Ensure query keys are printed with reduced queries

2 files changed, 8 insertions, 5 deletions

diff --git a/compiler/rustc_query_system/src/dep_graph/dep_node.rs b/compiler/rustc_query_system/src/dep_graph/dep_node.rs
index c0b3bd43e25..bdd1d5f3e88 100644
--- a/compiler/rustc_query_system/src/dep_graph/dep_node.rs
+++ b/compiler/rustc_query_system/src/dep_graph/dep_node.rs
@@ -178,9 +178,7 @@ pub trait DepNodeParams<Tcx: DepContext>: fmt::Debug + Sized {
         panic!("Not implemented. Accidentally called on anonymous node?")
     }
 
-    fn to_debug_str(&self, _: Tcx) -> String {
-        format!("{self:?}")
-    }
+    fn to_debug_str(&self, tcx: Tcx) -> String;
 
     /// This method tries to recover the query key from the given `DepNode`,
     /// something which is needed when forcing `DepNode`s during red-green
@@ -210,8 +208,11 @@ where
     }
 
     #[inline(always)]
-    default fn to_debug_str(&self, _: Tcx) -> String {
-        format!("{:?}", *self)
+    default fn to_debug_str(&self, tcx: Tcx) -> String {
+        // Make sure to print dep node params with reduced queries since printing
+        // may themselves call queries, which may lead to (possibly untracked!)
+        // query cycles.
+        tcx.with_reduced_queries(|| format!("{self:?}"))
     }
 
     #[inline(always)]
diff --git a/compiler/rustc_query_system/src/dep_graph/mod.rs b/compiler/rustc_query_system/src/dep_graph/mod.rs
index 89d1db87809..512034a8b2f 100644
--- a/compiler/rustc_query_system/src/dep_graph/mod.rs
+++ b/compiler/rustc_query_system/src/dep_graph/mod.rs
@@ -88,6 +88,8 @@ pub trait DepContext: Copy {
             f(self, dep_node)
         }
     }
+
+    fn with_reduced_queries<T>(self, _: impl FnOnce() -> T) -> T;
 }
 
 pub trait Deps: DynSync {