diff --git a/src/librustc_interface/passes.rs b/src/librustc_interface/passes.rs
index 4357f11776c..533d0a6d383 100644
--- a/src/librustc_interface/passes.rs
+++ b/src/librustc_interface/passes.rs
@@ -892,7 +892,7 @@ fn analysis(tcx: TyCtxt<'_>, cnum: CrateNum) -> Result<()> {
 
             if tcx.hir().body_const_context(def_id).is_some() {
                 tcx.ensure()
-                    .mir_drops_elaborated_and_const_checked(ty::WithOptConstParam::dummy(def_id));
+                    .mir_drops_elaborated_and_const_checked(ty::WithOptConstParam::unknown(def_id));
             }
         }
     });
diff --git a/src/librustc_middle/ty/instance.rs b/src/librustc_middle/ty/instance.rs
index 114ce491f27..1a5c7fe4859 100644
--- a/src/librustc_middle/ty/instance.rs
+++ b/src/librustc_middle/ty/instance.rs
@@ -196,7 +196,7 @@ impl<'tcx> InstanceDef<'tcx> {
             | InstanceDef::Intrinsic(def_id)
             | InstanceDef::ClosureOnceShim { call_once: def_id }
             | InstanceDef::DropGlue(def_id, _)
-            | InstanceDef::CloneShim(def_id, _) => ty::WithOptConstParam::dummy(def_id),
+            | InstanceDef::CloneShim(def_id, _) => ty::WithOptConstParam::unknown(def_id),
         }
     }
 
@@ -298,7 +298,7 @@ impl<'tcx> Instance<'tcx> {
             def_id,
             substs
         );
-        Instance { def: InstanceDef::Item(ty::WithOptConstParam::dummy(def_id)), substs }
+        Instance { def: InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), substs }
     }
 
     pub fn mono(tcx: TyCtxt<'tcx>, def_id: DefId) -> Instance<'tcx> {
diff --git a/src/librustc_middle/ty/mod.rs b/src/librustc_middle/ty/mod.rs
index 26ce8e54a65..497004b80a5 100644
--- a/src/librustc_middle/ty/mod.rs
+++ b/src/librustc_middle/ty/mod.rs
@@ -1613,7 +1613,8 @@ pub struct WithOptConstParam<T> {
 }
 
 impl<T> WithOptConstParam<T> {
-    pub fn dummy(did: T) -> WithOptConstParam<T> {
+    /// Creates a new `WithOptConstParam` setting `const_param_did` to `None`.
+    pub fn unknown(did: T) -> WithOptConstParam<T> {
         WithOptConstParam { did, const_param_did: None }
     }
 }
diff --git a/src/librustc_middle/ty/sty.rs b/src/librustc_middle/ty/sty.rs
index 8cdfe5e5ac6..3104d2ee36a 100644
--- a/src/librustc_middle/ty/sty.rs
+++ b/src/librustc_middle/ty/sty.rs
@@ -2210,7 +2210,7 @@ impl<'tcx> Const<'tcx> {
     /// Literals and const generic parameters are eagerly converted to a constant, everything else
     /// becomes `Unevaluated`.
     pub fn from_anon_const(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &'tcx Self {
-        Self::from_opt_const_arg_anon_const(tcx, ty::WithOptConstParam::dummy(def_id))
+        Self::from_opt_const_arg_anon_const(tcx, ty::WithOptConstParam::unknown(def_id))
     }
 
     pub fn from_opt_const_arg_anon_const(
diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index 348c50720be..d8d988717b8 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -88,7 +88,7 @@ const DEREF_PROJECTION: &[PlaceElem<'_>; 1] = &[ProjectionElem::Deref];
 
