From 71e7eb5258d14740a42fdeb16094d51fddf6d680 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Thu, 17 Nov 2022 18:05:26 +0300
Subject: [PATCH] privacy: Relax some asserts on effective visibilities

The first invariant is hard to enforce in presence of errors.

The second invariant is expensive to enforce fully precisely, so it no longer makes sense given that we were trying to enforce it for performance
---
 compiler/rustc_middle/src/middle/privacy.rs   |  9 +-----
 .../effective_visibilities_invariants.rs      | 12 +++++++
 .../effective_visibilities_invariants.stderr  | 32 +++++++++++++++++++
 3 files changed, 45 insertions(+), 8 deletions(-)
 create mode 100644 src/test/ui/privacy/effective_visibilities_invariants.rs
 create mode 100644 src/test/ui/privacy/effective_visibilities_invariants.stderr

diff --git a/compiler/rustc_middle/src/middle/privacy.rs b/compiler/rustc_middle/src/middle/privacy.rs
index 3a91522d36229..28a7598a7c195 100644
--- a/compiler/rustc_middle/src/middle/privacy.rs
+++ b/compiler/rustc_middle/src/middle/privacy.rs
@@ -4,7 +4,6 @@
 use crate::ty::{DefIdTree, TyCtxt, Visibility};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_hir::def::DefKind;
 use rustc_macros::HashStable;
 use rustc_query_system::ich::StableHashingContext;
 use rustc_span::def_id::LocalDefId;
@@ -167,7 +166,7 @@ impl EffectiveVisibilities {
             // and all effective visibilities are larger or equal than private visibility.
             let private_vis = Visibility::Restricted(tcx.parent_module_from_def_id(def_id));
             let span = tcx.def_span(def_id.to_def_id());
-            if !ev.direct.is_at_least(private_vis, tcx) {
+            if !ev.direct.is_at_least(private_vis, tcx) && tcx.sess.has_errors().is_none() {
                 span_bug!(span, "private {:?} > direct {:?}", private_vis, ev.direct);
             }
             if !ev.reexported.is_at_least(ev.direct, tcx) {
@@ -185,7 +184,6 @@ impl EffectiveVisibilities {
                 );
             }
             let nominal_vis = tcx.visibility(def_id);
-            let def_kind = tcx.opt_def_kind(def_id);
             // FIXME: `rustc_privacy` is not yet updated for the new logic and can set
             // effective visibilities that are larger than the nominal one.
             if !nominal_vis.is_at_least(ev.reachable_through_impl_trait, tcx) && early {
@@ -197,11 +195,6 @@ impl EffectiveVisibilities {
                     nominal_vis
                 );
             }
-            // Fully private items are never put into the table, this is important for performance.
-            // FIXME: Fully private `mod` items are currently put into the table.
-            if ev.reachable_through_impl_trait == private_vis && def_kind != Some(DefKind::Mod) {
-                span_bug!(span, "fully private item in the table {:?}: {:?}", def_id, ev.direct);
-            }
         }
     }
 }
diff --git a/src/test/ui/privacy/effective_visibilities_invariants.rs b/src/test/ui/privacy/effective_visibilities_invariants.rs
new file mode 100644
index 0000000000000..af5a2bed6ab24
--- /dev/null
+++ b/src/test/ui/privacy/effective_visibilities_invariants.rs
@@ -0,0 +1,12 @@
+// Invariant checking doesn't ICE in some cases with errors (issue #104249).
+
+#![feature(staged_api)] //~ ERROR module has missing stability attribute
+
+pub mod m {} //~ ERROR module has missing stability attribute
+
+pub mod m { //~ ERROR the name `m` is defined multiple times
+    mod inner {}
+    type Inner = u8;
+}
+
+fn main() {}
diff --git a/src/test/ui/privacy/effective_visibilities_invariants.stderr b/src/test/ui/privacy/effective_visibilities_invariants.stderr
new file mode 100644
index 0000000000000..fd205f4058ae0
--- /dev/null
+++ b/src/test/ui/privacy/effective_visibilities_invariants.stderr
@@ -0,0 +1,32 @@
+error[E0428]: the name `m` is defined multiple times
+  --> $DIR/effective_visibilities_invariants.rs:7:1
+   |
+LL | pub mod m {}
+   | --------- previous definition of the module `m` here
+LL |
+LL | pub mod m {
+   | ^^^^^^^^^ `m` redefined here
+   |
+   = note: `m` must be defined only once in the type namespace of this module
+
+error: module has missing stability attribute
+  --> $DIR/effective_visibilities_invariants.rs:3:1
+   |
+LL | / #![feature(staged_api)]
+LL | |
+LL | | pub mod m {}
+LL | |
+...  |
+LL | |
+LL | | fn main() {}
+   | |____________^
+
+error: module has missing stability attribute
+  --> $DIR/effective_visibilities_invariants.rs:5:1
+   |
+LL | pub mod m {}
+   | ^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0428`.