{"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"let"}]}
    let closure_sig = ClosureSubst(closure_substs).sig_ty().clone();
fn coerce_closure_fn_ty(closure_substs: &Substitution, safety: chalk_ir::Safety) -> Ty {
    match closure_sig.kind(Interner) {