Unit test for match against unresolvable wildcard

See gh-33982

Author: jhoeller

Diff for: spring-core/src/main/java/org/springframework/core/ResolvableType.java

@@ -309,12 +309,12 @@ private boolean isAssignableFrom(ResolvableType other, boolean strict, @Nullable
 
 		// Deal with wildcard bounds
 		WildcardBounds ourBounds = WildcardBounds.get(this);
-		WildcardBounds typeBounds = WildcardBounds.get(other);
+		WildcardBounds otherBounds = WildcardBounds.get(other);
 
 		// In the form X is assignable to <? extends Number>
-		if (typeBounds != null) {
-			return (ourBounds != null && ourBounds.isSameKind(typeBounds) &&
-					ourBounds.isAssignableFrom(typeBounds.getBounds()));
+		if (otherBounds != null) {
+			return (ourBounds != null && ourBounds.isSameKind(otherBounds) &&
+					ourBounds.isAssignableFrom(otherBounds.getBounds()));
 		}
 
 		// In the form <? extends Number> is assignable to X...
@@ -365,8 +365,8 @@ private boolean isAssignableFrom(ResolvableType other, boolean strict, @Nullable
 		if (checkGenerics) {
 			// Recursively check each generic
 			ResolvableType[] ourGenerics = getGenerics();
-			ResolvableType[] typeGenerics = other.as(ourResolved).getGenerics();
-			if (ourGenerics.length != typeGenerics.length) {
+			ResolvableType[] otherGenerics = other.as(ourResolved).getGenerics();
+			if (ourGenerics.length != otherGenerics.length) {
 				return false;
 			}
 			if (ourGenerics.length > 0) {
@@ -375,7 +375,7 @@ private boolean isAssignableFrom(ResolvableType other, boolean strict, @Nullable
 				}
 				matchedBefore.put(this.type, other.type);
 				for (int i = 0; i < ourGenerics.length; i++) {
-					if (!ourGenerics[i].isAssignableFrom(typeGenerics[i], true, matchedBefore)) {
+					if (!ourGenerics[i].isAssignableFrom(otherGenerics[i], true, matchedBefore)) {
 						return false;
 					}
 				}

Diff for: spring-core/src/test/java/org/springframework/core/ResolvableTypeTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -169,7 +169,7 @@ void forInstanceProvider() {
 
 	@Test
 	void forInstanceProviderNull() {
-		ResolvableType type = ResolvableType.forInstance(new MyGenericInterfaceType<String>(null));
+		ResolvableType type = ResolvableType.forInstance(new MyGenericInterfaceType<>(null));
 		assertThat(type.getType()).isEqualTo(MyGenericInterfaceType.class);
 		assertThat(type.resolve()).isEqualTo(MyGenericInterfaceType.class);
 	}
@@ -1177,6 +1177,20 @@ void isAssignableFromForComplexWildcards() throws Exception {
 		assertThatResolvableType(complex4).isNotAssignableFrom(complex3);
 	}
 
+	@Test
+	void isAssignableFromForUnresolvedWildcards() {
+		ResolvableType wildcard = ResolvableType.forInstance(new Wildcard<>());
+		ResolvableType wildcardFixed = ResolvableType.forInstance(new WildcardFixed());
+		ResolvableType wildcardConcrete = ResolvableType.forClassWithGenerics(Wildcard.class, Number.class);
+
+		assertThat(wildcard.isAssignableFrom(wildcardFixed)).isTrue();
+		assertThat(wildcard.isAssignableFrom(wildcardConcrete)).isTrue();
+		assertThat(wildcardFixed.isAssignableFrom(wildcard)).isFalse();
+		assertThat(wildcardFixed.isAssignableFrom(wildcardConcrete)).isFalse();
+		assertThat(wildcardConcrete.isAssignableFrom(wildcard)).isTrue();
+		assertThat(wildcardConcrete.isAssignableFrom(wildcardFixed)).isFalse();
+	}
+
 	@Test
 	void identifyTypeVariable() throws Exception {
 		Method method = ClassArguments.class.getMethod("typedArgumentFirst", Class.class, Class.class, Class.class);
@@ -1574,7 +1588,6 @@ public ResolvableType getResolvableType() {
 		}
 	}
 
-
 	public class MySimpleInterfaceType implements MyInterfaceType<String> {
 	}
 
@@ -1584,28 +1597,24 @@ public abstract class MySimpleInterfaceTypeWithImplementsRaw implements MyInterf
 	public abstract class ExtendsMySimpleInterfaceTypeWithImplementsRaw extends MySimpleInterfaceTypeWithImplementsRaw {
 	}
 
-
 	public class MyCollectionInterfaceType implements MyInterfaceType<Collection<String>> {
 	}
 
 
 	public abstract class MySuperclassType<T> {
 	}
 
-
 	public class MySimpleSuperclassType extends MySuperclassType<String> {
 	}
 
-
 	public class MyCollectionSuperclassType extends MySuperclassType<Collection<String>> {
 	}
 
 
-	interface Wildcard<T extends Number> extends List<T> {
+	public class Wildcard<T extends Number> {
 	}
 
-
-	interface RawExtendsWildcard extends Wildcard {
+	public class WildcardFixed extends Wildcard<Integer> {
 	}