From d2b5a64579aace20b1288f346787d0feb76e3742 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Sun, 16 Apr 2023 14:01:43 +1000
Subject: [PATCH] Simplify `CloneLiftImpls` and `TrivialTypeTraversalImpls`.

They both allow for a lifetime other than `'tcx`, but this isn't needed.
---
 compiler/rustc_middle/src/infer/canonical.rs  |  6 ++--
 compiler/rustc_middle/src/macros.rs           | 34 +++++--------------
 compiler/rustc_middle/src/mir/mod.rs          |  4 +--
 .../rustc_middle/src/mir/type_foldable.rs     |  4 +--
 compiler/rustc_middle/src/ty/context.rs       |  9 +++--
 .../rustc_middle/src/ty/structural_impls.rs   |  4 +--
 6 files changed, 20 insertions(+), 41 deletions(-)

diff --git a/compiler/rustc_middle/src/infer/canonical.rs b/compiler/rustc_middle/src/infer/canonical.rs
index b5b712c367d08..bec8e7565a463 100644
--- a/compiler/rustc_middle/src/infer/canonical.rs
+++ b/compiler/rustc_middle/src/infer/canonical.rs
@@ -400,10 +400,8 @@ pub type QueryOutlivesConstraint<'tcx> =
     (ty::OutlivesPredicate<GenericArg<'tcx>, Region<'tcx>>, ConstraintCategory<'tcx>);
 
 TrivialTypeTraversalAndLiftImpls! {
-    for <'tcx> {
-        crate::infer::canonical::Certainty,
-        crate::infer::canonical::CanonicalTyVarKind,
-    }
+    crate::infer::canonical::Certainty,
+    crate::infer::canonical::CanonicalTyVarKind,
 }
 
 impl<'tcx> CanonicalVarValues<'tcx> {
diff --git a/compiler/rustc_middle/src/macros.rs b/compiler/rustc_middle/src/macros.rs
index 89014f62d4d69..cd1c6c330bc1e 100644
--- a/compiler/rustc_middle/src/macros.rs
+++ b/compiler/rustc_middle/src/macros.rs
@@ -43,34 +43,26 @@ macro_rules! span_bug {
 
 #[macro_export]
 macro_rules! CloneLiftImpls {
-    (for <$tcx:lifetime> { $($ty:ty,)+ }) => {
+    ($($ty:ty,)+) => {
         $(
-            impl<$tcx> $crate::ty::Lift<$tcx> for $ty {
+            impl<'tcx> $crate::ty::Lift<'tcx> for $ty {
                 type Lifted = Self;
-                fn lift_to_tcx(self, _: $crate::ty::TyCtxt<$tcx>) -> Option<Self> {
+                fn lift_to_tcx(self, _: $crate::ty::TyCtxt<'tcx>) -> Option<Self> {
                     Some(self)
                 }
             }
         )+
     };
-
-    ($($ty:ty,)+) => {
-        CloneLiftImpls! {
-            for <'tcx> {
-                $($ty,)+
-            }
-        }
-    };
 }
 
 /// Used for types that are `Copy` and which **do not care arena
 /// allocated data** (i.e., don't need to be folded).
 #[macro_export]
 macro_rules! TrivialTypeTraversalImpls {
-    (for <$tcx:lifetime> { $($ty:ty,)+ }) => {
+    ($($ty:ty,)+) => {
         $(
-            impl<$tcx> $crate::ty::fold::TypeFoldable<$crate::ty::TyCtxt<$tcx>> for $ty {
-                fn try_fold_with<F: $crate::ty::fold::FallibleTypeFolder<$crate::ty::TyCtxt<$tcx>>>(
+            impl<'tcx> $crate::ty::fold::TypeFoldable<$crate::ty::TyCtxt<'tcx>> for $ty {
+                fn try_fold_with<F: $crate::ty::fold::FallibleTypeFolder<$crate::ty::TyCtxt<'tcx>>>(
                     self,
                     _: &mut F,
                 ) -> ::std::result::Result<Self, F::Error> {
@@ -78,7 +70,7 @@ macro_rules! TrivialTypeTraversalImpls {
                 }
 
