Fix some corner cases found in jdk12 sources

pmd-java/etc/grammar/Java.jjt

@@ -2521,14 +2521,13 @@ void PrimaryPrefix() #void :
 // This describes the cases where the PrimaryPrefix may fall
 // into PrimaryStep2. Notice that type arguments is still possible,
 // as well as annotations ("@") before an annotated array type.
-// If we are in an explicit constructor invocation, then super or
-// this are disallowed.
+// If we are in an explicit constructor invocation, then super is disallowed.
 private void Step2Lahead() #void:
 {}
 {
    "::" | "(" | "@" | "[" | TypeArguments()
    | LOOKAHEAD({!inExplicitConstructorInvoc}) "."
-   | LOOKAHEAD({inExplicitConstructorInvoc}) "." ("class" | <IDENTIFIER> | TypeArguments() <IDENTIFIER> | "new") // not super or this in this case
+   | LOOKAHEAD({inExplicitConstructorInvoc}) "." ("class" | <IDENTIFIER> | TypeArguments() <IDENTIFIER> | "new" | "this") // not super in this case
 }
 
 private void SuffixLAhead() #void:
@@ -2548,8 +2547,8 @@ private void SuffixLAhead() #void:
 void PrimaryStep2() #void:
 {}
 {
-      // Can't be followed by array dims, because it would raise an error for generic array creation
-      {forceTypeContext();} TypeArguments() {injectTop();} ( "." ClassTypeSegment() )* MethodReference()
+      // If the class is a parameterised type, then we can only expect a method reference
+      {forceTypeContext();} TypeArguments() {injectTop();} ( "." ClassTypeSegment() )* [ Dims() #ArrayType(2) ] MethodReference()
     | MethodReference()
     | ArgumentList()                          #MethodCall(2)
     | "." (

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

@@ -41,7 +41,9 @@ public enum BinaryOp {
 
     // shift
     LEFT_SHIFT("<<"),
+    /** Token {@code >> } */
     RIGHT_SHIFT(">>"),
+    /** Token {@code >>>} */
     UNSIGNED_RIGHT_SHIFT(">>>"),
 
     // additive

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

@@ -147,6 +147,24 @@ class ASTExplicitConstructorInvocationTest : ParserTestSpec({
             }
         }
 
+        "public TabbedPaneLayout() { MetalTabbedPaneUI.this.super(); }" should matchDeclaration<ASTConstructorDeclaration> {
+
+            child<ASTFormalParameters> { }
+
+            child<ASTExplicitConstructorInvocation> {
+                it::isThis shouldBe false
+                it::isSuper shouldBe true
+                it::isQualified shouldBe true
+                it::getExplicitTypeArguments shouldBe null
+                it::getArgumentCount shouldBe 0
+
+                it::getLhsExpression shouldBe child<ASTThisExpression>(ignoreChildren = true) { }
+
+
+                it::getArgumentsList shouldBe child { }
+            }
+        }
+
         // An explicit constructor invocation statement in a constructor body may not refer to any instance
         // variables or instance methods or inner classes declared in this class or any superclass, or use
         // this or super in any expression; otherwise, a compile-time error occurs.

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

@@ -165,6 +165,23 @@ class ASTMethodReferenceTest : ParserTestSpec({
                 }
             }
 
+            "Class<?>[]::new" should parseAs {
+                constructorRef {
+                    it::getTypeArguments shouldBe null
+
+                    arrayType {
+                        classType("Class") {
+                            typeArgList {
+                                child<ASTWildcardType> { }
+                            }
+                        }
+                        it::getDimensions shouldBe child {
+                            arrayDim()
+                        }
+                    }
+                }
+            }
+
             "ArrayList::<String>new" should parseAs {
                 constructorRef {
                     val lhs = classType("ArrayList")

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

@@ -36,6 +36,19 @@ class ASTShiftExpressionTest : ParserTestSpec({
             child<ASTNumericLiteral> {}
         }
 
+        "i < width >> 1" should matchExpr<ASTRelationalExpression> {
+            it::getOp shouldBe BinaryOp.LE
+
+            variableRef("i")
+
+            child<ASTShiftExpression> {
+                it::getOp shouldBe BinaryOp.RIGHT_SHIFT
+
+                variableRef("width")
+                int(1)
+            }
+        }
+
     }
 
     parserTest("Changing operators should push a new node") {