syntax_data: {"ast_node_type":"variable","tokens":[{"end":39,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let opt_old_mode_span =
context_before:                 // Track the default binding mode for the Rust 2024 migration suggestion.
context_after:                     self.rust_2024_migration.as_mut().and_then(|s| s.visit_explicit_deref());