4 files changed, 76 insertions, 4 deletions
diff --git a/compiler/rustc_smir/src/rustc_internal/mod.rs b/compiler/rustc_smir/src/rustc_internal/mod.rs
index 6a26a4a22ed..39541c845b3 100644
--- a/compiler/rustc_smir/src/rustc_internal/mod.rs
+++ b/compiler/rustc_smir/src/rustc_internal/mod.rs
@@ -68,6 +68,10 @@ impl<'tcx> Tables<'tcx> {
         self.def_ids[item.0]
     }
 
+    pub fn trait_def_id(&self, trait_def: &stable_mir::ty::TraitDef) -> DefId {
+        self.def_ids[trait_def.0]
+    }
+
     pub fn crate_item(&mut self, did: DefId) -> stable_mir::CrateItem {
         stable_mir::CrateItem(self.create_def_id(did))
     }
diff --git a/compiler/rustc_smir/src/rustc_smir/mod.rs b/compiler/rustc_smir/src/rustc_smir/mod.rs
index 6eb7e930425..239b61b433d 100644
--- a/compiler/rustc_smir/src/rustc_smir/mod.rs
+++ b/compiler/rustc_smir/src/rustc_smir/mod.rs
@@ -41,6 +41,13 @@ impl<'tcx> Context for Tables<'tcx> {
     fn entry_fn(&mut self) -> Option<stable_mir::CrateItem> {
         Some(self.crate_item(self.tcx.entry_fn(())?.0))
     }
+
+    fn trait_decl(&mut self, trait_def: &stable_mir::ty::TraitDef) -> stable_mir::ty::TraitDecl {
+        let def_id = self.trait_def_id(trait_def);
+        let trait_def = self.tcx.trait_def(def_id);
+        trait_def.stable(self)
+    }
+
     fn mir_body(&mut self, item: &stable_mir::CrateItem) -> stable_mir::mir::Body {
         let def_id = self.item_def_id(item);
         let mir = self.tcx.optimized_mir(def_id);
@@ -515,7 +522,7 @@ impl<'tcx> Stable<'tcx> for mir::RetagKind {
     }
 }
 
-impl<'tcx> Stable<'tcx> for rustc_middle::ty::UserTypeAnnotationIndex {
+impl<'tcx> Stable<'tcx> for ty::UserTypeAnnotationIndex {
     type T = usize;
     fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
         self.as_usize()
@@ -1045,7 +1052,7 @@ impl<'tcx> Stable<'tcx> for Ty<'tcx> {
     }
 }
 
-impl<'tcx> Stable<'tcx> for rustc_middle::ty::ParamTy {
+impl<'tcx> Stable<'tcx> for ty::ParamTy {
     type T = stable_mir::ty::ParamTy;
     fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
         use stable_mir::ty::ParamTy;
@@ -1053,7 +1060,7 @@ impl<'tcx> Stable<'tcx> for rustc_middle::ty::ParamTy {
     }
 }
 
-impl<'tcx> Stable<'tcx> for rustc_middle::ty::BoundTy {
+impl<'tcx> Stable<'tcx> for ty::BoundTy {
     type T = stable_mir::ty::BoundTy;
     fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
         use stable_mir::ty::BoundTy;
@@ -1091,3 +1098,42 @@ impl<'tcx> Stable<'tcx> for mir::interpret::Allocation {
         }
     }
 }
+
+impl<'tcx> Stable<'tcx> for ty::trait_def::TraitSpecializationKind {
+    type T = stable_mir::ty::TraitSpecializationKind;
+    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+        use stable_mir::ty::TraitSpecializationKind;
+
+        match self {
+            ty::trait_def::TraitSpecializationKind::None => TraitSpecializationKind::None,
+            ty::trait_def::TraitSpecializationKind::Marker => TraitSpecializationKind::Marker,
+            ty::trait_def::TraitSpecializationKind::AlwaysApplicable => {
+                TraitSpecializationKind::AlwaysApplicable
+            }
+        }
+    }
+}
+
+impl<'tcx> Stable<'tcx> for ty::TraitDef {
+    type T = stable_mir::ty::TraitDecl;
+    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+        use stable_mir::ty::TraitDecl;
+
+        TraitDecl {
+            def_id: rustc_internal::trait_def(self.def_id),
+            unsafety: self.unsafety.stable(tables),
+            paren_sugar: self.paren_sugar,
+            has_auto_impl: self.has_auto_impl,
+            is_marker: self.is_marker,
+            is_coinductive: self.is_coinductive,
+            skip_array_during_method_dispatch: self.skip_array_during_method_dispatch,
+            specialization_kind: self.specialization_kind.stable(tables),
+            must_implement_one_of: self
+                .must_implement_one_of
+                .as_ref()
+                .map(|idents| idents.iter().map(|ident| opaque(ident)).collect()),
+            implement_via_object: self.implement_via_object,
+            deny_explicit_impl: self.deny_explicit_impl,
+        }
+    }
+}
diff --git a/compiler/rustc_smir/src/stable_mir/mod.rs b/compiler/rustc_smir/src/stable_mir/mod.rs
index 5e599a77bcd..0f32f07dcb5 100644
--- a/compiler/rustc_smir/src/stable_mir/mod.rs
+++ b/compiler/rustc_smir/src/stable_mir/mod.rs
@@ -15,7 +15,7 @@ use std::cell::Cell;
 
 use crate::rustc_smir::Tables;
 
-use self::ty::{Ty, TyKind};
+use self::ty::{TraitDecl, TraitDef, Ty, TyKind};
 
 pub mod mir;
 pub mod ty;
@@ -84,6 +84,7 @@ pub trait Context {
     /// Retrieve all items of the local crate that have a MIR associated with them.
     fn all_local_items(&mut self) -> CrateItems;
     fn mir_body(&mut self, item: &CrateItem) -> mir::Body;
+    fn trait_decl(&mut self, trait_def: &TraitDef) -> TraitDecl;
     /// Get information about the local crate.
     fn local_crate(&self) -> Crate;
     /// Retrieve a list of all external crates.
diff --git a/compiler/rustc_smir/src/stable_mir/ty.rs b/compiler/rustc_smir/src/stable_mir/ty.rs
index be917b2e140..03089fef01a 100644
--- a/compiler/rustc_smir/src/stable_mir/ty.rs
+++ b/compiler/rustc_smir/src/stable_mir/ty.rs
@@ -11,6 +11,7 @@ impl Ty {
 }
 
 pub(crate) type Const = Opaque;
+type Ident = Opaque;
 pub(crate) type Region = Opaque;
 type Span = Opaque;
 
@@ -258,3 +259,23 @@ pub struct Allocation {
     pub align: Align,
     pub mutability: Mutability,
 }
+
+pub enum TraitSpecializationKind {
+    None,
+    Marker,
+    AlwaysApplicable,
+}
+
+pub struct TraitDecl {
+    pub def_id: TraitDef,
+    pub unsafety: Safety,
+    pub paren_sugar: bool,
+    pub has_auto_impl: bool,
+    pub is_marker: bool,
+    pub is_coinductive: bool,
+    pub skip_array_during_method_dispatch: bool,
+    pub specialization_kind: TraitSpecializationKind,
+    pub must_implement_one_of: Option<Vec<Ident>>,
+    pub implement_via_object: bool,
+    pub deny_explicit_impl: bool,
+}