Fix a bug in HHIR's emitParent

We actually grabbed the parent of the parent.  This means
things like parent::foo() were skipping the immediate parent.

hphp/runtime/vm/translator/hopt/codegen.cpp

@@ -4035,9 +4035,10 @@ void CodeGenerator::emitGetCtxFwdCallWithThis(PhysReg ctxReg,
 }
 
 /**
- * This method is similar to emitGetCtxFwdCallWithThis above,
- * but whether or not the callee is a static method is uknown at JIT time,
- * and that is determined dynamically by looking up into the StaticMethodFCache.
+ * This method is similar to emitGetCtxFwdCallWithThis above, but
+ * whether or not the callee is a static method is unknown at JIT
+ * time, and that is determined dynamically by looking up into the
+ * StaticMethodFCache.
  */
 void CodeGenerator::emitGetCtxFwdCallWithThisDyn(PhysReg      destCtxReg,
                                                  PhysReg      thisReg,

hphp/runtime/vm/translator/hopt/hhbctranslator.cpp

@@ -550,7 +550,7 @@ void HhbcTranslator::emitLateBoundCls() {
 
 void HhbcTranslator::emitSelf() {
   Class* clss = getCurClass();
-  if (clss == NULL) {
+  if (clss == nullptr) {
     emitInterpOne(Type::Cls, 0);
   } else {
     push(m_tb->genDefConst(clss));
@@ -558,8 +558,8 @@ void HhbcTranslator::emitSelf() {
 }
 
 void HhbcTranslator::emitParent() {
-  const Class* clss = getCurClass()->parent();
-  if (clss == NULL || clss->parent() == NULL) {
+  auto const clss = getCurClass();
+  if (clss == nullptr || clss->parent() == nullptr) {
     emitInterpOne(Type::Cls, 0);
   } else {
     push(m_tb->genDefConst(clss->parent()));

hphp/test/slow/traits/hhir_parent.php

@@ -0,0 +1,31 @@
+<?php
+
+class B {
+  public static function bar() {
+    echo "B\n";
+  }
+}
+
+class D extends B {
+  public static function bar() {
+    echo "D\n";
+  }
+}
+
+trait Yeah {
+  public function foo() {
+    // Bug #2339698.  Parent was skipping one.
+    parent::bar();
+  }
+}
+
+class C extends D {
+  use Yeah;
+}
+
+function foo() {
+  $k = new C();
+  $k->foo();
+}
+
+foo();

hphp/test/slow/traits/hhir_parent.php.expect

@@ -0,0 +1 @@
+D