Remove HirCollector::sess.

It's redundant w.r.t. `HirCollector::tcx`. This removes the unnecessary
`'a` lifetime.

src/librustdoc/doctest.rs

@@ -186,7 +186,6 @@ pub(crate) fn run(
 
                 let mut collector = CreateRunnableDocTests::new(options, opts);
                 let hir_collector = HirCollector::new(
-                    &compiler.sess,
                     tcx.hir(),
                     ErrorCodes::from(compiler.sess.opts.unstable_features.is_nightly_build()),
                     enable_per_target_ignores,

src/librustdoc/doctest/rust.rs

@@ -10,7 +10,6 @@ use rustc_middle::hir::map::Map;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::TyCtxt;
 use rustc_resolve::rustdoc::span_of_fragments;
-use rustc_session::Session;
 use rustc_span::source_map::SourceMap;
 use rustc_span::{BytePos, DUMMY_SP, FileName, Pos, Span};
 
@@ -63,30 +62,28 @@ impl DocTestVisitor for RustCollector {
     fn visit_header(&mut self, _name: &str, _level: u32) {}
 }
 
-pub(super) struct HirCollector<'a, 'tcx> {
-    sess: &'a Session,
+pub(super) struct HirCollector<'tcx> {
     map: Map<'tcx>,
     codes: ErrorCodes,
     tcx: TyCtxt<'tcx>,
     enable_per_target_ignores: bool,
     collector: RustCollector,
 }
 
-impl<'a, 'tcx> HirCollector<'a, 'tcx> {
+impl<'tcx> HirCollector<'tcx> {
     pub fn new(
-        sess: &'a Session,
         map: Map<'tcx>,
         codes: ErrorCodes,
         enable_per_target_ignores: bool,
         tcx: TyCtxt<'tcx>,
     ) -> Self {
         let collector = RustCollector {
-            source_map: sess.psess.clone_source_map(),
+            source_map: tcx.sess.psess.clone_source_map(),
             cur_path: vec![],
             position: DUMMY_SP,
             tests: vec![],
         };
-        Self { sess, map, codes, enable_per_target_ignores, tcx, collector }
+        Self { map, codes, enable_per_target_ignores, tcx, collector }
     }
 
     pub fn collect_crate(mut self) -> Vec<ScrapedDocTest> {
@@ -98,7 +95,7 @@ impl<'a, 'tcx> HirCollector<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> HirCollector<'a, 'tcx> {
+impl<'tcx> HirCollector<'tcx> {
     fn visit_testable<F: FnOnce(&mut Self)>(
         &mut self,
         name: String,
@@ -108,7 +105,7 @@ impl<'a, 'tcx> HirCollector<'a, 'tcx> {
     ) {
         let ast_attrs = self.tcx.hir().attrs(self.tcx.local_def_id_to_hir_id(def_id));
         if let Some(ref cfg) = ast_attrs.cfg(self.tcx, &FxHashSet::default()) {
-            if !cfg.matches(&self.sess.psess, Some(self.tcx.features())) {
+            if !cfg.matches(&self.tcx.sess.psess, Some(self.tcx.features())) {
                 return;
             }
         }
@@ -141,7 +138,7 @@ impl<'a, 'tcx> HirCollector<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> intravisit::Visitor<'tcx> for HirCollector<'a, 'tcx> {
+impl<'tcx> intravisit::Visitor<'tcx> for HirCollector<'tcx> {
     type NestedFilter = nested_filter::All;
 
     fn nested_visit_map(&mut self) -> Self::Map {