fix: remove generics cast when object types match (#591) (PR #592)

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

@@ -740,13 +740,18 @@ public class InsnGen {
 				return false;
 			}
 		}
-		if (!arg.getType().equals(origType)) {
-			code.add('(');
-			useType(code, origType);
-			code.add(") ");
-			return true;
+		ArgType argType = arg.getType();
+		if (argType.equals(origType)) {
+			return false;
 		}
-		return false;
+		if (origType.isGeneric()
+				&& origType.getObject().equals(argType.getObject())) {
+			return false;
+		}
+		code.add('(');
+		useType(code, origType);
+		code.add(") ");
+		return true;
 	}
 
 	/**

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

@@ -2,6 +2,10 @@ package jadx.core.dex.instructions;
 
 import java.io.EOFException;
 
+import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import com.android.dex.Code;
 import com.android.dx.io.OpcodeInfo;
 import com.android.dx.io.Opcodes;
@@ -10,10 +14,8 @@ import com.android.dx.io.instructions.FillArrayDataPayloadDecodedInstruction;
 import com.android.dx.io.instructions.PackedSwitchPayloadDecodedInstruction;
 import com.android.dx.io.instructions.ShortArrayCodeInput;
 import com.android.dx.io.instructions.SparseSwitchPayloadDecodedInstruction;
-import org.jetbrains.annotations.NotNull;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
+import jadx.core.Consts;
 import jadx.core.dex.info.FieldInfo;
 import jadx.core.dex.info.MethodInfo;
 import jadx.core.dex.instructions.args.ArgType;
@@ -119,9 +121,13 @@ public class InsnDecoder {
 				return constStrInsn;
 
 			case Opcodes.CONST_CLASS:
-				InsnNode constClsInsn = new ConstClassNode(dex.getType(insn.getIndex()));
-				constClsInsn.setResult(InsnArg.reg(insn, 0, ArgType.CLASS));
+				{
+				ArgType clsType = dex.getType(insn.getIndex());
+				InsnNode constClsInsn = new ConstClassNode(clsType);
+				constClsInsn.setResult(
+						InsnArg.reg(insn, 0, ArgType.generic(Consts.CLASS_CLASS, clsType)));
 				return constClsInsn;
+				}
 
 			case Opcodes.MOVE:
 			case Opcodes.MOVE_16:

jadx-core/src/main/java/jadx/core/dex/instructions/args/ArgType.java

@@ -83,7 +83,7 @@ public abstract class ArgType {
 		return new SignatureParser(sign).consumeType();
 	}
 
-	public static ArgType generic(String obj, ArgType[] generics) {
+	public static ArgType generic(String obj, ArgType... generics) {
 		return new GenericObject(obj, generics);
 	}
 

jadx-core/src/main/java/jadx/core/dex/visitors/regions/LoopRegionVisitor.java

@@ -326,7 +326,7 @@ public class LoopRegionVisitor extends AbstractVisitor implements IRegionVisitor
 			return true;
 		}
 		// TODO: add checks
-		iterableType = ArgType.generic(iterableType.getObject(), new ArgType[]{varType});
+		iterableType = ArgType.generic(iterableType.getObject(), varType);
 		iterableArg.setType(iterableType);
 		return true;
 	}

jadx-core/src/test/java/jadx/core/dex/visitors/typeinference/TypeCompareTest.java

@@ -76,7 +76,7 @@ public class TypeCompareTest {
 
 		ArgType keyType = ArgType.genericType("K");
 		ArgType valueType = ArgType.genericType("V");
-		ArgType mapGeneric = ArgType.generic(mapCls.getObject(), new ArgType[]{keyType, valueType});
+		ArgType mapGeneric = ArgType.generic(mapCls.getObject(), keyType, valueType);
 
 		check(mapGeneric, mapCls, TypeCompareEnum.NARROW_BY_GENERIC);
 		check(mapCls, mapGeneric, TypeCompareEnum.WIDER_BY_GENERIC);

