Auto merge of #90076 - jackh726:wherethewhere, r=nikomatsakis

Change location of where clause on GATs

Closes #89122

~Blocked on lang FCP~

r? `@nikomatsakis`

41 files changed, 251 insertions, 203 deletions

diff --git a/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs b/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs
index 1d2be3657ff..c5c13451488 100644
--- a/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs
+++ b/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs
@@ -24,7 +24,7 @@ trait Bar {
 }
 
 impl Bar for Foo {
-    type Assoc where Self: Sized = Foo;
+    type Assoc = Foo where Self: Sized;
     //~^ ERROR where clauses on associated types are unstable
 }
 
diff --git a/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr b/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr
index 6c2c3ed9c36..12a40ff0a12 100644
--- a/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr
+++ b/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr
@@ -55,7 +55,7 @@ LL |     type Assoc where Self: Sized;
 error[E0658]: where clauses on associated types are unstable
   --> $DIR/feature-gate-generic_associated_types.rs:27:5
    |
-LL |     type Assoc where Self: Sized = Foo;
+LL |     type Assoc = Foo where Self: Sized;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87735.rs b/src/test/ui/generic-associated-types/bugs/issue-87735.rs
index 6d6063f8085..53e3ad7fe69 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87735.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-87735.rs
@@ -12,7 +12,7 @@ pub trait AsRef2 {
 }
 
 impl<T> AsRef2 for Vec<T> {
-  type Output<'a> where Self: 'a = &'a [T];
+  type Output<'a> = &'a [T] where Self: 'a;
 
   fn as_ref2<'a>(&'a self) -> Self::Output<'a> {
     &self[..]
@@ -33,7 +33,7 @@ where
     T: AsRef2<Output<'b> = &'b [U]>,
     U: 'b
 {
-  type Output<'a> where Self: 'a = FooRef<'a, U>;
+  type Output<'a> = FooRef<'a, U> where Self: 'a;
 
   fn as_ref2<'a>(&'a self) -> Self::Output<'a> {
     FooRef(self.0.as_ref2())
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87748.rs b/src/test/ui/generic-associated-types/bugs/issue-87748.rs
index ffcfd62cbb3..6e7cd45bdb1 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87748.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-87748.rs
@@ -13,7 +13,7 @@ trait MyTrait {
 struct Foo;
 
 impl MyTrait for Foo {
-    type Assoc<'a, 'b> where 'b: 'a = u32;
+    type Assoc<'a, 'b> = u32 where 'b: 'a;
 
     fn do_sth(_: u32) {}
     // fn do_sth(_: Self::Assoc<'static, 'static>) {}
diff --git a/src/test/ui/generic-associated-types/collections-project-default.rs b/src/test/ui/generic-associated-types/collections-project-default.rs
index 5b94cdee7c9..157e1b1d295 100644
--- a/src/test/ui/generic-associated-types/collections-project-default.rs
+++ b/src/test/ui/generic-associated-types/collections-project-default.rs
@@ -32,7 +32,7 @@ impl CollectionFamily for VecFamily {
 }
 
 impl<T> Collection<T> for Vec<T> {
-    type Iter<'iter> where T: 'iter = std::slice::Iter<'iter, T>;
+    type Iter<'iter> = std::slice::Iter<'iter, T> where T: 'iter;
     type Family = VecFamily;
 
     fn empty() -> Self {
diff --git a/src/test/ui/generic-associated-types/collections.rs b/src/test/ui/generic-associated-types/collections.rs
index b0f2fb3f567..1c00aa73feb 100644
--- a/src/test/ui/generic-associated-types/collections.rs
+++ b/src/test/ui/generic-associated-types/collections.rs
@@ -32,7 +32,7 @@ impl CollectionFamily for VecFamily {
 }
 
 impl<T> Collection<T> for Vec<T> {
-    type Iter<'iter> where T: 'iter = std::slice::Iter<'iter, T>;
+    type Iter<'iter> = std::slice::Iter<'iter, T> where T: 'iter;
     type Family = VecFamily;
 
     fn empty() -> Self {
diff --git a/src/test/ui/generic-associated-types/construct_with_other_type.rs b/src/test/ui/generic-associated-types/construct_with_other_type.rs
index 9ae328cc48b..060804269aa 100644
--- a/src/test/ui/generic-associated-types/construct_with_other_type.rs
+++ b/src/test/ui/generic-associated-types/construct_with_other_type.rs
@@ -16,9 +16,9 @@ trait Baz {
 }
 
 impl<T> Baz for T where T: Foo {
-    type Quux<'a> where T: 'a = T;
+    type Quux<'a> = T where T: 'a;
 
-    type Baa<'a> where T: 'a = &'a <T as Foo>::Bar<'a, 'static>;
+    type Baa<'a> = &'a <T as Foo>::Bar<'a, 'static> where T: 'a;
 }
 
 fn main() {}
diff --git a/src/test/ui/generic-associated-types/gat-in-trait-path.rs b/src/test/ui/generic-associated-types/gat-in-trait-path.rs
index fb03a86e169..7bbcf950ae1 100644
--- a/src/test/ui/generic-associated-types/gat-in-trait-path.rs
+++ b/src/test/ui/generic-associated-types/gat-in-trait-path.rs
@@ -15,7 +15,7 @@ impl Foo for Fooy {
 struct Fooer<T>(T);
 
 impl<T> Foo for Fooer<T> {
-    type A<'x> where T: 'x = &'x ();
+    type A<'x> = &'x () where T: 'x;
 }
 
