syntax_data: {"ast_node_type":"other","tokens":[{"end":61,"kind":"keyword","start":0,"text":"this.with_let_source(let_source,"}]}
source_snippet:                     this.with_let_source(let_source, |this| {
context_before:                         if else_block.is_some() { LetSource::LetElse } else { LetSource::PlainLet };
context_after:                         this.check_let(pattern, initializer, span)