jadx-core/src/test/java/jadx/tests/functional/SignatureParserTest.java

@@ -43,12 +43,12 @@ class SignatureParserTest {
 	@Test
 	public void testGenerics() {
 		checkType("TD;", genericType("D"));
-		checkType("La<TV;Lb;>;", generic("La;", new ArgType[]{genericType("V"), object("b")}));
-		checkType("La<Lb<Lc;>;>;", generic("La;", new ArgType[]{generic("Lb;", new ArgType[]{object("Lc;")})}));
-		checkType("La/b/C<Ld/E<Lf/G;>;>;", generic("La/b/C;", new ArgType[]{generic("Ld/E;", new ArgType[]{object("Lf/G;")})}));
-		checkType("La<TD;>.c;", genericInner(generic("La;", new ArgType[]{genericType("D")}), "c", null));
-		checkType("La<TD;>.c/d;", genericInner(generic("La;", new ArgType[]{genericType("D")}), "c.d", null));
-		checkType("La<Lb;>.c<TV;>;", genericInner(generic("La;", new ArgType[]{object("Lb;")}), "c", new ArgType[]{genericType("V")}));
+		checkType("La<TV;Lb;>;", generic("La;", genericType("V"), object("b")));
+		checkType("La<Lb<Lc;>;>;", generic("La;", generic("Lb;", object("Lc;"))));
+		checkType("La/b/C<Ld/E<Lf/G;>;>;", generic("La/b/C;", generic("Ld/E;", object("Lf/G;"))));
+		checkType("La<TD;>.c;", genericInner(generic("La;", genericType("D")), "c", null));
+		checkType("La<TD;>.c/d;", genericInner(generic("La;", genericType("D")), "c.d", null));
+		checkType("La<Lb;>.c<TV;>;", genericInner(generic("La;", object("Lb;")), "c", new ArgType[]{genericType("V")}));
 	}
 
 	@Test
@@ -107,7 +107,7 @@ class SignatureParserTest {
 		List<ArgType> argTypes = new SignatureParser("(Ljava/util/List<*>;)V").consumeMethodArgs();
 
 		assertThat(argTypes, hasSize(1));
-		assertThat(argTypes.get(0), is(generic("Ljava/util/List;", new ArgType[]{wildcard()})));
+		assertThat(argTypes.get(0), is(generic("Ljava/util/List;", wildcard())));
 	}
 
 	@Test
@@ -117,7 +117,7 @@ class SignatureParserTest {
 		assertThat(argTypes, hasSize(1));
 		ArgType argType = argTypes.get(0);
 		assertThat(argType.getObject().indexOf('/'), is(-1));
-		assertThat(argType, is(genericInner(generic("La/b/C;", new ArgType[]{genericType("T")}), "d.E", null)));
+		assertThat(argType, is(genericInner(generic("La/b/C;", genericType("T")), "d.E", (ArgType[]) null)));
 	}
 
 	@Test

jadx-core/src/test/java/jadx/tests/integration/generics/TestGenerics7.java

+package jadx.tests.integration.generics;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.IntegrationTest;
+
+public class TestGenerics7 extends IntegrationTest {
+
+	public static class TestCls {
+
+		public void test() {
+			declare(String.class);
+		}
+
+		public <T> T declare(Class<T> cls) {
+	    	return null;
+	    }
+
+		public void declare(Object cls) {
+	    }
+	}
+
+	@Test
+	public void test() {
+		ClassNode cls = getClassNode(TestCls.class);
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsString("declare(String.class);"));
+	}
+}

jadx-core/src/test/java/jadx/tests/integration/invoke/TestCastInOverloadedInvoke.java

@@ -55,7 +55,7 @@ public class TestCastInOverloadedInvoke extends IntegrationTest {
 		ClassNode cls = getClassNode(TestCls.class);
 		String code = cls.getCode().toString();
 
-		assertThat(code, containsOne("call((ArrayList<String>) new ArrayList());"));
+		assertThat(code, containsOne("call(new ArrayList());"));
 		assertThat(code, containsOne("call((List<String>) new ArrayList());"));
 
 		assertThat(code, containsOne("call((String) obj);"));