fix: simplify cascading casts (#1336)

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

@@ -655,7 +655,7 @@ public abstract class ArgType {
 		if (from.equals(to)) {
 			return false;
 		}
-		TypeCompareEnum result = root.getTypeUpdate().getTypeCompare().compareTypes(from, to);
+		TypeCompareEnum result = root.getTypeCompare().compareTypes(from, to);
 		return !result.isNarrow();
 	}
 

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

@@ -38,6 +38,7 @@ import jadx.core.dex.nodes.MethodNode;
 import jadx.core.dex.nodes.RootNode;
 import jadx.core.dex.regions.conditions.IfCondition;
 import jadx.core.dex.visitors.shrink.CodeShrinkVisitor;
+import jadx.core.dex.visitors.typeinference.TypeCompareEnum;
 import jadx.core.utils.BlockUtils;
 import jadx.core.utils.InsnList;
 import jadx.core.utils.InsnRemover;
@@ -82,7 +83,7 @@ public class SimplifyVisitor extends AbstractVisitor {
 		for (int i = 0; i < list.size(); i++) {
 			InsnNode insn = list.get(i);
 			int insnCount = list.size();
-			InsnNode modInsn = simplifyInsn(mth, insn);
+			InsnNode modInsn = simplifyInsn(mth, insn, null);
 			if (modInsn != null) {
 				modInsn.rebindArgs();
 				if (i < list.size() && list.get(i) == insn) {
@@ -110,7 +111,7 @@ public class SimplifyVisitor extends AbstractVisitor {
 		for (InsnArg arg : insn.getArguments()) {
 			if (arg.isInsnWrap()) {
 				InsnNode wrapInsn = ((InsnWrapArg) arg).getWrapInsn();
-				InsnNode replaceInsn = simplifyInsn(mth, wrapInsn);
+				InsnNode replaceInsn = simplifyInsn(mth, wrapInsn, insn);
 				if (replaceInsn != null) {
 					arg.wrapInstruction(mth, replaceInsn);
 					InsnRemover.unbindInsn(mth, wrapInsn);
@@ -123,7 +124,7 @@ public class SimplifyVisitor extends AbstractVisitor {
 		}
 	}
 
-	private InsnNode simplifyInsn(MethodNode mth, InsnNode insn) {
+	private InsnNode simplifyInsn(MethodNode mth, InsnNode insn, @Nullable InsnNode parentInsn) {
 		if (insn.contains(AFlag.DONT_GENERATE)) {
 			return null;
 		}
@@ -146,8 +147,9 @@ public class SimplifyVisitor extends AbstractVisitor {
 			case SPUT:
 				return convertFieldArith(mth, insn);
 
+			case CAST:
 			case CHECK_CAST:
-				return processCast(mth, (IndexInsnNode) insn);
+				return processCast(mth, (IndexInsnNode) insn, parentInsn);
 
 			case MOVE:
 				InsnArg firstArg = insn.getArg(0);
@@ -212,7 +214,7 @@ public class SimplifyVisitor extends AbstractVisitor {
 		return null;
 	}
 
-	private static InsnNode processCast(MethodNode mth, IndexInsnNode castInsn) {
+	private static InsnNode processCast(MethodNode mth, IndexInsnNode castInsn, @Nullable InsnNode parentInsn) {
 		if (castInsn.contains(AFlag.EXPLICIT_CAST)) {
 			return null;
 		}
@@ -229,7 +231,8 @@ public class SimplifyVisitor extends AbstractVisitor {
 
 		ArgType castToType = (ArgType) castInsn.getIndex();
 		if (!ArgType.isCastNeeded(mth.root(), argType, castToType)
-				|| isCastDuplicate(castInsn)) {
+				|| isCastDuplicate(castInsn)
+				|| shadowedByOuterCast(mth.root(), castToType, parentInsn)) {
 			InsnNode insnNode = new InsnNode(InsnType.MOVE, 1);
 			insnNode.setOffset(castInsn.getOffset());
 			insnNode.setResult(castInsn.getResult());
@@ -254,6 +257,15 @@ public class SimplifyVisitor extends AbstractVisitor {
 		return false;
 	}
 
+	private static boolean shadowedByOuterCast(RootNode root, ArgType castType, @Nullable InsnNode parentInsn) {
+		if (parentInsn != null && parentInsn.getType() == InsnType.CAST) {
+			ArgType parentCastType = (ArgType) ((IndexInsnNode) parentInsn).getIndex();
+			TypeCompareEnum result = root.getTypeCompare().compareTypes(parentCastType, castType);
+			return result.isNarrow();
+		}
+		return false;
+	}
+
 	/**
 	 * Simplify 'cmp' instruction in if condition
 	 */

