syntax_data: {"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // Give a specific `let_source` for the condition.
context_before:             ExprKind::If { cond, then, else_opt, if_then_scope: _ } => {
context_after:                 let let_source = match ex.span.desugaring_kind() {