+            inexactStart,
+            "Explicit inexact syntax must appear at the end of an inexact object",
+          );
+        }
       }
 
       this.expect(endDelim);
@@ -990,10 +1005,38 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       allowSpread: boolean,
       allowInexact: boolean,
     ): (N.FlowObjectTypeProperty | N.FlowObjectTypeSpreadProperty) | null {
-      if (this.match(tt.ellipsis)) {
+      if (this.eat(tt.ellipsis)) {
+        const isInexactToken =
+          this.match(tt.comma) ||
+          this.match(tt.semi) ||
+          this.match(tt.braceR) ||
+          this.match(tt.braceBarR);
+
+        if (isInexactToken) {
+          if (!allowSpread) {
+            this.raise(
+              this.state.lastTokStart,
+              "Explicit inexact syntax cannot appear in class or interface definitions",
+            );
+          } else if (!allowInexact) {
+            this.raise(
+              this.state.lastTokStart,
+              "Explicit inexact syntax cannot appear inside an explicit exact object type",
+            );
+          }
+          if (variance) {
+            this.raise(
+              variance.start,
+              "Explicit inexact syntax cannot have variance",
+            );
+          }
+
+          return null;
+        }
+
         if (!allowSpread) {
-          this.unexpected(
+          this.raise(
-            null,
+            this.state.lastTokStart,
             "Spread operator cannot appear in class or interface definitions",
           );
         }
@@ -1001,35 +1044,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           this.unexpected(protoStart);
         }
         if (variance) {
-          this.unexpected(
+          this.raise(variance.start, "Spread properties cannot have variance");
-            variance.start,
-            "Spread properties cannot have variance",
-          );
-        }
-        this.expect(tt.ellipsis);
-        const isInexactToken = this.eat(tt.comma) || this.eat(tt.semi);
-
-        if (this.match(tt.braceR)) {
-          if (allowInexact) return null;
-          this.unexpected(
-            null,
-            "Explicit inexact syntax is only allowed inside inexact objects",
-          );
         }
 
-        if (this.match(tt.braceBarR)) {
-          this.unexpected(
-            null,
-            "Explicit inexact syntax cannot appear inside an explicit exact object type",
-          );
-        }
-
-        if (isInexactToken) {
-          this.unexpected(
-            null,
-            "Explicit inexact syntax must appear at the end of an inexact object",
-          );
-        }
         node.argument = this.flowParseType();
         return this.finishNode(node, "ObjectTypeSpreadProperty");
       } else {
@@ -1400,8 +1417,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
               );
             }
 
-            this.unexpected(
+            throw this.raise(
-              null,
+              this.state.start,
               `Unexpected token, expected "number" or "bigint"`,
             );
           }
@@ -1720,23 +1737,23 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     ): N.Expression {
       if (!this.match(tt.question)) return expr;
 
-      // only do the expensive clone if there is a question mark
+      // only use the expensive "tryParse" method if there is a question mark
       // and if we come from inside parens
       if (refNeedsArrowPos) {
-        const state = this.state.clone();
+        const result = this.tryParse(() =>
-        try {
+          super.parseConditional(expr, noIn, startPos, startLoc),
-          return super.parseConditional(expr, noIn, startPos, startLoc);
+        );
-        } catch (err) {
+
-          if (err instanceof SyntaxError) {
+        if (!result.node) {
-            this.state = state;
+          // $FlowIgnore
-            refNeedsArrowPos.start = err.pos || this.state.start;
+          refNeedsArrowPos.start = result.error.pos || this.state.start;
-            return expr;
+          return expr;
-          } else {
-            // istanbul ignore next: no such error is expected
-            throw err;
-          }
         }
+
+        if (result.error) this.state = result.failState;
+        return result.node;
       }
+
       this.expect(tt.question);
       const state = this.state.clone();
       const originalNoArrowAt = this.state.noArrowAt;
@@ -1776,10 +1793,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           this.state.noArrowAt = noArrowAt.concat(valid[0].start);
           ({ consequent, failed } = this.tryParseConditionalConsequent());
         }
-
-        this.getArrowLikeExpressions(consequent, true);
       }
 
+      this.getArrowLikeExpressions(consequent, true);
+
       this.state.noArrowAt = originalNoArrowAt;
       this.expect(tt.colon);
 
@@ -1825,19 +1842,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         if (node.type === "ArrowFunctionExpression") {
           if (node.typeParameters || !node.returnType) {
             // This is an arrow expression without ambiguity, so check its parameters
-            this.toAssignableList(
+            this.finishArrowValidation(node);
-              // node.params is Expression[] instead of $ReadOnlyArray<Pattern> because it
-              // has not been converted yet.
-              ((node.params: any): N.Expression[]),
-              true,
-              "arrow function parameters",
-              node.extra?.trailingComma,
-            );
-            // Enter scope, as checkParams defines bindings
-            this.scope.enter(functionFlags(false, false) | SCOPE_ARROW);
-            // Use super's method to force the parameters to be checked
-            super.checkParams(node, false, true);
-            this.scope.exit();
           } else {
             arrows.push(node);
           }
@@ -1849,30 +1854,29 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
 
       if (disallowInvalid) {
-        for (let i = 0; i < arrows.length; i++) {
+        arrows.forEach(node => this.finishArrowValidation(node));
-          this.toAssignableList(
-            ((node.params: any): N.Expression[]),
-            true,
-            "arrow function parameters",
-            node.extra?.trailingComma,
-          );
-        }
         return [arrows, []];
       }
 
-      return partition(arrows, node => {
+      return partition(arrows, node =>
-        try {
+        node.params.every(param => this.isAssignable(param, true)),
-          this.toAssignableList(
+      );
-            ((node.params: any): N.Expression[]),
+    }
-            true,
+
-            "arrow function parameters",
+    finishArrowValidation(node: N.ArrowFunctionExpression) {
-            node.extra?.trailingComma,
+      this.toAssignableList(
-          );
+        // node.params is Expression[] instead of $ReadOnlyArray<Pattern> because it
-          return true;
+        // has not been converted yet.
-        } catch (err) {
+        ((node.params: any): N.Expression[]),
-          return false;
+        true,
-        }
+        "arrow function parameters",
-      });
+        node.extra?.trailingComma,
+      );
+      // Enter scope, as checkParams defines bindings
+      this.scope.enter(functionFlags(false, false) | SCOPE_ARROW);
+      // Use super's method to force the parameters to be checked
+      super.checkParams(node, false, true);
+      this.scope.exit();
     }
 
     forwardNoArrowParamsConversionAt<T>(node: N.Node, parse: () => T): T {
@@ -2025,6 +2029,49 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
     }
 
+    isAssignable(node: N.Node, isBinding?: boolean): boolean {
+      switch (node.type) {
+        case "Identifier":
+        case "ObjectPattern":
+        case "ArrayPattern":
+        case "AssignmentPattern":
+          return true;
+
+        case "ObjectExpression": {
+          const last = node.properties.length - 1;
+          return node.properties.every((prop, i) => {
+            return (
+              prop.type !== "ObjectMethod" &&
+              (i === last || prop.type === "SpreadElement") &&
+              this.isAssignable(prop)
+            );
+          });
+        }
+
+        case "ObjectProperty":
+          return this.isAssignable(node.value);
+
+        case "SpreadElement":
+          return this.isAssignable(node.argument);
+
+        case "ArrayExpression":
+          return node.elements.every(element => this.isAssignable(element));
+
+        case "AssignmentExpression":
+          return node.operator === "=";
+
+        case "ParenthesizedExpression":
+          return this.isAssignable(node.expression);
+
+        case "MemberExpression":
+        case "OptionalMemberExpression":
+          return !isBinding;
+
+        default:
+          return false;
+      }
+    }
+
     toAssignable(
       node: N.Node,
       isBinding: ?boolean,
@@ -2253,13 +2300,13 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     parseAssignableListItemTypes(param: N.Pattern): N.Pattern {
       if (this.eat(tt.question)) {
         if (param.type !== "Identifier") {
-          throw this.raise(
+          this.raise(
             param.start,
             "A binding pattern parameter cannot be optional in an implementation signature.",
           );
         }
 
-        param.optional = true;
+        ((param: any): N.Identifier).optional = true;
       }
       if (this.match(tt.colon)) {
         param.typeAnnotation = this.flowParseTypeAnnotation();
@@ -2490,45 +2537,50 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       afterLeftParse?: Function,
       refNeedsArrowPos?: ?Pos,
     ): N.Expression {
-      let jsxError = null;
+      let state = null;
+
+      let jsx;
+
       if (
         this.hasPlugin("jsx") &&
         (this.match(tt.jsxTagStart) || this.isRelational("<"))
       ) {
-        const state = this.state.clone();
+        state = this.state.clone();
-        try {
-          return super.parseMaybeAssign(
-            noIn,
-            refShorthandDefaultPos,
-            afterLeftParse,
-            refNeedsArrowPos,
-          );
-        } catch (err) {
-          if (err instanceof SyntaxError) {
-            this.state = state;
 