 fn f(_arg : Box<dyn for<'a> Foo<A<'a> = &'a ()>>) {}
diff --git a/src/test/ui/generic-associated-types/generic-associated-types-where.rs b/src/test/ui/generic-associated-types/generic-associated-types-where.rs
index 592ff939923..2ecbc8c5912 100644
--- a/src/test/ui/generic-associated-types/generic-associated-types-where.rs
+++ b/src/test/ui/generic-associated-types/generic-associated-types-where.rs
@@ -19,7 +19,7 @@ impl Foo for Bar {
     type Assoc = usize;
     type Assoc2<T> = Vec<T>;
     //~^ ERROR `T` doesn't implement `std::fmt::Display`
-    type Assoc3<T> where T: Iterator = Vec<T>;
+    type Assoc3<T> = Vec<T> where T: Iterator;
     //~^ ERROR impl has stricter requirements than trait
     type WithDefault<'a, T: Debug + 'a> = &'a dyn Iterator<Item=T>;
     type NoGenerics = ::std::cell::Cell<i32>;
diff --git a/src/test/ui/generic-associated-types/generic-associated-types-where.stderr b/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
index 544f2bcbbd7..68594bba486 100644
--- a/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
+++ b/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
@@ -16,7 +16,7 @@ error[E0276]: impl has stricter requirements than trait
 LL |     type Assoc3<T>;
    |     --------------- definition of `Assoc3` from trait
 ...
-LL |     type Assoc3<T> where T: Iterator = Vec<T>;
+LL |     type Assoc3<T> = Vec<T> where T: Iterator;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ impl has extra requirement `T: Iterator`
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/generic-associated-types/impl_bounds.rs b/src/test/ui/generic-associated-types/impl_bounds.rs
index ff2ffec22c4..bb5992c88f0 100644
--- a/src/test/ui/generic-associated-types/impl_bounds.rs
+++ b/src/test/ui/generic-associated-types/impl_bounds.rs
@@ -12,12 +12,12 @@ trait Foo {
 struct Fooy<T>(T);
 
 impl<T> Foo for Fooy<T> {
-    type A<'a> where Self: 'static = (&'a ());
+    type A<'a> = (&'a ()) where Self: 'static;
     //~^ ERROR `impl` associated type
-    type B<'a, 'b> where 'b: 'a = (&'a(), &'b ());
+    type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
     //~^ ERROR `impl` associated type
     //~| ERROR lifetime bound not satisfied
-    type C where Self: Copy = String;
+    type C = String where Self: Copy;
     //~^ ERROR the trait bound `T: Copy` is not satisfied
     fn d() where Self: Copy {}
     //~^ ERROR the trait bound `T: Copy` is not satisfied
diff --git a/src/test/ui/generic-associated-types/impl_bounds.stderr b/src/test/ui/generic-associated-types/impl_bounds.stderr
index bd0dea37219..3d90471e398 100644
--- a/src/test/ui/generic-associated-types/impl_bounds.stderr
+++ b/src/test/ui/generic-associated-types/impl_bounds.stderr
@@ -4,7 +4,7 @@ error: `impl` associated type signature for `A` doesn't match `trait` associated
 LL |     type A<'a> where Self: 'a;
    |     -------------------------- expected
 ...
-LL |     type A<'a> where Self: 'static = (&'a ());
+LL |     type A<'a> = (&'a ()) where Self: 'static;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found
 
 error: `impl` associated type signature for `B` doesn't match `trait` associated type signature
@@ -13,35 +13,33 @@ error: `impl` associated type signature for `B` doesn't match `trait` associated
 LL |     type B<'a, 'b> where 'a: 'b;
    |     ---------------------------- expected
 ...
-LL |     type B<'a, 'b> where 'b: 'a = (&'a(), &'b ());
+LL |     type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found
 
 error[E0478]: lifetime bound not satisfied
-  --> $DIR/impl_bounds.rs:17:35
+  --> $DIR/impl_bounds.rs:17:22
    |
 LL |     type B<'a, 'b> where 'a: 'b;
    |     ---------------------------- definition of `B` from trait
 ...
-LL |     type B<'a, 'b> where 'b: 'a = (&'a(), &'b ());
-   |                                -  ^^^^^^^^^^^^^^^
-   |                                |
-   |                                help: try copying this clause from the trait: `, 'a: 'b`
+LL |     type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
+   |                      ^^^^^^^^^^^^^^^             - help: try copying this clause from the trait: `, 'a: 'b`
    |
 note: lifetime parameter instantiated with the lifetime `'a` as defined here
   --> $DIR/impl_bounds.rs:17:12
    |
-LL |     type B<'a, 'b> where 'b: 'a = (&'a(), &'b ());
+LL |     type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
    |            ^^
 note: but lifetime parameter must outlive the lifetime `'b` as defined here
   --> $DIR/impl_bounds.rs:17:16
    |
-LL |     type B<'a, 'b> where 'b: 'a = (&'a(), &'b ());
+LL |     type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
    |                ^^
 
 error[E0277]: the trait bound `T: Copy` is not satisfied
   --> $DIR/impl_bounds.rs:20:5
    |
-LL |     type C where Self: Copy = String;
+LL |     type C = String where Self: Copy;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `T`
    |
 note: required because of the requirements on the impl of `Copy` for `Fooy<T>`
diff --git a/src/test/ui/generic-associated-types/impl_bounds_ok.rs b/src/test/ui/generic-associated-types/impl_bounds_ok.rs
index 08120b9670f..4df8235d95f 100644
--- a/src/test/ui/generic-associated-types/impl_bounds_ok.rs
+++ b/src/test/ui/generic-associated-types/impl_bounds_ok.rs
@@ -22,9 +22,9 @@ impl Foo for Fooy {
 struct Fooer<T>(T);
 
