2 files changed, 14 insertions, 1 deletions
diff --git a/compiler/rustc_middle/src/query/erase.rs b/compiler/rustc_middle/src/query/erase.rs
index ea62461ebeb..bea2191c560 100644
--- a/compiler/rustc_middle/src/query/erase.rs
+++ b/compiler/rustc_middle/src/query/erase.rs
@@ -6,6 +6,7 @@ use rustc_span::ErrorGuaranteed;
 
 use crate::mir::interpret::EvalToValTreeResult;
 use crate::query::CyclePlaceholder;
+use crate::traits::solve;
 use crate::ty::adjustment::CoerceUnsizedInfo;
 use crate::ty::{self, Ty, TyCtxt};
 use crate::{mir, traits};
@@ -219,6 +220,10 @@ impl<T0, T1> EraseType for (&'_ T0, &'_ T1) {
     type Result = [u8; size_of::<(&'static (), &'static ())>()];
 }
 
+impl<T0> EraseType for (solve::QueryResult<'_>, &'_ T0) {
+    type Result = [u8; size_of::<(solve::QueryResult<'static>, &'static ())>()];
+}
+
 impl<T0, T1> EraseType for (&'_ T0, &'_ [T1]) {
     type Result = [u8; size_of::<(&'static (), &'static [()])>()];
 }
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 8ce70f75c67..874cee54c7c 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -131,7 +131,7 @@ use crate::traits::query::{
 };
 use crate::traits::{
     CodegenObligationError, DynCompatibilityViolation, EvaluationResult, ImplSource,
-    ObligationCause, OverflowError, WellFormedLoc, specialization_graph,
+    ObligationCause, OverflowError, WellFormedLoc, solve, specialization_graph,
 };
 use crate::ty::fast_reject::SimplifiedType;
 use crate::ty::layout::ValidityRequirement;
@@ -2563,6 +2563,14 @@ rustc_queries! {
         desc { "computing autoderef types for `{}`", goal.canonical.value.value }
     }
 
+    /// Used by `-Znext-solver` to compute proof trees.
+    query evaluate_root_goal_for_proof_tree_raw(
+        goal: solve::CanonicalInput<'tcx>,
+    ) -> (solve::QueryResult<'tcx>, &'tcx solve::inspect::Probe<TyCtxt<'tcx>>) {
+        no_hash
+        desc { "computing proof tree for `{}`", goal.canonical.value.goal.predicate }
+    }
+
     /// Returns the Rust target features for the current target. These are not always the same as LLVM target features!
     query rust_target_features(_: CrateNum) -> &'tcx UnordMap<String, rustc_target::target_features::Stability> {
         arena_cache