-            // Remove `tc.j_expr` and `tc.j_oTag` from context added
+        jsx = this.tryParse(
-            // by parsing `jsxTagStart` to stop the JSX plugin from
+          () =>
-            // messing with the tokens
+            super.parseMaybeAssign(
-            const cLength = this.state.context.length;
+              noIn,
-            if (this.state.context[cLength - 1] === tc.j_oTag) {
+              refShorthandDefaultPos,
-              this.state.context.length -= 2;
+              afterLeftParse,
-            }
+              refNeedsArrowPos,
+            ),
+          state,
+        );
+        /*:: invariant(!jsx.aborted) */
 
-            jsxError = err;
+        if (!jsx.error) return jsx.node;
-          } else {
+
-            // istanbul ignore next: no such error is expected
+        // Remove `tc.j_expr` and `tc.j_oTag` from context added
-            throw err;
+        // by parsing `jsxTagStart` to stop the JSX plugin from
-          }
+        // messing with the tokens
+        const { context } = this.state;
+        if (context[context.length - 1] === tc.j_oTag) {
+          context.length -= 2;
+        } else if (context[context.length - 1] === tc.j_expr) {
+          context.length -= 1;
         }
       }
 
-      if (jsxError != null || this.isRelational("<")) {
+      if ((jsx && jsx.error) || this.isRelational("<")) {
-        let arrowExpression;
+        state = state || this.state.clone();
+
         let typeParameters;
-        try {
+
+        const arrow = this.tryParse(() => {
           typeParameters = this.flowParseTypeParameterDeclaration();
-          arrowExpression = this.forwardNoArrowParamsConversionAt(
+
+          const arrowExpression = this.forwardNoArrowParamsConversionAt(
             typeParameters,
             () =>
               super.parseMaybeAssign(
@@ -2540,20 +2592,43 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           );
           arrowExpression.typeParameters = typeParameters;
           this.resetStartLocationFromNode(arrowExpression, typeParameters);
-        } catch (err) {
+
-          throw jsxError || err;
+          return arrowExpression;
+        }, state);
+
+        const arrowExpression: ?N.ArrowFunctionExpression =
+          arrow.node && arrow.node.type === "ArrowFunctionExpression"
+            ? arrow.node
+            : null;
+
+        if (!arrow.error && arrowExpression) return arrowExpression;
+
+        // If we are here, both JSX and Flow parsing attemps failed.
+        // Give the precedence to the JSX error, except if JSX had an
+        // unrecoverable error while Flow didn't.
+        // If the error is recoverable, we can only re-report it if there is
+        // a node we can return.
+
+        if (jsx && jsx.node) {
+          /*:: invariant(jsx.failState) */
+          this.state = jsx.failState;
+          return jsx.node;
         }
 
-        if (arrowExpression.type === "ArrowFunctionExpression") {
+        if (arrowExpression) {
+          /*:: invariant(arrow.failState) */
+          this.state = arrow.failState;
           return arrowExpression;
-        } else if (jsxError != null) {
-          throw jsxError;
-        } else {
-          this.raise(
-            typeParameters.start,
-            "Expected an arrow function after this type parameter declaration",
-          );
         }
+
+        if (jsx && jsx.thrown) throw jsx.error;
+        if (arrow.thrown) throw arrow.error;
+
+        /*:: invariant(typeParameters) */
+        throw this.raise(
+          typeParameters.start,
+          "Expected an arrow function after this type parameter declaration",
+        );
       }
 
       return super.parseMaybeAssign(
@@ -2567,8 +2642,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     // handle return types for arrow functions
     parseArrow(node: N.ArrowFunctionExpression): ?N.ArrowFunctionExpression {
       if (this.match(tt.colon)) {
-        const state = this.state.clone();
+        const result = this.tryParse(() => {
-        try {
           const oldNoAnonFunctionType = this.state.noAnonFunctionType;
           this.state.noAnonFunctionType = true;
 
@@ -2586,18 +2660,18 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           if (this.canInsertSemicolon()) this.unexpected();
           if (!this.match(tt.arrow)) this.unexpected();
 
-          // assign after it is clear it is an arrow
+          return typeNode;
-          node.returnType = typeNode.typeAnnotation
+        });
-            ? this.finishNode(typeNode, "TypeAnnotation")
+
-            : null;
+        if (result.thrown) return null;
-        } catch (err) {
+        /*:: invariant(result.node) */
-          if (err instanceof SyntaxError) {
+
-            this.state = state;
+        if (result.error) this.state = result.failState;
-          } else {
+
-            // istanbul ignore next: no such error is expected
+        // assign after it is clear it is an arrow
-            throw err;
+        node.returnType = result.node.typeAnnotation
-          }
+          ? this.finishNode(result.node, "TypeAnnotation")
-        }
+          : null;
       }
 
       return super.parseArrow(node);
@@ -2630,7 +2704,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         return;
       }
 
-      return super.checkParams(node, allowDuplicates, isArrowFunction);
+      return super.checkParams(...arguments);
     }
 
     parseParenAndDistinguishExpression(canBeArrow: boolean): N.Expression {
@@ -2662,23 +2736,33 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         this.isRelational("<")
       ) {
         const state = this.state.clone();
-        let error;
+        const arrow = this.tryParse(
-        try {
+          abort =>
-          const node = this.parseAsyncArrowWithTypeParameters(
+            this.parseAsyncArrowWithTypeParameters(startPos, startLoc) ||
-            startPos,
+            abort(),
-            startLoc,
+          state,
-          );
+        );
-          if (node) return node;
+
-        } catch (e) {
+        if (!arrow.error && !arrow.aborted) return arrow.node;
-          error = e;
+
+        const result = this.tryParse(
+          () => super.parseSubscripts(base, startPos, startLoc, noCalls),
+          state,
+        );
+
+        if (result.node && !result.error) return result.node;
+
+        if (arrow.node) {
+          this.state = arrow.failState;
+          return arrow.node;
         }
 
-        this.state = state;
+        if (result.node) {
-        try {
+          this.state = result.failState;
-          return super.parseSubscripts(base, startPos, startLoc, noCalls);
+          return result.node;
-        } catch (e) {
-          throw error || e;
         }
+
+        throw arrow.error || result.error;
       }
 
       return super.parseSubscripts(base, startPos, startLoc, noCalls);
@@ -2717,8 +2801,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       ) {
         const node = this.startNodeAt(startPos, startLoc);
         node.callee = base;
-        const state = this.state.clone();
+
-        try {
+        const result = this.tryParse(() => {
           node.typeArguments = this.flowParseTypeParameterInstantiationCallOrNew();
           this.expect(tt.parenL);
           node.arguments = this.parseCallExpressionArguments(tt.parenR, false);
@@ -2727,12 +2811,11 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             node,
             subscriptState.optionalChainMember,
           );
-        } catch (e) {
+        });
-          if (e instanceof SyntaxError) {
+
-            this.state = state;
+        if (result.node) {
-          } else {
+          if (result.error) this.state = result.failState;
-            throw e;
+          return result.node;
-          }
         }
       }
 
@@ -2748,16 +2831,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     parseNewArguments(node: N.NewExpression): void {
       let targs = null;
       if (this.shouldParseTypes() && this.isRelational("<")) {
-        const state = this.state.clone();
+        targs = this.tryParse(() =>
-        try {
+          this.flowParseTypeParameterInstantiationCallOrNew(),
-          targs = this.flowParseTypeParameterInstantiationCallOrNew();
+        ).node;
-        } catch (e) {
-          if (e instanceof SyntaxError) {
-            this.state = state;
-          } else {
-            throw e;
-          }
-        }
       }
       node.typeArguments = targs;
 
@@ -2811,7 +2887,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     parseTopLevel(file: N.File, program: N.Program): N.File {
       const fileNode = super.parseTopLevel(file, program);
       if (this.state.hasFlowComment) {
-        this.unexpected(null, "Unterminated flow-comment");
+        this.raise(this.state.pos, "Unterminated flow-comment");
       }
       return fileNode;
     }
@@ -2832,7 +2908,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
       if (this.state.hasFlowComment) {
         const end = this.input.indexOf("*-/", (this.state.pos += 2));
-        if (end === -1) this.raise(this.state.pos - 2, "Unterminated comment");
+        if (end === -1) {
+          throw this.raise(this.state.pos - 2, "Unterminated comment");
+        }
         this.state.pos = end + 3;
         return;
       }
@@ -2874,7 +2952,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     hasFlowCommentCompletion(): void {
       const end = this.input.indexOf("*/", this.state.pos);
       if (end === -1) {
-        this.raise(this.state.pos, "Unterminated comment");
+        throw this.raise(this.state.pos, "Unterminated comment");
       }
     }
 