 impl<T> Foo for Fooer<T> {
-    type A<'x> where T: 'x = (&'x ());
-    type B<'u, 'v> where 'u: 'v = (&'v &'u ());
-    type C where Self: Clone + ToOwned = String;
+    type A<'x> = (&'x ()) where T: 'x;
+    type B<'u, 'v> = (&'v &'u ()) where 'u: 'v;
+    type C = String where Self: Clone + ToOwned;
 }
 
 fn main() {}
diff --git a/src/test/ui/generic-associated-types/issue-47206-where-clause.rs b/src/test/ui/generic-associated-types/issue-47206-where-clause.rs
index da5fca2a656..d352c1948f2 100644
--- a/src/test/ui/generic-associated-types/issue-47206-where-clause.rs
+++ b/src/test/ui/generic-associated-types/issue-47206-where-clause.rs
@@ -9,7 +9,7 @@ trait Foo {
 struct Bar;
 
 impl Foo for Bar {
-    type Assoc3<T> where T: Iterator = Vec<T>;
+    type Assoc3<T> = Vec<T> where T: Iterator;
     //~^ ERROR impl has stricter requirements than trait
 }
 
diff --git a/src/test/ui/generic-associated-types/issue-47206-where-clause.stderr b/src/test/ui/generic-associated-types/issue-47206-where-clause.stderr
index 56677457726..39beac38c0b 100644
--- a/src/test/ui/generic-associated-types/issue-47206-where-clause.stderr
+++ b/src/test/ui/generic-associated-types/issue-47206-where-clause.stderr
@@ -4,7 +4,7 @@ error[E0276]: impl has stricter requirements than trait
 LL |     type Assoc3<T>;
    |     --------------- definition of `Assoc3` from trait
 ...
-LL |     type Assoc3<T> where T: Iterator = Vec<T>;
+LL |     type Assoc3<T> = Vec<T> where T: Iterator;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ impl has extra requirement `T: Iterator`
 
 error: aborting due to previous error
diff --git a/src/test/ui/generic-associated-types/issue-76826.rs b/src/test/ui/generic-associated-types/issue-76826.rs
index d3201a156a1..28eb3b0e750 100644
--- a/src/test/ui/generic-associated-types/issue-76826.rs
+++ b/src/test/ui/generic-associated-types/issue-76826.rs
@@ -29,7 +29,7 @@ impl<T> Windows<T> {
 }
 
 impl<T> Iter for Windows<T> {
-    type Item<'a> where T: 'a = &'a mut [T];
+    type Item<'a> = &'a mut [T] where T: 'a;
 
     fn next<'a>(&'a mut self) -> Option<Self::Item<'a>> {
         let slice = self.items.get_mut(self.start..self.start + self.len)?;
diff --git a/src/test/ui/generic-associated-types/issue-79422.rs b/src/test/ui/generic-associated-types/issue-79422.rs
index 47ef38ff45d..b9a3c583f7c 100644
--- a/src/test/ui/generic-associated-types/issue-79422.rs
+++ b/src/test/ui/generic-associated-types/issue-79422.rs
@@ -22,7 +22,7 @@ trait MapLike<K, V> {
 }
 
 impl<K: Ord, V: 'static> MapLike<K, V> for std::collections::BTreeMap<K, V> {
-    type VRefCont<'a> where Self: 'a = &'a V;
+    type VRefCont<'a> = &'a V where Self: 'a;
     fn get<'a>(&'a self, key: &K) -> Option<&'a V> {
         std::collections::BTreeMap::get(self, key)
     }
diff --git a/src/test/ui/generic-associated-types/issue-84931.stderr b/src/test/ui/generic-associated-types/issue-84931.stderr
index 47decb70ae7..11c3dffde4b 100644
--- a/src/test/ui/generic-associated-types/issue-84931.stderr
+++ b/src/test/ui/generic-associated-types/issue-84931.stderr
@@ -2,9 +2,9 @@ error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/issue-84931.rs:15:21
    |
 LL |     type Item<'a> = &'a mut T;
-   |                  -  ^^^^^^^^^ ...so that the reference type `&'a mut T` does not outlive the data it points at
-   |                  |
-   |                  help: consider adding a where clause: `where T: 'a`
+   |                     ^^^^^^^^^- help: consider adding a where clause: `where T: 'a`
+   |                     |
+   |                     ...so that the reference type `&'a mut T` does not outlive the data it points at
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/generic-associated-types/issue-86787.rs b/src/test/ui/generic-associated-types/issue-86787.rs
index 5863bac2f9d..0f8096c8a7c 100644
--- a/src/test/ui/generic-associated-types/issue-86787.rs
+++ b/src/test/ui/generic-associated-types/issue-86787.rs
@@ -21,13 +21,10 @@ where
     Right: HasChildrenOf,
 {
     type T = Either<Left::T, Right::T>;
-    // We used to error below because the where clause doesn't match the trait.
-    // Now, we error early on the trait itself.
-    type TRef<'a>
+    type TRef<'a> = Either<&'a Left::T, &'a Right::T>
     where
-    <Left as HasChildrenOf>::T: 'a,
-    <Right as HasChildrenOf>::T: 'a
-    = Either<&'a Left::T, &'a Right::T>;
+        <Left as HasChildrenOf>::T: 'a,
+        <Right as HasChildrenOf>::T: 'a;
 
