diff --git a/src/index.ts b/src/index.ts
index 0ffeea3fc..0544b2d98 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -605,7 +605,7 @@ export function create(rawOptions: CreateOptions = {}): Service {
     const projectLocalResolveHelper =
       createProjectLocalResolveHelper(relativeToPath);
     const compiler = projectLocalResolveHelper(name || 'typescript', true);
-    const ts: typeof _ts = attemptRequireWithV8CompileCache(require, compiler);
+    const ts: TSCommon = attemptRequireWithV8CompileCache(require, compiler);
     return { compiler, ts, projectLocalResolveHelper };
   }
 
diff --git a/src/resolver-functions.ts b/src/resolver-functions.ts
index 3e8d7ffff..ecb5d98e2 100644
--- a/src/resolver-functions.ts
+++ b/src/resolver-functions.ts
@@ -7,7 +7,7 @@ import type { ProjectLocalResolveHelper } from './util';
  * In a factory because these are shared across both CompilerHost and LanguageService codepaths
  */
 export function createResolverFunctions(kwargs: {
-  ts: TSCommon & TSInternal;
+  ts: TSCommon;
   host: TSCommon.ModuleResolutionHost;
   cwd: string;
   getCanonicalFileName: (filename: string) => string;
@@ -140,7 +140,10 @@ export function createResolverFunctions(kwargs: {
         const nameIsString = typeof typeDirectiveName === 'string';
         const mode = nameIsString
           ? undefined
-          : ts.getModeForFileReference!(typeDirectiveName, containingFileMode);
+          : (ts as any as TSInternal).getModeForFileReference!(
+              typeDirectiveName,
+              containingFileMode
+            );
         const strName = nameIsString
           ? typeDirectiveName
           : typeDirectiveName.fileName.toLowerCase();