Merge pull request #658 from babel/expect

Syntax Error: add message with the plugin that should be enabled

.eslintrc

@@ -5,7 +5,8 @@
     "prettier"
   ],
   "rules": {
-    "prettier/prettier": ["error", { "trailingComma": "all" }]
+    "prettier/prettier": ["error", { "trailingComma": "all" }],
+    "no-case-declarations": "error"
   },
   "env": {
     "node": true

src/parser/expression.js

@@ -433,12 +433,7 @@ export default class ExpressionParser extends LValParser {
         noCalls,
       );
     } else if (this.match(tt.questionDot)) {
-      if (!this.hasPlugin("optionalChaining")) {
-        this.raise(
-          startPos,
-          "You can only use optional-chaining when the 'optionalChaining' plugin is enabled.",
-        );
-      }
+      this.expectPlugin("optionalChaining");
 
       if (noCalls && this.lookahead().type == tt.parenL) {
         state.stop = true;
@@ -660,11 +655,11 @@ export default class ExpressionParser extends LValParser {
         return this.finishNode(node, "Super");
 
       case tt._import:
-        if (this.hasPlugin("importMeta") && this.lookahead().type === tt.dot) {
+        if (this.lookahead().type === tt.dot) {
           return this.parseImportMetaProperty();
         }
 
-        if (!this.hasPlugin("dynamicImport")) this.unexpected();
+        this.expectPlugin("dynamicImport");
 
         node = this.startNode();
         this.next();
@@ -681,7 +676,7 @@ export default class ExpressionParser extends LValParser {
       case tt._yield:
         if (this.state.inGenerator) this.unexpected();
 
-      case tt.name:
+      case tt.name: {
         node = this.startNode();
         const allowAwait = this.state.value === "await" && this.state.inAsync;
         const allowYield = this.shouldAllowYieldIdentifier();
@@ -710,27 +705,29 @@ export default class ExpressionParser extends LValParser {
         }
 
         return id;
+      }
 
-      case tt._do:
-        if (this.hasPlugin("doExpressions")) {
-          const node = this.startNode();
-          this.next();
-          const oldInFunction = this.state.inFunction;
-          const oldLabels = this.state.labels;
-          this.state.labels = [];
-          this.state.inFunction = false;
-          node.body = this.parseBlock(false);
-          this.state.inFunction = oldInFunction;
-          this.state.labels = oldLabels;
-          return this.finishNode(node, "DoExpression");
-        }
+      case tt._do: {
+        this.expectPlugin("doExpressions");
+        const node = this.startNode();
+        this.next();
+        const oldInFunction = this.state.inFunction;
+        const oldLabels = this.state.labels;
+        this.state.labels = [];
+        this.state.inFunction = false;
+        node.body = this.parseBlock(false);
+        this.state.inFunction = oldInFunction;
+        this.state.labels = oldLabels;
+        return this.finishNode(node, "DoExpression");
+      }
 
-      case tt.regexp:
+      case tt.regexp: {
         const value = this.state.value;
         node = this.parseLiteral(value.value, "RegExpLiteral");
         node.pattern = value.pattern;
         node.flags = value.flags;
         return node;
+      }
 
       case tt.num:
         return this.parseLiteral(this.state.value, "NumericLiteral");
@@ -784,7 +781,7 @@ export default class ExpressionParser extends LValParser {
       case tt.backQuote:
         return this.parseTemplate(false);
 
-      case tt.doubleColon:
+      case tt.doubleColon: {
         node = this.startNode();
         this.next();
         node.object = null;
@@ -797,6 +794,7 @@ export default class ExpressionParser extends LValParser {
             "Binding should be performed on object property.",
           );
         }
+      }
 