                 #[inline]
-                fn fold_with<F: $crate::ty::fold::TypeFolder<$crate::ty::TyCtxt<$tcx>>>(
+                fn fold_with<F: $crate::ty::fold::TypeFolder<$crate::ty::TyCtxt<'tcx>>>(
                     self,
                     _: &mut F,
                 ) -> Self {
@@ -86,9 +78,9 @@ macro_rules! TrivialTypeTraversalImpls {
                 }
             }
 
-            impl<$tcx> $crate::ty::visit::TypeVisitable<$crate::ty::TyCtxt<$tcx>> for $ty {
+            impl<'tcx> $crate::ty::visit::TypeVisitable<$crate::ty::TyCtxt<'tcx>> for $ty {
                 #[inline]
-                fn visit_with<F: $crate::ty::visit::TypeVisitor<$crate::ty::TyCtxt<$tcx>>>(
+                fn visit_with<F: $crate::ty::visit::TypeVisitor<$crate::ty::TyCtxt<'tcx>>>(
                     &self,
                     _: &mut F)
                     -> ::std::ops::ControlFlow<F::BreakTy>
@@ -98,14 +90,6 @@ macro_rules! TrivialTypeTraversalImpls {
             }
         )+
     };
-
-    ($($ty:ty,)+) => {
-        TrivialTypeTraversalImpls! {
-            for<'tcx> {
-                $($ty,)+
-            }
-        }
-    };
 }
 
 #[macro_export]
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 2ea8602af12a1..f985aae9a2255 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -714,9 +714,7 @@ pub enum BindingForm<'tcx> {
 }
 
 TrivialTypeTraversalAndLiftImpls! {
-    for<'tcx> {
-        BindingForm<'tcx>,
-    }
+    BindingForm<'tcx>,
 }
 
 mod binding_form_impl {
diff --git a/compiler/rustc_middle/src/mir/type_foldable.rs b/compiler/rustc_middle/src/mir/type_foldable.rs
index 9881583214eb4..ace856b9f95e0 100644
--- a/compiler/rustc_middle/src/mir/type_foldable.rs
+++ b/compiler/rustc_middle/src/mir/type_foldable.rs
@@ -25,9 +25,7 @@ TrivialTypeTraversalAndLiftImpls! {
 }
 
 TrivialTypeTraversalImpls! {
-    for <'tcx> {
-        ConstValue<'tcx>,
-    }
+    ConstValue<'tcx>,
 }
 
 impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx [InlineAsmTemplatePiece] {
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 63f7cc2ee7352..e5356581e6e1d 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1329,9 +1329,12 @@ nop_list_lift! {bound_variable_kinds; ty::BoundVariableKind => ty::BoundVariable
 // This is the impl for `&'a InternalSubsts<'a>`.
 nop_list_lift! {substs; GenericArg<'a> => GenericArg<'tcx>}
 
-CloneLiftImpls! { for<'tcx> {
-    Constness, traits::WellFormedLoc, ImplPolarity, crate::mir::ReturnConstraint,
-} }
+CloneLiftImpls! {
+    Constness,
+    traits::WellFormedLoc,
+    ImplPolarity,
+    crate::mir::ReturnConstraint,
+}
 
 macro_rules! sty_debug_print {
     ($fmt: expr, $ctxt: expr, $($variant: ident),*) => {{
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index 5c604bb6db274..59c05739b3cef 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -276,9 +276,7 @@ TrivialTypeTraversalAndLiftImpls! {
 }
 
 TrivialTypeTraversalAndLiftImpls! {
-    for<'tcx> {
-        ty::ValTree<'tcx>,
-    }
+    ty::ValTree<'tcx>,
 }
 
 ///////////////////////////////////////////////////////////////////////////