core: fix type detection for method arguments

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

@@ -680,7 +680,7 @@ public class InsnGen {
 				if (!arg.getType().equals(origType)) {
 					code.add('(');
 					useType(code, origType);
-					code.add(')');
+					code.add(") ");
 					addArg(code, arg, true);
 				} else {
 					addArg(code, arg, false);

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

@@ -39,6 +39,7 @@ public class MthParameterArg extends RegisterArg {
 		if (isThis) {
 			sVar.setName("this");
 		}
+		sVar.setTypeImmutable(type);
 		super.setSVar(sVar);
 	}
 

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

@@ -80,6 +80,7 @@ public class RegisterArg extends InsnArg implements Named {
 		setName(name);
 	}
 
+	@Deprecated
 	public void forceType(ArgType type) {
 		this.type = type;
 	}

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

@@ -19,6 +19,7 @@ public class SSAVar {
 	private PhiInsn usedInPhi;
 
 	private ArgType type;
+	private boolean typeImmutable;
 
 	public SSAVar(int regNum, int v, RegisterArg assign) {
 		this.regNum = regNum;
@@ -33,10 +34,6 @@ public class SSAVar {
 		endUseAddr = -1;
 	}
 
-	public int getRegNum() {
-		return regNum;
-	}
-
 	public int getStartAddr() {
 		if (startUseAddr == -1) {
 			calcUsageAddrRange();
@@ -48,7 +45,6 @@ public class SSAVar {
 		if (endUseAddr == -1) {
 			calcUsageAddrRange();
 		}
-
 		return endUseAddr;
 	}
 
@@ -78,12 +74,16 @@ public class SSAVar {
 			}
 		}
 
-		if ((start != Integer.MAX_VALUE) 
+		if ((start != Integer.MAX_VALUE)
 				&& (end != Integer.MIN_VALUE)) {
 			startUseAddr = start;
 			endUseAddr = end;
 		}
-	} 
+	}
+
+	public int getRegNum() {
+		return regNum;
+	}
 
 	public int getVersion() {
 		return version;
@@ -141,20 +141,32 @@ public class SSAVar {
 		return useList.size() + usedInPhi.getResult().getSVar().getUseCount();
 	}
 
-	public ArgType getType() {
-		return type;
-	}
-
 	public void setType(ArgType type) {
-		this.type = type;
+		ArgType acceptedType;
+		if (typeImmutable) {
+			// don't change type, just update types in useList
+			acceptedType = this.type;
+		} else {
+			acceptedType = type;
+			this.type = acceptedType;
+		}
 		if (assign != null) {
-			assign.type = type;
+			assign.type = acceptedType;
 		}
 		for (int i = 0, useListSize = useList.size(); i < useListSize; i++) {
-			useList.get(i).type = type;
+			useList.get(i).type = acceptedType;
 		}
 	}
 
+	public void setTypeImmutable(ArgType type) {
+		setType(type);
+		this.typeImmutable = true;
+	}
+
+	public boolean isTypeImmutable() {
+		return typeImmutable;
+	}
+
 	public void setName(String name) {
 		if (name != null) {
 			if (varName == null) {

jadx-core/src/main/java/jadx/core/dex/visitors/typeinference/PostTypeInference.java

@@ -85,20 +85,21 @@ public class PostTypeInference {
 
 			case CHECK_CAST: {
 				ArgType castType = (ArgType) ((IndexInsnNode) insn).getIndex();
-				SSAVar sVar = insn.getResult().getSVar();
+				RegisterArg result = insn.getResult();
 				// don't override generic types of same base class
-				boolean skip = castType.isObject() && castType.getObject().equals(sVar.getType().getObject());
+				boolean skip = castType.isObject() && castType.getObject().equals(result.getType().getObject());
 				if (!skip) {
 					// workaround for compiler bug (see TestDuplicateCast)
-					sVar.setType(castType);
+					result.getSVar().setType(castType);
 				}
 				return true;
 			}
 
 			case PHI: {
 				PhiInsn phi = (PhiInsn) insn;
-				SSAVar resultSVar = phi.getResult().getSVar();
-				if (resultSVar != null && !resultSVar.getType().isTypeKnown()) {
+				RegisterArg result = phi.getResult();
+				SSAVar resultSVar = result.getSVar();
+				if (resultSVar != null && !result.getType().isTypeKnown()) {
 					for (InsnArg arg : phi.getArguments()) {
 						ArgType argType = arg.getType();
 						if (argType.isTypeKnown()) {

jadx-core/src/main/java/jadx/core/dex/visitors/typeinference/TypeInference.java

@@ -44,8 +44,7 @@ public class TypeInference extends AbstractVisitor {
 	private static ArgType processType(SSAVar var) {
 		RegisterArg assign = var.getAssign();
 		List<RegisterArg> useList = var.getUseList();
-		if (assign != null
-				&& (useList.isEmpty() || assign.isTypeImmutable())) {
+		if (assign != null && (useList.isEmpty() || var.isTypeImmutable())) {
 			return assign.getType();
 		}
 		ArgType type;

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

+package jadx.tests.integration.invoke;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.IntegrationTest;
+
+import org.junit.Test;
+
+import static jadx.tests.api.utils.JadxMatchers.containsOne;
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.not;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+
+public class TestOverloadedMethodInvoke extends IntegrationTest {
+
+	public static class TestCls {
+		int c;
+
+		public void method(Throwable th) {
+			c++;
+			if (th != null) {
+				c+=100;
+			}
+		}
+
+		public void method(Exception e) {
+			c += 1000;
+			if (e != null) {
+				c += 10000;
+			}
+		}
+
+		public void test(Throwable th, Exception e) {
+			method(e);
+			method(th);
+			method((Throwable) e);
+			method((Exception) th);
+		}
+
+		public void check() {
+			test(null, new Exception());
+			assertEquals(12102, c);
+		}
+	}
+
+	@Test
+	public void test() {
+		ClassNode cls = getClassNode(TestCls.class);
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsString("public void test(Throwable th, Exception e) {"));
+		assertThat(code, containsOne("method(e);"));
+		assertThat(code, containsOne("method(th);"));
+		assertThat(code, containsOne("method((Throwable) e);"));
+		assertThat(code, containsOne("method((Exception) th);"));
+		assertThat(code, not(containsString("(Exception) e")));
+	}
+}

jadx-core/src/test/java/jadx/tests/integration/types/TestTypeResolver2.java

+package jadx.tests.integration.types;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.IntegrationTest;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+import static jadx.tests.api.utils.JadxMatchers.containsOne;
+import static org.junit.Assert.assertThat;
+
+public class TestTypeResolver2 extends IntegrationTest {
+
+	public static class TestCls {
+
+		private static boolean test(Object obj) throws IOException {
+			if (obj != null) {
+				return true;
+			}
+			throw new IOException();
+		}
+	}
+
+	@Test
+	public void test() {
+		noDebugInfo();
+
+		ClassNode cls = getClassNode(TestCls.class);
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsOne("if (obj != null) {"));
+	}
+}