fix(range): Range should be same for every subscriber (#3707)

spec/observables/range-spec.ts

@@ -31,6 +31,21 @@ describe('range', () => {
     expectObservable(e1).toBe(expected, values);
   });
 
+  it('should work for two subscribers', () => {
+    const e1 = range(1, 5)
+      .concatMap((x, i) => Observable.of(x).delay(i === 0 ? 0 : 20, rxTestScheduler));
+    const expected = 'a-b-c-d-(e|)';
+    const values = {
+      a: 1,
+      b: 2,
+      c: 3,
+      d: 4,
+      e: 5
+    };
+    expectObservable(e1).toBe(expected, values);
+    expectObservable(e1).toBe(expected, values);
+  });
+
   it('should synchronously create a range of values by default', () => {
     const results = [] as any[];
     range(12, 4).subscribe(function (x) {

src/internal/observable/range.ts

@@ -36,6 +36,7 @@ export function range(start: number = 0,
                       scheduler?: SchedulerLike): Observable<number> {
   return new Observable<number>(subscriber => {
     let index = 0;
+    let current = start;
 
     if (scheduler) {
       return scheduler.schedule(dispatch, 0, {
@@ -47,7 +48,7 @@ export function range(start: number = 0,
           subscriber.complete();
           break;
         }
-        subscriber.next(start++);
+        subscriber.next(current++);
         if (subscriber.closed) {
           break;
         }