     fn ref_children<'a>(&'a self) -> Vec<Self::TRef<'a>> {
         todo!()
diff --git a/src/test/ui/generic-associated-types/issue-88287.rs b/src/test/ui/generic-associated-types/issue-88287.rs
index df5586ed422..6b10edf073f 100644
--- a/src/test/ui/generic-associated-types/issue-88287.rs
+++ b/src/test/ui/generic-associated-types/issue-88287.rs
@@ -27,11 +27,10 @@ impl<T, Criteria> SearchableResourceExt<Criteria> for T
 where
     T: SearchableResource<Criteria>,
 {
-    type Future<'f, A, B: 'f>
+    type Future<'f, A, B: 'f> = SearchFutureTy<'f, A, B>
     where
         A: SearchableResource<B> + ?Sized + 'f,
-        Self: 'f,
-    = SearchFutureTy<'f, A, B>;
+        Self: 'f;
 
     fn search<'c>(&'c self, _client: &'c ()) -> Self::Future<'c, Self, Criteria> {
         async move { todo!() }
diff --git a/src/test/ui/generic-associated-types/issue-90014.stderr b/src/test/ui/generic-associated-types/issue-90014.stderr
index f8fb71bbddb..51fe3360c7e 100644
--- a/src/test/ui/generic-associated-types/issue-90014.stderr
+++ b/src/test/ui/generic-associated-types/issue-90014.stderr
@@ -5,9 +5,7 @@ LL |     type Fut<'a> where Self: 'a;
    |     ---------------------------- definition of `Fut` from trait
 ...
 LL |     type Fut<'a> = impl Future<Output = ()>;
-   |                 -  ^^^^^^^^^^^^^^^^^^^^^^^^
-   |                 |
-   |                 help: try copying this clause from the trait: `where Self: 'a`
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^- help: try copying this clause from the trait: `where Self: 'a`
    |
 note: type must outlive the lifetime `'a` as defined here
   --> $DIR/issue-90014.rs:14:14
diff --git a/src/test/ui/generic-associated-types/issue-91139.rs b/src/test/ui/generic-associated-types/issue-91139.rs
index 2b82d2946b3..5c4a7cf6ffc 100644
--- a/src/test/ui/generic-associated-types/issue-91139.rs
+++ b/src/test/ui/generic-associated-types/issue-91139.rs
@@ -9,10 +9,9 @@ trait Foo<T> {
 }
 
 impl<T> Foo<T> for () {
-    type Type<'a>
+    type Type<'a> = ()
     where
-        T: 'a,
-    = ();
+        T: 'a;
 }
 
 fn foo<T>() {
diff --git a/src/test/ui/generic-associated-types/issue-92033.stderr b/src/test/ui/generic-associated-types/issue-92033.stderr
index caa6618f398..5b90199b809 100644
--- a/src/test/ui/generic-associated-types/issue-92033.stderr
+++ b/src/test/ui/generic-associated-types/issue-92033.stderr
@@ -7,9 +7,7 @@ LL | |         Self: 'a;
    | |_________________- definition of `TextureIter` from trait
 ...
 LL |       type TextureIter<'a> = std::option::IntoIter<&'a Texture>;
-   |                           -  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |                           |
-   |                           help: try copying this clause from the trait: `where Self: 'a`
+   |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- help: try copying this clause from the trait: `where Self: 'a`
    |
 note: type must outlive the lifetime `'a` as defined here
   --> $DIR/issue-92033.rs:22:22
diff --git a/src/test/ui/generic-associated-types/issue-92280.rs b/src/test/ui/generic-associated-types/issue-92280.rs
index db26493ecad..81d000f1076 100644
--- a/src/test/ui/generic-associated-types/issue-92280.rs
+++ b/src/test/ui/generic-associated-types/issue-92280.rs
@@ -17,10 +17,9 @@ struct KeySegment_Broken<T> {
     key: T,
 }
 impl<S: HasAssoc> Iterate<S> for KeySegment_Broken<S::Assoc> {
-    type Iter<'a>
+    type Iter<'a> = ()
     where
-        Self: 'a,
-    = ();
+        Self: 'a;
 }
 
 fn main() {}
diff --git a/src/test/ui/generic-associated-types/iterable.rs b/src/test/ui/generic-associated-types/iterable.rs
index 952fca8ab8a..af0049891b6 100644
--- a/src/test/ui/generic-associated-types/iterable.rs
+++ b/src/test/ui/generic-associated-types/iterable.rs
@@ -11,8 +11,8 @@ trait Iterable {
 
 // Impl for struct type
 impl<T> Iterable for Vec<T> {
-    type Item<'a> where T: 'a = <std::slice::Iter<'a, T> as Iterator>::Item;
-    type Iter<'a> where T: 'a = std::slice::Iter<'a, T>;
+    type Item<'a> = <std::slice::Iter<'a, T> as Iterator>::Item where T: 'a;
+    type Iter<'a> = std::slice::Iter<'a, T> where T: 'a;
 
     fn iter<'a>(&'a self) -> Self::Iter<'a> {
         self[..].iter()
@@ -21,8 +21,8 @@ impl<T> Iterable for Vec<T> {
 
