5 files changed, 33 insertions, 12 deletions
diff --git a/compiler/rustc_middle/src/arena.rs b/compiler/rustc_middle/src/arena.rs
index 8a4fd01437f..e745913fabc 100644
--- a/compiler/rustc_middle/src/arena.rs
+++ b/compiler/rustc_middle/src/arena.rs
@@ -114,6 +114,7 @@ macro_rules! arena_types {
             [] mod_child: rustc_middle::metadata::ModChild,
             [] features: rustc_feature::Features,
             [decode] specialization_graph: rustc_middle::traits::specialization_graph::Graph,
+            [] crate_inherent_impls: rustc_middle::ty::CrateInherentImpls,
         ]);
     )
 }
diff --git a/compiler/rustc_middle/src/query/erase.rs b/compiler/rustc_middle/src/query/erase.rs
index b9200f1abf1..a49825bdd70 100644
--- a/compiler/rustc_middle/src/query/erase.rs
+++ b/compiler/rustc_middle/src/query/erase.rs
@@ -78,6 +78,10 @@ impl<T> EraseType for Result<&'_ T, rustc_errors::ErrorGuaranteed> {
     type Result = [u8; size_of::<Result<&'static (), rustc_errors::ErrorGuaranteed>>()];
 }
 
+impl<T> EraseType for Result<&'_ [T], rustc_errors::ErrorGuaranteed> {
+    type Result = [u8; size_of::<Result<&'static [()], rustc_errors::ErrorGuaranteed>>()];
+}
+
 impl<T> EraseType for Result<&'_ T, traits::CodegenObligationError> {
     type Result = [u8; size_of::<Result<&'static (), traits::CodegenObligationError>>()];
 }
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 15f0dc0208d..b3aa02e1aa3 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -859,13 +859,13 @@ rustc_queries! {
     /// Maps a `DefId` of a type to a list of its inherent impls.
     /// Contains implementations of methods that are inherent to a type.
     /// Methods in these implementations don't need to be exported.
-    query inherent_impls(key: DefId) -> &'tcx [DefId] {
+    query inherent_impls(key: DefId) -> Result<&'tcx [DefId], ErrorGuaranteed> {
         desc { |tcx| "collecting inherent impls for `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
     }
 
-    query incoherent_impls(key: SimplifiedType) -> &'tcx [DefId] {
+    query incoherent_impls(key: SimplifiedType) -> Result<&'tcx [DefId], ErrorGuaranteed> {
         desc { |tcx| "collecting all inherent impls for `{:?}`", key }
     }
 
@@ -1012,9 +1012,9 @@ rustc_queries! {
 
     /// Gets a complete map from all types to their inherent impls.
     /// Not meant to be used directly outside of coherence.
-    query crate_inherent_impls(k: ()) -> &'tcx CrateInherentImpls {
-        arena_cache
+    query crate_inherent_impls(k: ()) -> Result<&'tcx CrateInherentImpls, ErrorGuaranteed> {
         desc { "finding all inherent impls defined in crate" }
+        ensure_forwards_result_if_red
     }
 
     /// Checks all types in the crate for overlap in their inherent impls. Reports errors.
@@ -1647,7 +1647,7 @@ rustc_queries! {
     ///
     /// Do not call this directly, but instead use the `incoherent_impls` query.
     /// This query is only used to get the data necessary for that query.
-    query crate_incoherent_impls(key: (CrateNum, SimplifiedType)) -> &'tcx [DefId] {
+    query crate_incoherent_impls(key: (CrateNum, SimplifiedType)) -> Result<&'tcx [DefId], ErrorGuaranteed> {
         desc { |tcx| "collecting all impls for a type in a crate" }
         separate_provide_extern
     }
diff --git a/compiler/rustc_middle/src/query/plumbing.rs b/compiler/rustc_middle/src/query/plumbing.rs
index a41d4f1ad58..8d88488e167 100644
--- a/compiler/rustc_middle/src/query/plumbing.rs
+++ b/compiler/rustc_middle/src/query/plumbing.rs
@@ -174,7 +174,7 @@ pub fn query_ensure<'tcx, Cache>(
 }
 
