4 files changed, 43 insertions, 18 deletions
diff --git a/compiler/rustc_query_system/src/query/config.rs b/compiler/rustc_query_system/src/query/config.rs
index c4549cc9e..0a1cffa3b 100644
--- a/compiler/rustc_query_system/src/query/config.rs
+++ b/compiler/rustc_query_system/src/query/config.rs
@@ -49,8 +49,6 @@ impl<CTX: QueryContext, K, V> QueryVTable<CTX, K, V> {
 pub trait QueryDescription<CTX: QueryContext>: QueryConfig {
     type Cache: QueryCache<Key = Self::Key, Stored = Self::Stored, Value = Self::Value>;
 
-    fn describe(tcx: CTX, key: Self::Key) -> String;
-
     // Don't use this method to access query results, instead use the methods on TyCtxt
     fn query_state<'a>(tcx: CTX) -> &'a QueryState<Self::Key>
     where
diff --git a/compiler/rustc_query_system/src/query/job.rs b/compiler/rustc_query_system/src/query/job.rs
index 45b4079fb..ed65393f5 100644
--- a/compiler/rustc_query_system/src/query/job.rs
+++ b/compiler/rustc_query_system/src/query/job.rs
@@ -3,9 +3,11 @@ use crate::query::plumbing::CycleError;
 use crate::query::{QueryContext, QueryStackFrame};
 
 use rustc_data_structures::fx::FxHashMap;
-use rustc_errors::{Diagnostic, DiagnosticBuilder, ErrorGuaranteed, Handler, Level};
+use rustc_errors::{
+    Diagnostic, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic, Level,
+};
 use rustc_hir::def::DefKind;
-use rustc_session::{Session, SessionDiagnostic};
+use rustc_session::Session;
 use rustc_span::Span;
 
 use std::hash::Hash;
@@ -59,6 +61,7 @@ impl QueryJobId {
     }
 }
 
+#[derive(Clone)]
 pub struct QueryJobInfo {
     pub query: QueryStackFrame,
     pub job: QueryJob,
@@ -116,10 +119,10 @@ impl QueryJob {
     }
 }
 
-#[cfg(not(parallel_compiler))]
 impl QueryJobId {
     #[cold]
     #[inline(never)]
+    #[cfg(not(parallel_compiler))]
     pub(super) fn find_cycle_in_stack(
         &self,
         query_map: QueryMap,
@@ -156,6 +159,24 @@ impl QueryJobId {
 
         panic!("did not find a cycle")
     }
+
+    #[cold]
+    #[inline(never)]
+    pub fn try_find_layout_root(&self, query_map: QueryMap) -> Option<(QueryJobInfo, usize)> {
+        let mut last_layout = None;
+        let mut current_id = Some(*self);
+        let mut depth = 0;
+
+        while let Some(id) = current_id {
+            let info = query_map.get(&id).unwrap();
+            if info.query.name == "layout_of" {
+                depth += 1;
+                last_layout = Some((info.clone(), depth));
+            }
+            current_id = info.job.parent;
+        }
+        last_layout
+    }
 }
 
 #[cfg(parallel_compiler)]
@@ -530,7 +551,7 @@ pub fn deadlock(query_map: QueryMap, registry: &rayon_core::Registry) {
 #[cold]
 pub(crate) fn report_cycle<'a>(
     sess: &'a Session,
-    CycleError { usage, cycle: stack }: CycleError,
+    CycleError { usage, cycle: stack }: &CycleError,
 ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
     assert!(!stack.is_empty());
 
