From e94723452083283be04f6f55fca468b57bca32f3 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Mon, 11 Dec 2023 21:06:26 +0000
Subject: [PATCH] Simplify some Copy impls in rustc_type_ir

---
 compiler/rustc_type_ir/src/canonical.rs      | 18 ++--------
 compiler/rustc_type_ir/src/predicate_kind.rs | 35 +++++---------------
 compiler/rustc_type_ir/src/region_kind.rs    | 13 +-------
 3 files changed, 11 insertions(+), 55 deletions(-)

diff --git a/compiler/rustc_type_ir/src/canonical.rs b/compiler/rustc_type_ir/src/canonical.rs
index 572c6f201d3..5bc2bfe2893 100644
--- a/compiler/rustc_type_ir/src/canonical.rs
+++ b/compiler/rustc_type_ir/src/canonical.rs
@@ -119,12 +119,7 @@ fn visit_with<F: TypeVisitor<I>>(&self, folder: &mut F) -> ControlFlow<F::BreakT
 /// a copy of the canonical value in some other inference context,
 /// with fresh inference variables replacing the canonical values.
 #[derive(derivative::Derivative)]
-#[derivative(
-    Clone(bound = ""),
-    Hash(bound = ""),
-    Copy(bound = "CanonicalVarKind<I>: Copy"),
-    Debug(bound = "")
-)]
+#[derivative(Clone(bound = ""), Copy(bound = ""), Hash(bound = ""), Debug(bound = ""))]
 #[cfg_attr(feature = "nightly", derive(TyDecodable, TyEncodable, HashStable_NoContext))]
 pub struct CanonicalVarInfo<I: Interner> {
     pub kind: CanonicalVarKind<I>,
@@ -207,7 +202,7 @@ pub fn expect_placeholder_index(self) -> usize {
 /// in the type-theory sense of the term -- i.e., a "meta" type system
 /// that analyzes type-like values.
 #[derive(derivative::Derivative)]
-#[derivative(Clone(bound = ""), Hash(bound = ""), Debug(bound = ""))]
+#[derivative(Clone(bound = ""), Copy(bound = ""), Hash(bound = ""), Debug(bound = ""))]
 #[cfg_attr(feature = "nightly", derive(TyDecodable, TyEncodable, HashStable_NoContext))]
 pub enum CanonicalVarKind<I: Interner> {
     /// Some kind of type inference variable.
@@ -234,15 +229,6 @@ pub enum CanonicalVarKind<I: Interner> {
     PlaceholderConst(I::PlaceholderConst, I::Ty),
 }
 
-impl<I: Interner> Copy for CanonicalVarKind<I>
-where
-    I::PlaceholderTy: Copy,
-    I::PlaceholderRegion: Copy,
-    I::PlaceholderConst: Copy,
-    I::Ty: Copy,
-{
-}
-
 impl<I: Interner> PartialEq for CanonicalVarKind<I> {
     fn eq(&self, other: &Self) -> bool {
         match (self, other) {
diff --git a/compiler/rustc_type_ir/src/predicate_kind.rs b/compiler/rustc_type_ir/src/predicate_kind.rs
index b567fa8e2f6..8c4d0fda6af 100644
--- a/compiler/rustc_type_ir/src/predicate_kind.rs
+++ b/compiler/rustc_type_ir/src/predicate_kind.rs
@@ -8,7 +8,7 @@
 /// A clause is something that can appear in where bounds or be inferred
 /// by implied bounds.
 #[derive(derivative::Derivative)]
-#[derivative(Clone(bound = ""), Hash(bound = ""))]
+#[derivative(Clone(bound = ""), Copy(bound = ""), Hash(bound = ""))]
 #[cfg_attr(feature = "nightly", derive(TyEncodable, TyDecodable, HashStable_NoContext))]
 pub enum ClauseKind<I: Interner> {
     /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
@@ -37,18 +37,6 @@ pub enum ClauseKind<I: Interner> {
     ConstEvaluatable(I::Const),
 }
 
-impl<I: Interner> Copy for ClauseKind<I>
-where
-    I::Ty: Copy,
-    I::Const: Copy,
-    I::GenericArg: Copy,
-    I::TraitPredicate: Copy,
-    I::ProjectionPredicate: Copy,
-    I::TypeOutlivesPredicate: Copy,
-    I::RegionOutlivesPredicate: Copy,
-{
-}
-
 impl<I: Interner> PartialEq for ClauseKind<I> {
     fn eq(&self, other: &Self) -> bool {
         match (self, other) {
@@ -120,7 +108,13 @@ fn visit_with<V: TypeVisitor<I>>(&self, visitor: &mut V) -> ControlFlow<V::Break
 }
 
 #[derive(derivative::Derivative)]
-#[derivative(Clone(bound = ""), Hash(bound = ""), PartialEq(bound = ""), Eq(bound = ""))]
+#[derivative(
+    Clone(bound = ""),
+    Copy(bound = ""),
+    Hash(bound = ""),
+    PartialEq(bound = ""),
+    Eq(bound = "")
+)]
 #[cfg_attr(feature = "nightly", derive(TyEncodable, TyDecodable, HashStable_NoContext))]
 pub enum PredicateKind<I: Interner> {
     /// Prove a clause
@@ -169,19 +163,6 @@ pub enum PredicateKind<I: Interner> {
     AliasRelate(I::Term, I::Term, AliasRelationDirection),
 }
 
-impl<I: Interner> Copy for PredicateKind<I>
-where
-    I::DefId: Copy,
-    I::Const: Copy,
-    I::GenericArgs: Copy,
-    I::Term: Copy,
-    I::CoercePredicate: Copy,
-    I::SubtypePredicate: Copy,
-    I::NormalizesTo: Copy,
-    ClauseKind<I>: Copy,
-{
-}
-
 impl<I: Interner> TypeFoldable<I> for PredicateKind<I>
 where
     I::DefId: TypeFoldable<I>,
diff --git a/compiler/rustc_type_ir/src/region_kind.rs b/compiler/rustc_type_ir/src/region_kind.rs
index 4157d49287c..3b5e41e8d85 100644
--- a/compiler/rustc_type_ir/src/region_kind.rs
+++ b/compiler/rustc_type_ir/src/region_kind.rs
@@ -115,6 +115,7 @@
 #[derive(derivative::Derivative)]
 #[derivative(
     Clone(bound = ""),
+    Copy(bound = ""),
     PartialOrd(bound = ""),
     PartialOrd = "feature_allow_slow_enum",
     Ord(bound = ""),
@@ -189,18 +190,6 @@ const fn regionkind_discriminant<I: Interner>(value: &RegionKind<I>) -> usize {
     }
 }
 
-// This is manually implemented because a derive would require `I: Copy`
-impl<I: Interner> Copy for RegionKind<I>
-where
-    I::EarlyParamRegion: Copy,
-    I::BoundRegion: Copy,
-    I::LateParamRegion: Copy,
-    I::InferRegion: Copy,
-    I::PlaceholderRegion: Copy,
-    I::ErrorGuaranteed: Copy,
-{
-}
-
 // This is manually implemented because a derive would require `I: PartialEq`
 impl<I: Interner> PartialEq for RegionKind<I> {
     #[inline]