       default:
         throw this.unexpected();
@@ -825,11 +823,7 @@ export default class ExpressionParser extends LValParser {
   parseFunctionExpression(): N.FunctionExpression | N.MetaProperty {
     const node = this.startNode();
     const meta = this.parseIdentifier(true);
-    if (
-      this.state.inGenerator &&
-      this.hasPlugin("functionSent") &&
-      this.eat(tt.dot)
-    ) {
+    if (this.state.inGenerator && this.eat(tt.dot)) {
       return this.parseMetaProperty(node, meta, "sent");
     }
     return this.parseFunction(node, false);
@@ -841,6 +835,16 @@ export default class ExpressionParser extends LValParser {
     propertyName: string,
   ): N.MetaProperty {
     node.meta = meta;
+
+    if (meta.name === "function" && propertyName === "sent") {
+      if (this.isContextual(propertyName)) {
+        this.expectPlugin("functionSent");
+      } else if (!this.hasPlugin("functionSent")) {
+        // They didn't actually say `function.sent`, just `function.`, so a simple error would be less confusing.
+        this.unexpected();
+      }
+    }
+
     node.property = this.parseIdentifier(true);
 
     if (node.property.name !== propertyName) {
@@ -857,6 +861,18 @@ export default class ExpressionParser extends LValParser {
     const node = this.startNode();
     const id = this.parseIdentifier(true);
     this.expect(tt.dot);
+
+    if (id.name === "import") {
+      if (this.isContextual("meta")) {
+        this.expectPlugin("importMeta");
+      } else if (!this.hasPlugin("importMeta")) {
+        this.raise(
+          id.start,
+          `Dynamic imports require a parameter: import('a.js').then`,
+        );
+      }
+    }
+
     if (!this.inModule) {
       this.raise(
         id.start,
@@ -1141,7 +1157,8 @@ export default class ExpressionParser extends LValParser {
         decorators = [];
       }
 
-      if (this.hasPlugin("objectRestSpread") && this.match(tt.ellipsis)) {
+      if (this.match(tt.ellipsis)) {
+        this.expectPlugin("objectRestSpread");
         prop = this.parseSpread(isPattern ? { start: 0 } : undefined);
         if (isPattern) {
           this.toAssignable(prop, true, "object pattern");
@@ -1199,8 +1216,11 @@ export default class ExpressionParser extends LValParser {
           prop.computed = false;
         } else {
           isAsync = true;
-          if (this.hasPlugin("asyncGenerators"))
-            isGenerator = this.eat(tt.star);
+          if (this.match(tt.star)) {
+            this.expectPlugin("asyncGenerators");
+            this.next();
+            isGenerator = true;
+          }
           this.parsePropertyName(prop);
         }
       } else {

src/parser/location.js

@@ -10,7 +10,11 @@ import CommentsParser from "./comments";
 // message.
 
 export default class LocationParser extends CommentsParser {
-  raise(pos: number, message: string): empty {
+  raise(
+    pos: number,
+    message: string,
+    missingPluginNames?: Array<string>,
+  ): empty {
     const loc = getLineInfo(this.input, pos);
     message += ` (${loc.line}:${loc.column})`;
     // $FlowIgnore
@@ -19,6 +23,9 @@ export default class LocationParser extends CommentsParser {
     );
     err.pos = pos;
     err.loc = loc;
+    if (missingPluginNames) {
+      err.missingPlugin = missingPluginNames;
+    }
     throw err;
   }
 }

src/parser/lval.js

@@ -69,13 +69,14 @@ export default class LValParser extends NodeUtils {
           this.toAssignable(node.value, isBinding, contextDescription);
           break;
 
-        case "SpreadElement":
+        case "SpreadElement": {
           this.checkToRestConversion(node);
 
           node.type = "RestElement";
           const arg = node.argument;
           this.toAssignable(arg, isBinding, contextDescription);
           break;
+        }
 
         case "ArrayExpression":
           node.type = "ArrayPattern";
@@ -211,11 +212,12 @@ export default class LValParser extends NodeUtils {
       case tt.name:
         return this.parseBindingIdentifier();
 
-      case tt.bracketL:
+      case tt.bracketL: {
         const node = this.startNode();
         this.next();
         node.elements = this.parseBindingList(tt.bracketR, true);
         return this.finishNode(node, "ArrayPattern");
+      }
 
       case tt.braceL:
         return this.parseObj(true);

src/parser/statement.js

@@ -237,9 +237,7 @@ export default class StatementParser extends ExpressionParser {
   }
 
   parseDecorator(): N.Decorator {
-    if (!(this.hasPlugin("decorators") || this.hasPlugin("decorators2"))) {
-      this.unexpected();
-    }
+    this.expectOnePlugin(["decorators", "decorators2"]);
 
     const node = this.startNode();
     this.next();
@@ -340,11 +338,8 @@ export default class StatementParser extends ExpressionParser {
     this.state.labels.push(loopLabel);
 
     let forAwait = false;
-    if (
-      this.hasPlugin("asyncGenerators") &&
-      this.state.inAsync &&
-      this.isContextual("await")
-    ) {
+    if (this.state.inAsync && this.isContextual("await")) {
+      this.expectPlugin("asyncGenerators");
       forAwait = true;
       this.next();
     }
@@ -489,12 +484,13 @@ export default class StatementParser extends ExpressionParser {
     if (this.match(tt._catch)) {
       const clause = this.startNode();
       this.next();
-      if (this.match(tt.parenL) || !this.hasPlugin("optionalCatchBinding")) {
+      if (this.match(tt.parenL)) {
         this.expect(tt.parenL);
         clause.param = this.parseBindingAtom();
         this.checkLVal(clause.param, true, Object.create(null), "catch clause");
         this.expect(tt.parenR);
       } else {
+        this.expectPlugin("optionalCatchBinding");
         clause.param = null;
       }
       clause.body = this.parseBlock();
@@ -782,12 +778,11 @@ export default class StatementParser extends ExpressionParser {
     this.initFunction(node, isAsync);
 
     if (this.match(tt.star)) {
-      if (node.async && !this.hasPlugin("asyncGenerators")) {
-        this.unexpected();
-      } else {
-        node.generator = true;
-        this.next();
+      if (node.async) {
+        this.expectPlugin("asyncGenerators");
       }
+      node.generator = true;
+      this.next();
     }
 
     if (
@@ -960,8 +955,9 @@ export default class StatementParser extends ExpressionParser {
       isStatic = true;
     }
 
-    if (this.hasPlugin("classPrivateProperties") && this.match(tt.hash)) {
+    if (this.match(tt.hash)) {
       // Private property
+      this.expectPlugin("classPrivateProperties");
       this.next();
       const privateProp: N.ClassPrivateProperty = memberAny;
       privateProp.key = this.parseIdentifier(true);
@@ -1047,8 +1043,12 @@ export default class StatementParser extends ExpressionParser {
       this.pushClassProperty(classBody, prop);
     } else if (isSimple && key.name === "async" && !this.isLineTerminator()) {
       // an async method
-      const isGenerator =
-        this.hasPlugin("asyncGenerators") && this.eat(tt.star);
+      let isGenerator = false;
+      if (this.match(tt.star)) {
+        this.expectPlugin("asyncGenerators");
+        this.next();
+        isGenerator = true;
+      }
       method.kind = "method";
       this.parsePropertyName(method);
       if (this.isNonstaticConstructor(method)) {
@@ -1151,17 +1151,14 @@ export default class StatementParser extends ExpressionParser {
   }
 
   parseClassProperty(node: N.ClassProperty): N.ClassProperty {
-    const noPluginMsg =
-      "You can only use Class Properties when the 'classProperties' plugin is enabled.";
-    if (!node.typeAnnotation && !this.hasPlugin("classProperties")) {
-      this.raise(node.start, noPluginMsg);
+    if (!node.typeAnnotation) {
+      this.expectPlugin("classProperties");
     }
 
     this.state.inClassProperty = true;
 
     if (this.match(tt.eq)) {
-      if (!this.hasPlugin("classProperties"))
-        this.raise(this.state.start, noPluginMsg);
+      this.expectPlugin("classProperties");
       this.next();
       node.value = this.parseMaybeAssign();
     } else {
@@ -1169,6 +1166,7 @@ export default class StatementParser extends ExpressionParser {
     }
     this.semicolon();
     this.state.inClassProperty = false;
+
     return this.finishNode(node, "ClassProperty");
   }
 