@@ -548,10 +569,10 @@ pub(crate) fn report_cycle<'a>(
     }
 
     let mut cycle_usage = None;
-    if let Some((span, query)) = usage {
+    if let Some((span, ref query)) = *usage {
         cycle_usage = Some(crate::error::CycleUsage {
             span: query.default_span(span),
-            usage: query.description,
+            usage: query.description.to_string(),
         });
     }
 
diff --git a/compiler/rustc_query_system/src/query/mod.rs b/compiler/rustc_query_system/src/query/mod.rs
index 0b07bb64b..118703fc0 100644
--- a/compiler/rustc_query_system/src/query/mod.rs
+++ b/compiler/rustc_query_system/src/query/mod.rs
@@ -14,10 +14,11 @@ pub use self::caches::{
 mod config;
 pub use self::config::{QueryConfig, QueryDescription, QueryVTable};
 
-use crate::dep_graph::{DepContext, DepNodeIndex, HasDepContext, SerializedDepNodeIndex};
+use crate::dep_graph::{DepNodeIndex, HasDepContext, SerializedDepNodeIndex};
 use rustc_data_structures::sync::Lock;
 use rustc_errors::Diagnostic;
 use rustc_hir::def::DefKind;
+use rustc_span::def_id::DefId;
 use rustc_span::Span;
 use thin_vec::ThinVec;
 
@@ -29,7 +30,9 @@ pub struct QueryStackFrame {
     pub name: &'static str,
     pub description: String,
     span: Option<Span>,
-    def_kind: Option<DefKind>,
+    pub def_id: Option<DefId>,
+    pub def_kind: Option<DefKind>,
+    pub ty_adt_id: Option<DefId>,
     /// This hash is used to deterministically pick
     /// a query to remove cycles in the parallel compiler.
     #[cfg(parallel_compiler)]
@@ -42,14 +45,18 @@ impl QueryStackFrame {
         name: &'static str,
         description: String,
         span: Option<Span>,
+        def_id: Option<DefId>,
         def_kind: Option<DefKind>,
+        ty_adt_id: Option<DefId>,
         _hash: impl FnOnce() -> u64,
     ) -> Self {
         Self {
             name,
             description,
             span,
+            def_id,
             def_kind,
+            ty_adt_id,
             #[cfg(parallel_compiler)]
             hash: _hash(),
         }
@@ -123,7 +130,5 @@ pub trait QueryContext: HasDepContext {
         compute: impl FnOnce() -> R,
     ) -> R;
 
-    fn depth_limit_error(&self) {
-        self.dep_context().sess().emit_fatal(crate::error::QueryOverflow);
-    }
+    fn depth_limit_error(&self, job: QueryJobId);
 }
diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index 8179a674a..15b89daa6 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -119,7 +119,7 @@ where
 #[inline(never)]
 fn mk_cycle<CTX, V, R>(
     tcx: CTX,
-    error: CycleError,
+    cycle_error: CycleError,
     handler: HandleCycleError,
     cache: &dyn crate::query::QueryStorage<Value = V, Stored = R>,
 ) -> R
@@ -128,13 +128,14 @@ where
     V: std::fmt::Debug + Value<CTX::DepContext>,
     R: Clone,
 {
-    let error = report_cycle(tcx.dep_context().sess(), error);
-    let value = handle_cycle_error(*tcx.dep_context(), error, handler);
+    let error = report_cycle(tcx.dep_context().sess(), &cycle_error);
+    let value = handle_cycle_error(*tcx.dep_context(), &cycle_error, error, handler);
     cache.store_nocache(value)
 }
 
 fn handle_cycle_error<CTX, V>(
     tcx: CTX,
+    cycle_error: &CycleError,
     mut error: DiagnosticBuilder<'_, ErrorGuaranteed>,
     handler: HandleCycleError,
 ) -> V
@@ -146,7 +147,7 @@ where
     match handler {
         Error => {
             error.emit();
-            Value::from_cycle_error(tcx)
+            Value::from_cycle_error(tcx, &cycle_error.cycle)
         }
         Fatal => {
             error.emit();
@@ -155,7 +156,7 @@ where
         }
         DelayBug => {
             error.delay_as_bug();
-            Value::from_cycle_error(tcx)
+            Value::from_cycle_error(tcx, &cycle_error.cycle)
         }
     }
 }