Merge branch 'main' into regex-recovery

Author: graphemecluster

.eslintrc.json

@@ -127,6 +127,7 @@
                 "varsIgnorePattern": "^(_+$|_[^_])"
             }
         ],
+        "@typescript-eslint/no-inferrable-types": "off",
 
         // Pending https://github.com/typescript-eslint/typescript-eslint/issues/4820
         "@typescript-eslint/prefer-optional-chain": "off",

.github/workflows/ci.yml

@@ -29,6 +29,7 @@ jobs:
           - windows-latest
           - macos-14
         node-version:
+          - '22'
           - '20'
           - '18'
           - '16'

src/compiler/checker.ts

@@ -102,6 +102,7 @@ import {
     countWhere,
     createBinaryExpressionTrampoline,
     createCompilerDiagnostic,
+    createDetachedDiagnostic,
     createDiagnosticCollection,
     createDiagnosticForFileFromMessageChain,
     createDiagnosticForNode,
@@ -123,6 +124,7 @@ import {
     createPrinterWithRemoveCommentsNeverAsciiEscape,
     createPrinterWithRemoveCommentsOmitTrailingSemicolon,
     createPropertyNameNodeForIdentifierOrLiteral,
+    createScanner,
     createSymbolTable,
     createSyntacticTypeNodeBuilder,
     createTextWriter,
@@ -937,6 +939,7 @@ import {
     rangeOfTypeParameters,
     ReadonlyKeyword,
     reduceLeft,
+    RegularExpressionLiteral,
     RelationComparisonResult,
     relativeComplement,
     removeExtension,
@@ -953,6 +956,7 @@ import {
     ReverseMappedType,
     sameMap,
     SatisfiesExpression,
+    Scanner,
     scanTokenAtPosition,
     ScriptKind,
     ScriptTarget,
@@ -1446,6 +1450,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     var requestedExternalEmitHelperNames = new Set<string>();
     var requestedExternalEmitHelpers: ExternalEmitHelpers;
     var externalHelpersModule: Symbol;
+    var scanner: Scanner | undefined;
 
     var Symbol = objectAllocator.getSymbolConstructor();
     var Type = objectAllocator.getTypeConstructor();
@@ -6689,7 +6694,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     if (!nodeIsSynthesized(node) && getParseTreeNode(node) === node) {
                         return node;
                     }
-                    return setTextRange(context, factory.cloneNode(visitEachChild(node, deepCloneOrReuseNode, /*context*/ undefined, deepCloneOrReuseNodes)), node);
+                    return setTextRange(context, factory.cloneNode(visitEachChild(node, deepCloneOrReuseNode, /*context*/ undefined, deepCloneOrReuseNodes, deepCloneOrReuseNode)), node);
                 }
 
                 function deepCloneOrReuseNodes(
@@ -31353,6 +31358,48 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
     }
 
+    function checkGrammarRegularExpressionLiteral(node: RegularExpressionLiteral) {
+        const sourceFile = getSourceFileOfNode(node);
+        if (!hasParseDiagnostics(sourceFile)) {
+            let lastError: DiagnosticWithLocation | undefined;
+            scanner ??= createScanner(ScriptTarget.ESNext, /*skipTrivia*/ true);
+            scanner.setScriptTarget(sourceFile.languageVersion);
+            scanner.setLanguageVariant(sourceFile.languageVariant);
+            scanner.setOnError((message, length, arg0) => {
+                // emulate `parseErrorAtPosition` from parser.ts
+                const start = scanner!.getTokenEnd();
+                if (message.category === DiagnosticCategory.Message && lastError && start === lastError.start && length === lastError.length) {
+                    const error = createDetachedDiagnostic(sourceFile.fileName, sourceFile.text, start, length, message, arg0);
+                    addRelatedInfo(lastError, error);
+                }
+                else if (!lastError || start !== lastError.start) {
+                    lastError = createFileDiagnostic(sourceFile, start, length, message, arg0);
+                    diagnostics.add(lastError);
+                }
+            });
+            scanner.setText(sourceFile.text, node.pos, node.end - node.pos);
+            try {
+                scanner.scan();
+                Debug.assert(scanner.reScanSlashToken(/*reportErrors*/ true) === SyntaxKind.RegularExpressionLiteral, "Expected scanner to rescan RegularExpressionLiteral");
+                return !!lastError;
+            }
+            finally {
+                scanner.setText("");
+                scanner.setOnError(/*onError*/ undefined);
+            }
+        }
+        return false;
+    }
+
+    function checkRegularExpressionLiteral(node: RegularExpressionLiteral) {
+        const nodeLinks = getNodeLinks(node);
+        if (!(nodeLinks.flags & NodeCheckFlags.TypeChecked)) {
+            nodeLinks.flags |= NodeCheckFlags.TypeChecked;
+            addLazyDiagnostic(() => checkGrammarRegularExpressionLiteral(node));
+        }
+        return globalRegExpType;
+    }
+
     function checkSpreadExpression(node: SpreadElement, checkMode?: CheckMode): Type {
         if (languageVersion < LanguageFeatureMinimumTarget.SpreadElements) {
             checkExternalEmitHelpers(node, compilerOptions.downlevelIteration ? ExternalEmitHelpers.SpreadIncludes : ExternalEmitHelpers.SpreadArray);
@@ -38493,7 +38540,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                         parent = parent.parent;
                     }
                     if (operator === SyntaxKind.AmpersandAmpersandToken || isIfStatement(parent)) {
-                        checkTestingKnownTruthyCallableOrAwaitableType(node.left, leftType, isIfStatement(parent) ? parent.thenStatement : undefined);
+                        checkTestingKnownTruthyCallableOrAwaitableOrEnumMemberType(node.left, leftType, isIfStatement(parent) ? parent.thenStatement : undefined);
                     }
                     checkTruthinessOfType(leftType, node.left);
                 }
@@ -39127,7 +39174,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
 
