fix: resolve variable name shadowing in anonymous classes (#1124)

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

@@ -11,6 +11,7 @@ import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Stream;
 
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import jadx.api.ICodeInfo;
@@ -59,6 +60,9 @@ public class ClassGen {
 
 	private boolean bodyGenStarted;
 
+	@Nullable
+	private NameGen outerNameGen;
+
 	public ClassGen(ClassNode cls, JadxArgs jadxArgs) {
 		this(cls, null, jadxArgs.isUseImports(), jadxArgs.isFallbackMode(), jadxArgs.isShowInconsistentCode());
 	}
@@ -238,13 +242,12 @@ public class ClassGen {
 	 */
 	public void addClassBody(ICodeWriter clsCode, boolean printClassName) throws CodegenException {
 		clsCode.add('{');
+		if (printClassName) {
+			clsCode.add(" // from class: " + cls.getClassInfo().getFullName());
+		}
 		setBodyGenStarted(true);
 		clsDeclOffset = clsCode.getLength();
 		clsCode.incIndent();
-		if (printClassName) {
-			clsCode.startLine();
-			clsCode.add("/* class " + cls.getFullName() + " */");
-		}
 		addFields(clsCode);
 		addInnerClsAndMethods(clsCode);
 		clsCode.decIndent();
@@ -746,4 +749,13 @@ public class ClassGen {
 	public void setBodyGenStarted(boolean bodyGenStarted) {
 		this.bodyGenStarted = bodyGenStarted;
 	}
+
+	@Nullable
+	public NameGen getOuterNameGen() {
+		return outerNameGen;
+	}
+
+	public void setOuterNameGen(@NotNull NameGen outerNameGen) {
+		this.outerNameGen = outerNameGen;
+	}
 }

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

@@ -725,7 +725,10 @@ public class InsnGen {
 		MethodNode callMth = mth.root().resolveMethod(insn.getCallMth());
 		generateMethodArguments(code, insn, 0, callMth);
 		code.add(' ');
-		new ClassGen(cls, mgen.getClassGen().getParentGen()).addClassBody(code, true);
+
+		ClassGen classGen = new ClassGen(cls, mgen.getClassGen().getParentGen());
+		classGen.setOuterNameGen(mgen.getNameGen());
+		classGen.addClassBody(code, true);
 	}
 
 	private void makeInvoke(InvokeNode insn, ICodeWriter code) throws CodegenException {

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

@@ -58,7 +58,7 @@ public class MethodGen {
 		this.mth = mth;
 		this.classGen = classGen;
 		this.annotationGen = classGen.getAnnotationGen();
-		this.nameGen = new NameGen(mth, classGen.isFallbackMode());
+		this.nameGen = new NameGen(mth, classGen);
 	}
 
 	public ClassGen getClassGen() {

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

@@ -53,9 +53,13 @@ public class NameGen {
 				"java.lang.Exception", "exc");
 	}
 
-	public NameGen(MethodNode mth, boolean fallback) {
+	public NameGen(MethodNode mth, ClassGen classGen) {
 		this.mth = mth;
-		this.fallback = fallback;
+		this.fallback = classGen.isFallbackMode();
+		NameGen outerNameGen = classGen.getOuterNameGen();
+		if (outerNameGen != null) {
+			inheritUsedNames(outerNameGen);
+		}
 		addNamesUsedInClass();
 	}
 

jadx-core/src/test/java/jadx/tests/integration/names/TestDuplicateVarNames.java

+package jadx.tests.integration.names;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.IntegrationTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+public class TestDuplicateVarNames extends IntegrationTest {
+
+	public static class TestCls {
+		public static class A {
+			public String mth(A a) {
+				return null;
+			}
+
+			@Override
+			public String toString() {
+				return "1";
+			}
+		}
+
+		public A test(A a) {
+			return new A() {
+				@Override
+				public String mth(A innerA) {
+					return a + "." + innerA;
+				}
+			};
+		}
+
+		public void check() {
+			String str = test(new A()).mth(new A() {
+				@Override
+				public String toString() {
+					return "2";
+				}
+			});
+			assertThat(str).isEqualTo("1.2");
+		}
+	}
+
+	@Test
+	public void test() {
+		noDebugInfo();
+		ClassNode cls = getClassNode(TestCls.class);
+
+		assertThat(cls)
+				.code()
+				.doesNotContain("return a + \".\" + a;")
+				.doesNotContain("AnonymousClass1");
+	}
+}