 pub fn provide(providers: &mut Providers) {
     *providers = Providers {
-        mir_borrowck: |tcx, did| mir_borrowck(tcx, ty::WithOptConstParam::dummy(did)),
+        mir_borrowck: |tcx, did| mir_borrowck(tcx, ty::WithOptConstParam::unknown(did)),
         mir_borrowck_const_arg: |tcx, (did, param_did)| {
             mir_borrowck(tcx, ty::WithOptConstParam { did, const_param_did: Some(param_did) })
         },
diff --git a/src/librustc_mir/transform/check_unsafety.rs b/src/librustc_mir/transform/check_unsafety.rs
index 42ac4d126a1..024244582bb 100644
--- a/src/librustc_mir/transform/check_unsafety.rs
+++ b/src/librustc_mir/transform/check_unsafety.rs
@@ -491,7 +491,7 @@ impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> {
 pub(crate) fn provide(providers: &mut Providers) {
     *providers = Providers {
         unsafety_check_result: |tcx, def_id| {
-            unsafety_check_result(tcx, ty::WithOptConstParam::dummy(def_id))
+            unsafety_check_result(tcx, ty::WithOptConstParam::unknown(def_id))
         },
         unsafety_check_result_const_arg: |tcx, (did, param_did)| {
             unsafety_check_result(
diff --git a/src/librustc_mir/transform/mod.rs b/src/librustc_mir/transform/mod.rs
index ce8e71d878b..db091b3a0ab 100644
--- a/src/librustc_mir/transform/mod.rs
+++ b/src/librustc_mir/transform/mod.rs
@@ -49,7 +49,7 @@ pub(crate) fn provide(providers: &mut Providers) {
         mir_keys,
         mir_const,
         mir_const_qualif: |tcx, did| {
-            mir_const_qualif(tcx, ty::WithOptConstParam::dummy(did.expect_local()))
+            mir_const_qualif(tcx, ty::WithOptConstParam::unknown(did.expect_local()))
         },
         mir_const_qualif_const_arg: |tcx, (did, param_did)| {
             mir_const_qualif(tcx, ty::WithOptConstParam { did, const_param_did: Some(param_did) })
@@ -60,7 +60,7 @@ pub(crate) fn provide(providers: &mut Providers) {
         optimized_mir_of_const_arg,
         is_mir_available,
         promoted_mir: |tcx, def_id| {
-            promoted_mir(tcx, ty::WithOptConstParam::dummy(def_id.expect_local()))
+            promoted_mir(tcx, ty::WithOptConstParam::unknown(def_id.expect_local()))
         },
         promoted_mir_of_const_arg: |tcx, (did, param_did)| {
             promoted_mir(tcx, ty::WithOptConstParam { did, const_param_did: Some(param_did) })
@@ -128,7 +128,7 @@ pub struct MirSource<'tcx> {
 impl<'tcx> MirSource<'tcx> {
     pub fn item(def_id: DefId) -> Self {
         MirSource {
-            instance: InstanceDef::Item(ty::WithOptConstParam::dummy(def_id)),
+            instance: InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)),
             promoted: None,
         }
     }
@@ -414,7 +414,7 @@ fn run_post_borrowck_cleanup_passes<'tcx>(
     run_passes(
         tcx,
         body,
-        InstanceDef::Item(ty::WithOptConstParam::dummy(def_id.to_def_id())),
+        InstanceDef::Item(ty::WithOptConstParam::unknown(def_id.to_def_id())),
         promoted,
         MirPhase::DropElab,
         &[post_borrowck_cleanup],
@@ -478,7 +478,7 @@ fn run_optimization_passes<'tcx>(
     run_passes(
         tcx,
         body,
-        InstanceDef::Item(ty::WithOptConstParam::dummy(def_id.to_def_id())),
+        InstanceDef::Item(ty::WithOptConstParam::unknown(def_id.to_def_id())),
         promoted,
         MirPhase::Optimized,
         &[
@@ -493,7 +493,7 @@ fn optimized_mir<'tcx>(tcx: TyCtxt<'tcx>, did: DefId) -> &'tcx Body<'tcx> {
     if let Some(param_did) = tcx.opt_const_param_of(did) {
         tcx.optimized_mir_of_const_arg((did, param_did))
     } else {
-        tcx.arena.alloc(inner_optimized_mir(tcx, ty::WithOptConstParam::dummy(did)))
+        tcx.arena.alloc(inner_optimized_mir(tcx, ty::WithOptConstParam::unknown(did)))
     }
 }
 
