From 8365cee0b52d4b70385a128b9cc247773217a306 Mon Sep 17 00:00:00 2001
From: Evgeny Gerashchenko <Evgeny.Gerashchenko@jetbrains.com>
Date: Thu, 1 Nov 2012 20:21:45 +0400
Subject: [PATCH] Fixed bug in TypeUtils.intersect().

For "Foo", "Foo?" it returned "{Foo}" instead of "Foo"
---
 .../src/org/jetbrains/jet/lang/types/TypeUtils.java         | 6 ++++++
 .../tests/org/jetbrains/jet/types/JetTypeCheckerTest.java   | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/types/TypeUtils.java b/compiler/frontend/src/org/jetbrains/jet/lang/types/TypeUtils.java
index 32f50275153..ed37f91f74b 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/types/TypeUtils.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/types/TypeUtils.java
@@ -149,6 +149,12 @@ public class TypeUtils {
                 }
             }
 
+            // Don't add type if it is already present, to avoid trivial type intersections in result
+            for (JetType other : resultingTypes) {
+                if (typeChecker.equalTypes(other, type)) {
+                    continue outer;
+                }
+            }
             resultingTypes.add(type);
         }
         
diff --git a/compiler/tests/org/jetbrains/jet/types/JetTypeCheckerTest.java b/compiler/tests/org/jetbrains/jet/types/JetTypeCheckerTest.java
index beaba96fef2..07e8ce5f4bc 100644
--- a/compiler/tests/org/jetbrains/jet/types/JetTypeCheckerTest.java
+++ b/compiler/tests/org/jetbrains/jet/types/JetTypeCheckerTest.java
@@ -199,6 +199,10 @@ public class JetTypeCheckerTest extends JetLiteFixture {
     }
 
     public void testIntersect() throws Exception {
+        assertIntersection("Number", "Number?", "Hashable");
+        assertIntersection("Number", "Hashable", "Number?");
+        assertIntersection("Hashable", "Hashable?", "Hashable");
+
         assertIntersection("Int?", "Int?", "Int?");
         assertIntersection("Int", "Int?", "Int");
         assertIntersection("Int", "Int", "Int?");