 // Impl for a primitive type
 impl<T> Iterable for [T] {
-    type Item<'a> where T: 'a = <std::slice::Iter<'a, T> as Iterator>::Item;
-    type Iter<'a> where T: 'a = std::slice::Iter<'a, T>;
+    type Item<'a> = <std::slice::Iter<'a, T> as Iterator>::Item where T: 'a;
+    type Iter<'a> = std::slice::Iter<'a, T> where T: 'a;
 
     fn iter<'a>(&'a self) -> Self::Iter<'a> {
         self.iter()
diff --git a/src/test/ui/generic-associated-types/missing-where-clause-on-trait.rs b/src/test/ui/generic-associated-types/missing-where-clause-on-trait.rs
index ad9f2e3e4ec..5fb8f7a4773 100644
--- a/src/test/ui/generic-associated-types/missing-where-clause-on-trait.rs
+++ b/src/test/ui/generic-associated-types/missing-where-clause-on-trait.rs
@@ -6,7 +6,7 @@ trait Foo {
     type Assoc<'a, 'b>;
 }
 impl Foo for () {
-    type Assoc<'a, 'b> where 'a: 'b = ();
+    type Assoc<'a, 'b> = () where 'a: 'b;
     //~^ `impl` associated type
 }
 
diff --git a/src/test/ui/generic-associated-types/missing-where-clause-on-trait.stderr b/src/test/ui/generic-associated-types/missing-where-clause-on-trait.stderr
index 0e183c8d69a..9e0896127a8 100644
--- a/src/test/ui/generic-associated-types/missing-where-clause-on-trait.stderr
+++ b/src/test/ui/generic-associated-types/missing-where-clause-on-trait.stderr
@@ -4,7 +4,7 @@ error: `impl` associated type signature for `Assoc` doesn't match `trait` associ
 LL |     type Assoc<'a, 'b>;
    |     ------------------- expected
 ...
-LL |     type Assoc<'a, 'b> where 'a: 'b = ();
+LL |     type Assoc<'a, 'b> = () where 'a: 'b;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found
 
 error: aborting due to previous error
diff --git a/src/test/ui/generic-associated-types/projection-bound-cycle-generic.rs b/src/test/ui/generic-associated-types/projection-bound-cycle-generic.rs
index 7517e1fa9d0..794d677c8b6 100644
--- a/src/test/ui/generic-associated-types/projection-bound-cycle-generic.rs
+++ b/src/test/ui/generic-associated-types/projection-bound-cycle-generic.rs
@@ -22,7 +22,7 @@ impl<T> Foo for Number<T> {
     // }
     // ```
     // which it is :)
-    type Item where [T]: Sized = [T];
+    type Item = [T] where [T]: Sized;
 }
 
 struct OnlySized<T> where T: Sized { f: T }
diff --git a/src/test/ui/generic-associated-types/projection-bound-cycle.rs b/src/test/ui/generic-associated-types/projection-bound-cycle.rs
index 8f8cb679e9c..6564a3608ec 100644
--- a/src/test/ui/generic-associated-types/projection-bound-cycle.rs
+++ b/src/test/ui/generic-associated-types/projection-bound-cycle.rs
@@ -24,7 +24,7 @@ impl Foo for Number {
     // }
     // ```
     // which it is :)
-    type Item where str: Sized = str;
+    type Item = str where str: Sized;
 }
 
 struct OnlySized<T> where T: Sized { f: T }
diff --git a/src/test/ui/generic-associated-types/streaming_iterator.rs b/src/test/ui/generic-associated-types/streaming_iterator.rs
index f83d4d7b68e..e71b6805ad4 100644
--- a/src/test/ui/generic-associated-types/streaming_iterator.rs
+++ b/src/test/ui/generic-associated-types/streaming_iterator.rs
@@ -30,7 +30,7 @@ struct StreamEnumerate<I> {
 }
 
 impl<I: StreamingIterator> StreamingIterator for StreamEnumerate<I> {
-    type Item<'a> where Self: 'a = (usize, I::Item<'a>);
+    type Item<'a> = (usize, I::Item<'a>) where Self: 'a;
     fn next<'a>(&'a mut self) -> Option<Self::Item<'a>> {
         match self.iter.next() {
             None => None,
@@ -44,7 +44,7 @@ impl<I: StreamingIterator> StreamingIterator for StreamEnumerate<I> {
 }
 
 impl<I: Iterator> StreamingIterator for I {
-    type Item<'a> where Self: 'a = <I as Iterator>::Item;
+    type Item<'a> = <I as Iterator>::Item where Self: 'a;
     fn next(&mut self) -> Option<<I as StreamingIterator>::Item<'_>> {
         Iterator::next(self)
     }
diff --git a/src/test/ui/parser/bounds-lifetime-where.rs b/src/test/ui/parser/bounds-lifetime-where.rs
index e60cc153e67..7ff75233d3a 100644
--- a/src/test/ui/parser/bounds-lifetime-where.rs
+++ b/src/test/ui/parser/bounds-lifetime-where.rs
@@ -5,6 +5,6 @@ type A where 'a:, = u8; // OK
 type A where 'a: 'b + 'c = u8; // OK
 type A where = u8; // OK
 type A where 'a: 'b + = u8; // OK
-type A where , = u8; //~ ERROR expected one of `;`, `=`, lifetime, or type, found `,`
+type A where , = u8; //~ ERROR expected one of `;`, `=`, `where`, lifetime, or type, found `,`
 
