diff --git a/RxCocoa/RxCocoa/Common/RxCocoa.swift b/RxCocoa/RxCocoa/Common/RxCocoa.swift
index 36189452..71a23203 100644
--- a/RxCocoa/RxCocoa/Common/RxCocoa.swift
+++ b/RxCocoa/RxCocoa/Common/RxCocoa.swift
@@ -28,11 +28,18 @@ func rxError(errorCode: RxCocoaError, message: String) -> NSError {
     return NSError(domain: RxCocoaErrorDomain, code: errorCode.rawValue, userInfo: [NSLocalizedDescriptionKey: message])
 }
 
+#if !RELEASE
+public func _rxError(errorCode: RxCocoaError, message: String, userInfo: NSDictionary) -> NSError {
+    return rxError(errorCode, message, userInfo)
+}
+#endif
+
 func rxError(errorCode: RxCocoaError, message: String, userInfo: NSDictionary) -> NSError {
-    let mutableDictionary = NSMutableDictionary(dictionary: userInfo as! [NSObject : AnyObject])
-    mutableDictionary[NSLocalizedDescriptionKey] = message
-    // swift compiler :(
-    let resultInfo: [NSObject: AnyObject] = (userInfo as NSObject) as! [NSObject: AnyObject]
+    var resultInfo: [NSObject: AnyObject] = [:]
+    resultInfo[NSLocalizedDescriptionKey] = message
+    for k in userInfo.allKeys {
+        resultInfo[k as! NSObject] = userInfo[k as! NSCopying]
+    }
     return NSError(domain: RxCocoaErrorDomain, code: Int(errorCode.rawValue), userInfo: resultInfo)
 }
 
diff --git a/RxTests/RxCocoaTests/RxCocoaTests.swift b/RxTests/RxCocoaTests/RxCocoaTests.swift
new file mode 100644
index 00000000..6cdb39dd
--- /dev/null
+++ b/RxTests/RxCocoaTests/RxCocoaTests.swift
@@ -0,0 +1,23 @@
+//
+//  RxCocoaTests.swift
+//  RxTests
+//
+//  Created by Krunoslav Zaher on 7/6/15.
+//
+//
+
+import Foundation
+import XCTest
+import RxSwift
+import RxCocoa
+
+class RxCocoaTest : RxTest {
+#if !RELEASE
+    func testRxError() {
+        let result = _rxError(RxCocoaError.NetworkError, "my bad", ["a": 1])
+        
+        let dUserInfo = NSDictionary(dictionary: result.userInfo!)
+        XCTAssertTrue(dUserInfo.isEqualToDictionary([NSLocalizedDescriptionKey: "my bad", "a" : 1]))
+    }
+#endif
+}
\ No newline at end of file
diff --git a/RxTests/RxTests.xcodeproj/project.pbxproj b/RxTests/RxTests.xcodeproj/project.pbxproj
index 00c168dc..c8320f59 100644
--- a/RxTests/RxTests.xcodeproj/project.pbxproj
+++ b/RxTests/RxTests.xcodeproj/project.pbxproj
@@ -81,6 +81,7 @@
 		C897EC4B1B1123DA009C2CB0 /* Observable+MultipleTest+Zip.swift in Sources */ = {isa = PBXBuildFile; fileRef = C897EC491B1123DA009C2CB0 /* Observable+MultipleTest+Zip.swift */; };
 		C8AF26EF1B499E5C00131C03 /* DelegateProxyTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = C8AF26EE1B499E5C00131C03 /* DelegateProxyTest.swift */; };
 		C8AF26F01B499E5C00131C03 /* DelegateProxyTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = C8AF26EE1B499E5C00131C03 /* DelegateProxyTest.swift */; };
+		C8B5BEA11B4A6A82000D732C /* RxCocoaTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C8B5BEA01B4A6A82000D732C /* RxCocoaTests.swift */; };
 		C8B787FA1AF55CDE00206D02 /* Observable+ConcurrencyTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = C8B787F91AF55CDE00206D02 /* Observable+ConcurrencyTest.swift */; };
 		C8E381231B2063CC008CDC33 /* Observable+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = C8E381221B2063CC008CDC33 /* Observable+Extensions.swift */; };
 		C8E381281B207D03008CDC33 /* PrimitiveHotObservable.swift in Sources */ = {isa = PBXBuildFile; fileRef = C8E381271B207D03008CDC33 /* PrimitiveHotObservable.swift */; };
@@ -134,6 +135,7 @@
 		C897EC461B112070009C2CB0 /* Observable+MultipleTest+Zip.tt */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = "Observable+MultipleTest+Zip.tt"; sourceTree = "<group>"; };
 		C897EC491B1123DA009C2CB0 /* Observable+MultipleTest+Zip.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "Observable+MultipleTest+Zip.swift"; sourceTree = "<group>"; };
 		C8AF26EE1B499E5C00131C03 /* DelegateProxyTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DelegateProxyTest.swift; sourceTree = "<group>"; };
+		C8B5BEA01B4A6A82000D732C /* RxCocoaTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RxCocoaTests.swift; sourceTree = "<group>"; };
 		C8B787F91AF55CDE00206D02 /* Observable+ConcurrencyTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "Observable+ConcurrencyTest.swift"; sourceTree = "<group>"; };
 		C8E381221B2063CC008CDC33 /* Observable+Extensions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "Observable+Extensions.swift"; sourceTree = "<group>"; };
 		C8E381271B207D03008CDC33 /* PrimitiveHotObservable.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PrimitiveHotObservable.swift; sourceTree = "<group>"; };
@@ -208,6 +210,7 @@
 				C814CEA61AF642D600E98087 /* UI+RxTests.swift */,
 				5E5D10BA1B48355200432B25 /* UIControl+RxTests.swift */,
 				C8633AE41B0A9FF300375D60 /* KVOObservableTests.swift */,
+				C8B5BEA01B4A6A82000D732C /* RxCocoaTests.swift */,
 			);
 			path = RxCocoaTests;
 			sourceTree = SOURCE_ROOT;
@@ -419,6 +422,7 @@
 				C811085D1AF50E2A001C13E4 /* AssumptionsTest.swift in Sources */,
 				C81108501AF50E2A001C13E4 /* ConnectableObservable.swift in Sources */,
 				C814CEA31AF5622600E98087 /* VariableTest.swift in Sources */,
+				C8B5BEA11B4A6A82000D732C /* RxCocoaTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};