//! was re-used.
use rustc_ast as ast;
-use rustc_data_structures::stable_set::FxHashSet;
+use rustc_data_structures::fx::FxHashSet;
use rustc_hir::def_id::LOCAL_CRATE;
use rustc_middle::mir::mono::CodegenUnitNameBuilder;
use rustc_middle::ty::TyCtxt;