Correctly compare Stream IValues (#47303)

Summary:
Stream IValue equality comparison was comparing wrong object.

Pull Request resolved: #47303

Test Plan:
Added a new C++ test

Fixes #{issue number}

Reviewed By: bdhirsh

Differential Revision: D24752434

Pulled By: gmagogsfm

fbshipit-source-id: 78bc7a812740485ebbc7cf0c06c2e671a7ccd26f

aten/src/ATen/core/ivalue.cpp

@@ -273,7 +273,7 @@ IValue IValue::equals(const IValue& rhs) const {
     case Tag::Tuple:
       return rhs.isTuple() && *lhs.toTuple() == *rhs.toTuple();
     case Tag::Stream:
-      return rhs.isStream() && lhs.toStream() == lhs.toStream();
+      return rhs.isStream() && lhs.toStream() == rhs.toStream();
     case Tag::Device:
       return rhs.isDevice() && lhs.toDevice() == rhs.toDevice();
     case Tag::GenericList:

aten/src/ATen/test/ivalue_test.cpp

@@ -259,6 +259,18 @@ TEST(IValueTest, ListNestedEquality) {
   EXPECT_NE(c2, c3);
 }
 
+TEST(IValueTest, StreamEquality) {
+  at::Device device1 =  at::Device(kCUDA, 0);
+  at::Device device2 = at::Device(kCUDA, 1);
+  c10::Stream stream1 = c10::Stream(c10::Stream::Default::DEFAULT, device1);
+  c10::Stream stream2 = c10::Stream(c10::Stream::Default::DEFAULT, device2);
+  IValue lhs(stream1);
+  IValue rhs_different(stream2);
+  IValue rhs_same(stream1);
+  EXPECT_FALSE(lhs.equals(rhs_different).toBool());
+  EXPECT_TRUE(lhs.equals(rhs_same).toBool());
+}
+
 TEST(IValueTest, EnumEquality) {
   auto cu = std::make_shared<CompilationUnit>();
   IValue int_ivalue_1(1);