diff --git a/spec/operators/pluck-spec.ts b/spec/operators/pluck-spec.ts
index 2d710a92643..797b2f72ec1 100644
--- a/spec/operators/pluck-spec.ts
+++ b/spec/operators/pluck-spec.ts
@@ -82,6 +82,7 @@ describe('pluck operator', () => {
     const expected = '--r-x--y-z---w-|';
     const values: { [key: string]: number | undefined } = {r: 1, x: undefined, y: undefined, z: undefined, w: 5};
 
+    // @ts-ignore
     const r = a.pipe(pluck('a', 'b', 'c'));
     expectObservable(r).toBe(expected, values);
     expectSubscriptions(a.subscriptions).toBe(asubs);
@@ -89,6 +90,7 @@ describe('pluck operator', () => {
 
   it('should throw an error if not property is passed', () => {
     expect(() => {
+      // @ts-ignore
       of({prop: 1}, {prop: 2}).pipe(pluck());
     }).to.throw(Error, 'list of properties cannot be empty.');
   });
@@ -98,6 +100,7 @@ describe('pluck operator', () => {
     const asubs =    '(^!)';
     const expected = '#';
 
+    // @ts-ignore
     const r = a.pipe(pluck('whatever'));
     expectObservable(r).toBe(expected);
     expectSubscriptions(a.subscriptions).toBe(asubs);
@@ -120,6 +123,7 @@ describe('pluck operator', () => {
 
     const invoked = 0;
     const r = a.pipe(
+      // @ts-ignore
       pluck('whatever'),
       tap(null, null, () => {
         expect(invoked).to.equal(0);
@@ -169,7 +173,7 @@ describe('pluck operator', () => {
 
     const r = a.pipe(
       mergeMap((x: { prop: string }) => of(x)),
-      pluck<{ prop: string }, string>('prop'),
+      pluck('prop'),
       mergeMap((x: string) => of(x))
     );