@@ -2931,7 +3009,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         enumName,
         suppliedType,
       }: { enumName: string, suppliedType: null | string },
-    ): void {
+    ) {
       const suggestion =
         `Use one of \`boolean\`, \`number\`, \`string\`, or \`symbol\` in ` +
         `enum \`${enumName}\`.`;
@@ -2939,13 +3017,13 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         suppliedType === null
           ? `Supplied enum type is not valid. ${suggestion}`
           : `Enum type \`${suppliedType}\` is not valid. ${suggestion}`;
-      this.raise(pos, message);
+      return this.raise(pos, message);
     }
 
     flowEnumErrorInvalidMemberInitializer(
       pos: number,
       { enumName, explicitType, memberName }: EnumContext,
-    ): void {
+    ) {
       let message = null;
       switch (explicitType) {
         case "boolean":
@@ -2966,7 +3044,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             `The enum member initializer for \`${memberName}\` needs to be a literal (either ` +
             `a boolean, number, or string) in enum \`${enumName}\`.`;
       }
-      this.raise(pos, message);
+      return this.raise(pos, message);
     }
 
     flowEnumErrorNumberMemberNotInitialized(
@@ -3119,8 +3197,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             break;
           }
           case "invalid": {
-            this.flowEnumErrorInvalidMemberInitializer(init.pos, context);
+            throw this.flowEnumErrorInvalidMemberInitializer(init.pos, context);
-            break;
           }
           case "none": {
             switch (explicitType) {
@@ -3184,28 +3261,29 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       enumName: string,
     }): EnumExplicitType {
       if (this.eatContextual("of")) {
-        if (this.match(tt.name)) {
+        if (!this.match(tt.name)) {
-          switch (this.state.value) {
+          throw this.flowEnumErrorInvalidExplicitType(this.state.start, {
-            case "boolean":
-            case "number":
-            case "string":
-            case "symbol": {
-              const explicitType = this.state.value;
-              this.next();
-              return explicitType;
-            }
-            default:
-              this.flowEnumErrorInvalidExplicitType(this.state.start, {
-                enumName,
-                suppliedType: this.state.value,
-              });
-          }
-        } else {
-          this.flowEnumErrorInvalidExplicitType(this.state.start, {
             enumName,
             suppliedType: null,
           });
         }
+
+        const { value } = this.state;
+        this.next();
+
+        if (
+          value !== "boolean" &&
+          value !== "number" &&
+          value !== "string" &&
+          value !== "symbol"
+        ) {
+          this.flowEnumErrorInvalidExplicitType(this.state.start, {
+            enumName,
+            suppliedType: value,
+          });
+        }
+
+        return value;
       }
       return null;
     }

packages/babel-parser/src/plugins/jsx/index.js

@@ -82,7 +82,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       let chunkStart = this.state.pos;
       for (;;) {
         if (this.state.pos >= this.length) {
-          this.raise(this.state.start, "Unterminated JSX contents");
+          throw this.raise(this.state.start, "Unterminated JSX contents");
         }
 
         const ch = this.input.charCodeAt(this.state.pos);
@@ -142,7 +142,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       let chunkStart = ++this.state.pos;
       for (;;) {
         if (this.state.pos >= this.length) {
-          this.raise(this.state.start, "Unterminated string constant");
+          throw this.raise(this.state.start, "Unterminated string constant");
         }
 
         const ch = this.input.charCodeAt(this.state.pos);
@@ -279,13 +279,12 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           this.next();
           node = this.jsxParseExpressionContainer(node);
           if (node.expression.type === "JSXEmptyExpression") {
-            throw this.raise(
+            this.raise(
               node.start,
               "JSX attributes must only be assigned a non-empty expression",
             );
-          } else {
-            return node;
           }
+          return node;
 
         case tt.jsxTagStart:
         case tt.string:
@@ -485,12 +484,18 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         node.closingElement = closingElement;
       }
       node.children = children;
-      if (this.match(tt.relational) && this.state.value === "<") {
+      while (this.isRelational("<")) {
+        // In case we encounter an lt token here it will always be the start of
+        // jsx as the lt sign is not allowed in places that expect an expression
+        this.finishToken(tt.jsxTagStart);
+
         this.raise(
           this.state.start,
           "Adjacent JSX elements must be wrapped in an enclosing tag. " +
             "Did you want a JSX fragment <>...</>?",
         );
+
+        this.jsxParseElement();
       }
 
       return isFragment(openingElement)

packages/babel-parser/src/plugins/typescript/index.js

@@ -1,6 +1,9 @@
 // @flow
 
+/*:: declare var invariant; */
+
 import type { TokenType } from "../../tokenizer/types";
+import type State from "../../tokenizer/state";
 import { types as tt } from "../../tokenizer/types";
 import { types as ct } from "../../tokenizer/context";
 import * as N from "../../types";
@@ -234,8 +237,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       this.expect(tt._import);
       this.expect(tt.parenL);
       if (!this.match(tt.string)) {
-        throw this.unexpected(
+        this.raise(
-          null,
+          this.state.start,
           "Argument in a type import must be a string literal",
         );
       }
@@ -371,13 +374,13 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             pattern.type !== "ObjectPattern" &&
             pattern.type !== "ArrayPattern"
           ) {
-            throw this.unexpected(
+            this.raise(
               pattern.start,
               "Name in a signature must be an Identifier, ObjectPattern or ArrayPattern," +
                 `instead got ${pattern.type}`,
             );
           }
-          return pattern;
+          return (pattern: any);
         },
       );
     }
@@ -642,7 +645,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       const node: N.TsLiteralType = this.startNode();
       const templateNode = this.parseTemplate(false);
       if (templateNode.expressions.length > 0) {
-        throw this.raise(
+        this.raise(
           templateNode.expressions[0].start,
           "Template literal types cannot have any substitution",
         );
@@ -1276,17 +1279,12 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return res;
     }
 
-    tsTryParseAndCatch<T>(f: () => T): ?T {
+    tsTryParseAndCatch<T: ?N.NodeBase>(f: () => T): ?T {
-      const state = this.state.clone();
+      const result = this.tryParse(abort => f() || abort());
-      try {
+
-        return f();
+      if (result.aborted || !result.node) return undefined;
-      } catch (e) {
+      if (result.error) this.state = result.failState;
-        if (e instanceof SyntaxError) {
+      return result.node;
-          this.state = state;
-          return undefined;
-        }
-        throw e;
-      }
     }
 
     tsTryParse<T>(f: () => ?T): ?T {
@@ -1558,12 +1556,12 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         if (accessibility) pp.accessibility = accessibility;
         if (readonly) pp.readonly = readonly;
         if (elt.type !== "Identifier" && elt.type !== "AssignmentPattern") {
-          throw this.raise(
+          this.raise(
             pp.start,
             "A parameter property may not be declared using a binding pattern.",
           );
         }
-        pp.parameter = elt;
+        pp.parameter = ((elt: any): N.Identifier | N.AssignmentPattern);
         return this.finishNode(pp, "TSParameterProperty");
       }
 
@@ -1597,11 +1595,13 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       super.parseFunctionBodyAndFinish(node, type, isMethod);
     }
 
-    checkFunctionStatementId(node: N.Function): void {
+    registerFunctionStatementId(node: N.Function): void {
       if (!node.body && node.id) {
+        // Function ids are validated after parsing their body.
+        // For bodyless function, we need to do it here.
         this.checkLVal(node.id, BIND_TS_AMBIENT, null, "function name");
       } else {
-        super.checkFunctionStatementId(...arguments);
+        super.registerFunctionStatementId(...arguments);
       }
     }
 
@@ -1946,19 +1946,17 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         );
       }
 
-      const state = this.state.clone();
+      const result = this.tryParse(() =>
-      try {
+        super.parseConditional(expr, noIn, startPos, startLoc),
-        return super.parseConditional(expr, noIn, startPos, startLoc);
+      );
-      } catch (err) {
-        if (!(err instanceof SyntaxError)) {
-          // istanbul ignore next: no such error is expected
-          throw err;
-        }
 
-        this.state = state;
+      if (!result.node) {
-        refNeedsArrowPos.start = err.pos || this.state.start;
+        // $FlowIgnore
+        refNeedsArrowPos.start = result.error.pos || this.state.start;
         return expr;
       }
+      if (result.error) this.state = result.failState;
+      return result.node;
     }
 
     // Note: These "type casts" are *not* valid TS expressions.
@@ -2161,80 +2159,97 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     parseMaybeAssign(...args): N.Expression {
       // Note: When the JSX plugin is on, type assertions (`<T> x`) aren't valid syntax.
 
-      let jsxError: ?SyntaxError;
+      let state: ?State;
+      let jsx;
+      let typeCast;
 
       if (this.match(tt.jsxTagStart)) {
-        const context = this.curContext();
-        assert(context === ct.j_oTag);
-        // Only time j_oTag is pushed is right after j_expr.
-        assert(this.state.context[this.state.context.length - 2] === ct.j_expr);
-
         // Prefer to parse JSX if possible. But may be an arrow fn.
-        const state = this.state.clone();
+        state = this.state.clone();
-        try {
-          return super.parseMaybeAssign(...args);
-        } catch (err) {
-          if (!(err instanceof SyntaxError)) {
-            // istanbul ignore next: no such error is expected
-            throw err;
-          }
 
-          this.state = state;
+        jsx = this.tryParse(() => super.parseMaybeAssign(...args), state);
-          // Pop the context added by the jsxTagStart.
+        /*:: invariant(!jsx.aborted) */
-          assert(this.curContext() === ct.j_oTag);
+
-          this.state.context.pop();
+        if (!jsx.error) return jsx.node;
-          assert(this.curContext() === ct.j_expr);
+
-          this.state.context.pop();
+        // Remove `tc.j_expr` and `tc.j_oTag` from context added
-          jsxError = err;
+        // by parsing `jsxTagStart` to stop the JSX plugin from
+        // messing with the tokens
+        const { context } = this.state;
+        if (context[context.length - 1] === ct.j_oTag) {
+          context.length -= 2;
+        } else if (context[context.length - 1] === ct.j_expr) {
+          context.length -= 1;
         }
       }
 
-      if (jsxError === undefined && !this.isRelational("<")) {
+      if (!(jsx && jsx.error) && !this.isRelational("<")) {
         return super.parseMaybeAssign(...args);
       }
 
       // Either way, we're looking at a '<': tt.jsxTagStart or relational.
 
