fix: add cast for null in overloaded methods (#636) (PR #637)

jadx-core/src/main/java/jadx/core/codegen/InsnGen.java

@@ -762,7 +762,10 @@ public class InsnGen {
 			}
 		}
 		ArgType argType = arg.getType();
-		if (argType.equals(origType)) {
+		if (argType.equals(origType)
+				// null cast to object
+				&& (!arg.isLiteral() || ((LiteralArg) arg).getLiteral() != 0
+						|| (!argType.isArray() && !argType.isObject()))) {
 			return false;
 		}
 		if (origType.isGeneric()) {

jadx-core/src/test/java/jadx/tests/integration/others/TestCastOfNull.java

@@ -0,0 +1,35 @@
+package jadx.tests.integration.others;
+
+import static jadx.tests.api.utils.JadxMatchers.containsOne;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.NotYetImplemented;
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.IntegrationTest;
+
+public class TestCastOfNull extends IntegrationTest {
+
+	public static class TestCls {
+
+		public void test() {
+			m((long[]) null);
+			m((String) null);
+		}
+
+		public void m(long[] a) {
+		}
+		public void m(String s) {
+		}
+	}
+
+	@Test
+	public void test() {
+		ClassNode cls = getClassNode(TestCls.class);
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsOne("m((long[]) null);"));
+		assertThat(code, containsOne("m((String) null);"));
+	}
+}