 fn main() {}
diff --git a/src/test/ui/parser/bounds-lifetime-where.stderr b/src/test/ui/parser/bounds-lifetime-where.stderr
index 950fa46c66b..785a1fb6793 100644
--- a/src/test/ui/parser/bounds-lifetime-where.stderr
+++ b/src/test/ui/parser/bounds-lifetime-where.stderr
@@ -1,8 +1,8 @@
-error: expected one of `;`, `=`, lifetime, or type, found `,`
+error: expected one of `;`, `=`, `where`, lifetime, or type, found `,`
   --> $DIR/bounds-lifetime-where.rs:8:14
    |
 LL | type A where , = u8;
-   |              ^ expected one of `;`, `=`, lifetime, or type
+   |              ^ expected one of `;`, `=`, `where`, lifetime, or type
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/removed-syntax-ptr-lifetime.rs b/src/test/ui/parser/removed-syntax-ptr-lifetime.rs
index 5b551addbc8..cc69af44a13 100644
--- a/src/test/ui/parser/removed-syntax-ptr-lifetime.rs
+++ b/src/test/ui/parser/removed-syntax-ptr-lifetime.rs
@@ -1 +1 @@
-type bptr = &lifetime/isize; //~ ERROR expected one of `!`, `(`, `::`, `;`, or `<`, found `/`
+type bptr = &lifetime/isize; //~ ERROR expected one of `!`, `(`, `::`, `;`, `<`, or `where`, found `/`
diff --git a/src/test/ui/parser/removed-syntax-ptr-lifetime.stderr b/src/test/ui/parser/removed-syntax-ptr-lifetime.stderr
index 5b388ff4ce0..914de43e62d 100644
--- a/src/test/ui/parser/removed-syntax-ptr-lifetime.stderr
+++ b/src/test/ui/parser/removed-syntax-ptr-lifetime.stderr
@@ -1,8 +1,8 @@
-error: expected one of `!`, `(`, `::`, `;`, or `<`, found `/`
+error: expected one of `!`, `(`, `::`, `;`, `<`, or `where`, found `/`
   --> $DIR/removed-syntax-ptr-lifetime.rs:1:22
    |
 LL | type bptr = &lifetime/isize;
-   |                      ^ expected one of `!`, `(`, `::`, `;`, or `<`
+   |                      ^ expected one of `!`, `(`, `::`, `;`, `<`, or `where`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/type-alias-where-fixable.fixed b/src/test/ui/parser/type-alias-where-fixable.fixed
new file mode 100644
index 00000000000..41dd10676d5
--- /dev/null
+++ b/src/test/ui/parser/type-alias-where-fixable.fixed
@@ -0,0 +1,30 @@
+// check-pass
+// run-rustfix
+
+#![feature(generic_associated_types)]
+
+trait Trait {
+    // Fine.
+    type Assoc where u32: Copy;
+    // Fine.
+    type Assoc2 where u32: Copy, i32: Copy;
+}
+
+impl Trait for u32 {
+    // Not fine, suggests moving.
+    type Assoc  = () where u32: Copy;
+    //~^ WARNING where clause not allowed here
+    // Not fine, suggests moving `u32: Copy`
+    type Assoc2  = () where i32: Copy, u32: Copy;
+    //~^ WARNING where clause not allowed here
+}
+
+impl Trait for i32 {
+    // Fine.
+    type Assoc = () where u32: Copy;
+    // Not fine, suggests moving both.
+    type Assoc2  = () where u32: Copy, i32: Copy;
+    //~^ WARNING where clause not allowed here
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/type-alias-where-fixable.rs b/src/test/ui/parser/type-alias-where-fixable.rs
new file mode 100644
index 00000000000..562a530a7f3
--- /dev/null
+++ b/src/test/ui/parser/type-alias-where-fixable.rs
@@ -0,0 +1,30 @@
+// check-pass
+// run-rustfix
+
+#![feature(generic_associated_types)]
+
+trait Trait {
+    // Fine.
+    type Assoc where u32: Copy;
+    // Fine.
+    type Assoc2 where u32: Copy, i32: Copy;
+}
+
+impl Trait for u32 {
+    // Not fine, suggests moving.
+    type Assoc where u32: Copy = ();
+    //~^ WARNING where clause not allowed here
+    // Not fine, suggests moving `u32: Copy`
+    type Assoc2 where u32: Copy = () where i32: Copy;
+    //~^ WARNING where clause not allowed here
+}
+
+impl Trait for i32 {
+    // Fine.
+    type Assoc = () where u32: Copy;
+    // Not fine, suggests moving both.
+    type Assoc2 where u32: Copy, i32: Copy = ();
+    //~^ WARNING where clause not allowed here
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/type-alias-where-fixable.stderr b/src/test/ui/parser/type-alias-where-fixable.stderr
new file mode 100644
index 00000000000..7ec1a965bae
--- /dev/null
+++ b/src/test/ui/parser/type-alias-where-fixable.stderr
@@ -0,0 +1,42 @@
+warning: where clause not allowed here
+  --> $DIR/type-alias-where-fixable.rs:15:16
+   |
+LL |     type Assoc where u32: Copy = ();
+   |                ^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(deprecated_where_clause_location)]` on by default
+   = note: see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information
+help: move it to the end of the type declaration
+   |
+LL -     type Assoc where u32: Copy = ();
+LL +     type Assoc  = () where u32: Copy;
+   | 
+
+warning: where clause not allowed here
+  --> $DIR/type-alias-where-fixable.rs:18:17
+   |
+LL |     type Assoc2 where u32: Copy = () where i32: Copy;
+   |                 ^^^^^^^^^^^^^^^
+   |
+   = note: see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information
+help: move it to the end of the type declaration
+   |
+LL -     type Assoc2 where u32: Copy = () where i32: Copy;
+LL +     type Assoc2  = () where i32: Copy, u32: Copy;
+   | 
+
+warning: where clause not allowed here
+  --> $DIR/type-alias-where-fixable.rs:26:17
+   |
+LL |     type Assoc2 where u32: Copy, i32: Copy = ();
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information
+help: move it to the end of the type declaration
+   |
+LL -     type Assoc2 where u32: Copy, i32: Copy = ();
+LL +     type Assoc2  = () where u32: Copy, i32: Copy;
+   | 
+
+warning: 3 warnings emitted
+
diff --git a/src/test/ui/parser/type-alias-where.rs b/src/test/ui/parser/type-alias-where.rs
index a9fa23dd95e..f6e7dfb7b7b 100644
--- a/src/test/ui/parser/type-alias-where.rs
+++ b/src/test/ui/parser/type-alias-where.rs
@@ -6,32 +6,8 @@
 type Foo where u32: Copy = ();
 // Not fine.
 type Bar = () where u32: Copy;
-//~^ ERROR where clause not allowed here
+//~^ ERROR where clauses are not allowed
 type Baz = () where;
-//~^ ERROR where clause not allowed here
-
-trait Trait {
-    // Fine.
-    type Assoc where u32: Copy;
-    // Fine.
-    type Assoc2 where u32: Copy, i32: Copy;
-}
-
-impl Trait for u32 {
-    // Fine.
-    type Assoc where u32: Copy = ();
-    // Not fine, suggests moving `i32: Copy`
-    type Assoc2 where u32: Copy = () where i32: Copy;
-    //~^ ERROR where clause not allowed here
-}
-
-impl Trait for i32 {
-    // Not fine, suggests moving `u32: Copy`
-    type Assoc = () where u32: Copy;
-    //~^ ERROR where clause not allowed here
-    // Not fine, suggests moving both.
-    type Assoc2 = () where u32: Copy, i32: Copy;
-    //~^ ERROR where clause not allowed here
-}
+//~^ ERROR where clauses are not allowed
 
