syntax_data: {"ast_node_type":"import","tokens":[{"end":92,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // This works because `str` and `&str` have the same valtree representation.
context_before:                 // when lowering to MIR in `Builder::perform_test`, treat the constant as a `&str`.
context_after:                 let ref_str_ty = Ty::new_imm_ref(tcx, tcx.lifetimes.re_erased, ty);