My primary concern is performance. I'd rather avoid lookups against the `resolver` for every generated identifier, if possible. The only case where this check seems like it is needed is [here]([URL] so incurring the cost of the lookup for *every* hoisted variable is unnecessary overhead.
I would still recommend that we add `addBlockVariableDeclaration` for this case, but we can mark it as `/* [USER] */` for now and revisit the API for custom transformer consumption later.