syntax_data: {"ast_node_type":"other","tokens":[{"end":84,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// Returns the prior default binding mode; this should be followed by a call to
context_before:     /// Tracks the default binding mode when we're lowering a `&` or `&mut` pattern.
context_after:     /// [`PatMigration::leave_ref`] to restore it when we leave the pattern.