diff --git a/spec/Observable-spec.ts b/spec/Observable-spec.ts
index 6ea8a39fdb..49280149f9 100644
--- a/spec/Observable-spec.ts
+++ b/spec/Observable-spec.ts
@@ -193,6 +193,80 @@ describe('Observable', () => {
       source.subscribe();
     });
 
+    it('should work when subscribe is called with no arguments and other subscription with no arguments completes', (done: MochaDone) => {
+      let nextCalled = false;
+      const source = new Observable((subscriber: Rx.Subscriber<string>) => {
+        const id = setTimeout(() => {
+          subscriber.next('foo');
+          subscriber.complete();
+          nextCalled = true;
+        }, 1);
+        return () => {
+          clearTimeout(id);
+        };
+      });
+
+      source.subscribe();
+
+      Observable.empty().subscribe();
+
+      setTimeout(() => {
+        let err;
+        let errHappened = false;
+        try {
+          expect(nextCalled).to.be.true;
+        } catch (e) {
+          err = e;
+          errHappened = true;
+        } finally {
+          if (!errHappened) {
+            done();
+          } else {
+            done(err);
+          }
+        }
+      }, 100);
+    });
+
+    it('should work when subscribe is called with observer and other subscription with same observer instance completes', (done: MochaDone) => {
+      let nextCalled = false;
+      const source = new Observable((subscriber: Rx.Subscriber<string>) => {
+        const id = setTimeout(() => {
+          subscriber.next('foo');
+          subscriber.complete();
+          nextCalled = true;
+        }, 1);
+        return () => {
+          clearTimeout(id);
+        };
+      });
+
+      let observer = {
+        next: function () { /*noop*/ }
+      };
+
+      source.subscribe(observer);
+
+      Observable.empty().subscribe(observer);
+
+      setTimeout(() => {
+        let err;
+        let errHappened = false;
+        try {
+          expect(nextCalled).to.be.true;
+        } catch (e) {
+          err = e;
+          errHappened = true;
+        } finally {
+          if (!errHappened) {
+            done();
+          } else {
+            done(err);
+          }
+        }
+      }, 100);
+    });
+
     it('should run unsubscription logic when an error is sent synchronously and subscribe is called with no arguments', () => {
       let unsubscribeCalled = false;
       const source = new Observable((subscriber: Rx.Subscriber<string>) => {
diff --git a/spec/Subscriber-spec.ts b/spec/Subscriber-spec.ts
index 5a2daf4431..bafe6cc6a6 100644
--- a/spec/Subscriber-spec.ts
+++ b/spec/Subscriber-spec.ts
@@ -83,4 +83,18 @@ describe('Subscriber', () => {
     expect(times).to.equal(2);
     expect(completeCalled).to.be.false;
   });
+
+  it('should not be closed when other subscriber with same observer instance completes', () => {
+    let observer = {
+      next: function () { /*noop*/ }
+    };
+
+    const sub1 = new Subscriber(observer);
+    const sub2 = new Subscriber(observer);
+
+    sub2.complete();
+
+    expect(sub1.closed).to.be.false;
+    expect(sub2.closed).to.be.true;
+  });
 });
diff --git a/spec/util/toSubscriber-spec.ts b/spec/util/toSubscriber-spec.ts
new file mode 100644
index 0000000000..d17581fbd4
--- /dev/null
+++ b/spec/util/toSubscriber-spec.ts
@@ -0,0 +1,28 @@
+import {expect} from 'chai';
+import {toSubscriber} from '../../dist/cjs/util/toSubscriber';
+
+describe('toSubscriber', () => {
+  it('should not be closed when other subscriber created with no arguments completes', () => {
+    let sub1 = toSubscriber();
+    let sub2 = toSubscriber();
+
+    sub2.complete();
+
+    expect(sub1.closed).to.be.false;
+    expect(sub2.closed).to.be.true;
+  });
+
+it('should not be closed when other subscriber created with same observer instance completes', () => {
+    let observer = {
+      next: function () { /*noop*/ }
+    };
+
+    let sub1 = toSubscriber(observer);
+    let sub2 = toSubscriber(observer);
+
+    sub2.complete();
+
+    expect(sub1.closed).to.be.false;
+    expect(sub2.closed).to.be.true;
+  });
+});
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