fix: correct args shift for instance invoke-custom (#1816)

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

@@ -1014,9 +1014,10 @@ public class InsnGen {
 		// force set external arg names into call method args
 		int extArgsCount = customNode.getArgsCount();
 		int startArg = customNode.getHandleType() == MethodHandleType.INVOKE_STATIC ? 0 : 1; // skip 'this' arg
+		int callArg = 0;
 		for (int i = startArg; i < extArgsCount; i++) {
 			RegisterArg extArg = (RegisterArg) customNode.getArg(i);
-			RegisterArg callRegArg = callArgs.get(i);
+			RegisterArg callRegArg = callArgs.get(callArg++);
 			callRegArg.getSVar().setCodeVar(extArg.getSVar().getCodeVar());
 		}
 		code.add(" -> {");

jadx-core/src/test/java/jadx/tests/integration/java8/TestLambdaInstance2.java

@@ -0,0 +1,36 @@
+package jadx.tests.integration.java8;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.tests.api.IntegrationTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+public class TestLambdaInstance2 extends IntegrationTest {
+
+	public static class TestCls {
+		private String field;
+
+		public Runnable test(String str, int i) {
+			return () -> call(str, i);
+		}
+
+		public void call(String str, int i) {
+			field = str + '=' + i;
+		}
+
+		public void check() throws Exception {
+			field = "";
+			test("num", 7).run();
+			assertThat(field).isEqualTo("num=7");
+		}
+	}
+
+	@Test
+	public void test() {
+		assertThat(getClassNode(TestCls.class))
+				.code()
+				.doesNotContain("lambda$")
+				.containsOne("call(str, i)");
+	}
+}