Function resolve_body_widths 

pub fn resolve_body_widths<S, W: Width>(
    statements: &[Ast<S>],
    context: &impl PcodeLoweringContext,
) -> BodyWidths<W>

Resolves the widths of a body’s locals and reports the ones with none.

Unlike infer_local_sizes this also visits the body to find which locals it actually uses, so a caller can tell a width it failed to resolve from an id that no statement mentions. A body’s local_var_count is a high-water mark of the id space after macro inlining, not its live set.