java 8 interfaces: default/static preferences (IDEA-136171)

java/java-psi-impl/src/com/intellij/psi/impl/PsiSuperMethodImplUtil.java

@@ -307,9 +307,11 @@ public class PsiSuperMethodImplUtil {
             if (superClass != null) {
               if (superClass.isInterface() ||
                   CommonClassNames.JAVA_LANG_OBJECT.equals(superClass.getQualifiedName())) {
-                if (superMethod.hasModifierProperty(PsiModifier.STATIC)) {
+                if (superMethod.hasModifierProperty(PsiModifier.STATIC) ||
+                    superMethod.hasModifierProperty(PsiModifier.DEFAULT) && hierarchicalMethodSignature.getMethod().hasModifierProperty(PsiModifier.STATIC)) {
                   return false;
                 }
+
                 if (superMethod.hasModifierProperty(PsiModifier.DEFAULT) ||
                     hierarchicalMethodSignature.getMethod().hasModifierProperty(PsiModifier.DEFAULT)) {
                   return !InheritanceUtil.isInheritorOrSelf(superClass, containingClass, true);

java/java-psi-impl/src/com/intellij/psi/scope/conflictResolvers/JavaMethodsConflictResolver.java

@@ -534,6 +534,13 @@ public class JavaMethodsConflictResolver implements PsiConflictResolver{
           return Specifics.FIRST;
         }
 
+        if (method1.hasModifierProperty(PsiModifier.DEFAULT) && method2.hasModifierProperty(PsiModifier.STATIC)) {
+          return Specifics.FIRST;
+        }
+
+        if (method2.hasModifierProperty(PsiModifier.DEFAULT) && method1.hasModifierProperty(PsiModifier.STATIC)) {
+          return Specifics.SECOND;
+        }
       }
 
       if (languageLevel.isAtLeast(LanguageLevel.JDK_1_8) && myArgumentsList instanceof PsiExpressionList && (typeParameters1.length == 0 || typeParameters2.length == 0)) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/overloadResolution/PreferDefaultMethodsOverStatic.java

@@ -0,0 +1,18 @@
+class Test {
+  interface I {
+    default void f() {}
+  }
+
+  interface J {
+    static void f() {}
+  }
+
+  static class IJ implements I, J {}
+  static class JI implements J, I {}
+
+  public static void main(String[] args) {
+    new IJ(). f();
+    new JI(). f();
+    J.f();
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/OverloadResolutionTest.java

@@ -79,6 +79,10 @@ public class OverloadResolutionTest extends LightDaemonAnalyzerTestCase {
     doTest();
   }
 
+  public void testPreferDefaultMethodsOverStatic() throws Exception {
+    doTest();
+  }
+
   private void doTest() {
     doTest(true);
   }