Parse nodes expand into an array of variant<AstNode, ParseNode>. During expansion, the populated array is assumed to be owned to the caller as soon as the call returns. This process requires creating a handle for each array element which can manage the lifetime of the array element on the host side of the API.

This code is easy critical in order to prevent memory leaks in error situations.

We'd like to templatize this code so it can be used in other array cases with a low maintenance burden.