 fn main() {}
diff --git a/src/test/ui/parser/type-alias-where.stderr b/src/test/ui/parser/type-alias-where.stderr
index 7ab0b28c864..8789d2665ad 100644
--- a/src/test/ui/parser/type-alias-where.stderr
+++ b/src/test/ui/parser/type-alias-where.stderr
@@ -1,40 +1,18 @@
-error: where clause not allowed here
+error: where clauses are not allowed after the type for type aliases
   --> $DIR/type-alias-where.rs:8:15
    |
 LL | type Bar = () where u32: Copy;
-   |         -     ^^^^^^^^^^^^^^^
-   |         |
-   |         help: move it here: `where u32: Copy`
+   |               ^^^^^^^^^^^^^^^
+   |
+   = note: see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information
 
-error: where clause not allowed here
+error: where clauses are not allowed after the type for type aliases
   --> $DIR/type-alias-where.rs:10:15
    |
 LL | type Baz = () where;
    |               ^^^^^
-
-error: where clause not allowed here
-  --> $DIR/type-alias-where.rs:24:38
-   |
-LL |     type Assoc2 where u32: Copy = () where i32: Copy;
-   |                                -     ^^^^^^^^^^^^^^^
-   |                                |
-   |                                help: move it here: `, i32: Copy`
-
-error: where clause not allowed here
-  --> $DIR/type-alias-where.rs:30:21
-   |
-LL |     type Assoc = () where u32: Copy;
-   |               -     ^^^^^^^^^^^^^^^
-   |               |
-   |               help: move it here: `where u32: Copy`
-
-error: where clause not allowed here
-  --> $DIR/type-alias-where.rs:33:22
    |
-LL |     type Assoc2 = () where u32: Copy, i32: Copy;
-   |                -     ^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |                |
-   |                help: move it here: `where u32: Copy, i32: Copy`
+   = note: see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information
 
-error: aborting due to 5 previous errors
+error: aborting due to 2 previous errors
 
