MethodParameter.equals accepts subclasses pointing to same target declaration again

Issue: SPR-14438

spring-core/src/main/java/org/springframework/core/MethodParameter.java

@@ -579,7 +579,7 @@ public class MethodParameter {
 		if (this == other) {
 			return true;
 		}
-		if (other == null || getClass() != other.getClass()) {
+		if (!(other instanceof MethodParameter)) {
 			return false;
 		}
 		MethodParameter otherParam = (MethodParameter) other;

spring-core/src/test/java/org/springframework/core/annotation/SynthesizingMethodParameterTests.java

@@ -27,6 +27,7 @@ import static org.junit.Assert.*;
 
 /**
  * @author Juergen Hoeller
+ * @since 5.0
  */
 public class SynthesizingMethodParameterTests {
 
@@ -69,8 +70,8 @@ public class SynthesizingMethodParameterTests {
 		assertNotEquals(methodParameter, longParameter);
 
 		methodParameter = new MethodParameter(method, 0);
-		assertNotEquals(stringParameter, methodParameter);
-		assertNotEquals(methodParameter, stringParameter);
+		assertEquals(stringParameter, methodParameter);
+		assertEquals(methodParameter, stringParameter);
 		assertNotEquals(longParameter, methodParameter);
 		assertNotEquals(methodParameter, longParameter);
 	}