Rollup merge of #101801 - SparrowLii:query_depth_note, r=estebank

add note for `layout_of` when query depth overflows

Fixes #101747
Added `try_find_layout_root` function to add a note for `layout_of` when query depth overflows. This would make the error in #101747 look like this:
```
error: queries overflow the depth limit!
   |
note: Query depth increased by 66 when computing layout of `core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<alloc::boxed::Box<alloc::string::String>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`!
  --> D:\rust-backup\parallel_rust\query_depth.rs:40:1
   |
40 | fn main() {
   | ^^^^^^^^^

error: aborting due to previous error
```

cc ``@semicoleon``

1 files changed, 27 insertions, 2 deletions

diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs
index 6f39bbfc0dc..d819f4774d5 100644
--- a/compiler/rustc_query_impl/src/plumbing.rs
+++ b/compiler/rustc_query_impl/src/plumbing.rs
@@ -19,8 +19,10 @@ use rustc_query_system::query::{
     force_query, QueryConfig, QueryContext, QueryDescription, QueryJobId, QueryMap,
     QuerySideEffects, QueryStackFrame,
 };
-use rustc_query_system::Value;
+use rustc_query_system::{LayoutOfDepth, QueryOverflow, Value};
 use rustc_serialize::Decodable;
+use rustc_session::Limit;
+use rustc_span::def_id::LOCAL_CRATE;
 use std::any::Any;
 use std::num::NonZeroU64;
 use thin_vec::ThinVec;
@@ -109,7 +111,7 @@ impl QueryContext for QueryCtxt<'_> {
         // when accessing the `ImplicitCtxt`.
         tls::with_related_context(**self, move |current_icx| {
             if depth_limit && !self.recursion_limit().value_within_limit(current_icx.query_depth) {
-                self.depth_limit_error();
+                self.depth_limit_error(token);
             }
 
             // Update the `ImplicitCtxt` to point to our new query job.
@@ -127,6 +129,29 @@ impl QueryContext for QueryCtxt<'_> {
             })
         })
     }
+
+    fn depth_limit_error(&self, job: QueryJobId) {
+        let mut span = None;
+        let mut layout_of_depth = None;
+        if let Some(map) = self.try_collect_active_jobs() {
+            if let Some((info, depth)) = job.try_find_layout_root(map) {
+                span = Some(info.job.span);
+                layout_of_depth = Some(LayoutOfDepth { desc: info.query.description, depth });
+            }
+        }
+
+        let suggested_limit = match self.recursion_limit() {
+            Limit(0) => Limit(2),
+            limit => limit * 2,
+        };
+
+        self.sess.emit_fatal(QueryOverflow {
+            span,
+            layout_of_depth,
+            suggested_limit,
+            crate_name: self.crate_name(LOCAL_CRATE),
+        });
+    }
 }
 
 impl<'tcx> QueryCtxt<'tcx> {