From fb9161028b8a7f276d552296811630c157471766 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Mon, 4 Mar 2024 20:43:58 +0100
Subject: [PATCH] Avoid using unnecessary queries when printing the query stack
 in panics

---
 compiler/rustc_query_impl/src/plumbing.rs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs
index 1b546bf9103..b06d75be390 100644
--- a/compiler/rustc_query_impl/src/plumbing.rs
+++ b/compiler/rustc_query_impl/src/plumbing.rs
@@ -17,6 +17,7 @@
 use rustc_middle::query::on_disk_cache::AbsoluteBytePos;
 use rustc_middle::query::on_disk_cache::{CacheDecoder, CacheEncoder, EncodedDepNodeIndex};
 use rustc_middle::query::Key;
+use rustc_middle::ty::print::with_reduced_queries;
 use rustc_middle::ty::tls::{self, ImplicitCtxt};
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_query_system::dep_graph::{DepNodeParams, HasDepContext};
@@ -304,6 +305,10 @@ pub(crate) fn create_query_frame<
     kind: DepKind,
     name: &'static str,
 ) -> QueryStackFrame {
+    // If reduced queries are requested, we may be printing a query stack due
+    // to a panic. Avoid using `default_span` and `def_kind` in that case.
+    let reduce_queries = with_reduced_queries();
+
     // Avoid calling queries while formatting the description
     let description = ty::print::with_no_queries!(do_describe(tcx, key));
     let description = if tcx.sess.verbose_internals() {
@@ -311,7 +316,7 @@ pub(crate) fn create_query_frame<
     } else {
         description
     };
-    let span = if kind == dep_graph::dep_kinds::def_span {
+    let span = if kind == dep_graph::dep_kinds::def_span || reduce_queries {
         // The `def_span` query is used to calculate `default_span`,
         // so exit to avoid infinite recursion.
         None
@@ -319,7 +324,7 @@ pub(crate) fn create_query_frame<
         Some(key.default_span(tcx))
     };
     let def_id = key.key_as_def_id();
-    let def_kind = if kind == dep_graph::dep_kinds::def_kind {
+    let def_kind = if kind == dep_graph::dep_kinds::def_kind || reduce_queries {
         // Try to avoid infinite recursion.
         None
     } else {