diff --git a/packages/compiler-cli/src/ngtsc/tsc_plugin.ts b/packages/compiler-cli/src/ngtsc/tsc_plugin.ts
index 7c87be7f22..54c6238521 100644
--- a/packages/compiler-cli/src/ngtsc/tsc_plugin.ts
+++ b/packages/compiler-cli/src/ngtsc/tsc_plugin.ts
@@ -79,7 +79,7 @@ export class NgTscPlugin implements TscPlugin {
   }
 
   wrapHost(
-      host: ts.CompilerHost&UnifiedModulesHost, inputFiles: readonly string[],
+      host: ts.CompilerHost&Partial<UnifiedModulesHost>, inputFiles: readonly string[],
       options: ts.CompilerOptions): PluginCompilerHost {
     // TODO(alxhub): Eventually the `wrapHost()` API will accept the old `ts.Program` (if one is
     // available). When it does, its `ts.SourceFile`s need to be re-tagged to enable proper