Separate node kind for bindings inside var
#4822
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This is a step toward making binding pattern handling more robust, by removing its reliance on the node stack for context.
| // whether that pattern is nested inside a `var` pattern. | ||
| auto PushStateForPattern(State state, bool in_var_pattern) -> void { | ||
| PushState({.state = state, | ||
| .in_var_pattern = in_var_pattern, |
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Hm. With this field added, the first two overloads of PushState seem like they're inviting bugs. I wonder if it's worth making them CHECK- or DCHECK-fail when used to push a pattern state.
That said... I suppose the same is true when pushing an expression state, and we seem to not have problems with that. Maybe I'm worrying too much :)
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I agree that this is concerning, but I don't see a way to distinguish pattern states, other than to have a manually-curated list, which seems liable to fall out of date over time. It also seems like that check could be inefficient as the number of pattern states grows, unless we set up something like a perfect hash.
I feel like there's a higher level API to be discovered here, which might help prevent that kind of mistake, but I don't see it clearly yet.
This is a step toward making binding pattern handling more robust, by removing its reliance on the node stack for context.