Rollup merge of rust-lang#57436 - Xanewok:save-analysis-access-ice-fix, r=nikomatsakis

save-analysis: use a fallback when access levels couldn't be computed

Fixing an RLS regression I introduced in rust-lang#57343 😢

I missed a case where we get [called back with analysis when type checking fails](https://github.com/rust-lang/rust/blob/9d54812829e9d92dac35a4a0f358cdc5a2475371/src/librustc_driver/driver.rs#L1264). Since privacy checking normally is done afterwards, when we execute the `privacy_access_levels` query inside the save_analysis callback we'll calculate it for the first time and since typeck info isn't complete, we'll crash there.

Double-checked locally and it seems to have fixed the problem.

r? @nikomatsakis

Author: pietroalbini

src/librustc_save_analysis/dump_visitor.rs

@@ -14,7 +14,7 @@
 //! recording the output.
 
 use rustc::hir::def::Def as HirDef;
-use rustc::hir::def_id::{DefId, LOCAL_CRATE};
+use rustc::hir::def_id::DefId;
 use rustc::session::config::Input;
 use rustc::ty::{self, TyCtxt};
 use rustc_data_structures::fx::FxHashSet;
@@ -56,14 +56,14 @@ macro_rules! access_from {
     ($save_ctxt:expr, $vis:expr, $id:expr) => {
         Access {
             public: $vis.node.is_pub(),
-            reachable: $save_ctxt.tcx.privacy_access_levels(LOCAL_CRATE).is_reachable($id),
+            reachable: $save_ctxt.access_levels.is_reachable($id),
         }
     };
 
     ($save_ctxt:expr, $item:expr) => {
         Access {
             public: $item.vis.node.is_pub(),
-            reachable: $save_ctxt.tcx.privacy_access_levels(LOCAL_CRATE).is_reachable($item.id),
+            reachable: $save_ctxt.access_levels.is_reachable($item.id),
         }
     };
 }

src/librustc_save_analysis/lib.rs

@@ -35,11 +35,13 @@ use rustc::hir;
 use rustc::hir::def::Def as HirDef;
 use rustc::hir::Node;
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
+use rustc::middle::privacy::AccessLevels;
 use rustc::middle::cstore::ExternCrate;
 use rustc::session::config::{CrateType, Input, OutputType};
 use rustc::ty::{self, TyCtxt};
 use rustc_typeck::hir_ty_to_ty;
 use rustc_codegen_utils::link::{filename_for_metadata, out_filename};
+use rustc_data_structures::sync::Lrc;
 
 use std::cell::Cell;
 use std::default::Default;
@@ -68,6 +70,7 @@ use rls_data::config::Config;
 pub struct SaveContext<'l, 'tcx: 'l> {
     tcx: TyCtxt<'l, 'tcx, 'tcx>,
     tables: &'l ty::TypeckTables<'tcx>,
+    access_levels: &'l AccessLevels,
     analysis: &'l ty::CrateAnalysis,
     span_utils: SpanUtils<'tcx>,
     config: Config,
@@ -1124,10 +1127,18 @@ pub fn process_crate<'l, 'tcx, H: SaveHandler>(
     tcx.dep_graph.with_ignore(|| {
         info!("Dumping crate {}", cratename);
 
+        // Privacy checking requires and is done after type checking; use a
+        // fallback in case the access levels couldn't have been correctly computed.
+        let access_levels = match tcx.sess.compile_status() {
+            Ok(..) => tcx.privacy_access_levels(LOCAL_CRATE),
+            Err(..) => Lrc::new(AccessLevels::default()),
+        };
+
         let save_ctxt = SaveContext {
             tcx,
             tables: &ty::TypeckTables::empty(None),
             analysis,
+            access_levels: &access_levels,
             span_utils: SpanUtils::new(&tcx.sess),
             config: find_config(config),
             impl_counter: Cell::new(0),