Add tag step on StoredNode. (#1005)

Also moved tag step on Traversal[StoredNode] to expected place.

Author: ml86

semanticcpg/src/main/scala/io/shiftleft/semanticcpg/language/NodeSteps.scala

@@ -113,4 +113,11 @@ class NodeSteps[NodeType <: nodes.StoredNode](val traversal: Traversal[NodeType]
       taggedNode.tagList.l
     }.l
 
+  @Doc("Tags attached to this node")
+  def tag: Traversal[nodes.Tag] = {
+    traversal.flatMap { node =>
+      node.tag
+    }
+  }
+
 }

semanticcpg/src/main/scala/io/shiftleft/semanticcpg/language/nodemethods/StoredNodeMethods.scala

@@ -0,0 +1,11 @@
+package io.shiftleft.semanticcpg.language.nodemethods
+
+import io.shiftleft.codepropertygraph.generated.nodes
+import overflowdb.traversal.Traversal
+import scala.jdk.CollectionConverters._
+
+class StoredNodeMethods(val node: nodes.StoredNode) extends AnyVal {
+  def tag: Traversal[nodes.Tag] = {
+    node._taggedByOut().asScala.map(_.asInstanceOf[nodes.Tag]).to(Traversal)
+  }
+}

semanticcpg/src/main/scala/io/shiftleft/semanticcpg/language/package.scala

@@ -41,6 +41,7 @@ package object language extends operatorextension.Implicits {
 
   implicit def cfgNodeToAstNode(node: nodes.CfgNode): AstNodeMethods = new AstNodeMethods(node)
   implicit def toExtendedNode(node: nodes.CpgNode): NodeMethods = new NodeMethods(node)
+  implicit def toExtendedStoredNode(node: nodes.StoredNode): StoredNodeMethods = new StoredNodeMethods(node)
   implicit def withMethodMethodsQp(node: nodes.WithinMethod): WithinMethodMethods = new WithinMethodMethods(node)
   implicit def toAstNodeMethods(node: nodes.AstNode): AstNodeMethods = new AstNodeMethods(node)
   implicit def toCfgNodeMethods(node: nodes.CfgNode): CfgNodeMethods = new CfgNodeMethods(node)
@@ -78,15 +79,6 @@ package object language extends operatorextension.Implicits {
   implicit def toMethodRef(trav: Traversal[nodes.MethodRef]): MethodRef = new MethodRef(trav)
   implicit def toBinding(trav: Traversal[nodes.Binding]): Binding = new Binding(trav)
 
-  implicit class NodeStepsExt(val traversal: Traversal[_ <: StoredNode]) extends AnyVal {
-
-    /**
-    Traverse to tags of nodes in enhanced graph
-      */
-    def tag: Traversal[nodes.Tag] =
-      traversal.out(EdgeTypes.TAGGED_BY).cast[nodes.Tag]
-  }
-
   // Call graph extension
   implicit def toMethodForCallGraph(trav: Traversal[nodes.Method]): Method = new Method(trav)
   implicit def toCallForCallGraph(trav: Traversal[nodes.Call]): Call = new Call(trav)