{"ast_node_type":"variable","tokens":[{"end":69,"kind":"keyword","start":0,"text":"let"}]}
    let mut expr_collector = ExprCollector::new(db, module, file_id);
) -> (Arc<ExpressionStore>, Arc<GenericParams>, ExpressionStoreSourceMap) {
    let mut collector = generics::GenericParamsCollector::new(def);