fix: allow constructor invoke as lambda

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

@@ -792,14 +792,23 @@ public class InsnGen {
 	}
 
 	private void makeRefLambda(CodeWriter code, InvokeCustomNode customNode) {
-		InvokeNode invokeInsn = (InvokeNode) customNode.getCallInsn();
-		MethodInfo callMth = invokeInsn.getCallMth();
-		if (customNode.getHandleType() == MethodHandleType.INVOKE_STATIC) {
+		InsnNode callInsn = customNode.getCallInsn();
+		if (callInsn instanceof ConstructorInsn) {
+			MethodInfo callMth = ((ConstructorInsn) callInsn).getCallMth();
 			useClass(code, callMth.getDeclClass());
-		} else {
-			code.add("this");
+			code.add("::new");
+			return;
+		}
+		if (callInsn instanceof InvokeNode) {
+			InvokeNode invokeInsn = (InvokeNode) callInsn;
+			MethodInfo callMth = invokeInsn.getCallMth();
+			if (customNode.getHandleType() == MethodHandleType.INVOKE_STATIC) {
+				useClass(code, callMth.getDeclClass());
+			} else {
+				code.add("this");
+			}
+			code.add("::").add(callMth.getAlias());
 		}
-		code.add("::").add(callMth.getAlias());
 	}
 
 	private void makeSimpleLambda(CodeWriter code, InvokeCustomNode customNode) {

jadx-core/src/main/java/jadx/core/dex/instructions/InvokeCustomBuilder.java

@@ -17,6 +17,7 @@ import jadx.core.dex.info.MethodInfo;
 import jadx.core.dex.instructions.args.ArgType;
 import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.instructions.args.NamedArg;
+import jadx.core.dex.instructions.mods.ConstructorInsn;
 import jadx.core.dex.nodes.InsnNode;
 import jadx.core.dex.nodes.MethodNode;
 import jadx.core.dex.nodes.RootNode;
@@ -61,21 +62,56 @@ public class InvokeCustomBuilder {
 		invokeCustomNode.setImplMthInfo(implMthInfo);
 
 		MethodInfo callMthInfo = MethodInfo.fromRef(root, callMthHandle.getMethodRef());
+		InvokeNode invokeNode = buildInvokeNode(methodHandleType, invokeCustomNode, callMthInfo);
 
+		if (methodHandleType == MethodHandleType.INVOKE_CONSTRUCTOR) {
+			ConstructorInsn ctrInsn = new ConstructorInsn(mth, invokeNode);
+			invokeCustomNode.setCallInsn(ctrInsn);
+		} else {
+			invokeCustomNode.setCallInsn(invokeNode);
+		}
+
+		MethodNode callMth = root.resolveMethod(callMthInfo);
+		if (callMth != null) {
+			invokeCustomNode.getCallInsn().addAttr(callMth);
+			if (callMth.getAccessFlags().isSynthetic()
+					&& callMth.getUseIn().size() <= 1
+					&& callMth.getParentClass().equals(mth.getParentClass())) {
+				// inline only synthetic methods from same class
+				callMth.add(AFlag.DONT_GENERATE);
+				invokeCustomNode.setInlineInsn(true);
+			}
+		}
+		if (!invokeCustomNode.isInlineInsn()) {
+			IMethodProto effectiveMthProto = (IMethodProto) values.get(5).getValue();
+			List<ArgType> args = Utils.collectionMap(effectiveMthProto.getArgTypes(), ArgType::parse);
+			boolean sameArgs = args.equals(callMthInfo.getArgumentsTypes());
+			invokeCustomNode.setUseRef(sameArgs);
+		}
+
+		// prevent args inlining into not generated invoke custom node
+		for (InsnArg arg : invokeCustomNode.getArguments()) {
+			arg.add(AFlag.DONT_INLINE);
+		}
+		return invokeCustomNode;
+	}
+
+	@NotNull
+	private static InvokeNode buildInvokeNode(MethodHandleType methodHandleType, InvokeCustomNode invokeCustomNode,
+			MethodInfo callMthInfo) {
 		InvokeType invokeType = convertInvokeType(methodHandleType);
 		int callArgsCount = callMthInfo.getArgsCount();
 		boolean instanceCall = invokeType != InvokeType.STATIC;
 		if (instanceCall) {
 			callArgsCount++;
 		}
-		InvokeNode callInsn = new InvokeNode(callMthInfo, invokeType, callArgsCount);
-		invokeCustomNode.setCallInsn(callInsn);
+		InvokeNode invokeNode = new InvokeNode(callMthInfo, invokeType, callArgsCount);
 
 		// copy insn args
 		int argsCount = invokeCustomNode.getArgsCount();
 		for (int i = 0; i < argsCount; i++) {
 			InsnArg arg = invokeCustomNode.getArg(i);
-			callInsn.addArg(arg.duplicate());
+			invokeNode.addArg(arg.duplicate());
 		}
 		if (callArgsCount > argsCount) {
 			// fill remaining args with NamedArg
@@ -92,33 +128,10 @@ public class InvokeCustomBuilder {
 				} else {
 					argType = callArgTypes.get(callArgNum++);
 				}
-				callInsn.addArg(new NamedArg("v" + i, argType));
-			}
-		}
-
-		MethodNode callMth = root.resolveMethod(callMthInfo);
-		if (callMth != null) {
-			callInsn.addAttr(callMth);
-			if (callMth.getAccessFlags().isSynthetic()
-					&& callMth.getUseIn().size() <= 1
-					&& callMth.getParentClass().equals(mth.getParentClass())) {
-				// inline only synthetic methods from same class
-				callMth.add(AFlag.DONT_GENERATE);
-				invokeCustomNode.setInlineInsn(true);
+				invokeNode.addArg(new NamedArg("v" + i, argType));
 			}
 		}
-		if (!invokeCustomNode.isInlineInsn()) {
-			IMethodProto effectiveMthProto = (IMethodProto) values.get(5).getValue();
-			List<ArgType> args = Utils.collectionMap(effectiveMthProto.getArgTypes(), ArgType::parse);
-			boolean sameArgs = args.equals(callMthInfo.getArgumentsTypes());
-			invokeCustomNode.setUseRef(sameArgs);
-		}
-
-		// prevent args inlining into not generated invoke custom node
-		for (InsnArg arg : invokeCustomNode.getArguments()) {
-			arg.add(AFlag.DONT_INLINE);
-		}
-		return invokeCustomNode;
+		return invokeNode;
 	}
 