src/parser/util.js

@@ -109,4 +109,26 @@ export default class UtilParser extends Tokenizer {
     }
     throw this.raise(pos != null ? pos : this.state.start, messageOrType);
   }
+
+  expectPlugin(name: string): void {
+    if (!this.hasPlugin(name)) {
+      throw this.raise(
+        this.state.start,
+        `This experimental syntax requires enabling the parser plugin: '${name}'`,
+        [name],
+      );
+    }
+  }
+
+  expectOnePlugin(names: Array<string>): void {
+    if (!names.some(n => this.hasPlugin(n))) {
+      throw this.raise(
+        this.state.start,
+        `This experimental syntax requires enabling one of the following parser plugin(s): '${names.join(
+          ", ",
+        )}'`,
+        names,
+      );
+    }
+  }
 }

src/plugins/typescript.js

@@ -540,7 +540,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       switch (this.state.type) {
         case tt.name:
         case tt._void:
-        case tt._null:
+        case tt._null: {
           const type = this.match(tt._void)
             ? "TSVoidKeyword"
             : this.match(tt._null)
@@ -552,6 +552,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             return this.finishNode(node, type);
           }
           return this.tsParseTypeReference();
+        }
         case tt.string:
         case tt.num:
         case tt._true:
@@ -573,13 +574,14 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             return this.finishNode(node, "TSLiteralType");
           }
           break;
-        case tt._this:
+        case tt._this: {
           const thisKeyword = this.tsParseThisTypeNode();
           if (this.isContextual("is") && !this.hasPrecedingLineBreak()) {
             return this.tsParseThisTypePredicate(thisKeyword);
           } else {
             return thisKeyword;
           }
+        }
         case tt._typeof:
           return this.tsParseTypeQuery();
         case tt.braceL:
@@ -1038,13 +1040,14 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         case tt._var:
         case tt._let:
           return this.parseVarStatement(nany, this.state.type);
-        case tt.name:
+        case tt.name: {
           const value = this.state.value;
           if (value === "global") {
             return this.tsParseAmbientExternalModuleDeclaration(nany);
           } else {
             return this.tsParseDeclaration(nany, value, /* next */ true);
           }
+        }
       }
     }
 
@@ -1064,14 +1067,14 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
     tsParseExpressionStatement(node: any, expr: N.Identifier): ?N.Declaration {
       switch (expr.name) {
-        case "declare":
+        case "declare": {
           const declaration = this.tsTryParseDeclare(node);
           if (declaration) {
             declaration.declare = true;
             return declaration;
           }
           break;
-
+        }
         case "global":
           // `global { }` (with no `declare`) may appear inside an ambient module declaration.
           // Would like to use tsParseAmbientExternalModuleDeclaration here, but already ran past "global".

src/tokenizer/index.js

@@ -595,11 +595,13 @@ export default class Tokenizer extends LocationParser {
         ++this.state.pos;
         return this.finishToken(tt.backQuote);
 
-      case 48: // '0'
+      case 48: {
+        // '0'
         const next = this.input.charCodeAt(this.state.pos + 1);
         if (next === 120 || next === 88) return this.readRadixNumber(16); // '0x', '0X' - hex number
         if (next === 111 || next === 79) return this.readRadixNumber(8); // '0o', '0O' - octal number
         if (next === 98 || next === 66) return this.readRadixNumber(2); // '0b', '0B' - binary number
+      }
       // Anything else beginning with a digit is an integer, octal
       // number, or float.
       case 49:

test/fixtures/es2017/async-functions/no-method-asi/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "You can only use Class Properties when the 'classProperties' plugin is enabled. (2:2)"
+  "throws": "This experimental syntax requires enabling the parser plugin: 'classProperties' (3:2)"
 }

test/fixtures/experimental/_no-plugin/.bigint/actual.js

@@ -0,0 +1 @@
+1n

test/fixtures/experimental/_no-plugin/.bigint/options.json

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

test/fixtures/experimental/_no-plugin/.class-private-properties/actual.js

@@ -0,0 +1,4 @@
+class Point {
+  #x = 1;
+  #y = 2;
+}

test/fixtures/experimental/_no-plugin/.class-private-properties/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'classPrivateProperties' (2:3)",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/.export-extensions/actual.js

