Function c2rust_refactor::ast_manip::lr_expr::fold_expr_with_context

pub fn fold_expr_with_context<F>(e: &mut P<Expr>, start: Context, callback: F) where
    F: FnMut(&mut P<Expr>, Context), 

Perform a bottom-up rewrite of an Expr, indicating at each step whether the expr is in an rvalue, (immutable) lvalue, or mutable lvalue context.

start is the context of the outermost expression e.