Add annexb: false parser option to disable Annex B (#15320)

babel · Feb 18, 2023 · 3c26949 · 3c26949
1 parent 1004037
commit 3c26949
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Showing 49 changed files with 1,335 additions and 27 deletions.
diff --git a/packages/babel-parser/src/options.ts b/packages/babel-parser/src/options.ts
@@ -22,6 +22,7 @@ export type Options = {
   createParenthesizedExpressions: boolean;
   errorRecovery: boolean;
   attachComment: boolean;
+  annexB: boolean;
 };
 
 export const defaultOptions: Options = {
@@ -74,11 +75,18 @@ export const defaultOptions: Options = {
   // is vital to preserve comments after transform. If you don't print AST back,
   // consider set this option to `false` for performance
   attachComment: true,
+  // When enabled, the parser will support Annex B syntax.
+  // https://tc39.es/ecma262/#sec-additional-ecmascript-features-for-web-browsers
+  annexB: true,
 };
 
 // Interpret and default an options object
 
 export function getOptions(opts?: Options | null): Options {
+  if (opts && opts.annexB != null && opts.annexB !== false) {
+    throw new Error("The `annexB` option can only be set to `false`.");
+  }
+
   const options: any = {};
   for (const key of Object.keys(defaultOptions)) {
     // @ts-expect-error key may not exist in opts

diff --git a/packages/babel-parser/src/parse-error/standard-errors.ts b/packages/babel-parser/src/parse-error/standard-errors.ts
@@ -226,6 +226,8 @@ export default {
   RecordNoProto: "'__proto__' is not allowed in Record expressions.",
   RestTrailingComma: "Unexpected trailing comma after rest element.",
   SloppyFunction:
+    "In non-strict mode code, functions can only be declared at top level or inside a block.",
+  SloppyFunctionAnnexB:
     "In non-strict mode code, functions can only be declared at top level, inside a block, or as the body of an if statement.",
   StaticPrototype: "Classes may not have static property named prototype.",
   SuperNotAllowed:

diff --git a/packages/babel-parser/src/parser/statement.ts b/packages/babel-parser/src/parser/statement.ts
@@ -354,6 +354,8 @@ export default abstract class StatementParser extends ExpressionParser {
       ParseStatementFlag.AllowImportExport |
         ParseStatementFlag.AllowDeclaration |
         ParseStatementFlag.AllowFunctionDeclaration |
+        // This function is actually also used to parse StatementItems,
+        // which with Annex B enabled allows labeled functions.
         ParseStatementFlag.AllowLabeledFunction,
     );
   }
@@ -363,18 +365,24 @@ export default abstract class StatementParser extends ExpressionParser {
     return this.parseStatementLike(
       ParseStatementFlag.AllowDeclaration |
         ParseStatementFlag.AllowFunctionDeclaration |
-        ParseStatementFlag.AllowLabeledFunction,
+        (!this.options.annexB || this.state.strict
+          ? 0
+          : ParseStatementFlag.AllowLabeledFunction),
     );
   }
 
-  parseStatementOrFunctionDeclaration(
+  parseStatementOrSloppyAnnexBFunctionDeclaration(
     this: Parser,
-    disallowLabeledFunction: boolean,
+    allowLabeledFunction: boolean = false,
   ) {
-    return this.parseStatementLike(
-      ParseStatementFlag.AllowFunctionDeclaration |
-        (disallowLabeledFunction ? 0 : ParseStatementFlag.AllowLabeledFunction),
-    );
+    let flags: ParseStatementFlag = ParseStatementFlag.StatementOnly;
+    if (this.options.annexB && !this.state.strict) {
+      flags |= ParseStatementFlag.AllowFunctionDeclaration;
+      if (allowLabeledFunction) {
+        flags |= ParseStatementFlag.AllowLabeledFunction;
+      }
+    }
+    return this.parseStatementLike(flags);
   }
 