 	/**
@@ -149,6 +162,7 @@ public class InvokeCustomBuilder {
 			case INVOKE_INSTANCE:
 				return InvokeType.VIRTUAL;
 			case INVOKE_DIRECT:
+			case INVOKE_CONSTRUCTOR:
 				return InvokeType.DIRECT;
 			case INVOKE_INTERFACE:
 				return InvokeType.INTERFACE;

jadx-core/src/main/java/jadx/core/dex/instructions/mods/ConstructorInsn.java

@@ -7,6 +7,7 @@ import jadx.core.dex.info.MethodInfo;
 import jadx.core.dex.instructions.BaseInvokeNode;
 import jadx.core.dex.instructions.InsnType;
 import jadx.core.dex.instructions.InvokeNode;
+import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.instructions.args.RegisterArg;
 import jadx.core.dex.nodes.InsnNode;
 import jadx.core.dex.nodes.MethodNode;
@@ -26,31 +27,25 @@ public final class ConstructorInsn extends BaseInvokeNode {
 	public ConstructorInsn(MethodNode mth, InvokeNode invoke) {
 		super(InsnType.CONSTRUCTOR, invoke.getArgsCount() - 1);
 		this.callMth = invoke.getCallMth();
-		ClassInfo classType = callMth.getDeclClass();
-		RegisterArg instanceArg = (RegisterArg) invoke.getArg(0);
+		this.callType = getCallType(mth, callMth.getDeclClass(), invoke.getArg(0));
+		int argsCount = invoke.getArgsCount();
+		for (int i = 1; i < argsCount; i++) {
+			addArg(invoke.getArg(i));
+		}
+	}
 
+	private CallType getCallType(MethodNode mth, ClassInfo classType, InsnArg instanceArg) {
 		if (instanceArg.isThis()) {
 			if (classType.equals(mth.getParentClass().getClassInfo())) {
 				if (callMth.getShortId().equals(mth.getMethodInfo().getShortId())) {
 					// self constructor
-					callType = CallType.SELF;
-				} else {
-					callType = CallType.THIS;
+					return CallType.SELF;
 				}
-			} else {
-				callType = CallType.SUPER;
+				return CallType.THIS;
 			}
-		} else {
-			callType = CallType.CONSTRUCTOR;
-			setResult(instanceArg);
-			// convert from 'use' to 'assign'
-			instanceArg.getSVar().setAssign(instanceArg);
-		}
-		instanceArg.getSVar().removeUse(instanceArg);
-		int argsCount = invoke.getArgsCount();
-		for (int i = 1; i < argsCount; i++) {
-			addArg(invoke.getArg(i));
+			return CallType.SUPER;
 		}
+		return CallType.CONSTRUCTOR;
 	}
 
 	public ConstructorInsn(MethodInfo callMth, CallType callType) {

jadx-core/src/main/java/jadx/core/dex/visitors/ConstructorVisitor.java

@@ -60,8 +60,16 @@ public class ConstructorVisitor extends AbstractVisitor {
 		if (!callMth.isConstructor()) {
 			return;
 		}
-		InsnNode instArgAssignInsn = ((RegisterArg) inv.getArg(0)).getAssignInsn();
+		RegisterArg instanceArg = ((RegisterArg) inv.getArg(0));
+		InsnNode instArgAssignInsn = instanceArg.getAssignInsn();
 		ConstructorInsn co = new ConstructorInsn(mth, inv);
+		if (co.isNewInstance()) {
+			co.setResult(instanceArg);
+			// convert from 'use' to 'assign'
+			instanceArg.getSVar().setAssign(instanceArg);
+		}
+		instanceArg.getSVar().removeUse(instanceArg);
+
 		co.rebindArgs();
 		boolean remove = false;
 		if (co.isSuper() && (co.getArgsCount() == 0 || parentClass.isEnum())) {

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

+package jadx.tests.integration.java8;
+
+import java.util.function.Supplier;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.tests.api.IntegrationTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+public class TestLambdaConstructor extends IntegrationTest {
+
+	public static class TestCls {
+
+		public Supplier<Exception> test() {
+			return RuntimeException::new;
+		}
+
+		public void check() throws Exception {
+			assertThat(test().get()).isInstanceOf(RuntimeException.class);
+		}
+	}
+
+	@Test
+	public void test() {
+		assertThat(getClassNode(TestCls.class))
+				.code()
+				.containsOne("return RuntimeException::new;");
+	}
+
+	@Test
+	public void testFallback() {
+		setFallback();
+		assertThat(getClassNode(TestCls.class))
+				.code()
+				.containsOne("RuntimeException::new");
+	}
+}