fix: lambda decoding and code generation (#2139)

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

@@ -936,7 +936,7 @@ public class InsnGen {
 		makeInlinedLambdaMethod(code, customNode, callMth);
 	}
 
-	private void makeRefLambda(ICodeWriter code, InvokeCustomNode customNode) {
+	private void makeRefLambda(ICodeWriter code, InvokeCustomNode customNode) throws CodegenException {
 		InsnNode callInsn = customNode.getCallInsn();
 		if (callInsn instanceof ConstructorInsn) {
 			MethodInfo callMth = ((ConstructorInsn) callInsn).getCallMth();
@@ -950,7 +950,7 @@ public class InsnGen {
 			if (customNode.getHandleType() == MethodHandleType.INVOKE_STATIC) {
 				useClass(code, callMth.getDeclClass());
 			} else {
-				code.add("this");
+				addArg(code, customNode.getArg(0));
 			}
 			code.add("::").add(callMth.getAlias());
 		}

jadx-core/src/test/java/jadx/tests/integration/java8/TestLambdaInstance3.java

@@ -0,0 +1,54 @@
+package jadx.tests.integration.java8;
+
+import java.util.function.Supplier;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.tests.api.RaungTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+@SuppressWarnings("DataFlowIssue")
+public class TestLambdaInstance3 extends RaungTest {
+
+	public interface TestCls<R> extends Supplier<R> {
+		default TestCls<R> test() {
+			return (TestCls<R> & Memoized) Lazy.of(this)::get;
+		}
+	}
+
+	public static final class Lazy<T> implements Supplier<T> {
+		public static <T> Lazy<T> of(Supplier<? extends T> supplier) {
+			return null;
+		}
+
+		@Override
+		public T get() {
+			return null;
+		}
+	}
+
+	interface Memoized {
+	}
+
+	@Test
+	public void test() {
+		// some java versions failed to compile usage of interface with '$' in name
+		addClsRename("jadx.tests.integration.java8.TestLambdaInstance3$TestCls", "java8.TestCls");
+		assertThat(getClassNode(TestCls.class))
+				.code()
+				.doesNotContain("this::get")
+				.containsOne("return (TestCls) of::get;");
+		// TODO: type inference set type for 'of' to Memoized and cast incorrectly removed
+		// .containsOne("Memoized)");
+	}
+
+	@Test
+	public void testRaung() {
+		disableCompilation();
+		assertThat(getClassNodeFromRaung())
+				.code()
+				.doesNotContain("this::get")
+				.containsOne(" of::get");
+	}
+}

jadx-core/src/test/raung/java8/TestLambdaInstance3.raung

@@ -0,0 +1,45 @@
+.version 52  # Java 8
+.class public interface abstract java8/TestLambdaInstance3
+.implements java/io/Serializable
+.implements java/util/function/Supplier
+.signature <R:Ljava/lang/Object;>Ljava/lang/Object;Ljava/io/Serializable;Ljava/util/function/Supplier<TR;>;
+.source "Function0.java"
+.annotation runtime Ljava/lang/FunctionalInterface;
+.end annotation
+
+
+.method public memoized()Ljava8/TestLambdaInstance3;
+    .signature ()Ljava8/TestLambdaInstance3<TR;>;
+    .max stack 2
+    .max locals 1
+
+    .local 0 "this" Ljava8/TestLambdaInstance3; Ljava8/TestLambdaInstance3<TR;>;
+    .line 197
+    aload 0
+    invokeinterface java8/TestLambdaInstance3 isMemoized ()Z
+    ifeq :L1
+    .line 198
+    aload 0
+    areturn
+  :L1
+    .line 200
+    .stack same
+    aload 0
+    invokestatic test/Lazy of (Ljava/util/function/Supplier;)Ltest/Lazy;
+    dup
+    invokevirtual java/lang/Object getClass ()Ljava/lang/Class;
+    pop
+    invokedynamic apply (Ltest/Lazy;)Ljava8/TestLambdaInstance3;
+        .handle invoke-static java/lang/invoke/LambdaMetafactory altMetafactory (Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;
+        .arg 0 .methodtype ()Ljava/lang/Object;
+        .arg 1 .handle invoke-virtual test/Lazy get ()Ljava/lang/Object;
+        .arg 2 .methodtype ()Ljava/lang/Object;
+        .arg 3 7
+        .arg 4 1
+        .arg 5 Ltest/Memoized;
+        .arg 6 0
+    .end invokedynamic
+    checkcast test/Memoized
+    checkcast java8/TestLambdaInstance3
+    areturn
+.end method

jadx-plugins/jadx-java-input/src/main/java/jadx/plugins/input/java/data/ConstPoolReader.java

@@ -221,6 +221,8 @@ public class ConstPoolReader {
 				return new EncodedValue(EncodedType.ENCODED_LONG, data.readS8());
 			case DOUBLE:
 				return new EncodedValue(EncodedType.ENCODED_DOUBLE, Double.longBitsToDouble(data.readU8()));
+			case CLASS:
+				return new EncodedValue(EncodedType.ENCODED_TYPE, getClass(idx));
 			case METHOD_TYPE:
 				return new EncodedValue(EncodedType.ENCODED_METHOD_TYPE, DescriptorParser.parseToMethodProto(getUtf8(readU2())));
 			case METHOD_HANDLE: