EA-41372 - AIOOBE: JavaMethodsConflictResolver.isMoreSpecific

(cherry picked from commit 6f6a46ec1e26294e4a478fc6dee158123ccba406)

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

@@ -456,8 +456,8 @@ public class JavaMethodsConflictResolver implements PsiConflictResolver{
     PsiType[] types1 = new PsiType[max];
     PsiType[] types2 = new PsiType[max];
     for (int i = 0; i < max; i++) {
-      PsiType type1 = params1[Math.min(i, params1.length - 1)].getType();
-      PsiType type2 = params2[Math.min(i, params2.length - 1)].getType();
+      PsiType type1 = params1.length > 0 ? params1[Math.min(i, params1.length - 1)].getType() : null;
+      PsiType type2 = params2.length > 0 ? params2[Math.min(i, params2.length - 1)].getType() : null;
       if (applicabilityLevel == MethodCandidateInfo.ApplicabilityLevel.VARARGS) {
         if (type1 instanceof PsiEllipsisType && type2 instanceof PsiEllipsisType && 
             (!JavaVersionService.getInstance().isAtLeast(class1, JavaSdkVersion.JDK_1_7) || ((PsiArrayType)type1).getComponentType().equalsToText(CommonClassNames.JAVA_LANG_OBJECT) || ((PsiArrayType)type2).getComponentType().equalsToText(CommonClassNames.JAVA_LANG_OBJECT))) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/methodRef/ResolveConflicts.java

@@ -0,0 +1,12 @@
+interface Func<TIn, TOut>{
+    TOut run(TIn in);
+}
+
+
+class Main {
+
+    public static void main(final String[] args) {
+        Func<Integer, String> func =  Integer::toString;
+        System.out.println(func.run(6));
+    }
+}

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

@@ -145,6 +145,10 @@ public class MethodRefHighlightingTest extends LightDaemonAnalyzerTestCase {
     doTest(true);
   }
 
+  public void testResolveConflicts() throws Exception {
+    doTest(true);
+  }
+
   private void doTest() throws Exception {
     doTest(false);
   }