diff --git a/src/compiler/moduleSpecifiers.ts b/src/compiler/moduleSpecifiers.ts
index 7b3ab92f60b..9088d6ee482 100644
--- a/src/compiler/moduleSpecifiers.ts
+++ b/src/compiler/moduleSpecifiers.ts
@@ -31,6 +31,7 @@ import {
     flatten,
     forEach,
     forEachAncestorDirectory,
+    FutureSourceFile,
     getBaseFileName,
     GetCanonicalFileName,
     getConditions,
@@ -126,7 +127,7 @@ interface Preferences {
 function getPreferences(
     { importModuleSpecifierPreference, importModuleSpecifierEnding }: UserPreferences,
     compilerOptions: CompilerOptions,
-    importingSourceFile: SourceFile,
+    importingSourceFile: SourceFile | FutureSourceFile,
     oldImportSpecifier?: string,
 ): Preferences {
     const preferredEnding = getPreferredEnding();
@@ -212,7 +213,7 @@ export function getModuleSpecifier(
 /** @internal */
 export function getNodeModulesPackageName(
     compilerOptions: CompilerOptions,
-    importingSourceFile: SourceFile,
+    importingSourceFile: SourceFile | FutureSourceFile,
     nodeModulesFileName: string,
     host: ModuleSpecifierResolutionHost,
     preferences: UserPreferences,
@@ -243,14 +244,14 @@ function getModuleSpecifierWorker(
 /** @internal */
 export function tryGetModuleSpecifiersFromCache(
     moduleSymbol: Symbol,
-    importingSourceFile: SourceFile,
+    importingSourceFilePath: Path,
     host: ModuleSpecifierResolutionHost,
     userPreferences: UserPreferences,
     options: ModuleSpecifierOptions = {},
 ): readonly string[] | undefined {
     return tryGetModuleSpecifiersFromCacheWorker(
         moduleSymbol,
-        importingSourceFile,
+        importingSourceFilePath,
         host,
         userPreferences,
         options)[0];
@@ -258,7 +259,7 @@ export function tryGetModuleSpecifiersFromCache(
 
 function tryGetModuleSpecifiersFromCacheWorker(
     moduleSymbol: Symbol,
-    importingSourceFile: SourceFile,
+    importingSourceFilePath: Path,
     host: ModuleSpecifierResolutionHost,
     userPreferences: UserPreferences,
     options: ModuleSpecifierOptions = {},
@@ -269,7 +270,7 @@ function tryGetModuleSpecifiersFromCacheWorker(
     }
 
     const cache = host.getModuleSpecifierCache?.();
-    const cached = cache?.get(importingSourceFile.path, moduleSourceFile.path, userPreferences, options);
+    const cached = cache?.get(importingSourceFilePath, moduleSourceFile.path, userPreferences, options);
     return [cached?.moduleSpecifiers, moduleSourceFile, cached?.modulePaths, cache];
 }
 
@@ -303,7 +304,7 @@ export function getModuleSpecifiersWithCacheInfo(
     moduleSymbol: Symbol,
     checker: TypeChecker,
     compilerOptions: CompilerOptions,
-    importingSourceFile: SourceFile,
+    importingSourceFile: SourceFile | FutureSourceFile,
     host: ModuleSpecifierResolutionHost,
     userPreferences: UserPreferences,
     options: ModuleSpecifierOptions = {},
@@ -315,7 +316,7 @@ export function getModuleSpecifiersWithCacheInfo(
     // eslint-disable-next-line prefer-const
     let [specifiers, moduleSourceFile, modulePaths, cache] = tryGetModuleSpecifiersFromCacheWorker(
         moduleSymbol,
-        importingSourceFile,
+        importingSourceFile.path,
         host,
         userPreferences,
         options
@@ -333,14 +334,14 @@ export function getModuleSpecifiersWithCacheInfo(
 function computeModuleSpecifiers(
     modulePaths: readonly ModulePath[],
     compilerOptions: CompilerOptions,
-    importingSourceFile: SourceFile,
+    importingSourceFile: SourceFile | FutureSourceFile,
     host: ModuleSpecifierResolutionHost,
     userPreferences: UserPreferences,
     options: ModuleSpecifierOptions = {},
 ): readonly string[] {
     const info = getInfo(importingSourceFile.path, host);
     const preferences = getPreferences(userPreferences, compilerOptions, importingSourceFile);
-    const existingSpecifier = forEach(modulePaths, modulePath => forEach(
+    const existingSpecifier = importingSourceFile.kind && forEach(modulePaths, modulePath => forEach(
         host.getFileIncludeReasons().get(toPath(modulePath.path, host.getCurrentDirectory(), info.getCanonicalFileName)),
         reason => {
             if (reason.kind !== FileIncludeKind.Import || reason.file !== importingSourceFile.path) return undefined;
@@ -877,7 +878,7 @@ function tryGetModuleNameFromRootDirs(rootDirs: readonly string[], moduleFileNam
     return processEnding(shortest, allowedEndings, compilerOptions);
 }
 
-function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCanonicalFileName, sourceDirectory }: Info, importingSourceFile: SourceFile, host: ModuleSpecifierResolutionHost, options: CompilerOptions, userPreferences: UserPreferences, packageNameOnly?: boolean, overrideMode?: ResolutionMode): string | undefined {
+function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCanonicalFileName, sourceDirectory }: Info, importingSourceFile: SourceFile | FutureSourceFile, host: ModuleSpecifierResolutionHost, options: CompilerOptions, userPreferences: UserPreferences, packageNameOnly?: boolean, overrideMode?: ResolutionMode): string | undefined {
     if (!host.fileExists || !host.readFile) {
         return undefined;
     }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 7e14ff22ded..edbb47928c3 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -4220,6 +4220,15 @@ export interface SourceFileLike {
     getPositionOfLineAndCharacter?(line: number, character: number, allowEdits?: true): number;
 }
 
+/** @internal */
+export interface FutureSourceFile {
+    readonly kind?: undefined;
+    readonly fileName: string;
+    readonly path: Path;
+    readonly impliedNodeFormat?: ResolutionMode;
+    readonly commonJsModuleIndicator?: boolean;
+    readonly externalModuleIndicator?: boolean;
+}
 
 /** @internal */
 export interface RedirectInfo {
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index bf657d5a15d..65b5aa5be2e 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -157,6 +157,7 @@ import {
     FunctionDeclaration,
     FunctionExpression,
     FunctionLikeDeclaration,
+    FutureSourceFile,
     GetAccessorDeclaration,
     getBaseFileName,
     GetCanonicalFileName,
@@ -9160,7 +9161,7 @@ export function usesExtensionsOnImports({ imports }: SourceFile, hasExtension: (
 }
 
 /** @internal */
-export function getModuleSpecifierEndingPreference(preference: UserPreferences["importModuleSpecifierEnding"], resolutionMode: ResolutionMode, compilerOptions: CompilerOptions, sourceFile: SourceFile): ModuleSpecifierEnding {
+export function getModuleSpecifierEndingPreference(preference: UserPreferences["importModuleSpecifierEnding"], resolutionMode: ResolutionMode, compilerOptions: CompilerOptions, sourceFile: SourceFile | FutureSourceFile): ModuleSpecifierEnding {
     if (preference === "js" || resolutionMode === ModuleKind.ESNext) {
         // Extensions are explicitly requested or required. Now choose between .js and .ts.
         if (!shouldAllowImportingTsExtension(compilerOptions)) {
@@ -9185,27 +9186,30 @@ export function getModuleSpecifierEndingPreference(preference: UserPreferences["
     // accurately, and more importantly, literally nobody wants `Index` and its existence is a mystery.
     if (!shouldAllowImportingTsExtension(compilerOptions)) {
         // If .ts imports are not valid, we only need to see one .js import to go with that.
-        return usesExtensionsOnImports(sourceFile) ? ModuleSpecifierEnding.JsExtension : ModuleSpecifierEnding.Minimal;
+        return sourceFile.kind && usesExtensionsOnImports(sourceFile) ? ModuleSpecifierEnding.JsExtension : ModuleSpecifierEnding.Minimal;
     }
 
