canonicalize rustc_session imports

src/librustc/hir/map/collector.rs

@@ -6,11 +6,10 @@ use crate::hir::intravisit::{NestedVisitorMap, Visitor};
 use crate::hir::map::HirEntryMap;
 use crate::ich::Fingerprint;
 use crate::middle::cstore::CrateStore;
-use crate::session::CrateDisambiguator;
-use crate::session::Session;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::svh::Svh;
 use rustc_index::vec::IndexVec;
+use rustc_session::{CrateDisambiguator, Session};
 use rustc_span::source_map::SourceMap;
 use rustc_span::Span;
 use std::iter::repeat;

src/librustc/hir/map/mod.rs

@@ -1203,7 +1203,7 @@ impl Named for ImplItem<'_> {
 }
 
 pub fn map_crate<'hir>(
-    sess: &crate::session::Session,
+    sess: &rustc_session::Session,
     cstore: &CrateStoreDyn,
     forest: &'hir Forest<'hir>,
     definitions: Definitions,