core: fix duplicate cast

jadx-core/src/main/java/jadx/core/dex/visitors/typeresolver/TypeResolver.java

 package jadx.core.dex.visitors.typeresolver;
 
 import jadx.core.dex.attributes.BlockRegState;
-import jadx.core.dex.instructions.IndexInsnNode;
-import jadx.core.dex.instructions.InsnType;
-import jadx.core.dex.instructions.args.ArgType;
 import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.instructions.args.RegisterArg;
 import jadx.core.dex.nodes.BlockNode;
@@ -20,8 +17,6 @@ public class TypeResolver extends AbstractVisitor {
 		if (mth.isNoCode()) {
 			return;
 		}
-		prepare(mth);
-
 		visitBlocks(mth);
 		visitEdges(mth);
 
@@ -32,20 +27,6 @@ public class TypeResolver extends AbstractVisitor {
 		}
 	}
 
-	/**
-	 * Check argument types (can be broken after merging debug info)
-	 */
-	private static void prepare(MethodNode mth) {
-		for (BlockNode block : mth.getBasicBlocks()) {
-			for (InsnNode insn : block.getInstructions()) {
-				if (insn.getType() == InsnType.CHECK_CAST) {
-					ArgType castType = (ArgType) ((IndexInsnNode) insn).getIndex();
-					insn.getResult().getTypedVar().forceSetType(castType);
-				}
-			}
-		}
-	}
-
 	private static void visitBlocks(MethodNode mth) {
 		for (BlockNode block : mth.getBasicBlocks()) {
 			BlockRegState state = new BlockRegState(mth);

jadx-core/src/main/java/jadx/core/dex/visitors/typeresolver/finish/PostTypeResolver.java

 package jadx.core.dex.visitors.typeresolver.finish;
 
 import jadx.core.dex.info.MethodInfo;
+import jadx.core.dex.instructions.IndexInsnNode;
 import jadx.core.dex.instructions.InvokeNode;
 import jadx.core.dex.instructions.args.ArgType;
 import jadx.core.dex.instructions.args.InsnArg;
@@ -85,6 +86,13 @@ public class PostTypeResolver {
 				return change;
 			}
 
+			case CHECK_CAST: {
+				ArgType castType = (ArgType) ((IndexInsnNode) insn).getIndex();
+				// workaround for compiler bug (see TestDuplicateCast)
+				insn.getResult().getTypedVar().forceSetType(castType);
+				return true;
+			}
+
 			default:
 				break;
 		}

jadx-core/src/test/java/jadx/tests/internal/TestDuplicateCast.java

@@ -9,12 +9,18 @@ import jadx.core.dex.nodes.MethodNode;
 
 import java.util.List;
 
+import org.junit.Test;
+
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
+/**
+ * Test duplicate 'check-cast' instruction produced because of bug in javac:
+ * http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6246854
+ */
 public class TestDuplicateCast extends InternalJadxTest {
 
 	public static class TestCls {
@@ -23,7 +29,7 @@ public class TestDuplicateCast extends InternalJadxTest {
 		}
 	}
 
-	//@Test
+	@Test
 	public void test() {
 		ClassNode cls = getClassNode(TestCls.class);
 		MethodNode mth = getMethod(cls, "method");