     function checkConditionalExpression(node: ConditionalExpression, checkMode?: CheckMode): Type {
         const type = checkTruthinessExpression(node.condition, checkMode);
-        checkTestingKnownTruthyCallableOrAwaitableType(node.condition, type, node.whenTrue);
+        checkTestingKnownTruthyCallableOrAwaitableOrEnumMemberType(node.condition, type, node.whenTrue);
         const type1 = checkExpression(node.whenTrue, checkMode);
         const type2 = checkExpression(node.whenFalse, checkMode);
         return getUnionType([type1, type2], UnionReduction.Subtype);
@@ -39662,7 +39709,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             case SyntaxKind.TemplateExpression:
                 return checkTemplateExpression(node as TemplateExpression);
             case SyntaxKind.RegularExpressionLiteral:
-                return globalRegExpType;
+                return checkRegularExpressionLiteral(node as RegularExpressionLiteral);
             case SyntaxKind.ArrayLiteralExpression:
                 return checkArrayLiteral(node as ArrayLiteralExpression, checkMode, forceTuple);
             case SyntaxKind.ObjectLiteralExpression:
@@ -43101,7 +43148,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         // Grammar checking
         checkGrammarStatementInAmbientContext(node);
         const type = checkTruthinessExpression(node.expression);
-        checkTestingKnownTruthyCallableOrAwaitableType(node.expression, type, node.thenStatement);
+        checkTestingKnownTruthyCallableOrAwaitableOrEnumMemberType(node.expression, type, node.thenStatement);
         checkSourceElement(node.thenStatement);
 
         if (node.thenStatement.kind === SyntaxKind.EmptyStatement) {
@@ -43111,7 +43158,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         checkSourceElement(node.elseStatement);
     }
 
-    function checkTestingKnownTruthyCallableOrAwaitableType(condExpr: Expression, condType: Type, body?: Statement | Expression) {
+    function checkTestingKnownTruthyCallableOrAwaitableOrEnumMemberType(condExpr: Expression, condType: Type, body?: Statement | Expression) {
         if (!strictNullChecks) return;
         bothHelper(condExpr, body);
 
@@ -43136,6 +43183,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 return;
             }
             const type = location === condExpr ? condType : checkTruthinessExpression(location);
+            if (type.flags & TypeFlags.EnumLiteral && isPropertyAccessExpression(location) && (getNodeLinks(location.expression).resolvedSymbol ?? unknownSymbol).flags & SymbolFlags.Enum) {
+                // EnumLiteral type at condition with known value is always truthy or always falsy, likely an error
+                error(location, Diagnostics.This_condition_will_always_return_0, !!(type as LiteralType).value ? "true" : "false");
+                return;
+            }
             const isPropertyExpressionCast = isPropertyAccessExpression(location) && isTypeAssertion(location.expression);
             if (!hasTypeFacts(type, TypeFacts.Truthy) || isPropertyExpressionCast) return;
 
@@ -46279,7 +46331,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             // If we hit an import declaration in an illegal context, just bail out to avoid cascading errors.
             return;
         }
-        if (!checkGrammarModifiers(node) && hasEffectiveModifiers(node)) {
+        if (!checkGrammarModifiers(node) && node.modifiers) {
             grammarErrorOnFirstToken(node, Diagnostics.An_import_declaration_cannot_have_modifiers);
         }
         if (checkExternalImportOrExportDeclaration(node)) {

src/compiler/corePublic.ts

@@ -3,7 +3,6 @@
 export const versionMajorMinor = "5.5";
 // The following is baselined as a literal template type without intervention
 /** The version of the TypeScript compiler release */
-// eslint-disable-next-line @typescript-eslint/no-inferrable-types
 export const version: string = `${versionMajorMinor}.0-dev`;
 
 /**

src/compiler/diagnosticMessages.json

@@ -1785,11 +1785,11 @@
         "category": "Error",
         "code": 1532
     },
-    "A decimal escape must refer to an existent capturing group. There are only {0} capturing groups in this regular expression.": {
+    "This backreference refers to a group that does not exist. There are only {0} capturing groups in this regular expression.": {
         "category": "Error",
         "code": 1533
     },
-    "Decimal escapes are invalid when there are no capturing groups in a regular expression.": {
+    "This backreference is invalid because the containing regular expression contains no capturing groups.": {
         "category": "Error",
         "code": 1534
     },

src/compiler/emitter.ts

@@ -533,7 +533,7 @@ function getSourceMapFilePath(jsFilePath: string, options: CompilerOptions) {
 }
 
 /** @internal */
-export function getOutputExtension(fileName: string, options: CompilerOptions): Extension {
+export function getOutputExtension(fileName: string, options: Pick<CompilerOptions, "jsx">): Extension {
     return fileExtensionIs(fileName, Extension.Json) ? Extension.Json :
         options.jsx === JsxEmit.Preserve && fileExtensionIsOneOf(fileName, [Extension.Jsx, Extension.Tsx]) ? Extension.Jsx :
         fileExtensionIsOneOf(fileName, [Extension.Mts, Extension.Mjs]) ? Extension.Mjs :