     return inferPreference();
 
     function inferPreference() {
-        let usesJsExtensions = false;
-        const specifiers = sourceFile.imports.length ? sourceFile.imports.map(i => i.text) :
-            isSourceFileJS(sourceFile) ? getRequiresAtTopOfFile(sourceFile).map(r => r.arguments[0].text) :
-            emptyArray;
-        for (const specifier of specifiers) {
-            if (pathIsRelative(specifier)) {
-                if (hasTSFileExtension(specifier)) {
-                    return ModuleSpecifierEnding.TsExtension;
-                }
-                if (hasJSFileExtension(specifier)) {
-                    usesJsExtensions = true;
+        if (sourceFile.kind) {
+            let usesJsExtensions = false;
+            const specifiers = sourceFile.imports.length ? sourceFile.imports.map(i => i.text) :
+                isSourceFileJS(sourceFile) ? getRequiresAtTopOfFile(sourceFile).map(r => r.arguments[0].text) :
+                emptyArray;
+            for (const specifier of specifiers) {
+                if (pathIsRelative(specifier)) {
+                    if (hasTSFileExtension(specifier)) {
+                        return ModuleSpecifierEnding.TsExtension;
+                    }
+                    if (hasJSFileExtension(specifier)) {
+                        usesJsExtensions = true;
+                    }
                 }
             }
+            return usesJsExtensions ? ModuleSpecifierEnding.JsExtension : ModuleSpecifierEnding.Minimal;
         }
-        return usesJsExtensions ? ModuleSpecifierEnding.JsExtension : ModuleSpecifierEnding.Minimal;
+        return ModuleSpecifierEnding.Minimal;
     }
 }
 
diff --git a/src/services/codefixes/convertFunctionToEs6Class.ts b/src/services/codefixes/convertFunctionToEs6Class.ts
index 5073d687a67..5c46bed9c57 100644
--- a/src/services/codefixes/convertFunctionToEs6Class.ts
+++ b/src/services/codefixes/convertFunctionToEs6Class.ts
@@ -21,7 +21,7 @@ import {
     FunctionExpression,
     getEmitScriptTarget,
     getNameOfDeclaration,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getTokenAtPosition,
     idText,
     isAccessExpression,
@@ -211,7 +211,7 @@ function doChange(changes: textChanges.ChangeTracker, sourceFile: SourceFile, po
 
             // f.x = expr
             if (isAccessExpression(memberDeclaration) && (isFunctionExpression(assignmentExpr) || isArrowFunction(assignmentExpr))) {
-                const quotePreference = getQuotePreference(sourceFile, preferences);
+                const quotePreference = getQuotePreferenceFromFile(sourceFile, preferences);
                 const name = tryGetPropertyName(memberDeclaration, compilerOptions, quotePreference);
                 if (name) {
                     createFunctionLikeExpressionMember(members, assignmentExpr, name);
diff --git a/src/services/codefixes/convertToEsModule.ts b/src/services/codefixes/convertToEsModule.ts
index b15a0521c1c..1f8b08d5e9b 100644
--- a/src/services/codefixes/convertToEsModule.ts
+++ b/src/services/codefixes/convertToEsModule.ts
@@ -27,7 +27,7 @@ import {
     FunctionExpression,
     getEmitScriptTarget,
     getModeForUsageLocation,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getResolvedModule,
     getSynthesizedDeepClone,
     getSynthesizedDeepClones,
@@ -87,10 +87,10 @@ registerCodeFix({
     getCodeActions(context) {
         const { sourceFile, program, preferences } = context;
         const changes = textChanges.ChangeTracker.with(context, changes => {
-            const moduleExportsChangedToDefault = convertFileToEsModule(sourceFile, program.getTypeChecker(), changes, getEmitScriptTarget(program.getCompilerOptions()), getQuotePreference(sourceFile, preferences));
+            const moduleExportsChangedToDefault = convertFileToEsModule(sourceFile, program.getTypeChecker(), changes, getEmitScriptTarget(program.getCompilerOptions()), getQuotePreferenceFromFile(sourceFile, preferences));
             if (moduleExportsChangedToDefault) {
                 for (const importingFile of program.getSourceFiles()) {
-                    fixImportOfModuleExports(importingFile, sourceFile, changes, getQuotePreference(importingFile, preferences));
+                    fixImportOfModuleExports(importingFile, sourceFile, changes, getQuotePreferenceFromFile(importingFile, preferences));
                 }
             }
         });
diff --git a/src/services/codefixes/fixAddMissingMember.ts b/src/services/codefixes/fixAddMissingMember.ts
index 3d46bc1511d..464d58653a7 100644
--- a/src/services/codefixes/fixAddMissingMember.ts
+++ b/src/services/codefixes/fixAddMissingMember.ts
@@ -33,7 +33,7 @@ import {
     getNodeId,
     getObjectFlags,
     getOrUpdate,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getSourceFileOfNode,
     getTokenAtPosition,
     hasAbstractModifier,
@@ -597,7 +597,7 @@ function addEnumMemberDeclaration(changes: textChanges.ChangeTracker, checker: T
 }
 
 function addFunctionDeclaration(changes: textChanges.ChangeTracker, context: CodeFixContextBase, info: FunctionInfo | SignatureInfo) {
-    const quotePreference = getQuotePreference(context.sourceFile, context.preferences);
+    const quotePreference = getQuotePreferenceFromFile(context.sourceFile, context.preferences);
     const importAdder = createImportAdder(context.sourceFile, context.program, context.preferences, context.host);
     const functionDeclaration = info.kind === InfoKind.Function
         ? createSignatureDeclarationFromCallExpression(SyntaxKind.FunctionDeclaration, context, importAdder, info.call, idText(info.token), info.modifierFlags, info.parentDeclaration)
@@ -614,7 +614,7 @@ function addFunctionDeclaration(changes: textChanges.ChangeTracker, context: Cod
 
 function addJsxAttributes(changes: textChanges.ChangeTracker, context: CodeFixContextBase, info: JsxAttributesInfo) {
     const importAdder = createImportAdder(context.sourceFile, context.program, context.preferences, context.host);
-    const quotePreference = getQuotePreference(context.sourceFile, context.preferences);
+    const quotePreference = getQuotePreferenceFromFile(context.sourceFile, context.preferences);
     const checker = context.program.getTypeChecker();
     const jsxAttributesNode = info.parentDeclaration.attributes;
     const hasSpreadAttribute = some(jsxAttributesNode.properties, isJsxSpreadAttribute);
@@ -634,7 +634,7 @@ function addJsxAttributes(changes: textChanges.ChangeTracker, context: CodeFixCo
 
 function addObjectLiteralProperties(changes: textChanges.ChangeTracker, context: CodeFixContextBase, info: ObjectLiteralInfo) {
     const importAdder = createImportAdder(context.sourceFile, context.program, context.preferences, context.host);
-    const quotePreference = getQuotePreference(context.sourceFile, context.preferences);
+    const quotePreference = getQuotePreferenceFromFile(context.sourceFile, context.preferences);
     const target = getEmitScriptTarget(context.program.getCompilerOptions());
     const checker = context.program.getTypeChecker();
     const props = map(info.properties, prop => {
diff --git a/src/services/codefixes/fixInvalidImportSyntax.ts b/src/services/codefixes/fixInvalidImportSyntax.ts
index bae3f2d2c0f..9a88b3b49fc 100644
--- a/src/services/codefixes/fixInvalidImportSyntax.ts
+++ b/src/services/codefixes/fixInvalidImportSyntax.ts
@@ -8,7 +8,7 @@ import {
     findAncestor,
     getEmitModuleKind,
     getNamespaceDeclarationNode,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getSourceFileOfNode,
     getTokenAtPosition,
     ImportDeclaration,
@@ -39,7 +39,7 @@ function getCodeFixesForImportDeclaration(context: CodeFixContext, node: ImportD
     const variations: CodeFixAction[] = [];
 
