#1286 UnusedPrivateMethod returns false positives for varags and enums

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/symboltable/ClassScope.java

@@ -324,12 +324,18 @@ public class ClassScope extends AbstractJavaScope {
                     ASTClassOrInterfaceType classInterface = (ASTClassOrInterfaceType)child.jjtGetChild(0);
                     type = convertToSimpleType(classInterface);
                 }
-                if (type == null && parameterTypes.size() > i) {
+                if (type == null && !parameterTypes.isEmpty()) {
                     // replace the unknown type with the correct parameter type of the method.
                     // in case the argument is itself a method call, we can't determine the result type of the called
                     // method. Therefore the parameter type is used.
                     // This might cause confusion, if method overloading is used.
-                    type = parameterTypes.get(i);
+
+                    // the method might be vararg, so, there might be more arguments than parameterTypes
+                    if (parameterTypes.size() > i) {
+                        type = parameterTypes.get(i);
+                    } else {
+                        type = parameterTypes.get(parameterTypes.size() - 1); // last parameter is the vararg type
+                    }
                 }
                 if (type != null && type.getType() == null) {
                     Class<?> typeBound = resolveGenericType(argument, type.getTypeImage());

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/unusedcode/xml/UnusedPrivateMethod.xml

@@ -1324,6 +1324,33 @@ public class SuperClassFalsePositive {
             super(message);
         }
     }
+}
+        ]]></code>
+    </test-code>
+    <test-code>
+        <description>#1286 UnusedPrivateMethod returns false positives for varags</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class VaragsFalsePositive {
+
+    enum Sizes
+    {
+        TINY,
+        MEDIUM
+    }
+
+    public boolean containsTiny(){
+        return hasTiny(Sizes.MEDIUM, Sizes.TINY);
+    }
+
+    private boolean hasTiny(Sizes... sizes) {
+        for (Sizes size : sizes) {
+            if (size==Sizes.TINY) {
+                return true;
+            }
+        }
+        return false;
+    }
 }
         ]]></code>
     </test-code>

src/site/markdown/overview/changelog.md

@@ -16,3 +16,4 @@
 * [#1281](https://sourceforge.net/p/pmd/bugs/1281/): UnusedPrivateMethod incorrectly flagged for methods nested private classes
 * [#1282](https://sourceforge.net/p/pmd/bugs/1282/): False Positive with implicit String.valuesOf() (Java)
 * [#1285](https://sourceforge.net/p/pmd/bugs/1285/): Prevent to modify the System environment
+* [#1286](https://sourceforge.net/p/pmd/bugs/1286/): UnusedPrivateMethod returns false positives for varags and enums