   // Parse a single statement.
@@ -438,12 +446,15 @@ export default abstract class StatementParser extends ExpressionParser {
         return this.parseForStatement(node as Undone<N.ForStatement>);
       case tt._function:
         if (this.lookaheadCharCode() === charCodes.dot) break;
-        if (!allowDeclaration) {
-          if (this.state.strict) {
-            this.raise(Errors.StrictFunction, { at: this.state.startLoc });
-          } else if (!allowFunctionDeclaration) {
-            this.raise(Errors.SloppyFunction, { at: this.state.startLoc });
-          }
+        if (!allowFunctionDeclaration) {
+          this.raise(
+            this.state.strict
+              ? Errors.StrictFunction
+              : this.options.annexB
+              ? Errors.SloppyFunctionAnnexB
+              : Errors.SloppyFunction,
+            { at: this.state.startLoc },
+          );
         }
         return this.parseFunctionStatement(
           node as Undone<N.FunctionDeclaration>,
@@ -981,12 +992,9 @@ export default abstract class StatementParser extends ExpressionParser {
     node.test = this.parseHeaderExpression();
     // Annex B.3.3
     // https://tc39.es/ecma262/#sec-functiondeclarations-in-ifstatement-statement-clauses
-    node.consequent = this.parseStatementOrFunctionDeclaration(
-      // https://tc39.es/ecma262/#sec-if-statement-static-semantics-early-errors
-      true,
-    );
+    node.consequent = this.parseStatementOrSloppyAnnexBFunctionDeclaration();
     node.alternate = this.eat(tt._else)
-      ? this.parseStatementOrFunctionDeclaration(true)
+      ? this.parseStatementOrSloppyAnnexBFunctionDeclaration()
       : null;
     return this.finishNode(node, "IfStatement");
   }
@@ -1074,8 +1082,11 @@ export default abstract class StatementParser extends ExpressionParser {
   parseCatchClauseParam(this: Parser): N.Pattern {
     const param = this.parseBindingAtom();
 
-    const simple = param.type === "Identifier";
-    this.scope.enter(simple ? SCOPE_SIMPLE_CATCH : 0);
+    this.scope.enter(
+      this.options.annexB && param.type === "Identifier"
+        ? SCOPE_SIMPLE_CATCH
+        : 0,
+    );
     this.checkLVal(param, {
       in: { type: "CatchClause" },
       binding: BIND_CATCH_PARAM,
@@ -1234,7 +1245,7 @@ export default abstract class StatementParser extends ExpressionParser {
     // https://tc39.es/ecma262/#prod-LabelledItem
     node.body =
       flags & ParseStatementFlag.AllowLabeledFunction
-        ? this.parseStatementOrFunctionDeclaration(false)
+        ? this.parseStatementOrSloppyAnnexBFunctionDeclaration(true)
         : this.parseStatement();
 
     this.state.labels.pop();
@@ -1419,6 +1430,7 @@ export default abstract class StatementParser extends ExpressionParser {
       init.type === "VariableDeclaration" &&
       init.declarations[0].init != null &&
       (!isForIn ||
+        !this.options.annexB ||
         this.state.strict ||
         init.kind !== "var" ||
         init.declarations[0].id.type !== "Identifier")
@@ -1626,7 +1638,7 @@ export default abstract class StatementParser extends ExpressionParser {
     // treatFunctionsAsVar).
     this.scope.declareName(
       node.id.name,
-      this.state.strict || node.generator || node.async
+      !this.options.annexB || this.state.strict || node.generator || node.async
         ? this.scope.treatFunctionsAsVar
           ? BIND_VAR
           : BIND_LEXICAL

diff --git a/packages/babel-parser/src/plugins/placeholders.ts b/packages/babel-parser/src/plugins/placeholders.ts
@@ -194,7 +194,7 @@ export default (superClass: typeof Parser) =>
         const stmt: N.LabeledStatement = node;
         stmt.label = this.finishPlaceholder(expr, "Identifier");
         this.next();
-        stmt.body = super.parseStatementOrFunctionDeclaration(false);
+        stmt.body = super.parseStatementOrSloppyAnnexBFunctionDeclaration();
         return this.finishNode(stmt, "LabeledStatement");
       }
 