     // import Bluebird from "bluebird";
-    variations.push(createAction(context, sourceFile, node, makeImport(namespace.name, /*namedImports*/ undefined, node.moduleSpecifier, getQuotePreference(sourceFile, context.preferences))));
+    variations.push(createAction(context, sourceFile, node, makeImport(namespace.name, /*namedImports*/ undefined, node.moduleSpecifier, getQuotePreferenceFromFile(sourceFile, context.preferences))));
 
     if (getEmitModuleKind(opts) === ModuleKind.CommonJS) {
         // import Bluebird = require("bluebird");
diff --git a/src/services/codefixes/fixNoPropertyAccessFromIndexSignature.ts b/src/services/codefixes/fixNoPropertyAccessFromIndexSignature.ts
index 7a351260329..1e517583bf8 100644
--- a/src/services/codefixes/fixNoPropertyAccessFromIndexSignature.ts
+++ b/src/services/codefixes/fixNoPropertyAccessFromIndexSignature.ts
@@ -2,7 +2,7 @@ import {
     cast,
     Diagnostics,
     factory,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getTokenAtPosition,
     isPropertyAccessChain,
     isPropertyAccessExpression,
@@ -37,7 +37,7 @@ registerCodeFix({
 });
 
 function doChange(changes: textChanges.ChangeTracker, sourceFile: SourceFile, node: PropertyAccessExpression, preferences: UserPreferences): void {
-    const quotePreference = getQuotePreference(sourceFile, preferences);
+    const quotePreference = getQuotePreferenceFromFile(sourceFile, preferences);
     const argumentsExpression = factory.createStringLiteral(node.name.text, quotePreference === QuotePreference.Single);
     changes.replaceNode(
         sourceFile,
diff --git a/src/services/codefixes/helpers.ts b/src/services/codefixes/helpers.ts
index e47e4c99777..00a878b049d 100644
--- a/src/services/codefixes/helpers.ts
+++ b/src/services/codefixes/helpers.ts
@@ -27,7 +27,7 @@ import {
     getModuleSpecifierResolverHost,
     getNameForExportedSymbol,
     getNameOfDeclaration,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getSetAccessorValueParameter,
     getSynthesizedDeepClone,
     getTokenAtPosition,
@@ -205,7 +205,7 @@ export function addNewNodeForMemberSymbol(
     const type = checker.getWidenedType(checker.getTypeOfSymbolAtLocation(symbol, enclosingDeclaration));
     const optional = !!(symbol.flags & SymbolFlags.Optional);
     const ambient = !!(enclosingDeclaration.flags & NodeFlags.Ambient) || isAmbient;
-    const quotePreference = getQuotePreference(sourceFile, preferences);
+    const quotePreference = getQuotePreferenceFromFile(sourceFile, preferences);
 
     switch (kind) {
         case SyntaxKind.PropertySignature:
@@ -467,7 +467,7 @@ export function createSignatureDeclarationFromCallExpression(
     modifierFlags: ModifierFlags,
     contextNode: Node
 ): MethodDeclaration | FunctionDeclaration | MethodSignature {
-    const quotePreference = getQuotePreference(context.sourceFile, context.preferences);
+    const quotePreference = getQuotePreferenceFromFile(context.sourceFile, context.preferences);
     const scriptTarget = getEmitScriptTarget(context.program.getCompilerOptions());
     const tracker = getNoopSymbolTrackerWithResolver(context);
     const checker = context.program.getTypeChecker();
diff --git a/src/services/codefixes/importFixes.ts b/src/services/codefixes/importFixes.ts
index 6e7f9916748..feeeceed0b7 100644
--- a/src/services/codefixes/importFixes.ts
+++ b/src/services/codefixes/importFixes.ts
@@ -31,6 +31,7 @@ import {
     flatMapIterator,
     forEachExternalModuleToImportFrom,
     formatting,
+    FutureSourceFile,
     getAllowSyntheticDefaultImports,
     getBaseFileName,
     getDefaultExportInfoWorker,
@@ -46,11 +47,13 @@ import {
     getNodeId,
     getQuoteFromPreference,
     getQuotePreference,
+    getQuotePreferenceFromFile,
     getSourceFileOfNode,
     getSymbolId,
     getTokenAtPosition,
     getTypeKeywordOfTypeOnlyImport,
     getUniqueSymbolId,
+    hasJSFileExtension,
     hostGetCanonicalFileName,
     Identifier,
     ImportClause,
@@ -61,7 +64,6 @@ import {
     ImportsNotUsedAsValues,
     insertImports,
     InternalSymbolName,
-    isExternalModule,
     isExternalModuleReference,
     isIdentifier,
     isIdentifierPart,
@@ -208,7 +210,7 @@ interface AddToExistingState {
     readonly namedImports: Map<string, AddAsTypeOnly>;
 }
 
-function createImportAdderWorker(sourceFile: SourceFile, program: Program, useAutoImportProvider: boolean, preferences: UserPreferences, host: LanguageServiceHost, cancellationToken: CancellationToken | undefined): ImportAdder {
+function createImportAdderWorker(sourceFile: SourceFile | FutureSourceFile, program: Program, useAutoImportProvider: boolean, preferences: UserPreferences, host: LanguageServiceHost, cancellationToken: CancellationToken | undefined): ImportAdder {
     const compilerOptions = program.getCompilerOptions();
     // Namespace fixes don't conflict, so just build a list.
     const addToNamespace: FixUseNamespaceImport[] = [];
@@ -232,7 +234,7 @@ function createImportAdderWorker(sourceFile: SourceFile, program: Program, useAu
         const symbolName = getNameForExportedSymbol(exportedSymbol, getEmitScriptTarget(compilerOptions));
         const checker = program.getTypeChecker();
         const symbol = checker.getMergedSymbol(skipAlias(exportedSymbol, checker));
-        const exportInfo = getAllExportInfoForSymbol(sourceFile, symbol, symbolName, moduleSymbol, /*preferCapitalized*/ false, program, host, preferences, cancellationToken);
+        const exportInfo = getAllExportInfoForSymbol(sourceFile.path, symbol, symbolName, moduleSymbol, /*preferCapitalized*/ false, program, host, preferences, cancellationToken);
         const useRequire = shouldUseRequire(sourceFile, program);
         const fix = getImportFixForSymbol(sourceFile, Debug.checkDefined(exportInfo), program, /*position*/ undefined, !!isValidTypeOnlyUseSite, useRequire, host, preferences);
         if (fix) {
@@ -346,14 +348,17 @@ function createImportAdderWorker(sourceFile: SourceFile, program: Program, useAu
     }
 
     function writeFixes(changeTracker: textChanges.ChangeTracker) {
-        const quotePreference = getQuotePreference(sourceFile, preferences);
+        const quotePreference = sourceFile.kind ? getQuotePreferenceFromFile(sourceFile, preferences) : getQuotePreference(preferences);
         for (const fix of addToNamespace) {
+            Debug.assert(sourceFile.kind, "Cannot add to an existing import in a non-existent file.");
             addNamespaceQualifier(changeTracker, sourceFile, fix);
         }
         for (const fix of importType) {
+            Debug.assert(sourceFile.kind, "Cannot add to an existing import in a non-existent file.");
             addImportType(changeTracker, sourceFile, fix, quotePreference);
         }
         addToExisting.forEach(({ importClauseOrBindingPattern, defaultImport, namedImports }) => {
+            Debug.assert(sourceFile.kind, "Cannot add to an existing import in a non-existent file.");
             doAddExistingFix(
                 changeTracker,
                 sourceFile,
@@ -509,14 +514,14 @@ export function getImportCompletionAction(
     if (exportMapKey) {
         // The new way: `exportMapKey` should be in the `data` of each auto-import completion entry and
         // sent back when asking for details.
-        exportInfos = getExportInfoMap(sourceFile, host, program, preferences, cancellationToken).get(sourceFile.path, exportMapKey);
+        exportInfos = getExportInfoMap(sourceFile.path, host, program, preferences, cancellationToken).get(sourceFile.path, exportMapKey);
         Debug.assertIsDefined(exportInfos, "Some exportInfo should match the specified exportMapKey");
     }
     else {
         // The old way, kept alive for super old editors that don't give us `data` back.
         exportInfos = pathIsBareSpecifier(stripQuotes(moduleSymbol.name))
             ? [getSingleExportInfoForSymbol(targetSymbol, symbolName, moduleSymbol, program, host)]
-            : getAllExportInfoForSymbol(sourceFile, targetSymbol, symbolName, moduleSymbol, isJsxTagName, program, host, preferences, cancellationToken);
+            : getAllExportInfoForSymbol(sourceFile.path, targetSymbol, symbolName, moduleSymbol, isJsxTagName, program, host, preferences, cancellationToken);
         Debug.assertIsDefined(exportInfos, "Some exportInfo should match the specified symbol / moduleSymbol");
     }
 
