syntax_data: {"ast_node_type":"variable","tokens":[{"end":52,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let usize_ty = self.tcx.types.usize;
context_before:             TestKind::Len { len, op } => {
context_after:                 let actual = self.temp(usize_ty, test.span);