-use rustc::mir::ConstraintCategory;
-use rustc::ty::RegionVid;
use rustc_data_structures::graph;
use rustc_index::vec::IndexVec;
+use rustc_middle::mir::ConstraintCategory;
+use rustc_middle::ty::RegionVid;
use rustc_span::DUMMY_SP;
use crate::borrow_check::{