-      let arrowExpression;
       let typeParameters: N.TsTypeParameterDeclaration;
-      const state = this.state.clone();
+      state = state || this.state.clone();
-      try {
+
+      const arrow = this.tryParse(abort => {
         // This is similar to TypeScript's `tryParseParenthesizedArrowFunctionExpression`.
         typeParameters = this.tsParseTypeParameters();
-        arrowExpression = super.parseMaybeAssign(...args);
+        const expr = super.parseMaybeAssign(...args);
+
         if (
-          arrowExpression.type !== "ArrowFunctionExpression" ||
+          expr.type !== "ArrowFunctionExpression" ||
-          (arrowExpression.extra && arrowExpression.extra.parenthesized)
+          (expr.extra && expr.extra.parenthesized)
         ) {
-          this.unexpected(); // Go to the catch block (needs a SyntaxError).
+          abort();
-        }
-      } catch (err) {
-        if (!(err instanceof SyntaxError)) {
-          // istanbul ignore next: no such error is expected
-          throw err;
         }
 
-        if (jsxError) {
+        // Correct TypeScript code should have at least 1 type parameter, but don't crash on bad code.
-          throw jsxError;
+        if (typeParameters && typeParameters.params.length !== 0) {
+          this.resetStartLocationFromNode(expr, typeParameters);
         }
+        expr.typeParameters = typeParameters;
+        return expr;
+      }, state);
 
+      if (!arrow.error && !arrow.aborted) return arrow.node;
+
+      if (!jsx) {
         // Try parsing a type cast instead of an arrow function.
         // This will never happen outside of JSX.
         // (Because in JSX the '<' should be a jsxTagStart and not a relational.
         assert(!this.hasPlugin("jsx"));
-        // Parsing an arrow function failed, so try a type cast.
+
-        this.state = state;
         // This will start with a type assertion (via parseMaybeUnary).
         // But don't directly call `this.tsParseTypeAssertion` because we want to handle any binary after it.
-        return super.parseMaybeAssign(...args);
+        typeCast = this.tryParse(() => super.parseMaybeAssign(...args), state);
+        /*:: invariant(!typeCast.aborted) */
+        if (!typeCast.error) return typeCast.node;
       }
 
-      // Correct TypeScript code should have at least 1 type parameter, but don't crash on bad code.
+      if (jsx && jsx.node) {
-      if (typeParameters && typeParameters.params.length !== 0) {
+        /*:: invariant(jsx.failState) */
-        this.resetStartLocationFromNode(arrowExpression, typeParameters);
+        this.state = jsx.failState;
+        return jsx.node;
       }
-      arrowExpression.typeParameters = typeParameters;
+
-      return arrowExpression;
+      if (arrow.node) {
+        /*:: invariant(arrow.failState) */
+        this.state = arrow.failState;
+        return arrow.node;
+      }
+
+      if (typeCast && typeCast.node) {
+        /*:: invariant(typeCast.failState) */
+        this.state = typeCast.failState;
+        return typeCast.node;
+      }
+
+      if (jsx && jsx.thrown) throw jsx.error;
+      if (arrow.thrown) throw arrow.error;
+      if (typeCast && typeCast.thrown) throw typeCast.error;
+
+      throw (jsx && jsx.error) || arrow.error || (typeCast && typeCast.error);
     }
 
     // Handle type assertions
@@ -2250,23 +2265,20 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       if (this.match(tt.colon)) {
         // This is different from how the TS parser does it.
         // TS uses lookahead. The Babel Parser parses it as a parenthesized expression and converts.
-        const state = this.state.clone();
+
-        try {
+        const result = this.tryParse(abort => {
           const returnType = this.tsParseTypeOrTypePredicateAnnotation(
             tt.colon,
           );
-          if (this.canInsertSemicolon() || !this.match(tt.arrow)) {
+          if (this.canInsertSemicolon() || !this.match(tt.arrow)) abort();
-            this.state = state;
+          return returnType;
-            return undefined;
+        });
-          }
+
-          node.returnType = returnType;
+        if (result.aborted) return;
-        } catch (err) {
+
-          if (err instanceof SyntaxError) {
+        if (!result.thrown) {
-            this.state = state;
+          if (result.error) this.state = result.failState;
-          } else {
+          node.returnType = result.node;
-            // istanbul ignore next: no such error is expected
-            throw err;
-          }
         }
       }
 
@@ -2277,13 +2289,13 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     parseAssignableListItemTypes(param: N.Pattern) {
       if (this.eat(tt.question)) {
         if (param.type !== "Identifier") {
-          throw this.raise(
+          this.raise(
             param.start,
             "A binding pattern parameter cannot be optional in an implementation signature.",
           );
         }
 
-        param.optional = true;
+        ((param: any): N.Identifier).optional = true;
       }
       const type = this.tsTryParseTypeAnnotation();
       if (type) param.typeAnnotation = type;

packages/babel-parser/src/tokenizer/index.js

@@ -126,8 +126,11 @@ export default class Tokenizer extends LocationParser {
   // Move to the next token
 
   next(): void {
-    if (this.options.tokens && !this.isLookahead) {
+    if (!this.isLookahead) {
-      this.state.tokens.push(new Token(this.state));
+      this.checkKeywordEscapes();
+      if (this.options.tokens) {
+        this.state.tokens.push(new Token(this.state));
+      }
     }
 
     this.state.lastTokEnd = this.state.end;
@@ -248,7 +251,7 @@ export default class Tokenizer extends LocationParser {
     const startLoc = this.state.curPosition();
     const start = this.state.pos;
     const end = this.input.indexOf("*/", this.state.pos + 2);
-    if (end === -1) this.raise(start, "Unterminated comment");
+    if (end === -1) throw this.raise(start, "Unterminated comment");
 
     this.state.pos = end + 2;
     lineBreakG.lastIndex = start;
@@ -384,7 +387,7 @@ export default class Tokenizer extends LocationParser {
     const nextPos = this.state.pos + 1;
     const next = this.input.charCodeAt(nextPos);
     if (next >= charCodes.digit0 && next <= charCodes.digit9) {
-      this.raise(this.state.pos, "Unexpected digit after hash token");
+      throw this.raise(this.state.pos, "Unexpected digit after hash token");
     }
 
     if (
@@ -400,7 +403,7 @@ export default class Tokenizer extends LocationParser {
     ) {
       this.finishOp(tt.hash, 1);
     } else {
-      this.raise(this.state.pos, "Unexpected character '#'");
+      throw this.raise(this.state.pos, "Unexpected character '#'");
     }
   }
 
@@ -808,7 +811,7 @@ export default class Tokenizer extends LocationParser {
         }
     }
 
-    this.raise(
+    throw this.raise(
       this.state.pos,
       `Unexpected character '${String.fromCodePoint(code)}'`,
     );
@@ -825,11 +828,11 @@ export default class Tokenizer extends LocationParser {
     let escaped, inClass;
     for (;;) {
       if (this.state.pos >= this.length) {
-        this.raise(start, "Unterminated regular expression");
+        throw this.raise(start, "Unterminated regular expression");
       }
       const ch = this.input.charAt(this.state.pos);
       if (lineBreak.test(ch)) {
-        this.raise(start, "Unterminated regular expression");
+        throw this.raise(start, "Unterminated regular expression");
       }
       if (escaped) {
         escaped = false;
@@ -858,9 +861,6 @@ export default class Tokenizer extends LocationParser {
         if (mods.indexOf(char) > -1) {
           this.raise(this.state.pos + 1, "Duplicate regular expression flag");
         }
-
-        ++this.state.pos;
-        mods += char;
       } else if (
         isIdentifierChar(charCode) ||
         charCode === charCodes.backslash
@@ -869,6 +869,9 @@ export default class Tokenizer extends LocationParser {
       } else {
         break;
       }
+
+      ++this.state.pos;
+      mods += char;
     }
 
     this.finishToken(tt.regexp, {
@@ -880,10 +883,16 @@ export default class Tokenizer extends LocationParser {
   // Read an integer in the given radix. Return null if zero digits
   // were read, the integer value otherwise. When `len` is given, this
   // will return `null` unless the integer has exactly `len` digits.
+  // When `forceLen` is `true`, it means that we already know that in case
+  // of a malformed number we have to skip `len` characters anyway, instead
+  // of bailing out early. For example, in "\u{123Z}" we want to read up to }
+  // anyway, while in "\u00Z" we will stop at Z instead of consuming four
+  // characters (and thus the closing quote).
 
