angular
diff --git a/‎packages/compiler-cli/src/ngtsc/typecheck/src/oob.ts
+11 b/‎packages/compiler-cli/src/ngtsc/typecheck/src/oob.ts
+11
diff --git a/‎packages/compiler-cli/src/ngtsc/typecheck/test/diagnostics_spec.ts
+26 b/‎packages/compiler-cli/src/ngtsc/typecheck/test/diagnostics_spec.ts
+26
@@ -73,6 +73,12 @@ export interface OutOfBandDiagnosticRecorder {
 export class OutOfBandDiagnosticRecorderImpl implements OutOfBandDiagnosticRecorder {
   private _diagnostics: TemplateDiagnostic[] = [];
 
+  /**
+   * Tracks which `BindingPipe` nodes have already been recorded as invalid, so only one diagnostic
+   * is ever produced per node.
+   */
+  private recordedPipes = new Set<BindingPipe>();
+
   constructor(private resolver: TemplateSourceResolver) {}
 
   get diagnostics(): ReadonlyArray<TemplateDiagnostic> {
@@ -90,6 +96,10 @@ export class OutOfBandDiagnosticRecorderImpl implements OutOfBandDiagnosticRecor
   }
 
   missingPipe(templateId: TemplateId, ast: BindingPipe): void {
+    if (this.recordedPipes.has(ast)) {
+      return;
+    }
+
     const mapping = this.resolver.getSourceMapping(templateId);
     const errorMsg = `No pipe found with name '${ast.name}'.`;
 
@@ -101,6 +111,7 @@ export class OutOfBandDiagnosticRecorderImpl implements OutOfBandDiagnosticRecor
     this._diagnostics.push(makeTemplateDiagnostic(
         templateId, mapping, sourceSpan, ts.DiagnosticCategory.Error,
         ngErrorCode(ErrorCode.MISSING_PIPE), errorMsg));
+    this.recordedPipes.add(ast);
   }
 
   illegalAssignmentToTemplateVar(
 
@@ -195,6 +195,32 @@ runInEachFileSystem(() => {
       ]);
     });
 
+    it('does not repeat diagnostics for missing pipes in directive inputs', () => {
+      // The directive here is structured so that a type constructor is used, which resuts in each
+      // input binding being processed twice. This results in the 'uppercase' pipe being resolved
+      // twice, and since it doesn't exist this operation will fail. The test is here to verify that
+      // failing to resolve the pipe twice only produces a single diagnostic (no duplicates).
+      const messages = diagnose(
+          '<div *dir="let x of name | uppercase"></div>', `
+            class Dir<T> {
+              dirOf: T;
+            }
+
+            class TestComponent {
+              name: string;
+            }`,
+          [{
+            type: 'directive',
+            name: 'Dir',
+            selector: '[dir]',
+            inputs: {'dirOf': 'dirOf'},
+            isGeneric: true,
+          }]);
+
+      expect(messages.length).toBe(1);
+      expect(messages[0]).toContain(`No pipe found with name 'uppercase'.`);
+    });
+
     it('does not repeat diagnostics for errors within LHS of safe-navigation operator', () => {
       const messages = diagnose(`{{ personn?.name }} {{ personn?.getName() }}`, `
          class TestComponent {