trait_sel: `{Meta,Pointee}Sized` on `?Sized` types

Expand the automatic implementation of `MetaSized` and `PointeeSized` so
that it is also implemented on non-`Sized` types, just not `ty::Foreign`
(extern type).

5 files changed, 31 insertions, 12 deletions

diff --git a/compiler/rustc_middle/src/query/keys.rs b/compiler/rustc_middle/src/query/keys.rs
index 9ed1f10455a..4d914c42cfc 100644
--- a/compiler/rustc_middle/src/query/keys.rs
+++ b/compiler/rustc_middle/src/query/keys.rs
@@ -328,6 +328,14 @@ impl Key for (DefId, SimplifiedType) {
     }
 }
 
+impl Key for (DefId, ty::SizedTraitKind) {
+    type Cache<V> = DefaultCache<Self, V>;
+
+    fn default_span(&self, tcx: TyCtxt<'_>) -> Span {
+        self.0.default_span(tcx)
+    }
+}
+
 impl<'tcx> Key for GenericArgsRef<'tcx> {
     type Cache<V> = DefaultCache<Self, V>;
 
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 15e8c1ef3cc..e4fcd7e56f1 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -81,8 +81,8 @@ use crate::ty::layout::ValidityRequirement;
 use crate::ty::print::{PrintTraitRefExt, describe_as_module};
 use crate::ty::util::AlwaysRequiresDrop;
 use crate::ty::{
-    self, CrateInherentImpls, GenericArg, GenericArgsRef, PseudoCanonicalInput, Ty, TyCtxt,
-    TyCtxtFeed,
+    self, CrateInherentImpls, GenericArg, GenericArgsRef, PseudoCanonicalInput, SizedTraitKind, Ty,
+    TyCtxt, TyCtxtFeed,
 };
 use crate::{dep_graph, mir, thir};
 
@@ -854,9 +854,10 @@ rustc_queries! {
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
     }
-
-    query adt_sized_constraint(key: DefId) -> Option<ty::EarlyBinder<'tcx, Ty<'tcx>>> {
-        desc { |tcx| "computing the `Sized` constraint for `{}`", tcx.def_path_str(key) }
+    query adt_sizedness_constraint(
+        key: (DefId, SizedTraitKind)
+    ) -> Option<ty::EarlyBinder<'tcx, Ty<'tcx>>> {
+        desc { |tcx| "computing the sizedness constraint for `{}`", tcx.def_path_str(key.0) }
     }
 
     query adt_dtorck_constraint(
diff --git a/compiler/rustc_middle/src/ty/adt.rs b/compiler/rustc_middle/src/ty/adt.rs
index d92b4f9c06b..6d5a3abf665 100644
--- a/compiler/rustc_middle/src/ty/adt.rs
+++ b/compiler/rustc_middle/src/ty/adt.rs
@@ -229,8 +229,12 @@ impl<'tcx> rustc_type_ir::inherent::AdtDef<TyCtxt<'tcx>> for AdtDef<'tcx> {
         )
     }
 
-    fn sized_constraint(self, tcx: TyCtxt<'tcx>) -> Option<ty::EarlyBinder<'tcx, Ty<'tcx>>> {
-        self.sized_constraint(tcx)
+    fn sizedness_constraint(
+        self,
+        tcx: TyCtxt<'tcx>,
+        sizedness: ty::SizedTraitKind,
+    ) -> Option<ty::EarlyBinder<'tcx, Ty<'tcx>>> {
+        self.sizedness_constraint(tcx, sizedness)
     }
 
     fn is_fundamental(self) -> bool {
@@ -634,10 +638,15 @@ impl<'tcx> AdtDef<'tcx> {
         tcx.adt_async_destructor(self.did())
     }
 
-    /// Returns a type such that `Self: Sized` if and only if that type is `Sized`,
-    /// or `None` if the type is always sized.
-    pub fn sized_constraint(self, tcx: TyCtxt<'tcx>) -> Option<ty::EarlyBinder<'tcx, Ty<'tcx>>> {
-        if self.is_struct() { tcx.adt_sized_constraint(self.did()) } else { None }
+    /// If this ADT is a struct, returns a type such that `Self: {Meta,Pointee,}Sized` if and only
+    /// if that type is `{Meta,Pointee,}Sized`, or `None` if this ADT is always
+    /// `{Meta,Pointee,}Sized`.
+    pub fn sizedness_constraint(
+        self,
+        tcx: TyCtxt<'tcx>,
+        sizedness: ty::SizedTraitKind,
+    ) -> Option<ty::EarlyBinder<'tcx, Ty<'tcx>>> {
+        if self.is_struct() { tcx.adt_sizedness_constraint((self.did(), sizedness)) } else { None }
     }
 }
 
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 0402d098822..97408e31854 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -60,6 +60,7 @@ pub use rustc_type_ir::fast_reject::DeepRejectCtxt;
 )]
 use rustc_type_ir::inherent;
 pub use rustc_type_ir::relate::VarianceDiagInfo;
+pub use rustc_type_ir::solve::SizedTraitKind;
 pub use rustc_type_ir::*;
 #[allow(hidden_glob_reexports, unused_imports)]
 use rustc_type_ir::{InferCtxtLike, Interner};
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index cbf545c01c5..2adda8263a1 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -1816,7 +1816,7 @@ impl<'tcx> Ty<'tcx> {
             ty::Tuple(tys) => tys.last().is_none_or(|ty| ty.is_trivially_sized(tcx)),
 
             ty::Adt(def, args) => def
-                .sized_constraint(tcx)
+                .sizedness_constraint(tcx, ty::SizedTraitKind::Sized)
                 .is_none_or(|ty| ty.instantiate(tcx, args).is_trivially_sized(tcx)),
 
             ty::Alias(..) | ty::Param(_) | ty::Placeholder(..) | ty::Bound(..) => false,