From 17b020f7c2d18df5b8f98e441147de3a9225d15e Mon Sep 17 00:00:00 2001
From: Anna Kozlova <anna.kozlova@jetbrains.com>
Date: Thu, 17 Apr 2014 13:32:27 +0200
Subject: [PATCH] new overload resolution: covariant comparison of return types

---
 .../resolve/graphInference/InferenceSession.java |  4 ++--
 .../JavaMethodsConflictResolver.java             |  4 ++--
 .../mostSpecific/MostSpecificByReturnType.java   | 16 ++++++++++++++++
 .../lambda/MostSpecificResolutionTest.java       |  4 ++++
 4 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/mostSpecific/MostSpecificByReturnType.java

diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
index e681d2d5a31b..9d9c373159f9 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
@@ -1070,7 +1070,7 @@ public class InferenceSession {
           session.addConstraint(new StrictSubtypingConstraint(tReturnType, sReturnType));
           return true;
         } else {
-          return sReturnType != null && tReturnType != null && TypeConversionUtil.isAssignable(sReturnType, tReturnType); 
+          return sReturnType != null && tReturnType != null && TypeConversionUtil.isAssignable(tReturnType, sReturnType); 
         }
       }
     }
@@ -1115,7 +1115,7 @@ public class InferenceSession {
         session.addConstraint(new StrictSubtypingConstraint(tReturnType, sReturnType));
         return true;
       } else {
-        return sReturnType != null && tReturnType != null && TypeConversionUtil.isAssignable(sReturnType, tReturnType);
+        return sReturnType != null && tReturnType != null && TypeConversionUtil.isAssignable(tReturnType, sReturnType);
       }
     }
 
diff --git a/java/java-psi-impl/src/com/intellij/psi/scope/conflictResolvers/JavaMethodsConflictResolver.java b/java/java-psi-impl/src/com/intellij/psi/scope/conflictResolvers/JavaMethodsConflictResolver.java
index 5f1e2f696961..93a444036bef 100644
--- a/java/java-psi-impl/src/com/intellij/psi/scope/conflictResolvers/JavaMethodsConflictResolver.java
+++ b/java/java-psi-impl/src/com/intellij/psi/scope/conflictResolvers/JavaMethodsConflictResolver.java
@@ -624,11 +624,11 @@ public class JavaMethodsConflictResolver implements PsiConflictResolver{
             }
   
             if (!applicable12ignoreFunctionalType && applicable21ignoreFunctionalType) {
-              return specifics == Specifics.SECOND ? Specifics.SECOND : Specifics.NEITHER;
+              return specifics == Specifics.FIRST ? Specifics.FIRST : Specifics.NEITHER;
             }
   
             if (!applicable21ignoreFunctionalType && applicable12ignoreFunctionalType) {
-              return specifics == Specifics.FIRST ? Specifics.FIRST : Specifics.NEITHER;
+              return specifics == Specifics.SECOND ? Specifics.SECOND : Specifics.NEITHER;
             }
   
             return specifics;
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/mostSpecific/MostSpecificByReturnType.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/mostSpecific/MostSpecificByReturnType.java
new file mode 100644
index 000000000000..5588c3e623a1
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/mostSpecific/MostSpecificByReturnType.java
@@ -0,0 +1,16 @@
+class Test {
+  interface I { Object invoke(); }
+  interface IStr { String foo(); }
+
+  private static void call(IStr str) {
+    System.out.println(str);
+  }
+
+  private static void <warning descr="Private method 'call(Test.I)' is never used">call</warning>(I i) {
+    System.out.println(i);
+  }
+
+  public static void main(String[] args)   {
+      call(()-> null);
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/MostSpecificResolutionTest.java b/java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/MostSpecificResolutionTest.java
index 004b52072a84..bea020bb9017 100644
--- a/java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/MostSpecificResolutionTest.java
+++ b/java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/MostSpecificResolutionTest.java
@@ -79,6 +79,10 @@ public class MostSpecificResolutionTest extends LightDaemonAnalyzerTestCase {
     doTest(false);
   }
 
+  public void testMostSpecificByReturnType() throws Exception {
+    doTest();
+  }
+
   private void doTest() {
     doTest(true);
   }