for (int i = partsSize - 1; i >= 0; i--) {
      // Decode the current node.
      int firstChild = trieData.charAt(nodeIndex * NODE_SIZE + 1);
      int numChildren = trieData.charAt(nodeIndex * NODE_SIZE + 2) & CHILDREN_MASK;

      nodeIndex = findChild(firstChild, numChildren, labels.get(i));
      if (nodeIndex == -1) {
        break;
      }

pkg go/types, method (*Scope) Lookup(string) Object
pkg go/types, method (*Scope) LookupParent(string, token.Pos) (*Scope, Object)
pkg go/types, method (*Scope) Names() []string
pkg go/types, method (*Scope) NumChildren() int
pkg go/types, method (*Scope) Parent() *Scope
pkg go/types, method (*Scope) Pos() token.Pos
pkg go/types, method (*Scope) String() string
pkg go/types, method (*Scope) WriteTo(io.Writer, int, bool)