moveToNewFile: fix quotes for module specifiers (#60203)

Author: iisaduan

src/services/codefixes/importFixes.ts

@@ -494,8 +494,8 @@ function createImportAdderWorker(sourceFile: SourceFile | FutureSourceFile, prog
 
     function writeFixes(changeTracker: textChanges.ChangeTracker, oldFileQuotePreference?: QuotePreference) {
         let quotePreference: QuotePreference;
-        if (isFullSourceFile(sourceFile) && sourceFile.imports.length === 0 && oldFileQuotePreference !== undefined) {
-            // If the target file has no imports, we must use the same quote preference as the file we are importing from.
+        if (sourceFile.imports !== undefined && sourceFile.imports.length === 0 && oldFileQuotePreference !== undefined) {
+            // If the target file (including future files) has no imports, we must use the same quote preference as the file we are importing from.
             quotePreference = oldFileQuotePreference;
         }
         else {

tests/cases/fourslash/moveToNewFile_inferQuoteStyle.ts renamed to tests/cases/fourslash/moveToNewFile_inferQuoteStyle1.ts

@@ -0,0 +1,24 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////export const x = 0;
+////x;
+
+// @Filename: /b.ts
+////import { x } from './a'
+////
+////[|x|];
+
+
+verify.moveToNewFile({
+    newFileContents: {
+        "/newFile.ts": // module specifier should have the same quotes as import in the original file 
+`import { x } from './a';
+
+x;
+`,
+        "/b.ts":
+`
+`
+    },
+});

tests/cases/fourslash/moveToNewFile_inferQuoteStyle2.ts

@@ -0,0 +1,22 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /other.ts
+//// export function foo() { return 1 };
+
+// @Filename: /a.ts
+////import { foo as oFoo } from './other';
+////[|export const x = oFoo();|]
+////export const a = 0;
+
+verify.moveToNewFile({
+    newFileContents: {
+"/a.ts":
+`export const a = 0;`,
+
+"/x.ts":
+`import { foo as oFoo } from './other';
+
+export const x = oFoo();
+`
+    },
+});