   readInt(
     radix: number,
     len?: number,
+    forceLen?: boolean,
     allowNumSeparator: boolean = true,
   ): number | null {
     const start = this.state.pos;
@@ -900,6 +909,7 @@ export default class Tokenizer extends LocationParser {
         ? allowedNumericSeparatorSiblings.oct
         : allowedNumericSeparatorSiblings.bin;
 
+    let invalid = false;
     let total = 0;
 
     for (let i = 0, e = len == null ? Infinity : len; i < e; ++i) {
@@ -911,15 +921,19 @@ export default class Tokenizer extends LocationParser {
           const prev = this.input.charCodeAt(this.state.pos - 1);
           const next = this.input.charCodeAt(this.state.pos + 1);
           if (allowedSiblings.indexOf(next) === -1) {
-            this.raise(this.state.pos, "Invalid or unexpected token");
+            this.raise(
-          }
+              this.state.pos,
-
+              "A numeric separator is only allowed between two digits",
-          if (
+            );
+          } else if (
             forbiddenSiblings.indexOf(prev) > -1 ||
             forbiddenSiblings.indexOf(next) > -1 ||
             Number.isNaN(next)
           ) {
-            this.raise(this.state.pos, "Invalid or unexpected token");
+            this.raise(
+              this.state.pos,
+              "A numeric separator is only allowed between two digits",
+            );
           }
 
           if (!allowNumSeparator) {
@@ -944,13 +958,30 @@ export default class Tokenizer extends LocationParser {
       } else {
         val = Infinity;
       }
-      if (val >= radix) break;
+      if (val >= radix) {
+        // If we are in "errorRecovery" mode and we found a digit which is too big,
+        // don't break the loop.
+
+        if (this.options.errorRecovery && val <= 9) {
+          val = 0;
+          this.raise(
+            this.state.start + i + 2,
+            "Expected number in radix " + radix,
+          );
+        } else if (forceLen) {
+          val = 0;
+          invalid = true;
+        } else {
+          break;
+        }
+      }
       ++this.state.pos;
       total = total * radix + val;
     }
     if (
       this.state.pos === start ||
-      (len != null && this.state.pos - start !== len)
+      (len != null && this.state.pos - start !== len) ||
+      invalid
     ) {
       return null;
     }
@@ -976,7 +1007,7 @@ export default class Tokenizer extends LocationParser {
     }
 
     if (isIdentifierStart(this.input.codePointAt(this.state.pos))) {
-      this.raise(this.state.pos, "Identifier directly after number");
+      throw this.raise(this.state.pos, "Identifier directly after number");
     }
 
     if (isBigInt) {
@@ -1062,7 +1093,7 @@ export default class Tokenizer extends LocationParser {
     }
 
     if (isIdentifierStart(this.input.codePointAt(this.state.pos))) {
-      this.raise(this.state.pos, "Identifier directly after number");
+      throw this.raise(this.state.pos, "Identifier directly after number");
     }
 
     // remove "_" for numeric literal separator, and "n" for BigInts
@@ -1087,6 +1118,7 @@ export default class Tokenizer extends LocationParser {
       const codePos = ++this.state.pos;
       code = this.readHexChar(
         this.input.indexOf("}", this.state.pos) - this.state.pos,
+        true,
         throwOnInvalid,
       );
       ++this.state.pos;
@@ -1102,7 +1134,7 @@ export default class Tokenizer extends LocationParser {
         }
       }
     } else {
-      code = this.readHexChar(4, throwOnInvalid);
+      code = this.readHexChar(4, false, throwOnInvalid);
     }
     return code;
   }
@@ -1112,7 +1144,7 @@ export default class Tokenizer extends LocationParser {
       chunkStart = ++this.state.pos;
     for (;;) {
       if (this.state.pos >= this.length) {
-        this.raise(this.state.start, "Unterminated string constant");
+        throw this.raise(this.state.start, "Unterminated string constant");
       }
       const ch = this.input.charCodeAt(this.state.pos);
       if (ch === quote) break;
@@ -1128,7 +1160,7 @@ export default class Tokenizer extends LocationParser {
         ++this.state.pos;
         ++this.state.curLine;
       } else if (isNewLine(ch)) {
-        this.raise(this.state.start, "Unterminated string constant");
+        throw this.raise(this.state.start, "Unterminated string constant");
       } else {
         ++this.state.pos;
       }
@@ -1145,7 +1177,7 @@ export default class Tokenizer extends LocationParser {
       containsInvalid = false;
     for (;;) {
       if (this.state.pos >= this.length) {
-        this.raise(this.state.start, "Unterminated template");
+        throw this.raise(this.state.start, "Unterminated template");
       }
       const ch = this.input.charCodeAt(this.state.pos);
       if (
@@ -1214,7 +1246,7 @@ export default class Tokenizer extends LocationParser {
       case charCodes.lowercaseR:
         return "\r";
       case charCodes.lowercaseX: {
-        const code = this.readHexChar(2, throwOnInvalid);
+        const code = this.readHexChar(2, false, throwOnInvalid);
         return code === null ? null : String.fromCharCode(code);
       }
       case charCodes.lowercaseU: {
@@ -1288,9 +1320,13 @@ export default class Tokenizer extends LocationParser {
 
   // Used to read character escape sequences ('\x', '\u').
 
-  readHexChar(len: number, throwOnInvalid: boolean): number | null {
+  readHexChar(
+    len: number,
+    forceLen: boolean,
+    throwOnInvalid: boolean,
+  ): number | null {
     const codePos = this.state.pos;
-    const n = this.readInt(16, len, false);
+    const n = this.readInt(16, len, forceLen, false);
     if (n === null) {
       if (throwOnInvalid) {
         this.raise(codePos, "Bad character escape sequence");
@@ -1333,20 +1369,18 @@ export default class Tokenizer extends LocationParser {
             this.state.pos,
             "Expecting Unicode escape sequence \\uXXXX",
           );
+          continue;
         }
 
         ++this.state.pos;
         const esc = this.readCodePoint(true);
+        if (esc !== null) {
+          if (!identifierCheck(esc)) {
+            this.raise(escStart, "Invalid Unicode escape");
+          }
 
-        if (
+          word += String.fromCodePoint(esc);
-          // $FlowFixMe (thinks esc may be null, but throwOnInvalid is true)
-          !identifierCheck(esc, true)
-        ) {
-          this.raise(escStart, "Invalid Unicode escape");
         }
-
-        // $FlowFixMe
-        word += String.fromCodePoint(esc);
         chunkStart = this.state.pos;
       } else {
         break;
@@ -1364,7 +1398,7 @@ export default class Tokenizer extends LocationParser {
 
   readWord(): void {
     const word = this.readWord1();
-    const type = (!this.state.containsEsc && keywordTypes.get(word)) || tt.name;
+    const type = keywordTypes.get(word) || tt.name;
 
     // Allow @@iterator and @@asyncIterator as a identifier only inside type
     if (
@@ -1377,6 +1411,13 @@ export default class Tokenizer extends LocationParser {
     this.finishToken(type, word);
   }
 
+  checkKeywordEscapes(): void {
+    const kw = this.state.type.keyword;
+    if (kw && this.state.containsEsc) {
+      this.raise(this.state.start, `Escape sequence in keyword ${kw}`);
+    }
+  }
+
   braceIsBlock(prevType: TokenType): boolean {
     const parent = this.curContext();
     if (parent === ct.functionExpression || parent === ct.functionStatement) {

packages/babel-parser/src/tokenizer/state.js

@@ -38,6 +38,8 @@ export default class State {
     this.startLoc = this.endLoc = this.curPosition();
   }
 
+  errors: SyntaxError[] = [];
+
   // Used to signify the start of a potential arrow function
   potentialArrowAt: number = -1;
 

packages/babel-parser/src/util/identifier.js

@@ -21,9 +21,7 @@ const reservedWords = {
 };
 
 const reservedWordsStrictSet = new Set(reservedWords.strict);
-const reservedWordsStrictBindSet = new Set(
+const reservedWordsStrictBindSet = new Set(reservedWords.strictBind);
-  reservedWords.strict.concat(reservedWords.strictBind),
-);
 
 /**
  * Checks if word is a reserved word in non-strict mode
@@ -41,6 +39,14 @@ export function isStrictReservedWord(word: string, inModule: boolean): boolean {
   return isReservedWord(word, inModule) || reservedWordsStrictSet.has(word);
 }
 
