fix(ImportCleaner): resolve imports of parent types (#4353)

src/main/java/spoon/reflect/visitor/ImportCleaner.java

@@ -37,6 +37,7 @@
 import spoon.support.Experimental;
 import spoon.support.util.ModelList;
 import spoon.support.visitor.ClassTypingContext;
+import spoon.support.visitor.equals.EqualsVisitor;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -176,15 +177,23 @@ void addImport(CtReference ref) {
 				// we would like to add an import, but we don't know to where
 				return;
 			}
-			if (ref instanceof CtFieldReference<?>
-					&& !isReferenceToFieldPresentInImports((CtFieldReference<?>) ref)) {
+			if (ref instanceof CtFieldReference<?> && !isReferencePresentInImports(ref)) {
 				return;
 			}
 			CtTypeReference<?> topLevelTypeRef = typeRef.getTopLevelType();
 			if (typeRefQNames.contains(topLevelTypeRef.getQualifiedName())) {
 				//it is reference to a type of this CompilationUnit. Do not add it
 				return;
 			}
+			if (ref instanceof CtTypeReference<?>
+					&& !isReferencePresentInImports(topLevelTypeRef)
+					&& topLevelTypeRef != ref
+					&& !isReferencePresentInImports(ref)) {
+				// check if a top level type has been imported
+				// if it has been, we don't need to add a separate import for its subtype
+				// last condition ensures that if only the subtype has been imported, we do not remove it
+				return;
+			}
 			CtPackageReference packageRef = topLevelTypeRef.getPackage();
 			if (packageRef == null) {
 				return;
@@ -210,10 +219,26 @@ void addImport(CtReference ref) {
 			}
 		}
 
-		private boolean isReferenceToFieldPresentInImports(CtFieldReference ref) {
+		private boolean isReferencePresentInImports(CtReference ref) {
 			return compilationUnit.getImports()
 					.stream()
-					.anyMatch(ctImport -> ctImport.getReference() != null && ctImport.getReference().equals(ref));
+					.anyMatch(ctImport -> ctImport.getReference() != null
+							&& isEqualAfterSkippingRole(ctImport.getReference(), ref, CtRole.TYPE_ARGUMENT));
+		}
+
+		/**
+		 * Checks if element and other are equal if comparison for `role` value is skipped
+		 */
+		private boolean isEqualAfterSkippingRole(CtElement element, CtElement other, CtRole role) {
+			EqualsVisitor equalsVisitor = new EqualsVisitor();
+			boolean isEqual = equalsVisitor.checkEquals(element, other);
+			if (isEqual) {
+				return true;
+			}
+			if (role == equalsVisitor.getNotEqualRole()) {
+				return true;
+			}
+			return false;
 		}
 
 		void onCompilationUnitProcessed(CtCompilationUnit compilationUnit) {

src/test/java/spoon/reflect/visitor/ImportCleanerTest.java

@@ -15,6 +15,18 @@
 
 public class ImportCleanerTest {
 
+	@Test
+	void testDoesNotRemoveImportOfSubType() {
+		// contract: The import cleaner should not remove import of subtype if it is used by its simply qualified name
+		testImportCleanerDoesNotAlterImports("src/test/resources/importCleaner/DoNotRemoveSubType.java", "importCleaner.DoNotRemoveSubType");
+	}
+
+	@Test
+	void testDoesNotImportTypeWhoseParentTypeIsAlreadyImported() {
+		// contract: The import cleaner should not import the subtype if its parent has already been imported
+		testImportCleanerDoesNotAlterImports("src/test/resources/importCleaner/TypeImportButUseSubType.java", "importCleaner.TypeImportButUseSubType");
+	}
+
 	@Test
 	void testDoesNotRemoveImportForStaticFieldOfStaticClass() {
 		// contract: The import cleaner should not remove import of the static field

src/test/resources/importCleaner/DoNotRemoveSubType.java

@@ -0,0 +1,9 @@
+package importCleaner;
+
+import java.util.Map.Entry;
+
+public class DoNotRemoveSubType {
+    public void hey() {
+        Entry<String, String> f = null;
+    }
+}