resolve: Unload speculatively resolved crates before freezing cstore

2 files changed, 15 insertions, 7 deletions

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 1f2803d4368..c020c134b77 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -23,6 +23,7 @@ use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind, LifetimeRes, NonMacroAttrKind, PartialRes, PerNS};
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::{BindingAnnotation, PrimTy, TraitCandidate};
+use rustc_metadata::creader::CStore;
 use rustc_middle::middle::resolve_bound_vars::Set1;
 use rustc_middle::{bug, span_bug};
 use rustc_session::config::{CrateType, ResolveDocLinks};
@@ -4541,14 +4542,20 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
                 if let Some(res) = res
                     && let Some(def_id) = res.opt_def_id()
                     && !def_id.is_local()
-                    && self.r.tcx.crate_types().contains(&CrateType::ProcMacro)
-                    && matches!(
-                        self.r.tcx.sess.opts.resolve_doc_links,
-                        ResolveDocLinks::ExportedMetadata
-                    )
                 {
-                    // Encoding foreign def ids in proc macro crate metadata will ICE.
-                    return None;
+                    if self.r.tcx.crate_types().contains(&CrateType::ProcMacro)
+                        && matches!(
+                            self.r.tcx.sess.opts.resolve_doc_links,
+                            ResolveDocLinks::ExportedMetadata
+                        )
+                    {
+                        // Encoding foreign def ids in proc macro crate metadata will ICE.
+                        return None;
+                    }
+                    // Doc paths should be resolved speculatively and should not produce any
+                    // diagnostics, but if they are indeed resolved, then we need to keep the
+                    // corresponding crate alive.
+                    CStore::from_tcx_mut(self.r.tcx).set_used_recursively(def_id.krate);
                 }
                 res
             });
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 9d09d060b59..6ca9236075b 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -1625,6 +1625,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             self.tcx
                 .sess
                 .time("resolve_postprocess", || self.crate_loader(|c| c.postprocess(krate)));
+            self.crate_loader(|c| c.unload_unused_crates());
         });
 
         // Make sure we don't mutate the cstore from here on.