@@ -545,7 +550,7 @@ export function getPromoteTypeOnlyCompletionAction(sourceFile: SourceFile, symbo
     return fix && codeFixActionToCodeAction(codeActionForFix({ host, formatContext, preferences }, sourceFile, symbolName, fix, includeSymbolNameInDescription, compilerOptions, preferences));
 }
 
-function getImportFixForSymbol(sourceFile: SourceFile, exportInfos: readonly SymbolExportInfo[], program: Program, position: number | undefined, isValidTypeOnlyUseSite: boolean, useRequire: boolean, host: LanguageServiceHost, preferences: UserPreferences) {
+function getImportFixForSymbol(sourceFile: SourceFile | FutureSourceFile, exportInfos: readonly SymbolExportInfo[], program: Program, position: number | undefined, isValidTypeOnlyUseSite: boolean, useRequire: boolean, host: LanguageServiceHost, preferences: UserPreferences) {
     const packageJsonImportFilter = createPackageJsonImportFilter(sourceFile, preferences, host);
     return getBestFix(getImportFixes(exportInfos, position, isValidTypeOnlyUseSite, useRequire, program, sourceFile, host, preferences).fixes, sourceFile, program, packageJsonImportFilter, host);
 }
@@ -554,10 +559,10 @@ function codeFixActionToCodeAction({ description, changes, commands }: CodeFixAc
     return { description, changes, commands };
 }
 
-function getAllExportInfoForSymbol(importingFile: SourceFile, symbol: Symbol, symbolName: string, moduleSymbol: Symbol, preferCapitalized: boolean, program: Program, host: LanguageServiceHost, preferences: UserPreferences, cancellationToken: CancellationToken | undefined): readonly SymbolExportInfo[] | undefined {
+function getAllExportInfoForSymbol(importingFilePath: Path, symbol: Symbol, symbolName: string, moduleSymbol: Symbol, preferCapitalized: boolean, program: Program, host: LanguageServiceHost, preferences: UserPreferences, cancellationToken: CancellationToken | undefined): readonly SymbolExportInfo[] | undefined {
     const getChecker = createGetChecker(program, host);
-    return getExportInfoMap(importingFile, host, program, preferences, cancellationToken)
-        .search(importingFile.path, preferCapitalized, name => name === symbolName, info => {
+    return getExportInfoMap(importingFilePath, host, program, preferences, cancellationToken)
+        .search(importingFilePath, preferCapitalized, name => name === symbolName, info => {
             if (skipAlias(info[0].symbol, getChecker(info[0].isFromPackageJson)) === symbol && info.some(i => i.moduleSymbol === moduleSymbol || i.symbol.parent === moduleSymbol)) {
                 return info;
             }
@@ -591,16 +596,16 @@ function getImportFixes(
     isValidTypeOnlyUseSite: boolean,
     useRequire: boolean,
     program: Program,
-    sourceFile: SourceFile,
+    sourceFile: SourceFile | FutureSourceFile,
     host: LanguageServiceHost,
     preferences: UserPreferences,
-    importMap = createExistingImportMap(program.getTypeChecker(), sourceFile, program.getCompilerOptions()),
+    importMap = sourceFile.kind && createExistingImportMap(program.getTypeChecker(), sourceFile, program.getCompilerOptions()),
     fromCacheOnly?: boolean,
 ): { computedWithoutCacheCount: number, fixes: readonly ImportFixWithModuleSpecifier[] } {
     const checker = program.getTypeChecker();
-    const existingImports = flatMap(exportInfos, importMap.getImportsForExportInfo);
-    const useNamespace = usagePosition !== undefined && tryUseExistingNamespaceImport(existingImports, usagePosition);
-    const addToExisting = tryAddToExistingImport(existingImports, isValidTypeOnlyUseSite, checker, program.getCompilerOptions());
+    const existingImports = importMap && flatMap(exportInfos, importMap.getImportsForExportInfo);
+    const useNamespace = existingImports && usagePosition !== undefined && tryUseExistingNamespaceImport(existingImports, usagePosition);
+    const addToExisting = existingImports && tryAddToExistingImport(existingImports, isValidTypeOnlyUseSite, checker, program.getCompilerOptions());
     if (addToExisting) {
         // Don't bother providing an action to add a new import if we can add to an existing one.
         return {
@@ -787,9 +792,9 @@ function createExistingImportMap(checker: TypeChecker, importingFile: SourceFile
     };
 }
 
-function shouldUseRequire(sourceFile: SourceFile, program: Program): boolean {
+function shouldUseRequire(sourceFile: SourceFile | FutureSourceFile, program: Program): boolean {
     // 1. TypeScript files don't use require variable declarations
-    if (!isSourceFileJS(sourceFile)) {
+    if (sourceFile.kind && !isSourceFileJS(sourceFile) || !sourceFile.kind && !hasJSFileExtension(sourceFile.fileName)) {
         return false;
     }
 
@@ -820,7 +825,7 @@ function createGetChecker(program: Program, host: LanguageServiceHost) {
 
 function getNewImportFixes(
     program: Program,
-    sourceFile: SourceFile,
+    sourceFile: SourceFile | FutureSourceFile,
     usagePosition: number | undefined,
     isValidTypeOnlyUseSite: boolean,
     useRequire: boolean,
@@ -829,14 +834,14 @@ function getNewImportFixes(
     preferences: UserPreferences,
     fromCacheOnly?: boolean,
 ): { computedWithoutCacheCount: number, fixes: readonly (FixAddNewImport | FixAddJsdocTypeImport)[] } {
-    const isJs = isSourceFileJS(sourceFile);
+    const isJs = sourceFile.kind ? isSourceFileJS(sourceFile) : hasJSFileExtension(sourceFile.fileName);
     const compilerOptions = program.getCompilerOptions();
     const moduleSpecifierResolutionHost = createModuleSpecifierResolutionHost(program, host);
     const getChecker = createGetChecker(program, host);
     const moduleResolution = getEmitModuleResolutionKind(compilerOptions);
     const rejectNodeModulesRelativePaths = moduleResolutionUsesNodeModules(moduleResolution);
     const getModuleSpecifiers = fromCacheOnly
-        ? (moduleSymbol: Symbol) => ({ moduleSpecifiers: moduleSpecifiers.tryGetModuleSpecifiersFromCache(moduleSymbol, sourceFile, moduleSpecifierResolutionHost, preferences), computedWithoutCache: false })
+        ? (moduleSymbol: Symbol) => ({ moduleSpecifiers: moduleSpecifiers.tryGetModuleSpecifiersFromCache(moduleSymbol, sourceFile.path, moduleSpecifierResolutionHost, preferences), computedWithoutCache: false })
         : (moduleSymbol: Symbol, checker: TypeChecker) => moduleSpecifiers.getModuleSpecifiersWithCacheInfo(moduleSymbol, checker, compilerOptions, sourceFile, moduleSpecifierResolutionHost, preferences);
 
     let computedWithoutCacheCount = 0;
@@ -892,9 +897,9 @@ function getNewImportFixes(
 
 function getFixesForAddImport(
     exportInfos: readonly SymbolExportInfo[],
-    existingImports: readonly FixAddToExistingImportInfo[],
+    existingImports: readonly FixAddToExistingImportInfo[] | undefined,
     program: Program,
-    sourceFile: SourceFile,
+    sourceFile: SourceFile | FutureSourceFile,
     usagePosition: number | undefined,
     isValidTypeOnlyUseSite: boolean,
     useRequire: boolean,
@@ -958,7 +963,7 @@ function sortFixInfo(fixes: readonly (FixInfo & { fix: ImportFixWithModuleSpecif
         compareModuleSpecifiers(a.fix, b.fix, sourceFile, program, packageJsonImportFilter.allowsImportingSpecifier, _toPath));
 }
 
