Simplify some jjtree aspects

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/impl/javacc/JjtreeBuilder.java

@@ -57,24 +57,6 @@ public final class JjtreeBuilder<N extends AbstractJjtreeNode<?>> {
         return nodes.get(0);
     }
 
-    /***
-     * Extend the number of children of the current node of one to the left.
-     * If the node is closed, one additional node from the stack will be popped
-     * and added to its children. This allows mimicking "left-recursive" nodes,
-     * while keeping the parsing iterative.
-     *
-     * <p>Note that when the total number of children is definitely known, you
-     * can use "definite nodes", ie write the expected number of children (including
-     * the ones to the left) in the JJTree annotation (eg {@code #AdditiveExpression(2)}).
-     * So this is only useful when the number of children of the current node is not certain.
-     *
-     * <p>This method does not affect the stack unless the current jjtThis is
-     * closed in the future.
-     */
-    public void extendLeft() {
-        mk--;
-    }
-
     /***
      * Peek the nth node from the top of the stack.
      * peekNode(0) == peekNode()

pmd-java/etc/grammar/Java.jjt

@@ -1285,13 +1285,13 @@ void ClassOrInterfaceType() #void:
   { forceTypeContext(); }
 }
 
-private void ClassTypeSegment() #ClassOrInterfaceType:
+private void ClassTypeSegment() #ClassOrInterfaceType(jjtree.nodeArity() + 1):
 {}
 {
      TypeAnnotListNoInject()
      <IDENTIFIER>
      // We'll enclose the previous segment
-     { setLastTokenImage(jjtThis);  jjtree.extendLeft();}
+     { setLastTokenImage(jjtThis); }
      [ TypeArguments() ]
 }
 
@@ -1345,7 +1345,7 @@ void PrimitiveType() :
     | "float"
     | "double"
     )
-    {jjtThis.setImage(getToken(0).getImage());}
+    {setLastTokenImage(jjtThis);}
 }
 
 
@@ -1628,7 +1628,8 @@ void PrimaryPrefix() #void :
     ("." MemberSelector() | MethodReference())
 | UnqualifiedAllocationExpr()
 | ("void" "." "class")                    #ClassLiteral
-| (PrimitiveType() [ Dims() ] )           #ArrayType(>1)
+| LOOKAHEAD(1) // suppress the warning here.
+  (PrimitiveType() [ Dims() ] )           #ArrayType(>1)
     (
        MethodReference()
      | "." "class"                        #ClassLiteral(1)
@@ -1636,7 +1637,7 @@ void PrimaryPrefix() #void :
 
 // If annotations start the expression, it's necessarily a method or ctor reference
 // This is because types in class literals or in qualified super/this may not be annotated
-| LOOKAHEAD({getToken(1).kind == AT}) AnnotatedRefType() MethodReference()
+| LOOKAHEAD("@") AnnotatedRefType() MethodReference()
 
 | LOOKAHEAD(LambdaLahead()) LambdaExpression()
 
@@ -1738,10 +1739,10 @@ void MemberSelector() #void :
 |              (<IDENTIFIER> {setLastTokenImage(jjtThis);})                                  #FieldAccess(1)
 }
 
-void MethodReference(): // LHS is injected
+void MethodReference() #MethodReference(jjtree.nodeArity() + 1): // LHS is injected
 {}
 {
-  "::" {jjtree.extendLeft();}
+  "::"
   [TypeArguments()]
   ( "new" | <IDENTIFIER> ) {setLastTokenImage(jjtThis);}
   {/* empty, to set the image before jjtClose */}
@@ -1847,11 +1848,10 @@ void ArgumentList() :
 
 
 // more straightforward because can't be an array creation expr
-void QualifiedAllocationExpr() #ConstructorCall:
+void QualifiedAllocationExpr() #ConstructorCall(jjtree.nodeArity() + 1):
 {}
 {
    "new"
-   {jjtree.extendLeft();}
    [ TypeArguments() ]
    AnnotatedClassOrInterfaceType()
    ArgumentList()

pmd-java/src/test/kotlin/net/sourceforge/pmd/lang/java/ast/ASTMethodReferenceTest.kt

@@ -1,6 +1,7 @@
 package net.sourceforge.pmd.lang.java.ast
 
 import net.sourceforge.pmd.lang.ast.test.shouldBe
+import net.sourceforge.pmd.lang.java.ast.ASTPrimitiveType.PrimitiveType.BOOLEAN
 import net.sourceforge.pmd.lang.java.ast.ASTPrimitiveType.PrimitiveType.INT
 
 /**
@@ -157,6 +158,23 @@ class ASTMethodReferenceTest : ParserTestSpec({
                 }
             }
 
+            "boolean @A []::new" should parseAs {
+                constructorRef {
+                    it::getTypeArguments shouldBe null
+
+                    typeExpr {
+                        arrayType {
+                            primitiveType(BOOLEAN)
+                            it::getDimensions shouldBe child {
+                                arrayDim {
+                                    annotation("A")
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+
             "Class<?>[]::new" should parseAs {
                 constructorRef {
                     it::getTypeArguments shouldBe null