syntax_data: {"ast_node_type":"other","tokens":[{"end":74,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // write out some legible representation of an abstract const?
context_before:             // FIXME(generic_const_exprs):
context_after:             ty::ConstKind::Expr(expr) => self.pretty_print_const_expr(expr, print_ty)?,