syntax_data: {"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:                 if chain_refutabilities.iter().any(|x| x.is_some()) {
context_before:                 // If at least one of the operands is a `let ... = ...`.
context_after:                     self.check_let_chain(chain_refutabilities, ex.span);