SAM: skip allowed static methods as they are not supposed to be overridden (IDEA-101403)

java/java-psi-api/src/com/intellij/psi/LambdaUtil.java

@@ -264,6 +264,7 @@ public class LambdaUtil {
       for (HierarchicalMethodSignature signature : visibleSignatures) {
         final PsiMethod psiMethod = signature.getMethod();
         if (!psiMethod.hasModifierProperty(PsiModifier.ABSTRACT)) continue;
+        if (psiMethod.hasModifierProperty(PsiModifier.STATIC)) continue;
         if (!overridesPublicObjectMethod(psiMethod)) {
           methods.add(signature);
         }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/interfaceMethods/StaticMethodsInFunctionalInterface.java

@@ -0,0 +1,11 @@
+public interface Nat {
+    interface Nil extends Nat {}
+}
+
+interface Inc extends Nat {
+    Nat dec();
+
+    static Inc make(Nat dec) {
+        return () -> dec;
+    }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/Interface8MethodsHighlightingTest.java

@@ -28,6 +28,7 @@ public class Interface8MethodsHighlightingTest extends LightDaemonAnalyzerTestCa
   public void testInheritUnrelatedDefaults() { doTest(true, false); }
   public void testExtensionMethods() { doTest(false, false); }
   public void testInheritDefaultMethodInInterface() { doTest(false, false); }
+  public void testStaticMethodsInFunctionalInterface() { doTest(false, false); }
 
   public void testExtensionMethodSyntax() {
     enableInspectionTools(DeprecatedDefenderSyntaxInspection.class);