fix:bug in isSubtypeOf (broken contract X.isSubtypeOf(X)==true) (#1157)

* test X.isSubtypeOf(X)==true

* Change implementation of isSubtypeOf for different implementations to use method defined in CtTypeReferenceImpl.

* Add one more test to check isSubtypeOf for TypeParameters.

* fix checkstyle

* comment test of not yet supported isSubTypeOf TypedParameter

* added comment typeX.isSubtypeOf(typeX) is true

src/main/java/spoon/reflect/declaration/CtTypeInformation.java

@@ -98,6 +98,7 @@ public interface CtTypeInformation {
 
 	/**
 	 * Returns true if the referenced type is a sub-type of the given type.
+	 * Returns true is type is self, it means: typeX.isSubtypeOf(typeX) is true too
 	 */
 	boolean isSubtypeOf(CtTypeReference<?> type);
 

src/main/java/spoon/support/reflect/declaration/CtAnnotationTypeImpl.java

@@ -66,7 +66,7 @@ public <C extends CtType<T>> C setSuperInterfaces(Set<CtTypeReference<?>> interf
 
 	@Override
 	public boolean isSubtypeOf(CtTypeReference<?> type) {
-		return false;
+		return getReference().isSubtypeOf(type);
 	}
 
 	@Override

src/main/java/spoon/support/reflect/declaration/CtClassImpl.java

@@ -176,15 +176,7 @@ public boolean isAnonymous() {
 
 	@Override
 	public boolean isSubtypeOf(CtTypeReference<?> type) {
-		if ((getSuperclass() != null) && getSuperclass().isSubtypeOf(type)) {
-			return true;
-		}
-		for (CtTypeReference<?> ref : getSuperInterfaces()) {
-			if (ref.isSubtypeOf(type)) {
-				return true;
-			}
-		}
-		return false;
+		return getReference().isSubtypeOf(type);
 	}
 
 	@Override

src/main/java/spoon/support/reflect/declaration/CtEnumImpl.java

@@ -56,12 +56,7 @@ public Set<CtMethod<?>> getAllMethods() {
 
 	@Override
 	public boolean isSubtypeOf(CtTypeReference<?> type) {
-		for (CtTypeReference<?> ref : getSuperInterfaces()) {
-			if (ref.isSubtypeOf(type)) {
-				return true;
-			}
-		}
-		return getSuperclass().isSubtypeOf(type);
+		return getReference().isSubtypeOf(type);
 	}
 
 	@Override

src/main/java/spoon/support/reflect/declaration/CtInterfaceImpl.java

@@ -39,12 +39,7 @@ public void accept(CtVisitor visitor) {
 
 	@Override
 	public boolean isSubtypeOf(CtTypeReference<?> type) {
-		for (CtTypeReference<?> ref : getSuperInterfaces()) {
-			if (ref.isSubtypeOf(type)) {
-				return true;
-			}
-		}
-		return false;
+		return getReference().isSubtypeOf(type);
 	}
 
 	@Override

src/main/java/spoon/support/reflect/declaration/CtTypeParameterImpl.java

@@ -234,7 +234,7 @@ public List<CtFieldReference<?>> getDeclaredFields() {
 
 	@Override
 	public boolean isSubtypeOf(CtTypeReference<?> type) {
-		return false;
+		return getReference().isSubtypeOf(type);
 	}
 
 	@Override

src/main/java/spoon/support/reflect/reference/CtTypeParameterReferenceImpl.java

@@ -81,11 +81,6 @@ public boolean isGenerics() {
 		return true;
 	}
 
-	@Override
-	public boolean isSubtypeOf(CtTypeReference<?> type) {
-		return false;
-	}
-
 	@Override
 	public boolean isPrimitive() {
 		return false;

src/test/java/spoon/test/ctType/CtTypeTest.java

@@ -6,9 +6,14 @@
 import spoon.reflect.declaration.CtInterface;
 import spoon.reflect.declaration.CtMethod;
 import spoon.reflect.declaration.CtType;
+import spoon.reflect.declaration.CtTypeMember;
+import spoon.reflect.declaration.CtTypeParameter;
 import spoon.reflect.factory.Factory;
+import spoon.reflect.reference.CtTypeReference;
 import spoon.test.ctType.testclasses.X;
 
+import java.util.List;
+
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static spoon.testing.utils.ModelUtils.buildClass;
@@ -69,8 +74,37 @@ public void testHasMethodInDefaultMethod() throws Exception {
 	@Test
 	public void testIsSubTypeOf() throws Exception {
 		CtType<X> xCtType = buildClass(X.class);
+		CtType<?> yCtType = xCtType.getFactory().Type().get("spoon.test.ctType.testclasses.Y");
+
+		assertFalse(xCtType.isSubtypeOf(yCtType.getReference()));
+		assertTrue(yCtType.isSubtypeOf(xCtType.getReference()));
+		//contract: x isSubtypeOf x
+		//using CtTypeReference implementation
+		assertTrue(xCtType.getReference().isSubtypeOf(xCtType.getReference()));
+		//using CtType implementation
+		assertTrue(xCtType.isSubtypeOf(xCtType.getReference()));
+	}
+
+	@Test
+	public void testIsSubTypeOfonTypeParameters() throws Exception {
+		CtType<X> xCtType = buildClass(X.class);
+
+		CtType<?> oCtType = xCtType.getFactory().Type().get("spoon.test.ctType.testclasses.O");
+
+		List<CtTypeParameter> typeParameters = oCtType.getFormalCtTypeParameters();
+		assertTrue(typeParameters.size() == 1);
+
+		CtType<?> aCtType = typeParameters.get(0);
+
+		List<CtMethod<?>> methods = oCtType.getMethodsByName("foo");
+
+		assertTrue(methods.size() == 1);
+
+		CtMethod<?> fooMethod = methods.get(0);
+		CtType<?> bCtType = fooMethod.getType().getDeclaration();
 
-		assertFalse(xCtType.isSubtypeOf(xCtType.getFactory().Type().createReference("spoon.test.ctType.testclasses.Y")));
-		assertTrue(xCtType.getFactory().Type().get("spoon.test.ctType.testclasses.Y").isSubtypeOf(xCtType.getReference()));
+		//The TypeParameters are not supported yet
+//		assertTrue(bCtType.isSubtypeOf(xCtType.getReference()));
+//		assertTrue(bCtType.isSubtypeOf(aCtType.getReference()));
 	}
 }

src/test/java/spoon/test/ctType/testclasses/X.java

@@ -17,3 +17,9 @@ interface Z {
 abstract class W implements Z {
 }
 
+class O<A extends X> {
+	<B extends A> B foo() {
+		return null;
+	}
+}
+