diff --git a/src/internal/operators/elementAt.ts b/src/internal/operators/elementAt.ts
index 8c77f4d320..c50d5ff4b7 100644
--- a/src/internal/operators/elementAt.ts
+++ b/src/internal/operators/elementAt.ts
@@ -1,14 +1,10 @@
-<<<<<<< HEAD
-import { ArgumentOutOfRangeError } from '../util/ArgumentOutOfRangeError';
-=======
 import { createOutOfRangeError } from '../util/ArgumentOutOfRangeError';
->>>>>>> refactor(ArgumentOutOfRangeError): is now deprecated
 import { Observable } from '../Observable';
 import { MonoTypeOperatorFunction } from '../types';
 import { filter } from './filter';
 import { throwIfEmpty } from './throwIfEmpty';
 import { defaultIfEmpty } from './defaultIfEmpty';
-import { take } from './take';
+import { take } from './take';s
 
 /**
  * Emits the single value at the specified `index` in a sequence of emissions
diff --git a/src/internal/operators/last.ts b/src/internal/operators/last.ts
index 2dc2fdacfa..0e2698baaf 100644
--- a/src/internal/operators/last.ts
+++ b/src/internal/operators/last.ts
@@ -1,9 +1,5 @@
 import { Observable } from '../Observable';
-<<<<<<< HEAD
-import { EmptyError } from '../util/EmptyError';
-=======
 import { createEmptyError } from '../util/EmptyError';
->>>>>>> refactor(EmptyError): is deprecated
 import { OperatorFunction } from '../../internal/types';
 import { filter } from './filter';
 import { takeLast } from './takeLast';
diff --git a/src/internal/util/ArgumentOutOfRangeError.ts b/src/internal/util/ArgumentOutOfRangeError.ts
index 46fc424bd9..23f668e72e 100644
--- a/src/internal/util/ArgumentOutOfRangeError.ts
+++ b/src/internal/util/ArgumentOutOfRangeError.ts
@@ -33,5 +33,5 @@ ArgumentOutOfRangeErrorImpl.prototype = Object.create(Error.prototype);
 export const ArgumentOutOfRangeError: ArgumentOutOfRangeErrorCtor = ArgumentOutOfRangeErrorImpl as any;
 
 export function createOutOfRangeError() {
-  return createRxError('out of range', RxErrorCode.OutOfRangeError, ArgumentOutOfRangeError);
+  return createRxError('out of range', RxErrorCode.OutOfRange, ArgumentOutOfRangeError);
 }
diff --git a/src/internal/util/ObjectUnsubscribedError.ts b/src/internal/util/ObjectUnsubscribedError.ts
index 6ea14a6543..4fb1b03d87 100644
--- a/src/internal/util/ObjectUnsubscribedError.ts
+++ b/src/internal/util/ObjectUnsubscribedError.ts
@@ -32,5 +32,5 @@ ObjectUnsubscribedErrorImpl.prototype = Object.create(Error.prototype);
 export const ObjectUnsubscribedError: ObjectUnsubscribedErrorCtor = ObjectUnsubscribedErrorImpl as any;
 
 export function createObjectUnsubscribedError() {
-  return createRxError('object unsubscribed', RxErrorCode.ObjectUnsubscribedError, ObjectUnsubscribedError);
+  return createRxError('object unsubscribed', RxErrorCode.ObjectUnsubscribed, ObjectUnsubscribedError);
 }
diff --git a/src/internal/util/TimeoutError.ts b/src/internal/util/TimeoutError.ts
index e830bdfa68..b9e403ef0f 100644
--- a/src/internal/util/TimeoutError.ts
+++ b/src/internal/util/TimeoutError.ts
@@ -30,5 +30,5 @@ TimeoutErrorImpl.prototype = Object.create(Error.prototype);
 export const TimeoutError: TimeoutErrorCtor = TimeoutErrorImpl as any;
 
 export function createTimeoutError() {
-  return createRxError('observable timed out', RxErrorCode.TimeoutError, TimeoutError);
+  return createRxError('observable timed out', RxErrorCode.Timeout, TimeoutError);
 }
diff --git a/src/internal/util/UnsubscriptionError.ts b/src/internal/util/UnsubscriptionError.ts
index 7f808116b0..96e4353a9d 100644
--- a/src/internal/util/UnsubscriptionError.ts
+++ b/src/internal/util/UnsubscriptionError.ts
@@ -34,6 +34,6 @@ export const UnsubscriptionError: UnsubscriptionErrorCtor = UnsubscriptionErrorI
 
 export function createTeardownError(errors: any[]) {
   const error: any = new UnsubscriptionError(errors);
-  error.__rxjsErrorCode = RxErrorCode.TeardownError;
+  error.__rxjsErrorCode = RxErrorCode.Teardown;
   return error;
 }
diff --git a/src/internal/util/errors.ts b/src/internal/util/errors.ts
index 1ec36a63a8..96d8f7a1b0 100644
--- a/src/internal/util/errors.ts
+++ b/src/internal/util/errors.ts
@@ -1,12 +1,18 @@
 
+/**
+ * Used to identify different types of RxJS errors.
+ */
 export const enum RxErrorCode {
   Empty = 0,
-  OutOfRangeError = 1,
-  ObjectUnsubscribedError = 2,
-  TimeoutError = 3,
-  TeardownError = 4,
+  OutOfRange = 1,
+  ObjectUnsubscribed = 2,
+  Timeout = 3,
+  Teardown = 4,
 }
 
+/**
+ * Creates an error and decorates it with the appropriate error code for identification later.
+ */
 export function createRxError(message: string, code: RxErrorCode, ErrorType: any = Error) {
   const result = new ErrorType('RxJS: ' + message);
   (result as any).__rxjsErrorCode = code;
@@ -33,7 +39,7 @@ export function isEmptyError(err: any) {
  * was out of range.
  */
 export function isOutOfRangeError(err: any) {
-  return err.__rxjsErrorCode === RxErrorCode.OutOfRangeError;
+  return err.__rxjsErrorCode === RxErrorCode.OutOfRange;
 }
 
 /**
@@ -41,7 +47,7 @@ export function isOutOfRangeError(err: any) {
  * was unsubscribed, and an action was taken on it.
  */
 export function isObjectUnsubscribedError(err: any) {
-  return err.__rxjsErrorCode === RxErrorCode.ObjectUnsubscribedError;
+  return err.__rxjsErrorCode === RxErrorCode.ObjectUnsubscribed;
 }
 
 /**
@@ -49,7 +55,7 @@ export function isObjectUnsubscribedError(err: any) {
  * times out, for example with the {@link timeout} operator.
  */
 export function isTimeoutError(err: any) {
-  return err.__rxjsErrorCode === RxErrorCode.TimeoutError;
+  return err.__rxjsErrorCode === RxErrorCode.Timeout;
 }
 
 /**
@@ -58,5 +64,5 @@ export function isTimeoutError(err: any) {
  * chain.
  */
 export function isTeardownError(err: any) {
-  return err.__rxjsErrorCode === RxErrorCode.TeardownError;
+  return err.__rxjsErrorCode === RxErrorCode.Teardown;
 }