diff --git a/packages/babel-parser/src/tokenizer/index.ts b/packages/babel-parser/src/tokenizer/index.ts
@@ -373,7 +373,11 @@ export default abstract class Tokenizer extends CommentsParser {
         default:
           if (isWhitespace(ch)) {
             ++this.state.pos;
-          } else if (ch === charCodes.dash && !this.inModule) {
+          } else if (
+            ch === charCodes.dash &&
+            !this.inModule &&
+            this.options.annexB
+          ) {
             const pos = this.state.pos;
             if (
               this.input.charCodeAt(pos + 1) === charCodes.dash &&
@@ -389,7 +393,11 @@ export default abstract class Tokenizer extends CommentsParser {
             } else {
               break loop;
             }
-          } else if (ch === charCodes.lessThan && !this.inModule) {
+          } else if (
+            ch === charCodes.lessThan &&
+            !this.inModule &&
+            this.options.annexB
+          ) {
             const pos = this.state.pos;
             if (
               this.input.charCodeAt(pos + 1) === charCodes.exclamationMark &&

diff --git a/packages/babel-parser/src/util/scope.ts b/packages/babel-parser/src/util/scope.ts
@@ -184,6 +184,8 @@ export default class ScopeHandler<IScope extends Scope = Scope> {
 
     return (
       (scope.lexical.has(name) &&
+        // Annex B.3.4
+        // https://tc39.es/ecma262/#sec-variablestatements-in-catch-blocks
         !(
           scope.flags & SCOPE_SIMPLE_CATCH &&
           scope.lexical.values().next().value === name

