TypeVariablesVariableResolver compares variables by name

Issue: SPR-16456

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

@@ -1468,8 +1468,7 @@ public class ResolvableType implements Serializable {
 		@Nullable
 		public ResolvableType resolveVariable(TypeVariable<?> variable) {
 			for (int i = 0; i < this.variables.length; i++) {
-				if (ObjectUtils.nullSafeEquals(SerializableTypeWrapper.unwrap(this.variables[i]),
-						SerializableTypeWrapper.unwrap(variable))) {
+				if (ObjectUtils.nullSafeEquals(this.variables[i].getName(), variable.getName())) {
 					return this.generics[i];
 				}
 			}

spring-core/src/test/java/org/springframework/core/ResolvableTypeTests.java

@@ -1337,6 +1337,14 @@ public class ResolvableTypeTests {
 		assertTrue(setClass.isAssignableFrom(fromReturnType));
 	}
 
+	@Test
+	public void testSpr16456() throws Exception {
+		ResolvableType genericType = ResolvableType.forField(
+				UnresolvedWithGenerics.class.getDeclaredField("set")).asCollection();
+		ResolvableType type = ResolvableType.forClassWithGenerics(ArrayList.class, genericType.getGeneric());
+		assertThat(type.resolveGeneric(), equalTo(Integer.class));
+	}
+
 
 	private ResolvableType testSerialization(ResolvableType type) throws Exception {
 		ByteArrayOutputStream bos = new ByteArrayOutputStream();
@@ -1637,4 +1645,10 @@ public class ResolvableTypeTests {
 		public Collection<IBase<BT>> stuff;
 	}
 
+
+	public abstract class UnresolvedWithGenerics {
+
+		Set<Integer> set;
+	}
+
 }