-function getBestFix(fixes: readonly ImportFixWithModuleSpecifier[], sourceFile: SourceFile, program: Program, packageJsonImportFilter: PackageJsonImportFilter, host: LanguageServiceHost): ImportFixWithModuleSpecifier | undefined {
+function getBestFix(fixes: readonly ImportFixWithModuleSpecifier[], sourceFile: SourceFile | FutureSourceFile, program: Program, packageJsonImportFilter: PackageJsonImportFilter, host: LanguageServiceHost): ImportFixWithModuleSpecifier | undefined {
     if (!some(fixes)) return;
     // These will always be placed first if available, and are better than other kinds
     if (fixes[0].kind === ImportFixKind.UseNamespace || fixes[0].kind === ImportFixKind.AddToExisting) {
@@ -982,7 +987,7 @@ function getBestFix(fixes: readonly ImportFixWithModuleSpecifier[], sourceFile:
 function compareModuleSpecifiers(
     a: ImportFixWithModuleSpecifier,
     b: ImportFixWithModuleSpecifier,
-    importingFile: SourceFile,
+    importingFile: SourceFile | FutureSourceFile,
     program: Program,
     allowsImportingSpecifier: (specifier: string) => boolean,
     toPath: (fileName: string) => Path,
@@ -1003,7 +1008,7 @@ function compareModuleSpecifiers(
 // This can produce false positives or negatives if re-exports cross into sibling directories
 // (e.g. `export * from "../whatever"`) or are not named "index" (we don't even try to consider
 // this if we're in a resolution mode where you can't drop trailing "/index" from paths).
-function isFixPossiblyReExportingImportingFile(fix: ImportFixWithModuleSpecifier, importingFile: SourceFile, compilerOptions: CompilerOptions, toPath: (fileName: string) => Path): boolean {
+function isFixPossiblyReExportingImportingFile(fix: ImportFixWithModuleSpecifier, importingFile: SourceFile | FutureSourceFile, compilerOptions: CompilerOptions, toPath: (fileName: string) => Path): boolean {
     if (fix.isReExport &&
         fix.exportInfo?.moduleFileName &&
         getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.Node10 &&
@@ -1019,7 +1024,7 @@ function isIndexFileName(fileName: string) {
     return getBaseFileName(fileName, [".js", ".jsx", ".d.ts", ".ts", ".tsx"], /*ignoreCase*/ true) === "index";
 }
 
-function compareNodeCoreModuleSpecifiers(a: string, b: string, importingFile: SourceFile, program: Program): Comparison {
+function compareNodeCoreModuleSpecifiers(a: string, b: string, importingFile: SourceFile | FutureSourceFile, program: Program): Comparison {
     if (startsWith(a, "node:") && !startsWith(b, "node:")) return shouldUseUriStyleNodeCoreModules(importingFile, program) ? Comparison.LessThan : Comparison.GreaterThan;
     if (startsWith(b, "node:") && !startsWith(a, "node:")) return shouldUseUriStyleNodeCoreModules(importingFile, program) ? Comparison.GreaterThan : Comparison.LessThan;
     return Comparison.EqualTo;
@@ -1064,7 +1069,7 @@ function getUmdSymbol(token: Node, checker: TypeChecker): Symbol | undefined {
  *
  * @internal
  */
-export function getImportKind(importingFile: SourceFile, exportKind: ExportKind, compilerOptions: CompilerOptions, forceImportKeyword?: boolean): ImportKind {
+export function getImportKind(importingFile: SourceFile | FutureSourceFile, exportKind: ExportKind, compilerOptions: CompilerOptions, forceImportKeyword?: boolean): ImportKind {
     if (compilerOptions.verbatimModuleSyntax && (getEmitModuleKind(compilerOptions) === ModuleKind.CommonJS || importingFile.impliedNodeFormat === ModuleKind.CommonJS)) {
         // TODO: if the exporting file is ESM under nodenext, or `forceImport` is given in a JS file, this is impossible
         return ImportKind.CommonJS;
@@ -1078,7 +1083,7 @@ export function getImportKind(importingFile: SourceFile, exportKind: ExportKind,
     }
 }
 
-function getUmdImportKind(importingFile: SourceFile, compilerOptions: CompilerOptions, forceImportKeyword: boolean): ImportKind {
+function getUmdImportKind(importingFile: SourceFile | FutureSourceFile, compilerOptions: CompilerOptions, forceImportKeyword: boolean): ImportKind {
     // Import a synthetic `default` if enabled.
     if (getAllowSyntheticDefaultImports(compilerOptions)) {
         return ImportKind.Default;
@@ -1090,8 +1095,8 @@ function getUmdImportKind(importingFile: SourceFile, compilerOptions: CompilerOp
         case ModuleKind.AMD:
         case ModuleKind.CommonJS:
         case ModuleKind.UMD:
-            if (isInJSFile(importingFile)) {
-                return isExternalModule(importingFile) || forceImportKeyword ? ImportKind.Namespace : ImportKind.CommonJS;
+            if (importingFile.kind ? isInJSFile(importingFile) : hasJSFileExtension(importingFile.fileName)) {
+                return importingFile.externalModuleIndicator || forceImportKeyword ? ImportKind.Namespace : ImportKind.CommonJS;
             }
             return ImportKind.CommonJS;
         case ModuleKind.System:
@@ -1206,9 +1211,9 @@ function getExportInfos(
     return originalSymbolToExportInfos;
 }
 
-function getExportEqualsImportKind(importingFile: SourceFile, compilerOptions: CompilerOptions, forceImportKeyword: boolean): ImportKind {
+function getExportEqualsImportKind(importingFile: SourceFile | FutureSourceFile, compilerOptions: CompilerOptions, forceImportKeyword: boolean): ImportKind {
     const allowSyntheticDefaults = getAllowSyntheticDefaultImports(compilerOptions);
-    const isJS = isInJSFile(importingFile);
+    const isJS = importingFile.kind ? isInJSFile(importingFile) : hasJSFileExtension(importingFile.fileName);
     // 1. 'import =' will not work in es2015+ TS files, so the decision is between a default
     //    and a namespace import, based on allowSyntheticDefaultImports/esModuleInterop.
     if (!isJS && getEmitModuleKind(compilerOptions) >= ModuleKind.ES2015) {
@@ -1217,17 +1222,19 @@ function getExportEqualsImportKind(importingFile: SourceFile, compilerOptions: C
     // 2. 'import =' will not work in JavaScript, so the decision is between a default import,
     //    a namespace import, and const/require.
     if (isJS) {
-        return isExternalModule(importingFile) || forceImportKeyword
+        return importingFile.externalModuleIndicator || forceImportKeyword
             ? allowSyntheticDefaults ? ImportKind.Default : ImportKind.Namespace
             : ImportKind.CommonJS;
     }
     // 3. At this point the most correct choice is probably 'import =', but people
     //    really hate that, so look to see if the importing file has any precedent
     //    on how to handle it.
-    for (const statement of importingFile.statements) {
-        // `import foo` parses as an ImportEqualsDeclaration even though it could be an ImportDeclaration
-        if (isImportEqualsDeclaration(statement) && !nodeIsMissing(statement.moduleReference)) {
-            return ImportKind.CommonJS;
+    if (importingFile.kind) {
+        for (const statement of importingFile.statements) {
+            // `import foo` parses as an ImportEqualsDeclaration even though it could be an ImportDeclaration
+            if (isImportEqualsDeclaration(statement) && !nodeIsMissing(statement.moduleReference)) {
+                return ImportKind.CommonJS;
+            }
         }
     }
     // 4. We have no precedent to go on, so just use a default import if
@@ -1243,7 +1250,7 @@ function codeActionForFix(context: textChanges.TextChangesContext, sourceFile: S
     return createCodeFixAction(importFixName, changes, diag, importFixId, Diagnostics.Add_all_missing_imports);
 }
 function codeActionForFixWorker(changes: textChanges.ChangeTracker, sourceFile: SourceFile, symbolName: string, fix: ImportFix, includeSymbolNameInDescription: boolean, compilerOptions: CompilerOptions, preferences: UserPreferences): DiagnosticOrDiagnosticAndArguments {
-    const quotePreference = getQuotePreference(sourceFile, preferences);
+    const quotePreference = getQuotePreferenceFromFile(sourceFile, preferences);
     switch (fix.kind) {
         case ImportFixKind.UseNamespace:
             addNamespaceQualifier(changes, sourceFile, fix);
diff --git a/src/services/codefixes/useDefaultImport.ts b/src/services/codefixes/useDefaultImport.ts
index 75f72964530..5972b29ab1a 100644
--- a/src/services/codefixes/useDefaultImport.ts
+++ b/src/services/codefixes/useDefaultImport.ts
@@ -2,7 +2,7 @@ import {
     AnyImportSyntax,
     Diagnostics,
     Expression,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getTokenAtPosition,
     Identifier,
     isExternalModuleReference,
@@ -57,5 +57,5 @@ function getInfo(sourceFile: SourceFile, pos: number): Info | undefined {
 }
 
