Track bound types like bound regions

5 files changed, 21 insertions, 7 deletions

diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs
index 6b9a37d848d..1445bc1ed32 100644
--- a/compiler/rustc_middle/src/ty/fold.rs
+++ b/compiler/rustc_middle/src/ty/fold.rs
@@ -610,7 +610,9 @@ impl<'tcx> TyCtxt<'tcx> {
                 let index = entry.index();
                 let var = ty::BoundVar::from_usize(index);
                 let kind = entry
-                    .or_insert_with(|| ty::BoundVariableKind::Ty(ty::BoundTyKind::Anon))
+                    .or_insert_with(|| {
+                        ty::BoundVariableKind::Ty(ty::BoundTyKind::Anon(index as u32))
+                    })
                     .expect_ty();
                 self.tcx.mk_ty(ty::Bound(ty::INNERMOST, BoundTy { var, kind }))
             }
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 25c6777a14c..09c3d5b736c 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -1369,7 +1369,7 @@ pub struct Placeholder<T> {
 
 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
 
-pub type PlaceholderType = Placeholder<BoundVar>;
+pub type PlaceholderType = Placeholder<BoundTyKind>;
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
 #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)]
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index f2abec216b7..df4e8c1a52d 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -698,8 +698,10 @@ pub trait PrettyPrinter<'tcx>:
             ty::Error(_) => p!("[type error]"),
             ty::Param(ref param_ty) => p!(print(param_ty)),
             ty::Bound(debruijn, bound_ty) => match bound_ty.kind {
-                ty::BoundTyKind::Anon => self.pretty_print_bound_var(debruijn, bound_ty.var)?,
-                ty::BoundTyKind::Param(p) => p!(write("{}", p)),
+                ty::BoundTyKind::Anon(bv) => {
+                    self.pretty_print_bound_var(debruijn, ty::BoundVar::from_u32(bv))?
+                }
+                ty::BoundTyKind::Param(_, s) => p!(write("{}", s)),
             },
             ty::Adt(def, substs) => {
                 p!(print_def_path(def.did(), substs));
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index 034aab0c38e..8df639750c7 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -240,6 +240,7 @@ TrivialTypeTraversalAndLiftImpls! {
     crate::ty::AssocKind,
     crate::ty::AliasKind,
     crate::ty::Placeholder<crate::ty::BoundRegionKind>,
+    crate::ty::Placeholder<crate::ty::BoundTyKind>,
     crate::ty::ClosureKind,
     crate::ty::FreeRegion,
     crate::ty::InferTy,
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index f97d2e753a3..060d864389c 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -1504,13 +1504,22 @@ pub struct BoundTy {
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
 #[derive(HashStable)]
 pub enum BoundTyKind {
-    Anon,
-    Param(Symbol),
+    Anon(u32),
+    Param(DefId, Symbol),
+}
+
+impl BoundTyKind {
+    pub fn expect_anon(self) -> u32 {
+        match self {
+            BoundTyKind::Anon(i) => i,
+            _ => bug!(),
+        }
+    }
 }
 
 impl From<BoundVar> for BoundTy {
     fn from(var: BoundVar) -> Self {
-        BoundTy { var, kind: BoundTyKind::Anon }
+        BoundTy { var, kind: BoundTyKind::Anon(var.as_u32()) }
     }
 }