diff --git a/packages/compiler-cli/src/ngtsc/typecheck/api/checker.ts b/packages/compiler-cli/src/ngtsc/typecheck/api/checker.ts
index c8b60f410d..2354b85cf8 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/api/checker.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/api/checker.ts
@@ -168,9 +168,9 @@ export interface TemplateTypeChecker {
   /**
    * Constructs a `ts.Diagnostic` for a given `ParseSourceSpan` within a template.
    */
-  makeTemplateDiagnostic(
+  makeTemplateDiagnostic<T extends ErrorCode>(
       clazz: ts.ClassDeclaration, sourceSpan: ParseSourceSpan, category: ts.DiagnosticCategory,
-      errorCode: ErrorCode, message: string, relatedInformation?: {
+      errorCode: T, message: string, relatedInformation?: {
         text: string,
         start: number,
         end: number,
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/src/checker.ts b/packages/compiler-cli/src/ngtsc/typecheck/src/checker.ts
index 504314d6bf..2596222aa0 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/src/checker.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/src/checker.ts
@@ -309,9 +309,9 @@ export class TemplateTypeCheckerImpl implements TemplateTypeChecker {
     this.isComplete = false;
   }
 
-  makeTemplateDiagnostic(
+  makeTemplateDiagnostic<T extends ErrorCode>(
       clazz: ts.ClassDeclaration, sourceSpan: ParseSourceSpan, category: ts.DiagnosticCategory,
-      errorCode: ErrorCode, message: string, relatedInformation?: {
+      errorCode: T, message: string, relatedInformation?: {
         text: string,
         start: number,
         end: number,