 function doChange(changes: textChanges.ChangeTracker, sourceFile: SourceFile, info: Info, preferences: UserPreferences): void {
-    changes.replaceNode(sourceFile, info.importNode, makeImport(info.name, /*namedImports*/ undefined, info.moduleSpecifier, getQuotePreference(sourceFile, preferences)));
+    changes.replaceNode(sourceFile, info.importNode, makeImport(info.name, /*namedImports*/ undefined, info.moduleSpecifier, getQuotePreferenceFromFile(sourceFile, preferences)));
 }
diff --git a/src/services/completions.ts b/src/services/completions.ts
index 43ae8c2497a..01fa6ea982a 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -96,7 +96,7 @@ import {
     getNewLineKind,
     getNewLineOrDefaultFromHost,
     getPropertyNameForPropertyNameNode,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getReplacementSpanForContextToken,
     getRootDeclaration,
     getSourceFileOfModule,
@@ -790,7 +790,7 @@ function continuePreviousIncompleteResponse(
 
     const touchNode = getTouchingPropertyName(file, position);
     const lowerCaseTokenText = location.text.toLowerCase();
-    const exportMap = getExportInfoMap(file, host, program, preferences, cancellationToken);
+    const exportMap = getExportInfoMap(file.path, host, program, preferences, cancellationToken);
     const newEntries = resolvingModuleSpecifiers(
         "continuePreviousIncompleteResponse",
         host,
@@ -1105,7 +1105,7 @@ function getJSDocParamAnnotation(
                 const inferredType = checker.getTypeAtLocation(initializer.parent);
                 if (!(inferredType.flags & (TypeFlags.Any | TypeFlags.Void))) {
                     const sourceFile = initializer.getSourceFile();
-                    const quotePreference = getQuotePreference(sourceFile, preferences);
+                    const quotePreference = getQuotePreferenceFromFile(sourceFile, preferences);
                     const builderFlags = (quotePreference === QuotePreference.Single ? NodeBuilderFlags.UseSingleQuotesForStringLiteralType : NodeBuilderFlags.None);
                     const typeNode = checker.typeToTypeNode(inferredType, findAncestor(initializer, isFunctionLike), builderFlags);
                     if (typeNode) {
@@ -1353,7 +1353,7 @@ function getExhaustiveCaseSnippets(
         const tracker = newCaseClauseTracker(checker, clauses);
 
         const target = getEmitScriptTarget(options);
-        const quotePreference = getQuotePreference(sourceFile, preferences);
+        const quotePreference = getQuotePreferenceFromFile(sourceFile, preferences);
         const importAdder = codefix.createImportAdder(sourceFile, program, preferences, host);
         const elements: Expression[] = [];
         for (const type of switchType.types as LiteralType[]) {
@@ -2048,7 +2048,7 @@ function createObjectLiteralMethod(
     const declaration = declarations[0];
     const name = getSynthesizedDeepClone(getNameOfDeclaration(declaration), /*includeTrivia*/ false) as PropertyName;
     const type = checker.getWidenedType(checker.getTypeOfSymbolAtLocation(symbol, enclosingDeclaration));
-    const quotePreference = getQuotePreference(sourceFile, preferences);
+    const quotePreference = getQuotePreferenceFromFile(sourceFile, preferences);
     const builderFlags = NodeBuilderFlags.OmitThisParameter | (quotePreference === QuotePreference.Single ? NodeBuilderFlags.UseSingleQuotesForStringLiteralType : NodeBuilderFlags.None);
 
     switch (declaration.kind) {
@@ -3747,7 +3747,7 @@ function getCompletionData(
             "";
 
         const moduleSpecifierCache = host.getModuleSpecifierCache?.();
-        const exportInfo = getExportInfoMap(sourceFile, host, program, preferences, cancellationToken);
+        const exportInfo = getExportInfoMap(sourceFile.path, host, program, preferences, cancellationToken);
         const packageJsonAutoImportProvider = host.getPackageJsonAutoImportProvider?.();
         const packageJsonFilter = detailsEntryId ? undefined : createPackageJsonImportFilter(sourceFile, preferences, host);
         resolvingModuleSpecifiers(
diff --git a/src/services/exportInfoMap.ts b/src/services/exportInfoMap.ts
index 4651c1dac1c..d1029858b0a 100644
--- a/src/services/exportInfoMap.ts
+++ b/src/services/exportInfoMap.ts
@@ -451,7 +451,7 @@ function forEachExternalModule(checker: TypeChecker, allSourceFiles: readonly So
 }
 
 /** @internal */
-export function getExportInfoMap(importingFile: SourceFile, host: LanguageServiceHost, program: Program, preferences: UserPreferences, cancellationToken: CancellationToken | undefined): ExportInfoMap {
+export function getExportInfoMap(importingFilePath: Path, host: LanguageServiceHost, program: Program, preferences: UserPreferences, cancellationToken: CancellationToken | undefined): ExportInfoMap {
     const start = timestamp();
     // Pulling the AutoImportProvider project will trigger its updateGraph if pending,
     // which will invalidate the export map cache if things change, so pull it before
@@ -463,7 +463,7 @@ export function getExportInfoMap(importingFile: SourceFile, host: LanguageServic
         getGlobalTypingsCacheLocation: () => host.getGlobalTypingsCacheLocation?.(),
     });
 
