diff --git a/packages/typescript/lib/node/transform.ts b/packages/typescript/lib/node/transform.ts
index 4d3ddf8a..bbed9f1f 100644
--- a/packages/typescript/lib/node/transform.ts
+++ b/packages/typescript/lib/node/transform.ts
@@ -3,6 +3,7 @@ import type * as ts from 'typescript';
 import { getServiceScript, notEmpty } from './utils';
 
 const transformedDiagnostics = new WeakMap<ts.Diagnostic, ts.Diagnostic | undefined>();
+const transformedSourceFiles = new WeakMap<ts.SourceFile, ts.SourceFile>();
 
 export function transformCallHierarchyItem(language: Language, item: ts.CallHierarchyItem, filter: (data: CodeInformation) => boolean): ts.CallHierarchyItem {
 	const span = transformSpan(language, item.file, item.span, filter);
@@ -19,7 +20,6 @@ export function transformDiagnostic<T extends ts.Diagnostic>(language: Language,
 		transformedDiagnostics.set(diagnostic, undefined);
 
 		const { relatedInformation } = diagnostic;
-
 		if (relatedInformation) {
 			diagnostic.relatedInformation = relatedInformation
 				.map(d => transformDiagnostic(language, d))
@@ -39,6 +39,7 @@ export function transformDiagnostic<T extends ts.Diagnostic>(language: Language,
 						...diagnostic,
 						start: sourceSpan.start,
 						length: sourceSpan.length,
+						file: transformSourceFile(diagnostic.file, sourceScript.snapshot.getText(0, sourceScript.snapshot.getLength())),
 					});
 				}
 			}
@@ -53,6 +54,16 @@ export function transformDiagnostic<T extends ts.Diagnostic>(language: Language,
 	return transformedDiagnostics.get(diagnostic) as T | undefined;
 }
 
+export function transformSourceFile(sourceFile: ts.SourceFile, sourceText: string): ts.SourceFile {
+	if (!transformedSourceFiles.has(sourceFile)) {
+		transformedSourceFiles.set(sourceFile, {
+			...sourceFile,
+			text: sourceText,
+		});
+	}
+	return transformedSourceFiles.get(sourceFile)!;
+}
+
 export function transformFileTextChanges(language: Language, changes: ts.FileTextChanges, filter: (data: CodeInformation) => boolean): ts.FileTextChanges | undefined {
 	const [_, source] = getServiceScript(language, changes.fileName);
 	if (source) {