diff --git a/src/librustc_mir/util/pretty.rs b/src/librustc_mir/util/pretty.rs
index e01badde217..990bfc064c2 100644
--- a/src/librustc_mir/util/pretty.rs
+++ b/src/librustc_mir/util/pretty.rs
@@ -249,7 +249,7 @@ pub fn write_mir_pretty<'tcx>(
         for (i, body) in tcx.promoted_mir(def_id).iter_enumerated() {
             writeln!(w)?;
             let src = MirSource {
-                instance: ty::InstanceDef::Item(ty::WithOptConstParam::dummy(def_id)),
+                instance: ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)),
                 promoted: Some(i),
             };
             write_mir_fn(tcx, src, body, &mut |_, _| Ok(()), w)?;
diff --git a/src/librustc_mir_build/hair/cx/expr.rs b/src/librustc_mir_build/hair/cx/expr.rs
index 8692363d006..89ad8a1b337 100644
--- a/src/librustc_mir_build/hair/cx/expr.rs
+++ b/src/librustc_mir_build/hair/cx/expr.rs
@@ -601,7 +601,7 @@ fn make_mirror_unadjusted<'a, 'tcx>(
                             let substs = InternalSubsts::identity_for_item(cx.tcx(), did);
                             let lhs = mk_const(cx.tcx().mk_const(ty::Const {
                                 val: ty::ConstKind::Unevaluated(
-                                    ty::WithOptConstParam::dummy(did),
+                                    ty::WithOptConstParam::unknown(did),
                                     substs,
                                     None,
                                 ),
@@ -801,7 +801,7 @@ fn convert_path_expr<'a, 'tcx>(
             ExprKind::Literal {
                 literal: cx.tcx.mk_const(ty::Const {
                     val: ty::ConstKind::Unevaluated(
-                        ty::WithOptConstParam::dummy(def_id),
+                        ty::WithOptConstParam::unknown(def_id),
                         substs,
                         None,
                     ),
diff --git a/src/librustc_ty/instance.rs b/src/librustc_ty/instance.rs
index 1a3308468bb..0bc6c470978 100644
--- a/src/librustc_ty/instance.rs
+++ b/src/librustc_ty/instance.rs
@@ -21,7 +21,7 @@ fn resolve_instance<'tcx>(
         }
     }
 
-    inner_resolve_instance(tcx, param_env.and((ty::WithOptConstParam::dummy(did), substs)))
+    inner_resolve_instance(tcx, param_env.and((ty::WithOptConstParam::unknown(did), substs)))
 }
 
 fn resolve_instance_of_const_arg<'tcx>(
@@ -210,7 +210,7 @@ fn resolve_associated_item<'tcx>(
             Some(ty::Instance::new(leaf_def.item.def_id, substs))
         }
         traits::ImplSourceGenerator(generator_data) => Some(Instance {
-            def: ty::InstanceDef::Item(ty::WithOptConstParam::dummy(
+            def: ty::InstanceDef::Item(ty::WithOptConstParam::unknown(
                 generator_data.generator_def_id,
             )),
             substs: generator_data.substs,
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index 30aa861e55d..845a4fcafc2 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -424,7 +424,7 @@ fn check_type_defn<'tcx, F>(
                     cause,
                     fcx.param_env,
                     ty::PredicateKind::ConstEvaluatable(
-                        ty::WithOptConstParam::dummy(discr_def_id.to_def_id()),
+                        ty::WithOptConstParam::unknown(discr_def_id.to_def_id()),
                         discr_substs,
                     )
                     .to_predicate(fcx.tcx),
diff --git a/src/tools/clippy/clippy_lints/src/consts.rs b/src/tools/clippy/clippy_lints/src/consts.rs
index 891cb69bb56..e6ef54f528f 100644
--- a/src/tools/clippy/clippy_lints/src/consts.rs
+++ b/src/tools/clippy/clippy_lints/src/consts.rs
@@ -332,7 +332,7 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                 let result = self
                     .lcx
                     .tcx
-                    .const_eval_resolve(self.param_env, ty::WithOptConstParam::dummy(def_id), substs, None, None)
+                    .const_eval_resolve(self.param_env, ty::WithOptConstParam::unknown(def_id), substs, None, None)
                     .ok()
                     .map(|val| rustc_middle::ty::Const::from_value(self.lcx.tcx, val, ty))?;
                 let result = miri_to_const(&result);