@@ -0,0 +1 @@
+export A from 'test';

test/fixtures/experimental/_no-plugin/.export-extensions/options.json

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

test/fixtures/experimental/_no-plugin/.numeric-separator/actual.js

@@ -0,0 +1 @@
+1_0

test/fixtures/experimental/_no-plugin/.numeric-separator/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'numericSeparator' (1:17)",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/async-generators/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'asyncGenerators' (1:15)",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/class-properties-with-initializer-and-type/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["flow"],
+  "throws": "This experimental syntax requires enabling the parser plugin: 'classProperties' (2:14)"
+}

test/fixtures/experimental/_no-plugin/class-properties-with-initializer/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'classProperties' (2:6)",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/class-properties-without-initializer/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'classProperties' (2:5)",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/decorators/actual.js

@@ -0,0 +1,2 @@
+@memoize
+function() {}

test/fixtures/experimental/_no-plugin/decorators/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling one of the following parser plugin(s): 'decorators, decorators2' (1:0)",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/do-expressions/actual.js

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

test/fixtures/experimental/_no-plugin/do-expressions/options.json

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

test/fixtures/experimental/_no-plugin/dynamic-import/actual.js

@@ -0,0 +1 @@
+var $ = import("jquery");

test/fixtures/experimental/_no-plugin/dynamic-import/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'dynamicImport' (1:8)",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/import-meta/actual.js

@@ -0,0 +1 @@
+const x = import.meta;

test/fixtures/experimental/_no-plugin/import-meta/options.json

@@ -0,0 +1,5 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'importMeta' (1:17)",
+  "sourceType": "module",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/object-rest-spread/actual.js

@@ -0,0 +1 @@
+({...x})

test/fixtures/experimental/_no-plugin/object-rest-spread/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'objectRestSpread' (1:2)",
+  "plugins": []
+}

test/fixtures/experimental/_no-plugin/optional-chaining/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'optionalChaining' (1:1)"
+}

test/fixtures/experimental/async-generators/class-method-no-asi/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "You can only use Class Properties when the 'classProperties' plugin is enabled. (2:2)"
+  "throws": "This experimental syntax requires enabling the parser plugin: 'classProperties' (3:2)"
 }

test/fixtures/experimental/class-properties/with-initializer-and-type-no-plugin/options.json

@@ -1,4 +0,0 @@
-{
-  "plugins": ["flow"],
-  "throws": "You can only use Class Properties when the 'classProperties' plugin is enabled. (2:14)"
-}

test/fixtures/experimental/class-properties/with-initializer-missing-plugin/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "You can only use Class Properties when the 'classProperties' plugin is enabled. (2:2)"
-}

test/fixtures/experimental/class-properties/without-initializer-missing-plugin/options.json

@@ -1,3 +0,0 @@
-{
-  "throws": "You can only use Class Properties when the 'classProperties' plugin is enabled. (2:2)"
-}

test/fixtures/experimental/dynamic-import/direct-calls-only/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Unexpected token, expected ( (2:15)"
+  "throws": "Dynamic imports require a parameter: import('a.js').then (2:9)"
 }

test/fixtures/experimental/function-sent/disabled-function-keyword-declaration/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Unexpected token, expected ( (2:10)"
+  "throws": "This experimental syntax requires enabling the parser plugin: 'functionSent' (2:11)"
 }

test/fixtures/experimental/function-sent/disabled-function-keyword-expression/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Unexpected token, expected ( (2:11)"
+  "throws": "This experimental syntax requires enabling the parser plugin: 'functionSent' (2:12)"
 }

test/fixtures/experimental/function-sent/disabled-inside-generator/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Unexpected token, expected ( (2:17)"
+  "throws": "This experimental syntax requires enabling the parser plugin: 'functionSent' (2:18)"
 }

test/fixtures/experimental/function-sent/invalid-syntax/actual.js

@@ -0,0 +1,3 @@
+function* foo() {
+  if (true) function.;
+}

test/fixtures/experimental/function-sent/invalid-syntax/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token (2:21)"
+}

test/fixtures/experimental/no-async-generators/error-without-plugin/options.json

@@ -1,4 +0,0 @@
-{
-  "throws": "Unexpected token (1:15)",
-  "plugins": []
-}