const {
  bool is_compilable = true;
  is_compilable &= ExtractNodeDefAndCheckCompilability(
      if_node, "then_branch", "if_then", encapsulating_function, lib_runtime,
      stack_trace, uncompilable_nodes);
  if (!uncompilable_nodes && !is_compilable) return is_compilable;

  is_compilable &= ExtractNodeDefAndCheckCompilability(
      if_node, "else_branch", "if_else", encapsulating_function, lib_runtime,

                        UncompilableNodesMap* uncompilable_nodes) const;

  // Returns compilability of node def retrieved from `node`'s attribute with
  // name `attr_name`.
  bool ExtractNodeDefAndCheckCompilability(
      const Node& node, const std::string& attr_name,
      const std::string& call_name, NameAttrList* encapsulating_function,
      FunctionLibraryRuntime* lib_runtime,