+/**
+ * Checks if word is a reserved word in binding strict mode, but it is allowed as
+ * a normal identifier.
+ */
+export function isStrictBindOnlyReservedWord(word: string): boolean {
+  return reservedWordsStrictBindSet.has(word);
+}
+
 /**
  * Checks if word is a reserved word in binding strict mode
  *
@@ -50,7 +56,9 @@ export function isStrictBindReservedWord(
   word: string,
   inModule: boolean,
 ): boolean {
-  return isReservedWord(word, inModule) || reservedWordsStrictBindSet.has(word);
+  return (
+    isStrictReservedWord(word, inModule) || isStrictBindOnlyReservedWord(word)
+  );
 }
 
 export function isKeyword(word: string): boolean {

packages/babel-parser/test/expressions/is-expression-babel-parser/fail/7/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Illegal 'use strict' directive in function with non-simple parameter list (1:0)"
-}

packages/babel-parser/test/expressions/is-expression-babel-parser/fail/7/output.json

@@ -0,0 +1,128 @@
+{
+  "type": "FunctionExpression",
+  "start": 0,
+  "end": 40,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 40
+    }
+  },
+  "id": null,
+  "generator": false,
+  "async": false,
+  "params": [
+    {
+      "type": "AssignmentPattern",
+      "start": 10,
+      "end": 23,
+      "loc": {
+        "start": {
+          "line": 1,
+          "column": 10
+        },
+        "end": {
+          "line": 1,
+          "column": 23
+        }
+      },
+      "left": {
+        "type": "Identifier",
+        "start": 10,
+        "end": 11,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 10
+          },
+          "end": {
+            "line": 1,
+            "column": 11
+          },
+          "identifierName": "a"
+        },
+        "name": "a"
+      },
+      "right": {
+        "type": "StringLiteral",
+        "start": 14,
+        "end": 23,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 14
+          },
+          "end": {
+            "line": 1,
+            "column": 23
+          }
+        },
+        "extra": {
+          "rawValue": "default",
+          "raw": "\"default\""
+        },
+        "value": "default"
+      }
+    }
+  ],
+  "body": {
+    "type": "BlockStatement",
+    "start": 25,
+    "end": 40,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 25
+      },
+      "end": {
+        "line": 1,
+        "column": 40
+      }
+    },
+    "body": [],
+    "directives": [
+      {
+        "type": "Directive",
+        "start": 26,
+        "end": 39,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 26
+          },
+          "end": {
+            "line": 1,
+            "column": 39
+          }
+        },
+        "value": {
+          "type": "DirectiveLiteral",
+          "start": 26,
+          "end": 38,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 26
+            },
+            "end": {
+              "line": 1,
+              "column": 38
+            }
+          },
+          "value": "use strict",
+          "extra": {
+            "raw": "\"use strict\"",
+            "rawValue": "use strict"
+          }
+        }
+      }
+    ]
+  },
+  "errors": [
+    "SyntaxError: Illegal 'use strict' directive in function with non-simple parameter list (1:0)"
+  ]
+}

packages/babel-parser/test/expressions/is-expression-babel-parser/fail/8/options.json

@@ -1,4 +1,3 @@
 {
-  "strictMode": true,
+  "strictMode": true
-  "throws": "Unexpected reserved word 'public' (2:0)"
+}
-}

packages/babel-parser/test/expressions/is-expression-babel-parser/fail/8/output.json

@@ -0,0 +1,20 @@
+{
+  "type": "Identifier",
+  "start": 1,
+  "end": 7,
+  "loc": {
+    "start": {
+      "line": 2,
+      "column": 0
+    },
+    "end": {
+      "line": 2,
+      "column": 6
+    },
+    "identifierName": "public"
+  },
+  "name": "public",
+  "errors": [
+    "SyntaxError: Unexpected reserved word 'public' (2:0)"
+  ]
+}

packages/babel-parser/test/fixtures/core/categorized/invalid-fn-decl-inside-loop/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "In non-strict mode code, functions can only be declared at top level, inside a block, or as the body of an if statement (1:10)"
-}

packages/babel-parser/test/fixtures/core/categorized/invalid-fn-decl-inside-loop/output.json

@@ -0,0 +1,125 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 26,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 26
+    }
+  },
+  "errors": [
+    "SyntaxError: In non-strict mode code, functions can only be declared at top level, inside a block, or as the body of an if statement (1:10)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 26,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 26
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "WhileStatement",
+        "start": 0,
+        "end": 26,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 26
+          }
+        },
+        "test": {
+          "type": "NumericLiteral",
+          "start": 7,
+          "end": 8,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 7
+            },
+            "end": {
+              "line": 1,
+              "column": 8
+            }
+          },
+          "extra": {
+            "rawValue": 1,
+            "raw": "1"
+          },
+          "value": 1
+        },
+        "body": {
+          "type": "FunctionDeclaration",
+          "start": 10,
+          "end": 26,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 10
+            },
+            "end": {
+              "line": 1,
+              "column": 26
+            }
+          },
+          "id": {
+            "type": "Identifier",
+            "start": 19,
+            "end": 22,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 19
+              },
+              "end": {
+                "line": 1,
+                "column": 22
+              },
+              "identifierName": "foo"
+            },
+            "name": "foo"
+          },
+          "generator": false,
+          "async": false,
+          "params": [],
+          "body": {
+            "type": "BlockStatement",
+            "start": 24,
+            "end": 26,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 24
+              },
+              "end": {
+                "line": 1,
+                "column": 26
+              }
+            },
+            "body": [],
+            "directives": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/categorized/invalid-fn-decl-labeled-inside-loop/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "In non-strict mode code, functions can only be declared at top level, inside a block, or as the body of an if statement (1:20)"
-}

packages/babel-parser/test/fixtures/core/categorized/invalid-fn-decl-labeled-inside-loop/output.json

@@ -0,0 +1,189 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 36,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 36
+    }
+  },
+  "errors": [
+    "SyntaxError: In non-strict mode code, functions can only be declared at top level, inside a block, or as the body of an if statement (1:20)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 36,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 36
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "WhileStatement",
+        "start": 0,
+        "end": 36,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 36
+          }
+        },
+        "test": {
+          "type": "NumericLiteral",
+          "start": 7,
+          "end": 8,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 7
+            },
+            "end": {
+              "line": 1,
+              "column": 8
+            }
+          },
+          "extra": {
+            "rawValue": 1,
+            "raw": "1"
+          },
+          "value": 1
+        },
+        "body": {
+          "type": "LabeledStatement",
+          "start": 10,
+          "end": 36,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 10
+            },
+            "end": {
+              "line": 1,
+              "column": 36
+            }
+          },
+          "body": {
+            "type": "LabeledStatement",
+            "start": 15,
+            "end": 36,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 15
+              },
+              "end": {
+                "line": 1,
+                "column": 36
+              }
+            },
+            "body": {
+              "type": "FunctionDeclaration",
+              "start": 20,
+              "end": 36,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 20
+                },
+                "end": {
+                  "line": 1,
+                  "column": 36
+                }
+              },
+              "id": {
+                "type": "Identifier",
+                "start": 29,
+                "end": 32,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 29
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 32
+                  },
+                  "identifierName": "foo"
+                },
+                "name": "foo"
+              },
+              "generator": false,
+              "async": false,
+              "params": [],
+              "body": {
+                "type": "BlockStatement",
+                "start": 34,
+                "end": 36,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 34
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 36
+                  }
+                },
+                "body": [],
+                "directives": []
+              }
+            },
+            "label": {
+              "type": "Identifier",
+              "start": 15,
+              "end": 18,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 15
+                },
+                "end": {
+                  "line": 1,
+                  "column": 18
+                },
+                "identifierName": "bar"
+              },
+              "name": "bar"
+            }
+          },
+          "label": {
+            "type": "Identifier",
+            "start": 10,
+            "end": 13,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 10
+              },
+              "end": {
+                "line": 1,
+                "column": 13
+              },
+              "identifierName": "foo"
+            },
+            "name": "foo"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/escape-keyword/invalid/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Unexpected keyword 'break' (2:2)"
-}

packages/babel-parser/test/fixtures/core/escape-keyword/invalid/output.json

@@ -0,0 +1,160 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 25,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 3,
+      "column": 2
+    }
+  },
+  "errors": [
+    "SyntaxError: Unexpected keyword 'break' (2:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 25,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 3,
+        "column": 2
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 25,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 3,
+            "column": 2
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 4,
+            "end": 24,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 4
+              },
+              "end": {
+                "line": 3,
+                "column": 1
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 4,
+              "end": 5,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 4
+                },
+                "end": {
+                  "line": 1,
+                  "column": 5
+                },
+                "identifierName": "a"
+              },
+              "name": "a"
+            },
+            "init": {
+              "type": "ObjectExpression",
+              "start": 8,
+              "end": 24,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 8
+                },
+                "end": {
+                  "line": 3,
+                  "column": 1
+                }
+              },
+              "properties": [
+                {
+                  "type": "ObjectProperty",
+                  "start": 12,
+                  "end": 22,
+                  "loc": {
+                    "start": {
+                      "line": 2,
+                      "column": 2
+                    },
+                    "end": {
+                      "line": 2,
+                      "column": 12
+                    }
+                  },
+                  "method": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start": 12,
+                    "end": 22,
+                    "loc": {
+                      "start": {
+                        "line": 2,
+                        "column": 2
+                      },
+                      "end": {
+                        "line": 2,
+                        "column": 12
+                      },
+                      "identifierName": "break"
+                    },
+                    "name": "break"
+                  },
+                  "computed": false,
+                  "shorthand": true,
+                  "value": {
+                    "type": "Identifier",
+                    "start": 12,
+                    "end": 22,
+                    "loc": {
+                      "start": {
+                        "line": 2,
+                        "column": 2
+                      },
+                      "end": {
+                        "line": 2,
+                        "column": 12
+                      },
+                      "identifierName": "break"
+                    },
+                    "name": "break"
+                  },
+                  "extra": {
+                    "shorthand": true
+                  }
+                }
+              ]
+            }
+          }
+        ],
+        "kind": "var"
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/escape-template/non-octal-eight/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Invalid escape sequence in template (1:2)"
-}

packages/babel-parser/test/fixtures/core/escape-template/non-octal-eight/output.json