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

@@ -98,6 +98,10 @@ public class TypeCompare {
 					|| secondPrimitiveType == PrimitiveType.BOOLEAN) {
 				return CONFLICT;
 			}
+			if (swapEquals(firstPrimitiveType, secondPrimitiveType, PrimitiveType.CHAR, PrimitiveType.BYTE)
+					|| swapEquals(firstPrimitiveType, secondPrimitiveType, PrimitiveType.CHAR, PrimitiveType.SHORT)) {
+				return CONFLICT;
+			}
 			return firstPrimitiveType.compareTo(secondPrimitiveType) > 0 ? WIDER : NARROW;
 		}
 
@@ -105,6 +109,10 @@ public class TypeCompare {
 		return TypeCompareEnum.CONFLICT;
 	}
 
+	private boolean swapEquals(PrimitiveType first, PrimitiveType second, PrimitiveType a, PrimitiveType b) {
+		return (first == a && second == b) || (first == b && second == a);
+	}
+
 	private TypeCompareEnum compareArrayWithOtherType(ArgType array, ArgType other) {
 		if (!other.isTypeKnown()) {
 			if (other.contains(PrimitiveType.ARRAY)) {

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

@@ -63,10 +63,15 @@ public class TypeCompareTest {
 	public void comparePrimitives() {
 		check(INT, UNKNOWN_OBJECT, TypeCompareEnum.CONFLICT);
 		check(INT, OBJECT, TypeCompareEnum.CONFLICT);
-		check(INT, BOOLEAN, TypeCompareEnum.CONFLICT);
+
 		check(INT, CHAR, TypeCompareEnum.WIDER);
 		check(INT, SHORT, TypeCompareEnum.WIDER);
 
+		check(BOOLEAN, INT, TypeCompareEnum.CONFLICT);
+		check(BOOLEAN, CHAR, TypeCompareEnum.CONFLICT);
+		check(CHAR, BYTE, TypeCompareEnum.CONFLICT);
+		check(CHAR, SHORT, TypeCompareEnum.CONFLICT);
+
 		firstIsNarrow(CHAR, NARROW_INTEGRAL);
 		firstIsNarrow(array(CHAR), UNKNOWN_OBJECT);
 	}

jadx-core/src/test/java/jadx/tests/integration/inline/TestInline2.java

@@ -31,6 +31,6 @@ public class TestInline2 extends IntegrationTest {
 
 		assertThat(code, containsOne("int[] a = {1, 2, 4, 6, 8};"));
 		assertThat(code, containsOne("for (int i = 0; i < a.length; i += 2) {"));
-		assertThat(code, containsOne("for (long i2 = (long) b; i2 > 0; i2--) {"));
+		assertThat(code, containsOne("for (long i2 = b; i2 > 0; i2--) {"));
 	}
 }

jadx-core/src/test/java/jadx/tests/integration/others/TestPrimitiveCasts.java

@@ -17,16 +17,24 @@ public class TestPrimitiveCasts extends IntegrationTest {
 			useByte((byte) getInt());
 			useChar((char) 0);
 			useChar((char) getInt());
+
 			useShort((short) 0L);
 			useShort((short) getLong());
 			useByte((byte) 0L);
 			useByte((byte) getLong());
 			useChar((char) 0L);
 			useChar((char) getLong());
+
 			useShort((short) ' ');
 			useShort((short) getChar());
 			useByte((byte) ' ');
 			useByte((byte) getChar());
+
+			useInt((byte) 7);
+			useInt((char) ' ');
+			useInt(getChar());
+			useInt((int) 2L);
+			useInt((int) getLong());
 		}
 
 		private long getLong() {
@@ -49,6 +57,9 @@ public class TestPrimitiveCasts extends IntegrationTest {
 
 		private void useShort(short s) {
 		}
+
+		private void useInt(int i) {
+		}
 	}
 
 	@TestWithProfiles({ TestProfile.DX_J8, TestProfile.JAVA8 })
@@ -56,6 +67,7 @@ public class TestPrimitiveCasts extends IntegrationTest {
 		noDebugInfo();
 		assertThat(getClassNode(TestCls.class))
 				.code()
-				.doesNotContain("(0)");
+				.doesNotContain("(0)")
+				.doesNotContain(") ((int) getLong())");
 	}
 }