Currently the parameter is first parsed as a reference, and then translated into a parameter. The reference stays around though, and gets resolved to the parameter. That automatically creates a use. Now that I drop all unresolved references when we abort preparsing, that also drops the unresolved reference.

Instead, mark the variable as used when its marked as forced context allocation. That's what happens in almost all other cases.

This raises the question: does it really make sense to parse parameters this ways? It seems pretty generic, but neither fast nor memory-efficient ... Did I misunderstand something?

Just land if you think the CL looks good as is.

BUG=chromium:651613

Review-Url: https://codereview.chromium.org/2386623002
Cr-Commit-Position: refs/heads/master@{#39935}