diff --git a/compiler/rustc_middle/src/ty/consts/kind.rs b/compiler/rustc_middle/src/ty/consts/kind.rs
index 58c5e21df66..52f4414e37b 100644
--- a/compiler/rustc_middle/src/ty/consts/kind.rs
+++ b/compiler/rustc_middle/src/ty/consts/kind.rs
@@ -217,23 +217,21 @@ impl<'tcx> ConstKind<'tcx> {
             // Note that we erase regions *before* calling `with_reveal_all_normalized`,
             // so that we don't try to invoke this query with
             // any region variables.
-            let param_env_and = tcx
-                .erase_regions(param_env)
-                .with_reveal_all_normalized(tcx)
-                .and(tcx.erase_regions(unevaluated));
 
             // HACK(eddyb) when the query key would contain inference variables,
             // attempt using identity substs and `ParamEnv` instead, that will succeed
             // when the expression doesn't depend on any parameters.
             // FIXME(eddyb, skinny121) pass `InferCtxt` into here when it's available, so that
             // we can call `infcx.const_eval_resolve` which handles inference variables.
-            let param_env_and = if param_env_and.needs_infer() {
+            let param_env_and = if (param_env, unevaluated).has_non_region_infer() {
                 tcx.param_env(unevaluated.def.did).and(ty::UnevaluatedConst {
                     def: unevaluated.def,
                     substs: InternalSubsts::identity_for_item(tcx, unevaluated.def.did),
                 })
             } else {
-                param_env_and
+                tcx.erase_regions(param_env)
+                    .with_reveal_all_normalized(tcx)
+                    .and(tcx.erase_regions(unevaluated))
             };
 
             // FIXME(eddyb) maybe the `const_eval_*` methods should take
diff --git a/compiler/rustc_query_system/src/lib.rs b/compiler/rustc_query_system/src/lib.rs
index f47760e9ae6..623be668464 100644
--- a/compiler/rustc_query_system/src/lib.rs
+++ b/compiler/rustc_query_system/src/lib.rs
@@ -3,6 +3,7 @@
 #![feature(hash_raw_entry)]
 #![feature(min_specialization)]
 #![feature(extern_types)]
+#![feature(let_chains)]
 #![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index 53e04bcc132..21a0c73d720 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -2,7 +2,7 @@
 //! generate the actual methods on tcx which find and execute the provider,
 //! manage the caches, and so forth.
 
-use crate::dep_graph::{DepContext, DepKind, DepNode, DepNodeIndex};
+use crate::dep_graph::{DepContext, DepKind, DepNode, DepNodeIndex, DepNodeParams};
 use crate::ich::StableHashingContext;
 use crate::query::caches::QueryCache;
 use crate::query::job::{report_cycle, QueryInfo, QueryJob, QueryJobId, QueryJobInfo};
@@ -408,10 +408,27 @@ where
 
     // Fast path for when incr. comp. is off.
     if !dep_graph.is_fully_enabled() {
+        // Fingerprint the key, just to assert that it doesn't
+        // have anything we don't consider hashable
+        if cfg!(debug_assertions) {
+            let _ = key.to_fingerprint(*qcx.dep_context());
+        }
+
         let prof_timer = qcx.dep_context().profiler().query_provider();
         let result = qcx.start_query(job_id, Q::DEPTH_LIMIT, None, || Q::compute(qcx, key));
         let dep_node_index = dep_graph.next_virtual_depnode_index();
         prof_timer.finish_with_query_invocation_id(dep_node_index.into());
+
+        // Similarly, fingerprint the result to assert that
+        // it doesn't have anything not considered hashable.
+        if cfg!(debug_assertions)
+            && let Some(hash_result) = Q::HASH_RESULT
+        {
+            qcx.dep_context().with_stable_hashing_context(|mut hcx| {
+                hash_result(&mut hcx, &result);
+            });
+        }
+
         return (result, dep_node_index);
     }