@@ -0,0 +1,91 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 5,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 5
+    }
+  },
+  "errors": [
+    "SyntaxError: Invalid escape sequence in template (1:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 5,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 5
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 5,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 5
+          }
+        },
+        "expression": {
+          "type": "TemplateLiteral",
+          "start": 0,
+          "end": 4,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 4
+            }
+          },
+          "expressions": [],
+          "quasis": [
+            {
+              "type": "TemplateElement",
+              "start": 1,
+              "end": 3,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 1
+                },
+                "end": {
+                  "line": 1,
+                  "column": 3
+                }
+              },
+              "value": {
+                "raw": "\\8",
+                "cooked": null
+              },
+              "tail": true
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/escape-template/non-octal-nine/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Invalid escape sequence in template (1:2)"
-}

packages/babel-parser/test/fixtures/core/escape-template/non-octal-nine/output.json

@@ -0,0 +1,91 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 5,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 5
+    }
+  },
+  "errors": [
+    "SyntaxError: Invalid escape sequence in template (1:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 5,
+    "loc": {
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+        "column": 5
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
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+        "end": 5,
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+          "end": {
+            "line": 1,
+            "column": 5
+          }
+        },
+        "expression": {
+          "type": "TemplateLiteral",
+          "start": 0,
+          "end": 4,
+          "loc": {
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+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 4
+            }
+          },
+          "expressions": [],
+          "quasis": [
+            {
+              "type": "TemplateElement",
+              "start": 1,
+              "end": 3,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 1
+                },
+                "end": {
+                  "line": 1,
+                  "column": 3
+                }
+              },
+              "value": {
+                "raw": "\\9",
+                "cooked": null
+              },
+              "tail": true
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/regression/non-octal-float-strict-mode/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Legacy octal literals are not allowed in strict mode (1:0)"
+}
-}

packages/babel-parser/test/fixtures/core/regression/non-octal-float-strict-mode/output.json

@@ -0,0 +1,73 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 4,
+  "loc": {
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+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 4
+    }
+  },
+  "errors": [
+    "SyntaxError: Legacy octal literals are not allowed in strict mode (1:0)"
+  ],
+  "program": {
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+            "column": 4
+          }
+        },
+        "expression": {
+          "type": "NumericLiteral",
+          "start": 0,
+          "end": 4,
+          "loc": {
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+            },
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+              "column": 4
+            }
+          },
+          "extra": {
+            "rawValue": 9.5,
+            "raw": "09.5"
+          },
+          "value": 9.5
+        }
+      }
+    ],
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+  }
+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-2nd-lvl-lex-nested/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (4:6)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-2nd-lvl-lex-nested/output.json

@@ -0,0 +1,247 @@
+{
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+  "start": 0,
+  "end": 44,
+  "loc": {
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+  "errors": [
+    "SyntaxError: Identifier 'foo' has already been declared (4:6)"
+  ],
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+    "loc": {
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+      }
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+                    "identifierName": "foo"
+                  },
+                  "name": "foo"
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+                  "loc": {
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+                    "raw": "1"
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+                }
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-2nd-lvl-lex/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (3:4)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-2nd-lvl-lex/output.json

@@ -0,0 +1,229 @@
+{
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+  "loc": {
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+                "identifierName": "foo"
+              },
+              "name": "foo"
+            },
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+              "end": 33,
+              "loc": {
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-2nd-lvl-var-nested/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (4:6)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-2nd-lvl-var-nested/output.json

@@ -0,0 +1,247 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 44,
+  "loc": {
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+  ],
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+    "loc": {
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+    "interpreter": null,
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+            "loc": {
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+                  },
+                  "name": "foo"
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+                  "loc": {
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-2nd-lvl-var/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (3:4)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-2nd-lvl-var/output.json

@@ -0,0 +1,229 @@
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+  "loc": {
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packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-arr-destr/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (2:15)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-arr-destr/output.json

@@ -0,0 +1,154 @@
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packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-dbl-let/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (1:35)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-dbl-let/output.json

@@ -0,0 +1,222 @@
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packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-func/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (3:11)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-func/output.json

@@ -0,0 +1,173 @@
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packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-let/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (3:6)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-let/output.json

@@ -0,0 +1,172 @@
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packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-obj-destr/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (2:28)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-obj-destr/output.json

@@ -0,0 +1,293 @@
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packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-var-arr-destr/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (3:6)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-var-arr-destr/output.json

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packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-var-obj-destr/options.json

@@ -1,3 +0,0 @@
-{
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-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-catch-var-obj-destr/output.json

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packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-class/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (2:6)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-class/output.json

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packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-const/options.json

@@ -1,3 +0,0 @@
-{
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-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-const/output.json

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packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-func/options.json

@@ -1,3 +0,0 @@
-{
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-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-func/output.json

@@ -0,0 +1,169 @@
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packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-let/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (2:4)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-let/output.json

@@ -0,0 +1,172 @@
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-var/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (2:4)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-class-var/output.json

@@ -0,0 +1,153 @@
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-const-const/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (1:13)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-const-const/output.json

@@ -0,0 +1,160 @@
+{
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-func-gen/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'f' has already been declared (1:28)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-func-gen/output.json

@@ -0,0 +1,160 @@
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-func-module-sloppy/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Identifier 'foo' has already been declared (1:29)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-func-module-sloppy/output.json

@@ -0,0 +1,160 @@
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+            "async": false,
+            "params": [],
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-func-module/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Identifier 'foo' has already been declared (2:9)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-func-module/output.json

@@ -0,0 +1,142 @@
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+            "identifierName": "foo"
+          },
+          "name": "foo"
+        },
+        "generator": false,
+        "async": false,
+        "params": [],
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+  }
+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-func-var-sloppy/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (3:6)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-func-var-sloppy/output.json

@@ -0,0 +1,178 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 38,
+  "loc": {
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+    "SyntaxError: Identifier 'foo' has already been declared (3:6)"
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+                    },
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+                    "identifierName": "foo"
+                  },
+                  "name": "foo"
+                },
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+                  "end": 35,
+                  "loc": {
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+                    },
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+                    "raw": "1"
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+                }
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+            "kind": "var"
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+  }
+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-gen-func/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'f' has already been declared (1:28)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-gen-func/output.json

@@ -0,0 +1,160 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 36,
+  "loc": {
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+                "identifierName": "f"
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+              "name": "f"
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+            "generator": false,
+            "async": false,
+            "params": [],
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+              "end": 34,
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+        ],
+        "directives": []
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-let-let/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'foo' has already been declared (1:9)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-let-let/output.json

@@ -0,0 +1,122 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 13,
+  "loc": {
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+  ],
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+                "identifierName": "foo"
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+              },
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+              }
+            },
+            "id": {
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+              "end": 12,
+              "loc": {
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+                "identifierName": "foo"
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+        "kind": "let"
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+}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-nested-let-var/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'a' has already been declared (3:8)"
-}

packages/babel-parser/test/fixtures/core/scope/dupl-bind-nested-let-var/output.json

@@ -0,0 +1,176 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 25,
+  "loc": {
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+    "SyntaxError: Identifier 'a' has already been declared (3:8)"
+  ],
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+            ],
+            "kind": "let"
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+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/scope/for-var/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Identifier 'i' has already been declared (2:8)"
-}

packages/babel-parser/test/fixtures/core/scope/for-var/output.json

@@ -0,0 +1,194 @@
+{
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+  "end": 32,
+  "loc": {
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+                  "raw": "0"
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+        "update": null,
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+                  "end": 29,
+                  "loc": {
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+                    "end": 29,
+                    "loc": {
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+  }
+}

packages/babel-parser/test/fixtures/core/scope/undecl-export-as-default/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Export 'encrypt' is not defined (1:9)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/undecl-export-as-default/output.json

@@ -0,0 +1,106 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 30,
+  "loc": {
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+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 30
+    }
+  },
+  "errors": [
+    "SyntaxError: Export 'encrypt' is not defined (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 30,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 30
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 30,
+        "loc": {
+          "start": {
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+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 30
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 27,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 27
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 16,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 16
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 20,
+              "end": 27,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 20
+                },
+                "end": {
+                  "line": 1,
+                  "column": 27
+                },
+                "identifierName": "default"
+              },
+              "name": "default"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/scope/undecl-export-as/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Export 'encrypt' is not defined (1:9)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/undecl-export-as/output.json