-    if (cache.isUsableByFile(importingFile.path)) {
+    if (cache.isUsableByFile(importingFilePath)) {
         host.log?.("getExportInfoMap: cache hit");
         return cache;
     }
@@ -481,7 +481,7 @@ export function getExportInfoMap(importingFile: SourceFile, host: LanguageServic
             // can cause it to happen: see 'completionsImport_mergedReExport.ts'
             if (defaultInfo && isImportableSymbol(defaultInfo.symbol, checker)) {
                 cache.add(
-                    importingFile.path,
+                    importingFilePath,
                     defaultInfo.symbol,
                     defaultInfo.exportKind === ExportKind.Default ? InternalSymbolName.Default : InternalSymbolName.ExportEquals,
                     moduleSymbol,
@@ -493,7 +493,7 @@ export function getExportInfoMap(importingFile: SourceFile, host: LanguageServic
             checker.forEachExportAndPropertyOfModule(moduleSymbol, (exported, key) => {
                 if (exported !== defaultInfo?.symbol && isImportableSymbol(exported, checker) && addToSeen(seenExports, key)) {
                     cache.add(
-                        importingFile.path,
+                        importingFilePath,
                         exported,
                         key,
                         moduleSymbol,
diff --git a/src/services/refactors/moveToNewFile.ts b/src/services/refactors/moveToNewFile.ts
index 2fdff08a852..e420b6631a9 100644
--- a/src/services/refactors/moveToNewFile.ts
+++ b/src/services/refactors/moveToNewFile.ts
@@ -46,7 +46,7 @@ import {
     getLocaleSpecificMessage,
     getModifiers,
     getPropertySymbolFromBindingElement,
-    getQuotePreference,
+    getQuotePreferenceFromFile,
     getRangesWhere,
     getRefactorContextSpan,
     getRelativePathFromFile,
@@ -280,7 +280,7 @@ function getNewStatementsAndRemoveFromOldFile(
     }
 
     const useEsModuleSyntax = !!oldFile.externalModuleIndicator;
-    const quotePreference = getQuotePreference(oldFile, preferences);
+    const quotePreference = getQuotePreferenceFromFile(oldFile, preferences);
     const importsFromNewFile = createOldFileImportsFromNewFile(oldFile, usage.oldFileImportsFromNewFile, newFilename, program, host, useEsModuleSyntax, quotePreference);
     if (importsFromNewFile) {
         insertImports(changes, oldFile, importsFromNewFile, /*blankLineBetween*/ true, preferences);
diff --git a/src/services/textChanges.ts b/src/services/textChanges.ts
index 7ad7bf4cc33..5bfc12b8ca8 100644
--- a/src/services/textChanges.ts
+++ b/src/services/textChanges.ts
@@ -23,6 +23,7 @@ import {
     DeclarationStatement,
     EmitHint,
     EmitTextWriter,
+    emptyArray,
     endsWith,
     Expression,
     factory,
@@ -40,6 +41,7 @@ import {
     formatting,
     FunctionDeclaration,
     FunctionExpression,
+    FutureSourceFile,
     getAncestor,
     getFirstNonSpaceCharacterPosition,
     getFormatCodeSettingsForWriting,
@@ -337,6 +339,12 @@ interface ChangeText extends BaseChange {
     readonly text: string;
 }
 
+interface NewFileInsertion {
+    readonly fileName: string;
+    readonly oldFile?: SourceFile;
+    readonly statements: readonly (Statement | SyntaxKind.NewLineTrivia)[];
+}
+
 function getAdjustedRange(sourceFile: SourceFile, startNode: Node, endNode: Node, options: ConfigurableStartEnd): TextRange {
     return { pos: getAdjustedStartPosition(sourceFile, startNode, options), end: getAdjustedEndPosition(sourceFile, endNode, options) };
 }
@@ -480,7 +488,7 @@ export function isThisTypeAnnotatable(containingFunction: SignatureDeclaration):
 /** @internal */
 export class ChangeTracker {
     private readonly changes: Change[] = [];
-    private readonly newFiles: { readonly oldFile: SourceFile | undefined, readonly fileName: string, readonly statements: readonly (Statement | SyntaxKind.NewLineTrivia)[] }[] = [];
+    private newFileChanges?: NewFileInsertion[];
     private readonly classesWithNodesInsertedAtStart = new Map<number, { readonly node: ClassLikeDeclaration | InterfaceDeclaration | ObjectLiteralExpression, readonly sourceFile: SourceFile }>(); // Set<ClassDeclaration> implemented as Map<node id, ClassDeclaration>
     private readonly deletedNodes: { readonly sourceFile: SourceFile, readonly node: Node | NodeArray<TypeParameterDeclaration> }[] = [];
 
@@ -600,28 +608,42 @@ export class ChangeTracker {
         this.replaceRangeWithNodes(sourceFile, createRange(pos), newNodes, options);
     }
 
-    public insertNodeAtTopOfFile(sourceFile: SourceFile, newNode: Statement, blankLineBetween: boolean): void {
+    public insertNodeAtTopOfFile(sourceFile: SourceFile | FutureSourceFile, newNode: Statement, blankLineBetween: boolean): void {
         this.insertAtTopOfFile(sourceFile, newNode, blankLineBetween);
     }
 
-    public insertNodesAtTopOfFile(sourceFile: SourceFile, newNodes: readonly Statement[], blankLineBetween: boolean): void {
+    public insertNodesAtTopOfFile(sourceFile: SourceFile | FutureSourceFile, newNodes: readonly Statement[], blankLineBetween: boolean): void {
         this.insertAtTopOfFile(sourceFile, newNodes, blankLineBetween);
     }
 
-    private insertAtTopOfFile(sourceFile: SourceFile, insert: Statement | readonly Statement[], blankLineBetween: boolean): void {
-        const pos = getInsertionPositionAtSourceFileTop(sourceFile);
+    private insertAtTopOfFile(sourceFile: SourceFile | FutureSourceFile, insert: Statement | readonly Statement[], blankLineBetween: boolean): void {
+        const pos = sourceFile.kind ? getInsertionPositionAtSourceFileTop(sourceFile) : 0;
         const options = {
             prefix: pos === 0 ? undefined : this.newLineCharacter,
-            suffix: (isLineBreak(sourceFile.text.charCodeAt(pos)) ? "" : this.newLineCharacter) + (blankLineBetween ? this.newLineCharacter : ""),
+            suffix: (sourceFile.kind && isLineBreak(sourceFile.text.charCodeAt(pos)) ? "" : this.newLineCharacter) + (blankLineBetween ? this.newLineCharacter : ""),
         };
         if (isArray(insert)) {
-            this.insertNodesAt(sourceFile, pos, insert, options);
+            if (sourceFile.kind) {
+                this.insertNodesAt(sourceFile, pos, insert, options);
+            }
+            else {
+                this.insertStatementsInNewFile(sourceFile.fileName, insert);
+            }
         }
         else {
-            this.insertNodeAt(sourceFile, pos, insert, options);
+            if (sourceFile.kind) {
+                this.insertNodeAt(sourceFile, pos, insert, options);
+            }
+            else {
+                this.insertStatementsInNewFile(sourceFile.fileName, [insert]);
+            }
         }
     }
 
+    private insertStatementsInNewFile(fileName: string, statements: readonly (Statement | SyntaxKind.NewLineTrivia)[], oldFile?: SourceFile): void {
+        (this.newFileChanges ??= []).push({ fileName, statements, oldFile });
+    }
+
     public insertFirstParameter(sourceFile: SourceFile, parameters: NodeArray<ParameterDeclaration>, newParam: ParameterDeclaration): void {
         const p0 = firstOrUndefined(parameters);
         if (p0) {
@@ -1128,14 +1150,14 @@ export class ChangeTracker {
         this.finishDeleteDeclarations();
         this.finishClassesWithNodesInsertedAtStart();
         const changes = changesToText.getTextChangesFromChanges(this.changes, this.newLineCharacter, this.formatContext, validate);
-        for (const { oldFile, fileName, statements } of this.newFiles) {
+        for (const { oldFile, fileName, statements } of this.newFileChanges ?? emptyArray) {
             changes.push(changesToText.newFileChanges(oldFile, fileName, statements, this.newLineCharacter, this.formatContext));
         }
         return changes;
     }
 
     public createNewFile(oldFile: SourceFile | undefined, fileName: string, statements: readonly (Statement | SyntaxKind.NewLineTrivia)[]): void {
-        this.newFiles.push({ oldFile, fileName, statements });
+        this.insertStatementsInNewFile(fileName, statements, oldFile);
     }
 }
 