 #[inline]
-pub fn query_ensure_error_guaranteed<'tcx, Cache>(
+pub fn query_ensure_error_guaranteed<'tcx, Cache, T>(
     tcx: TyCtxt<'tcx>,
     execute_query: fn(TyCtxt<'tcx>, Span, Cache::Key, QueryMode) -> Option<Cache::Value>,
     query_cache: &Cache,
@@ -182,14 +182,16 @@ pub fn query_ensure_error_guaranteed<'tcx, Cache>(
     check_cache: bool,
 ) -> Result<(), ErrorGuaranteed>
 where
-    Cache: QueryCache<Value = super::erase::Erase<Result<(), ErrorGuaranteed>>>,
+    Cache: QueryCache<Value = super::erase::Erase<Result<T, ErrorGuaranteed>>>,
+    Result<T, ErrorGuaranteed>: EraseType,
 {
     let key = key.into_query_param();
     if let Some(res) = try_get_cached(tcx, query_cache, &key) {
-        super::erase::restore(res)
+        super::erase::restore(res).map(drop)
     } else {
         execute_query(tcx, DUMMY_SP, key, QueryMode::Ensure { check_cache })
             .map(super::erase::restore)
+            .map(|res| res.map(drop))
             // Either we actually executed the query, which means we got a full `Result`,
             // or we can just assume the query succeeded, because it was green in the
             // incremental cache. If it is green, that means that the previous compilation
@@ -205,7 +207,7 @@ macro_rules! query_ensure {
         query_ensure($($args)*)
     };
     ([(ensure_forwards_result_if_red) $($rest:tt)*]$($args:tt)*) => {
-        query_ensure_error_guaranteed($($args)*)
+        query_ensure_error_guaranteed($($args)*).map(|_| ())
     };
     ([$other:tt $($modifiers:tt)*]$($args:tt)*) => {
         query_ensure!([$($modifiers)*]$($args)*)
@@ -667,5 +669,7 @@ mod sealed {
 
 pub use sealed::IntoQueryParam;
 
+use super::erase::EraseType;
+
 #[derive(Copy, Clone, Debug, HashStable)]
 pub struct CyclePlaceholder(pub ErrorGuaranteed);
diff --git a/compiler/rustc_middle/src/ty/trait_def.rs b/compiler/rustc_middle/src/ty/trait_def.rs
index 227a0753d04..d85b541d363 100644
--- a/compiler/rustc_middle/src/ty/trait_def.rs
+++ b/compiler/rustc_middle/src/ty/trait_def.rs
@@ -254,16 +254,28 @@ pub(super) fn trait_impls_of_provider(tcx: TyCtxt<'_>, trait_id: DefId) -> Trait
 }
 
 /// Query provider for `incoherent_impls`.
-pub(super) fn incoherent_impls_provider(tcx: TyCtxt<'_>, simp: SimplifiedType) -> &[DefId] {
+pub(super) fn incoherent_impls_provider(
+    tcx: TyCtxt<'_>,
+    simp: SimplifiedType,
+) -> Result<&[DefId], ErrorGuaranteed> {
     let mut impls = Vec::new();
 
+    let mut res = Ok(());
     for cnum in iter::once(LOCAL_CRATE).chain(tcx.crates(()).iter().copied()) {
-        for &impl_def_id in tcx.crate_incoherent_impls((cnum, simp)) {
+        let incoherent_impls = match tcx.crate_incoherent_impls((cnum, simp)) {
+            Ok(impls) => impls,
+            Err(e) => {
+                res = Err(e);
+                continue;
+            }
+        };
+        for &impl_def_id in incoherent_impls {
             impls.push(impl_def_id)
         }
     }
 
     debug!(?impls);
+    res?;
 
-    tcx.arena.alloc_slice(&impls)
+    Ok(tcx.arena.alloc_slice(&impls))
 }