diff --git a/packages/babel-parser/test/fixtures/annex-b/disabled/1.1-html-comments-close/input.js b/packages/babel-parser/test/fixtures/annex-b/disabled/1.1-html-comments-close/input.js
@@ -0,0 +1 @@
+-->b;
diff --git a/packages/babel-parser/test/fixtures/annex-b/disabled/1.1-html-comments-close/options.json b/packages/babel-parser/test/fixtures/annex-b/disabled/1.1-html-comments-close/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token (1:2)"
+}
diff --git a/packages/babel-parser/test/fixtures/annex-b/disabled/1.1-html-comments-open/input.js b/packages/babel-parser/test/fixtures/annex-b/disabled/1.1-html-comments-open/input.js
@@ -0,0 +1 @@
+a<!--b;
diff --git a/packages/babel-parser/test/fixtures/annex-b/disabled/1.1-html-comments-open/output.json b/packages/babel-parser/test/fixtures/annex-b/disabled/1.1-html-comments-open/output.json
@@ -0,0 +1,44 @@
+{
+  "type": "File",
+  "start":0,"end":7,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":7,"index":7}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":7,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":7,"index":7}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":7,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":7,"index":7}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":6,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":6,"index":6}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":1,"index":1},"identifierName":"a"},
+            "name": "a"
+          },
+          "operator": "<",
+          "right": {
+            "type": "UnaryExpression",
+            "start":2,"end":6,"loc":{"start":{"line":1,"column":2,"index":2},"end":{"line":1,"column":6,"index":6}},
+            "operator": "!",
+            "prefix": true,
+            "argument": {
+              "type": "UpdateExpression",
+              "start":3,"end":6,"loc":{"start":{"line":1,"column":3,"index":3},"end":{"line":1,"column":6,"index":6}},
+              "operator": "--",
+              "prefix": true,
+              "argument": {
+                "type": "Identifier",
+                "start":5,"end":6,"loc":{"start":{"line":1,"column":5,"index":5},"end":{"line":1,"column":6,"index":6},"identifierName":"b"},
+                "name": "b"
+              }
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
diff --git a/...babel-parser/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions-if-body/input.js b/...babel-parser/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions-if-body/input.js
@@ -0,0 +1 @@
+if (0) x: function f() {}
diff --git a/...el-parser/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions-if-body/output.json b/...el-parser/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions-if-body/output.json
@@ -0,0 +1,57 @@
+{
+  "type": "File",
+  "start":0,"end":25,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":25,"index":25}},
+  "errors": [
+    "SyntaxError: In non-strict mode code, functions can only be declared at top level or inside a block. (1:10)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":25,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":25,"index":25}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "IfStatement",
+        "start":0,"end":25,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":25,"index":25}},
+        "test": {
+          "type": "NumericLiteral",
+          "start":4,"end":5,"loc":{"start":{"line":1,"column":4,"index":4},"end":{"line":1,"column":5,"index":5}},
+          "extra": {
+            "rawValue": 0,
+            "raw": "0"
+          },
+          "value": 0
+        },
+        "consequent": {
+          "type": "LabeledStatement",
+          "start":7,"end":25,"loc":{"start":{"line":1,"column":7,"index":7},"end":{"line":1,"column":25,"index":25}},
+          "body": {
+            "type": "FunctionDeclaration",
+            "start":10,"end":25,"loc":{"start":{"line":1,"column":10,"index":10},"end":{"line":1,"column":25,"index":25}},
+            "id": {
+              "type": "Identifier",
+              "start":19,"end":20,"loc":{"start":{"line":1,"column":19,"index":19},"end":{"line":1,"column":20,"index":20},"identifierName":"f"},
+              "name": "f"
+            },
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BlockStatement",
+              "start":23,"end":25,"loc":{"start":{"line":1,"column":23,"index":23},"end":{"line":1,"column":25,"index":25}},
+              "body": [],
+              "directives": []
+            }
+          },
+          "label": {
+            "type": "Identifier",
+            "start":7,"end":8,"loc":{"start":{"line":1,"column":7,"index":7},"end":{"line":1,"column":8,"index":8},"identifierName":"x"},
+            "name": "x"
+          }
+        },
+        "alternate": null
+      }
+    ],
+    "directives": []
+  }
+}
diff --git a/...rser/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions-multiple-labels/input.js b/...rser/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions-multiple-labels/input.js
@@ -0,0 +1 @@
+x: y: function fn() {}
diff --git a/...r/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions-multiple-labels/output.json b/...r/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions-multiple-labels/output.json
@@ -0,0 +1,52 @@
+{
+  "type": "File",
+  "start":0,"end":22,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":22,"index":22}},
+  "errors": [
+    "SyntaxError: In non-strict mode code, functions can only be declared at top level or inside a block. (1:6)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":22,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":22,"index":22}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "LabeledStatement",
+        "start":0,"end":22,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":22,"index":22}},
+        "body": {
+          "type": "LabeledStatement",
+          "start":3,"end":22,"loc":{"start":{"line":1,"column":3,"index":3},"end":{"line":1,"column":22,"index":22}},
+          "body": {
+            "type": "FunctionDeclaration",
+            "start":6,"end":22,"loc":{"start":{"line":1,"column":6,"index":6},"end":{"line":1,"column":22,"index":22}},
+            "id": {
+              "type": "Identifier",
+              "start":15,"end":17,"loc":{"start":{"line":1,"column":15,"index":15},"end":{"line":1,"column":17,"index":17},"identifierName":"fn"},
+              "name": "fn"
+            },
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BlockStatement",
+              "start":20,"end":22,"loc":{"start":{"line":1,"column":20,"index":20},"end":{"line":1,"column":22,"index":22}},
+              "body": [],
+              "directives": []
+            }
+          },
+          "label": {
+            "type": "Identifier",
+            "start":3,"end":4,"loc":{"start":{"line":1,"column":3,"index":3},"end":{"line":1,"column":4,"index":4},"identifierName":"y"},
+            "name": "y"
+          }
+        },
+        "label": {
+          "type": "Identifier",
+          "start":0,"end":1,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":1,"index":1},"identifierName":"x"},
+          "name": "x"
+        }
+      }
+    ],
+    "directives": []
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions/input.js b/packages/babel-parser/test/fixtures/annex-b/disabled/3.1-sloppy-labeled-functions/input.js
@@ -0,0 +1 @@
+x: function fn() {}