syntax_data: {"ast_node_type":"variable","tokens":[{"end":46,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let (uv, ty) = match constant.const_ {
context_before:         assert!(!constant.const_.ty().has_param());
context_after:             mir::Const::Unevaluated(uv, ty) => (uv.shrink(), ty),