+ * Licensed under the Moderne Source Available License (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + *
+ * https://docs.moderne.io/licensing/moderne-source-available-license + *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.staticanalysis;
+
+import lombok.RequiredArgsConstructor;
+import org.jspecify.annotations.Nullable;
+import org.openrewrite.*;
+import org.openrewrite.internal.ListUtils;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.MethodMatcher;
+import org.openrewrite.java.NoMissingTypes;
+import org.openrewrite.java.search.SemanticallyEqual;
+import org.openrewrite.java.tree.Expression;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.JavaType;
+import org.openrewrite.java.tree.Statement;
+
+import java.util.*;
+
+import static java.util.Collections.emptySet;
+import static java.util.Objects.requireNonNull;
+
+public class RemoveUnusedParams extends ScanningRecipe
+ * Licensed under the Moderne Source Available License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.staticanalysis;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.DocumentExample;
+import org.openrewrite.Issue;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+
+class RemoveUnusedParamsTest implements RewriteTest {
+
+ @Override
+ public void defaults(RecipeSpec spec) {
+ spec.recipe(new RemoveUnusedParams());
+ }
+
+ @DocumentExample
+ @Test
+ void removeUnusedMethodParameter() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void method(String unused) {
+ System.out.println("Hello");
+ }
+ }
+ """,
+ """
+ public class Test {
+ void method() {
+ System.out.println("Hello");
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void doNotRemoveUsedParameter() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void method(String input) {
+ System.out.println(input);
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void doNotRemoveOverriddenMethodParameter() {
+ rewriteRun(
+ java(
+ """
+ class Test {
+ void method(String param) {}
+ }
+ class Base {
+ void method(String param) {}
+ }
+ class Derived extends Base {
+ @Override
+ void method(String param) {
+ // not used but required
+ }
+ }
+ """,
+ """
+ class Test {
+ void method() {}
+ }
+ class Base {
+ void method(String param) {}
+ }
+ class Derived extends Base {
+ @Override
+ void method(String param) {
+ // not used but required
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void doNotRemoveAnnotatedParameter() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void method(@Deprecated String param) {}
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void removeMultipleUnusedParams() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void method(String a, int b, double c) {
+ System.out.println("Only prints this");
+ }
+ }
+ """,
+ """
+ public class Test {
+ void method() {
+ System.out.println("Only prints this");
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void preserveJavadocAndComments() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ /**
+ * Some doc
+ * @param unused this param is never used
+ */
+ void method(String unused) {
+ // comment
+ System.out.println("used");
+ }
+ }
+ """,
+ """
+ public class Test {
+ /**
+ * Some doc
+ * @param unused this param is never used
+ */
+ void method() {
+ // comment
+ System.out.println("used");
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Issue("https://github.com/openrewrite/rewrite-static-analysis/issues/559")
+ @Test
+ void shadowedParameterShouldStillBeRemoved() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void method(String input) {
+ String input = "shadowed";
+ System.out.println(input);
+ }
+ }
+ """,
+ """
+ public class Test {
+ void method() {
+ String input = "shadowed";
+ System.out.println(input);
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void removeUnusedStaticMethodParam() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ static void helper(String unused) {
+ // no use
+ }
+ }
+ """,
+ """
+ public class Test {
+ static void helper() {
+ // no use
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void removeUnusedConstructorParam() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ Test(String unused) {
+ // ctor body
+ }
+ }
+ """,
+ """
+ public class Test {
+ Test() {
+ // ctor body
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void removeUnusedVarargs() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void m(String... args) {
+ System.out.println("no args used");
+ }
+ }
+ """,
+ """
+ public class Test {
+ void m() {
+ System.out.println("no args used");
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void preserveAnnotatedParamButRemoveOthers() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void method(@Deprecated String keep, int removeMe) {
+ System.out.println(keep);
+ }
+ }
+ """,
+ """
+ public class Test {
+ void method(@Deprecated String keep) {
+ System.out.println(keep);
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void doNotRemoveNativeMethodParam() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ native void nativeCall(int mustStay);
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void interfaceMethodUnchanged() {
+ rewriteRun(
+ java(
+ """
+ interface I {
+ void foo(String param);
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void skipWronglyDueToSignatureCollision() {
+ rewriteRun(
+ java(
+ """
+ class Base {
+ void foo(int a, String b) {}
+ }
+ class Derived extends Base {
+ @Override
+ void foo(int a, String b) {}
+ void foo(String a, int b) {
+ // no use of a or b
+ }
+ }
+ """,
+ """
+ class Base {
+ void foo(int a, String b) {}
+ }
+ class Derived extends Base {
+ @Override
+ void foo(int a, String b) {}
+ void foo() {
+ // no use of a or b
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void nestedInheritanceOverrideChain() {
+ rewriteRun(
+ java(
+ """
+ class Lone { void solo(String x) {} }
+
+ class Grandparent { void greet(String msg) {} }
+ class Parent extends Grandparent { }
+ class Child extends Parent {
+ @Override
+ void greet(String msg) {
+ // required override
+ }
+ }
+ """,
+ """
+ class Lone { void solo() {} }
+
+ class Grandparent { void greet(String msg) {} }
+ class Parent extends Grandparent { }
+ class Child extends Parent {
+ @Override
+ void greet(String msg) {
+ // required override
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void avoidDirectConflict() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void method() {
+ System.out.println("Hello");
+ }
+ void method(String unused) {
+ System.out.println("Hello");
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void avoidInheritedConflict() {
+ rewriteRun(
+ java(
+ """
+ public class A {
+ String method() {
+ return "A String";
+ }
+ }
+ """
+ ),
+ java(
+ """
+ public class B extends A {
+ Long method(String unused) {
+ return 42L;
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void cascadeRemoveUnusedArguments() {
+ rewriteRun(
+ java(
+ """
+ public class Test {
+ void method1(String unused) {
+ method2(unused);
+ }
+ void method2(String unused) {
+ method3(unused);
+ }
+ void method3(String unused) {
+ System.out.println("Hello");
+ }
+ }
+ """,
+ """
+ public class Test {
+ void method1() {
+ method2();
+ }
+ void method2() {
+ method3();
+ }
+ void method3() {
+ System.out.println("Hello");
+ }
+ }
+ """
+ )
+ );
+ }
+}
"fully.qualified.ClassName#methodName(paramType1,paramType2,...)".
+ * Parameters of these methods are considered part of the public API
+ * and will not be removed even if they appear unused.
+ */
+ private final Set