Fix FPs around enums that are never referenced by name in UnusedType

Enums are considered used as long as any of their elements are used.

Author: cirras

CHANGELOG.md

@@ -34,6 +34,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - False positives on enumerable method `GetEnumerator` in `UnusedRoutine`.
 - False positives on enumerator method `MoveNext` in `UnusedRoutine`.
 - False positives on enumerator property `Current` in `UnusedProperty`.
+- False positives on enums that are never referenced by name (but have used values) in `UnusedType`.
 - Name resolution failures in legacy initialization sections referencing the implementation section.
 - Incorrect file position calculation for multiline string tokens.
 

delphi-checks/src/main/java/au/com/integradev/delphi/checks/UnusedTypeCheck.java

@@ -18,9 +18,14 @@
  */
 package au.com.integradev.delphi.checks;
 
+import java.util.List;
+import java.util.function.Predicate;
 import org.sonar.check.Rule;
 import org.sonar.check.RuleProperty;
+import org.sonar.plugins.communitydelphi.api.ast.EnumElementNode;
+import org.sonar.plugins.communitydelphi.api.ast.EnumTypeNode;
 import org.sonar.plugins.communitydelphi.api.ast.InterfaceSectionNode;
+import org.sonar.plugins.communitydelphi.api.ast.NameDeclarationNode;
 import org.sonar.plugins.communitydelphi.api.ast.TypeDeclarationNode;
 import org.sonar.plugins.communitydelphi.api.check.DelphiCheck;
 import org.sonar.plugins.communitydelphi.api.check.DelphiCheckContext;
@@ -63,6 +68,10 @@ private boolean isViolation(TypeDeclarationNode node) {
       return false;
     }
 
+    if (node.isEnum() && hasElementsWithUsages((EnumTypeNode) node.getTypeNode())) {
+      return false;
+    }
+
     if (excludeApi
         && (node.isPublic() || node.isPublished())
         && node.getFirstParentOfType(InterfaceSectionNode.class) != null) {
@@ -77,6 +86,13 @@ private boolean isViolation(TypeDeclarationNode node) {
         .allMatch(occurrence -> isWithinType(occurrence, type));
   }
 
+  private static boolean hasElementsWithUsages(EnumTypeNode node) {
+    return node.getElements().stream()
+        .map(EnumElementNode::getNameDeclarationNode)
+        .map(NameDeclarationNode::getUsages)
+        .anyMatch(Predicate.not(List::isEmpty));
+  }
+
   private static boolean isWithinType(NameOccurrence occurrence, Type type) {
     DelphiScope scope = occurrence.getLocation().getScope();
     while (scope != null) {

delphi-checks/src/test/java/au/com/integradev/delphi/checks/UnusedTypeCheckTest.java

@@ -212,4 +212,34 @@ void testUnusedTypeWithAttributeShouldNotAddIssue() {
                 .appendDecl("  end;"))
         .verifyNoIssues();
   }
+
+  @Test
+  void testUnusedEnumWithUsedElementsShouldNotAddIssue() {
+    CheckVerifier.newVerifier()
+        .withCheck(new UnusedTypeCheck())
+        .onFile(
+            new DelphiTestUnitBuilder()
+                .appendImpl("function Foo: Integer;")
+                .appendImpl("type")
+                .appendImpl("  TBar = (Baz, Flarp);")
+                .appendImpl("begin")
+                .appendImpl("  Result := Ord(Baz) + 123;")
+                .appendImpl("end;"))
+        .verifyNoIssues();
+  }
+
+  @Test
+  void testUnusedEnumWithUnusedElementsShouldAddIssue() {
+    CheckVerifier.newVerifier()
+        .withCheck(new UnusedTypeCheck())
+        .onFile(
+            new DelphiTestUnitBuilder()
+                .appendImpl("function Foo: Integer;")
+                .appendImpl("type")
+                .appendImpl("  TBar = (Baz, Flarp); // Noncompliant")
+                .appendImpl("begin")
+                .appendImpl("  Result := 123;")
+                .appendImpl("end;"))
+        .verifyIssues();
+  }
 }