Fixes #1484 UnusedLocalVariable - false positive - parenthesis

pmd-java/etc/grammar/Java.jjt

@@ -1,4 +1,10 @@
 /**
+ * Fix for an expression within an additive expression that was
+ * wrongly taken as a cast expression.
+ * Bug #1484
+ *
+ * Andreas Dangel 05/2016
+ *====================================================================
  * Fix for Lambda expression with one variable
  * Bug #1470
  *
@@ -1755,6 +1761,7 @@ void UnaryExpressionNotPlusMinus() #UnaryExpressionNotPlusMinus((jjtn000.getImag
 {}
 {
  ( "~" {jjtThis.setImage("~");} | "!" {jjtThis.setImage("!");} ) UnaryExpression()
+| LOOKAHEAD("(" <IDENTIFIER> ")" "+") PostfixExpression()
 | LOOKAHEAD( CastExpression() ) CastExpression()
 | LOOKAHEAD("(" Type() ")" "(") CastExpression()
 | PostfixExpression()

pmd-java/src/test/java/net/sourceforge/pmd/lang/java/ast/ParserCornersTest.java

@@ -131,6 +131,21 @@ public class ParserCornersTest extends ParserTst {
         parseJava18(c);
     }
 
+    /**
+     * This triggered bug #1484 UnusedLocalVariable - false positive - parenthesis
+     * @throws Exception
+     */
+    @Test
+    public void stringConcatentationShouldNotBeCast() throws Exception {
+        String code = "public class Test {\n" + 
+                "    public static void main(String[] args) {\n" + 
+                "        System.out.println(\"X\" + (args) + \"Y\");\n" + 
+                "    }\n" + 
+                "}";
+        ASTCompilationUnit cu = parseJava18(code);
+        Assert.assertEquals(0, cu.findDescendantsOfType(ASTCastExpression.class).size());
+    }
+
     private String readAsString(String resource) {
         InputStream in = ParserCornersTest.class.getResourceAsStream(resource);
         try {

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

@@ -342,6 +342,32 @@ public class Foo {
             // do something
         }
     }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>#1484 UnusedLocalVariable - false positive - parenthesis</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+import java.util.ArrayList;
+import java.util.List;
+
+public class Test {
+    public static void main(String[] args) {
+        List<String> list = new ArrayList<>();
+        list.add("first");
+        list.add("second");
+
+        int notEmpty = 0;
+        for (String string : list) {
+                if (!string.isEmpty()) {
+                    notEmpty++;
+                }
+        }
+
+        System.out.println(list.size() + " (" + (notEmpty) + " not empty)");
+    }
 }
         ]]></code>
     </test-code>

src/site/markdown/overview/changelog.md

@@ -14,6 +14,9 @@
 
 **Bugfixes:**
 
+*   java-unusedcode/UnusedLocalVariable
+    *   [#1484](https://sourceforge.net/p/pmd/bugs/1484/): UnusedLocalVariable - false positive - parenthesis
+
 **API Changes:**
 
 *   New command line parameter for PMD: `-norulesetcompatibility` - this disables the ruleset factory