@@ -0,0 +1,158 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 52,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 2,
+      "column": 21
+    }
+  },
+  "errors": [
+    "SyntaxError: Export 'encrypt' is not defined (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 52,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 2,
+        "column": 21
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 30,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 30
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 27,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 27
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 16,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 16
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 20,
+              "end": 27,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 20
+                },
+                "end": {
+                  "line": 1,
+                  "column": 27
+                },
+                "identifierName": "decrypt"
+              },
+              "name": "decrypt"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      },
+      {
+        "type": "FunctionDeclaration",
+        "start": 31,
+        "end": 52,
+        "loc": {
+          "start": {
+            "line": 2,
+            "column": 0
+          },
+          "end": {
+            "line": 2,
+            "column": 21
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 40,
+          "end": 47,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 9
+            },
+            "end": {
+              "line": 2,
+              "column": 16
+            },
+            "identifierName": "decrypt"
+          },
+          "name": "decrypt"
+        },
+        "generator": false,
+        "async": false,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start": 50,
+          "end": 52,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 19
+            },
+            "end": {
+              "line": 2,
+              "column": 21
+            }
+          },
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/scope/undecl-export-block/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Export 'encrypt' is not defined (4:9)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/undecl-export-block/output.json

@@ -0,0 +1,176 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 46,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 4,
+      "column": 18
+    }
+  },
+  "errors": [
+    "SyntaxError: Export 'encrypt' is not defined (4:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 46,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 4,
+        "column": 18
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "BlockStatement",
+        "start": 0,
+        "end": 27,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 3,
+            "column": 1
+          }
+        },
+        "body": [
+          {
+            "type": "FunctionDeclaration",
+            "start": 4,
+            "end": 25,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 2
+              },
+              "end": {
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+                "column": 23
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 13,
+              "end": 20,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 11
+                },
+                "end": {
+                  "line": 2,
+                  "column": 18
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            },
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BlockStatement",
+              "start": 23,
+              "end": 25,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 21
+                },
+                "end": {
+                  "line": 2,
+                  "column": 23
+                }
+              },
+              "body": [],
+              "directives": []
+            }
+          }
+        ],
+        "directives": []
+      },
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 28,
+        "end": 46,
+        "loc": {
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+            "column": 0
+          },
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+            "column": 18
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 37,
+            "end": 44,
+            "loc": {
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+                "column": 9
+              },
+              "end": {
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+                "column": 16
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 37,
+              "end": 44,
+              "loc": {
+                "start": {
+                  "line": 4,
+                  "column": 9
+                },
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+                  "line": 4,
+                  "column": 16
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 37,
+              "end": 44,
+              "loc": {
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+                  "line": 4,
+                  "column": 9
+                },
+                "end": {
+                  "line": 4,
+                  "column": 16
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/scope/undecl-export-builtin-as/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Export 'Object' is not defined (1:9)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/undecl-export-builtin-as/output.json

@@ -0,0 +1,106 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 25,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 25
+    }
+  },
+  "errors": [
+    "SyntaxError: Export 'Object' is not defined (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 25,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 25
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 25,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 25
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
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+            "end": 22,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
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+                "column": 22
+              }
+            },
+            "local": {
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+              "end": 15,
+              "loc": {
+                "start": {
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+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 15
+                },
+                "identifierName": "Object"
+              },
+              "name": "Object"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 19,
+              "end": 22,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 19
+                },
+                "end": {
+                  "line": 1,
+                  "column": 22
+                },
+                "identifierName": "Obj"
+              },
+              "name": "Obj"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/scope/undecl-export-builtin/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Export 'Object' is not defined (1:9)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/undecl-export-builtin/output.json

@@ -0,0 +1,106 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 18,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 18
+    }
+  },
+  "errors": [
+    "SyntaxError: Export 'Object' is not defined (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 18,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 18
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 18,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 18
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 15,
+            "loc": {
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+                "column": 9
+              },
+              "end": {
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+                "column": 15
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 15,
+              "loc": {
+                "start": {
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+                  "column": 9
+                },
+                "end": {
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+                  "column": 15
+                },
+                "identifierName": "Object"
+              },
+              "name": "Object"
+            },
+            "exported": {
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+              "start": 9,
+              "end": 15,
+              "loc": {
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+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 15
+                },
+                "identifierName": "Object"
+              },
+              "name": "Object"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/scope/undecl-export-if/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "In strict mode code, functions can only be declared at top level or inside a block (2:10)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/undecl-export-if/output.json

@@ -0,0 +1,191 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 51,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 2,
+      "column": 31
+    }
+  },
+  "errors": [
+    "SyntaxError: In strict mode code, functions can only be declared at top level or inside a block (2:10)",
+    "SyntaxError: Export 'encrypt' is not defined (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 51,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 2,
+        "column": 31
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 19,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 19
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 16,
+            "loc": {
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+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 16
+              }
+            },
+            "local": {
+              "type": "Identifier",
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+              "end": 16,
+              "loc": {
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+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 16
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 16,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 16
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      },
+      {
+        "type": "IfStatement",
+        "start": 20,
+        "end": 51,
+        "loc": {
+          "start": {
+            "line": 2,
+            "column": 0
+          },
+          "end": {
+            "line": 2,
+            "column": 31
+          }
+        },
+        "test": {
+          "type": "BooleanLiteral",
+          "start": 24,
+          "end": 28,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 4
+            },
+            "end": {
+              "line": 2,
+              "column": 8
+            }
+          },
+          "value": true
+        },
+        "consequent": {
+          "type": "FunctionDeclaration",
+          "start": 30,
+          "end": 51,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 10
+            },
+            "end": {
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+              "column": 31
+            }
+          },
+          "id": {
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+            "start": 39,
+            "end": 46,
+            "loc": {
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+                "line": 2,
+                "column": 19
+              },
+              "end": {
+                "line": 2,
+                "column": 26
+              },
+              "identifierName": "encrypt"
+            },
+            "name": "encrypt"
+          },
+          "generator": false,
+          "async": false,
+          "params": [],
+          "body": {
+            "type": "BlockStatement",
+            "start": 49,
+            "end": 51,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 29
+              },
+              "end": {
+                "line": 2,
+                "column": 31
+              }
+            },
+            "body": [],
+            "directives": []
+          }
+        },
+        "alternate": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/scope/undecl-export/options.json

@@ -1,4 +1,3 @@
 {
-  "sourceType": "module",
+  "sourceType": "module"
-  "throws": "Export 'encrypt' is not defined (1:9)"
+}
-}

packages/babel-parser/test/fixtures/core/scope/undecl-export/output.json

@@ -0,0 +1,106 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 19,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 19
+    }
+  },
+  "errors": [
+    "SyntaxError: Export 'encrypt' is not defined (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 19,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 19
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 19,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 19
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 16,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 16
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 16,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 16
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 16,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 16
+                },
+                "identifierName": "encrypt"
+              },
+              "name": "encrypt"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/uncategorised/108/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Invalid regular expression flag (1:17)"
-}

packages/babel-parser/test/fixtures/core/uncategorised/108/output.json

@@ -0,0 +1,112 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 22,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 22
+    }
+  },
+  "errors": [
+    "SyntaxError: Invalid regular expression flag (1:17)",
+    "SyntaxError: Invalid regular expression flag (1:19)",
+    "SyntaxError: Invalid regular expression flag (1:20)",
+    "SyntaxError: Invalid regular expression flag (1:21)",
+    "SyntaxError: Invalid regular expression flag (1:22)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 22,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 22
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 22,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 22
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 4,
+            "end": 22,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 4
+              },
+              "end": {
+                "line": 1,
+                "column": 22
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 4,
+              "end": 5,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 4
+                },
+                "end": {
+                  "line": 1,
+                  "column": 5
+                },
+                "identifierName": "x"
+              },
+              "name": "x"
+            },
+            "init": {
+              "type": "RegExpLiteral",
+              "start": 8,
+              "end": 22,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 8
+                },
+                "end": {
+                  "line": 1,
+                  "column": 22
+                }
+              },
+              "extra": {
+                "raw": "/[P QR]/\\u0067"
+              },
+              "pattern": "[P QR]",
+              "flags": "\\u0067"
+            }
+          }
+        ],
+        "kind": "var"
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/core/uncategorised/347/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Invalid number (1:0)"
+  "throws": "Identifier directly after number (1:2)"
-}
+}

packages/babel-parser/test/fixtures/core/uncategorised/349/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "Invalid number (1:0)"
-}

packages/babel-parser/test/fixtures/core/uncategorised/349/output.json

@@ -0,0 +1,73 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 2,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 2
+    }
+  },
+  "errors": [
+    "SyntaxError: Invalid number (1:0)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 2,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 2
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 2,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 2
+          }
+        },
+        "expression": {
+          "type": "NumericLiteral",
+          "start": 0,
+          "end": 2,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 2
+            }
+          },
+          "extra": {
+            "rawValue": 3,
+            "raw": "3e"
+          },
+          "value": 3
+        }
+      }
+    ],
+    "directives": []
+  }
+}