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 7b29fd02dfb..d237e191103 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -85,11 +85,13 @@ import {
     FunctionDeclaration,
     FunctionExpression,
     FunctionLikeDeclaration,
+    FutureSourceFile,
     getAssignmentDeclarationKind,
     getCombinedNodeFlagsAlwaysIncludeJSDoc,
     getDirectoryPath,
     getEmitScriptTarget,
     getExternalModuleImportEqualsDeclarationExpression,
+    getImpliedNodeFormatForFile,
     getIndentString,
     getJSDocEnumTag,
     getLastChild,
@@ -267,6 +269,8 @@ import {
     ModifierFlags,
     ModuleDeclaration,
     ModuleInstanceState,
+    ModuleKind,
+    ModuleResolutionHost,
     ModuleResolutionKind,
     ModuleSpecifierResolutionHost,
     moduleSpecifiers,
@@ -350,6 +354,7 @@ import {
     textSpanEnd,
     Token,
     tokenToString,
+    toPath,
     tryCast,
     Type,
     TypeChecker,
@@ -2472,9 +2477,14 @@ export function quotePreferenceFromString(str: StringLiteral, sourceFile: Source
 }
 
 /** @internal */
-export function getQuotePreference(sourceFile: SourceFile, preferences: UserPreferences): QuotePreference {
+export function getQuotePreference(preferences: UserPreferences): QuotePreference {
+    return preferences.quotePreference === "single" ? QuotePreference.Single : QuotePreference.Double;
+}
+
+/** @internal */
+export function getQuotePreferenceFromFile(sourceFile: SourceFile, preferences: UserPreferences): QuotePreference {
     if (preferences.quotePreference && preferences.quotePreference !== "auto") {
-        return preferences.quotePreference === "single" ? QuotePreference.Single : QuotePreference.Double;
+        return getQuotePreference(preferences);
     }
     else {
         // ignore synthetic import added when importHelpers: true
@@ -2561,17 +2571,18 @@ export function findModifier(node: Node, kind: Modifier["kind"]): Modifier | und
 }
 
 /** @internal */
-export function insertImports(changes: textChanges.ChangeTracker, sourceFile: SourceFile, imports: AnyImportOrRequireStatement | readonly AnyImportOrRequireStatement[], blankLineBetween: boolean, preferences: UserPreferences): void {
+export function insertImports(changes: textChanges.ChangeTracker, sourceFile: SourceFile | FutureSourceFile, imports: AnyImportOrRequireStatement | readonly AnyImportOrRequireStatement[], blankLineBetween: boolean, preferences: UserPreferences): void {
     const decl = isArray(imports) ? imports[0] : imports;
     const importKindPredicate: (node: Node) => node is AnyImportOrRequireStatement = decl.kind === SyntaxKind.VariableStatement ? isRequireVariableStatement : isAnyImportSyntax;
-    const existingImportStatements = filter(sourceFile.statements, importKindPredicate);
+    const existingImportStatements = sourceFile.kind ? filter(sourceFile.statements, importKindPredicate) : undefined;
     let sortKind = isArray(imports) ? OrganizeImports.detectImportDeclarationSorting(imports, preferences) : SortKind.Both;
     const comparer = OrganizeImports.getOrganizeImportsComparer(preferences, sortKind === SortKind.CaseInsensitive);
     const sortedNewImports = isArray(imports) ? stableSort(imports, (a, b) => OrganizeImports.compareImportsOrRequireStatements(a, b, comparer)) : [imports];
-    if (!existingImportStatements.length) {
+    if (!existingImportStatements?.length) {
         changes.insertNodesAtTopOfFile(sourceFile, sortedNewImports, blankLineBetween);
     }
     else if (existingImportStatements && (sortKind = OrganizeImports.detectImportDeclarationSorting(existingImportStatements, preferences))) {
+        Debug.assert(sourceFile.kind, "Cannot have existing import statements in a non-existent source file.");
         const comparer = OrganizeImports.getOrganizeImportsComparer(preferences, sortKind === SortKind.CaseInsensitive);
         for (const newImport of sortedNewImports) {
             const insertionIndex = OrganizeImports.getImportDeclarationInsertionIndex(existingImportStatements, newImport, comparer);
@@ -2590,6 +2601,7 @@ export function insertImports(changes: textChanges.ChangeTracker, sourceFile: So
     else {
         const lastExistingImport = lastOrUndefined(existingImportStatements);
         if (lastExistingImport) {
+            Debug.assert(sourceFile.kind, "Cannot have existing import statements in a non-existent source file.");
             changes.insertNodesAfter(sourceFile, lastExistingImport, sortedNewImports);
         }
         else {
@@ -3322,7 +3334,7 @@ export function getContextualTypeFromParent(node: Expression, checker: TypeCheck
 /** @internal */
 export function quote(sourceFile: SourceFile, preferences: UserPreferences, text: string): string {
     // Editors can pass in undefined or empty string - we want to infer the preference in those cases.
-    const quotePreference = getQuotePreference(sourceFile, preferences);
+    const quotePreference = getQuotePreferenceFromFile(sourceFile, preferences);
     const quoted = JSON.stringify(text);
     return quotePreference === QuotePreference.Single ? `'${stripQuotes(quoted).replace(/'/g, "\\'").replace(/\\"/g, '"')}'` : quoted;
 }
@@ -3683,7 +3695,7 @@ export interface PackageJsonImportFilter {
 }
 
 /** @internal */
-export function createPackageJsonImportFilter(fromFile: SourceFile, preferences: UserPreferences, host: LanguageServiceHost): PackageJsonImportFilter {
+export function createPackageJsonImportFilter(fromFile: SourceFile | FutureSourceFile, preferences: UserPreferences, host: LanguageServiceHost): PackageJsonImportFilter {
     const packageJsons = (
         (host.getPackageJsonsVisibleToFile && host.getPackageJsonsVisibleToFile(fromFile.fileName)) || getPackageJsonsVisibleToFile(fromFile.fileName, host)
       ).filter(p => p.parseable);
@@ -3783,7 +3795,7 @@ export function createPackageJsonImportFilter(fromFile: SourceFile, preferences:
         // from Node core modules or not. We can start by seeing if the user is actually using
         // any node core modules, as opposed to simply having @types/node accidentally as a
         // dependency of a dependency.
-        if (isSourceFileJS(fromFile) && JsTyping.nodeCoreModules.has(moduleSpecifier)) {
+        if (fromFile.kind && isSourceFileJS(fromFile) && JsTyping.nodeCoreModules.has(moduleSpecifier)) {
             if (usesNodeCoreModules === undefined) {
                 usesNodeCoreModules = consumesNodeCoreModules(fromFile);
             }
@@ -4041,8 +4053,8 @@ export function isDeprecatedDeclaration(decl: Declaration) {
 }
 
 /** @internal */
-export function shouldUseUriStyleNodeCoreModules(file: SourceFile, program: Program): boolean {
-    const decisionFromFile = firstDefined(file.imports, node => {
+export function shouldUseUriStyleNodeCoreModules(file: SourceFile | FutureSourceFile, program: Program): boolean {
+    const decisionFromFile = file.kind && firstDefined(file.imports, node => {
         if (JsTyping.nodeCoreModules.has(node.text)) {
             return startsWith(node.text, "node:");
         }
@@ -4064,6 +4076,27 @@ export function diagnosticToString(diag: DiagnosticOrDiagnosticAndArguments): st
         : getLocaleSpecificMessage(diag);
 }
 
+/** @internal */
+export function createFutureSourceFile(
+    fileName: string,
+    program: Program,
+    host: ModuleResolutionHost,
+    moduleSyntax?: ModuleKind.CommonJS | ModuleKind.ESNext,
+): FutureSourceFile {
+    const path = toPath(fileName, /*basePath*/ undefined, program.getCanonicalFileName);
+    const impliedNodeFormat = getImpliedNodeFormatForFile(path, program.getPackageJsonInfoCache?.(), host, program.getCompilerOptions());
+    if (moduleSyntax === ModuleKind.CommonJS && impliedNodeFormat === ModuleKind.ESNext) {
+        Debug.fail("ES Modules cannot contain CommonJS syntax");
+    }
+    return {
+        fileName,
+        path,
+        commonJsModuleIndicator: moduleSyntax === ModuleKind.CommonJS,
+        externalModuleIndicator: moduleSyntax === ModuleKind.ESNext,
+        impliedNodeFormat,
+    };
+}
+
 /**
  * Get format code settings for a code writing context (e.g. when formatting text changes or completions code).
  *