fixes #1455 PMD doesn't handle Java 8 explicit receiver parameters

Those parameters are correctly parsed now and can be found
with "//FormalParameter[@ExplicitReceiverParameter='true']"

pmd-java/etc/grammar/Java.jjt

@@ -1,4 +1,9 @@
 /**
+ * Added support for explicit receiver parameters.
+ * Bug #1455
+ *
+ * Andreas Dangel 01/2016
+ *====================================================================
  * Added capability for Tracking Tokens.
  *
  * Amit Kumar Prasad 10/2015
@@ -248,6 +253,11 @@ public class JavaParser {
       throwParseException("Cannot use type annotations when running in JDK inferior to 1.8 mode!");
     }
   }
+  private void checkforBadExplicitReceiverParameter() {
+    if (jdkVersion < 8) {
+      throwParseException("Cannot use explicit receiver parameters when running in JDK inferior to 1.8 mode!");
+    }
+  }
 
   // This is a semantic LOOKAHEAD to determine if we're dealing with an assert
   // Note that this can't be replaced with a syntactic lookahead
@@ -1390,14 +1400,20 @@ void VariableDeclarator() :
 }
 
 void VariableDeclaratorId() :
-{Token t;}
 {
-  t=<IDENTIFIER>
+  Token t;
+  String image;
+}
+{
+  (LOOKAHEAD(2) t=<IDENTIFIER> "." <THIS> { checkforBadExplicitReceiverParameter(); jjtThis.setExplicitReceiverParameter(); image=t.image + ".this"; }
+   | t=<THIS> { checkforBadExplicitReceiverParameter(); jjtThis.setExplicitReceiverParameter(); image = t.image;}
+   | t=<IDENTIFIER> { image = t.image; }
+  )
   ( "[" "]"  { jjtThis.bumpArrayDepth(); })*
   {
-    checkForBadAssertUsage(t.image, "a variable name");
-    checkForBadEnumUsage(t.image, "a variable name");
-    jjtThis.setImage( t.image );
+    checkForBadAssertUsage(image, "a variable name");
+    checkForBadEnumUsage(image, "a variable name");
+    jjtThis.setImage( image );
   }
 }
 
@@ -1778,7 +1794,7 @@ void PrimaryPrefix() :
 {Token t;}
 {
   Literal()
-| "this" {jjtThis.setUsesThisModifier();}
+| LOOKAHEAD(2) "this" {jjtThis.setUsesThisModifier();}
 | "super" {jjtThis.setUsesSuperModifier();}
 | LOOKAHEAD( "(" ")" "->" ) LambdaExpression()
 | LOOKAHEAD( <IDENTIFIER> "->" ) LambdaExpression()

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTFormalParameter.java

@@ -19,7 +19,11 @@ public class ASTFormalParameter extends AbstractJavaAccessNode implements Dimens
     public boolean isVarargs() {
         return isVarargs;
     }
-    
+
+    public boolean isExplicitReceiverParameter() {
+        return getDecl().isExplicitReceiverParameter();
+    }
+
     public ASTFormalParameter(int id) {
         super(id);
     }

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTVariableDeclaratorId.java

@@ -31,6 +31,7 @@ public class ASTVariableDeclaratorId extends AbstractJavaTypeNode {
 
     private int arrayDepth;
     private VariableNameDeclaration nameDeclaration;
+    private boolean explicitReceiverParameter = false;
 
     public VariableNameDeclaration getNameDeclaration() {
         return nameDeclaration;
@@ -60,6 +61,13 @@ public class ASTVariableDeclaratorId extends AbstractJavaTypeNode {
         return jjtGetParent().jjtGetParent() instanceof ASTTryStatement;
     }
 
+    public void setExplicitReceiverParameter() {
+        explicitReceiverParameter = true;
+    }
+    public boolean isExplicitReceiverParameter() {
+        return explicitReceiverParameter;
+    }
+
     public Node getTypeNameNode() {
         if (jjtGetParent() instanceof ASTFormalParameter) {
             return findTypeNameNode(jjtGetParent());

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

@@ -13,6 +13,7 @@ import net.sourceforge.pmd.PMD;
 import net.sourceforge.pmd.lang.java.ParserTst;
 
 import org.apache.commons.io.IOUtils;
+import org.junit.Assert;
 import org.junit.Test;
 
 public class ParserCornersTest extends ParserTst {
@@ -54,15 +55,25 @@ public class ParserCornersTest extends ParserTst {
     }
 
     @Test
-    public void testParsersCases() {
+    public void testParsersCases15() {
         String test15 = readAsString("/net/sourceforge/pmd/ast/ParserCornerCases.java");
         parseJava15(test15);
+    }
 
+    @Test
+    public void testParsersCases17() {
         String test17 = readAsString("/net/sourceforge/pmd/ast/ParserCornerCases17.java");
         parseJava17(test17);
+    }
 
+    @Test
+    public void testParsersCases18() throws Exception {
         String test18 = readAsString("/net/sourceforge/pmd/ast/ParserCornerCases18.java");
-        parseJava18(test18);
+        ASTCompilationUnit cu = parseJava18(test18);
+
+        Assert.assertEquals(13, cu.findChildNodesWithXPath("//FormalParameter").size());
+        Assert.assertEquals(4, cu.findChildNodesWithXPath("//FormalParameter[@ExplicitReceiverParameter='true']").size());
+        Assert.assertEquals(9, cu.findChildNodesWithXPath("//FormalParameter[@ExplicitReceiverParameter='false']").size());
     }
 
     /**

pmd-java/src/test/resources/net/sourceforge/pmd/ast/ParserCornerCases18.java

@@ -153,6 +153,22 @@ public class ParserCornerCases18 {
             };
         }
     }
+
+    /**
+     * Explicit receiver Parameters
+     * see: http://blog.joda.org/2015/12/explicit-receiver-parameters.html
+     * and: https://sourceforge.net/p/pmd/bugs/1455/
+     */
+    public void methodWithReceiverParameter(ParserCornerCases18 this) { }
+    public void methodWithReceiverAndOtherParameters(ParserCornerCases18 this, String other) { }
+    public void methodWithReceiverParameterWithAnnotation(@AnnotatedUsage ParserCornerCases18 this, String other) { }
+
+    @Target(ElementType.TYPE_USE)
+    public @interface AnnotatedUsage {}
+
+    class Inner {
+        Inner(ParserCornerCases18 ParserCornerCases18.this) {}
+    }
 }
 
 interface DefaultIterator<E> {

src/site/markdown/overview/changelog.md

@@ -29,6 +29,8 @@
     *   [#1449](https://sourceforge.net/p/pmd/bugs/1449/): false positive when casting a variable to short
 *   java-design/AccessorClassGeneration:
     *   [#1452](https://sourceforge.net/p/pmd/bugs/1452/): ArrayIndexOutOfBoundsException with Annotations for AccessorClassGenerationRule
+*   General
+    *   [#1455](https://sourceforge.net/p/pmd/bugs/1455/): PMD doesn't handle Java 8 explicit receiver parameters
 
 **API Changes:**