diff --git a/src/tools/clippy/clippy_utils/src/ast_utils.rs b/src/tools/clippy/clippy_utils/src/ast_utils.rs
index 3f4043ad052..3a47845ec82 100644
--- a/src/tools/clippy/clippy_utils/src/ast_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/ast_utils.rs
@@ -279,20 +279,8 @@ pub fn eq_item_kind(l: &ItemKind, r: &ItemKind) -> bool {
         (ForeignMod(l), ForeignMod(r)) => {
             both(&l.abi, &r.abi, eq_str_lit) && over(&l.items, &r.items, |l, r| eq_item(l, r, eq_foreign_item_kind))
         },
-        (
-            TyAlias(box ast::TyAlias {
-                defaultness: ld,
-                generics: lg,
-                bounds: lb,
-                ty: lt,
-            }),
-            TyAlias(box ast::TyAlias {
-                defaultness: rd,
-                generics: rg,
-                bounds: rb,
-                ty: rt,
-            }),
-        ) => {
+        (TyAlias(box ast::TyAlias { defaultness: ld, generics: lg, bounds: lb, ty: lt, .. }),
+         TyAlias(box ast::TyAlias { defaultness: rd, generics: rg, bounds: rb, ty: rt, .. })) => {
             eq_defaultness(*ld, *rd)
                 && eq_generics(lg, rg)
                 && over(lb, rb, eq_generic_bound)
@@ -382,20 +370,8 @@ pub fn eq_foreign_item_kind(l: &ForeignItemKind, r: &ForeignItemKind) -> bool {
         ) => {
             eq_defaultness(*ld, *rd) && eq_fn_sig(lf, rf) && eq_generics(lg, rg) && both(lb, rb, |l, r| eq_block(l, r))
         },
-        (
-            TyAlias(box ast::TyAlias {
-                defaultness: ld,
-                generics: lg,
-                bounds: lb,
-                ty: lt,
-            }),
-            TyAlias(box ast::TyAlias {
-                defaultness: rd,
-                generics: rg,
-                bounds: rb,
-                ty: rt,
-            }),
-        ) => {
+        (TyAlias(box ast::TyAlias { defaultness: ld, generics: lg, bounds: lb, ty: lt, .. }),
+         TyAlias(box ast::TyAlias { defaultness: rd, generics: rg, bounds: rb, ty: rt, .. })) => {
             eq_defaultness(*ld, *rd)
                 && eq_generics(lg, rg)
                 && over(lb, rb, eq_generic_bound)
@@ -426,20 +402,8 @@ pub fn eq_assoc_item_kind(l: &AssocItemKind, r: &AssocItemKind) -> bool {
         ) => {
             eq_defaultness(*ld, *rd) && eq_fn_sig(lf, rf) && eq_generics(lg, rg) && both(lb, rb, |l, r| eq_block(l, r))
         },
-        (
-            TyAlias(box ast::TyAlias {
-                defaultness: ld,
-                generics: lg,
-                bounds: lb,
-                ty: lt,
-            }),
-            TyAlias(box ast::TyAlias {
-                defaultness: rd,
-                generics: rg,
-                bounds: rb,
-                ty: rt,
-            }),
-        ) => {
+        (TyAlias(box ast::TyAlias { defaultness: ld, generics: lg, bounds: lb, ty: lt, .. }),
+         TyAlias(box ast::TyAlias { defaultness: rd, generics: rg, bounds: rb, ty: rt, .. })) => {
             eq_defaultness(*ld, *rd)
                 && eq_generics(lg, rg)
                 && over(lb, rb, eq_generic_bound)
diff --git a/src/tools/rustfmt/src/items.rs b/src/tools/rustfmt/src/items.rs
index babc56f86ed..8498cb6adda 100644
--- a/src/tools/rustfmt/src/items.rs
+++ b/src/tools/rustfmt/src/items.rs
@@ -694,7 +694,8 @@ pub(crate) fn format_impl(
     let where_span_end = context.snippet_provider.opt_span_before(missing_span, "{");
     let where_clause_str = rewrite_where_clause(
         context,
-        &generics.where_clause,
+        &generics.where_clause.predicates,
+        generics.where_clause.span,
         context.config.brace_style(),
         Shape::legacy(where_budget, offset.block_only()),
         false,
@@ -1059,7 +1060,8 @@ pub(crate) fn format_trait(
             let option = WhereClauseOption::snuggled(&generics_str);
             let where_clause_str = rewrite_where_clause(
                 context,
-                &generics.where_clause,
+                &generics.where_clause.predicates,
+                generics.where_clause.span,
                 context.config.brace_style(),
                 Shape::legacy(where_budget, offset.block_only()),
                 where_on_new_line,
@@ -1178,7 +1180,8 @@ impl<'a> Rewrite for TraitAliasBounds<'a> {
 
         let where_str = rewrite_where_clause(
             context,
-            &self.generics.where_clause,
+            &self.generics.where_clause.predicates,
+            self.generics.where_clause.span,
             context.config.brace_style(),
             shape,
             false,
@@ -1437,7 +1440,8 @@ fn format_tuple_struct(
             let option = WhereClauseOption::new(true, WhereClauseSpace::Newline);
             rewrite_where_clause(
                 context,
-                &generics.where_clause,
+                &generics.where_clause.predicates,
+                generics.where_clause.span,
                 context.config.brace_style(),
                 Shape::legacy(where_budget, offset.block_only()),
                 false,
@@ -1503,6 +1507,8 @@ struct TyAliasRewriteInfo<'c, 'g>(
     &'c RewriteContext<'c>,
     Indent,
     &'g ast::Generics,
+    (ast::TyAliasWhereClause, ast::TyAliasWhereClause),
+    usize,
     symbol::Ident,
     Span,
 );
@@ -1521,6 +1527,8 @@ pub(crate) fn rewrite_type_alias<'a, 'b>(
         ref generics,
         ref bounds,
         ref ty,
+        where_clauses,
+        where_predicates_split,
     } = *ty_alias_kind;
     let ty_opt = ty.as_ref();
     let (ident, vis) = match visitor_kind {
@@ -1528,7 +1536,15 @@ pub(crate) fn rewrite_type_alias<'a, 'b>(
         AssocTraitItem(i) | AssocImplItem(i) => (i.ident, &i.vis),
         ForeignItem(i) => (i.ident, &i.vis),
     };
-    let rw_info = &TyAliasRewriteInfo(context, indent, generics, ident, span);
+    let rw_info = &TyAliasRewriteInfo(
+        context,
+        indent,
+        generics,
+        where_clauses,
+        where_predicates_split,
+        ident,
+        span,
+    );
     let op_ty = opaque_ty(ty);
     // Type Aliases are formatted slightly differently depending on the context
     // in which they appear, whether they are opaque, and whether they are associated.
@@ -1564,7 +1580,22 @@ fn rewrite_ty<R: Rewrite>(
     vis: &ast::Visibility,
 ) -> Option<String> {
     let mut result = String::with_capacity(128);
-    let TyAliasRewriteInfo(context, indent, generics, ident, span) = *rw_info;
+    let TyAliasRewriteInfo(
+        context,
+        indent,
+        generics,
+        where_clauses,
+        where_predicates_split,
+        ident,
+        span,
+    ) = *rw_info;
+    let (before_where_predicates, after_where_predicates) = generics
+        .where_clause
+        .predicates
+        .split_at(where_predicates_split);
+    if !after_where_predicates.is_empty() {
+        return None;
+    }
     result.push_str(&format!("{}type ", format_visibility(context, vis)));
     let ident_str = rewrite_ident(context, ident);
 
@@ -1595,7 +1626,8 @@ fn rewrite_ty<R: Rewrite>(
     }
     let where_clause_str = rewrite_where_clause(
         context,
-        &generics.where_clause,
+        before_where_predicates,
+        where_clauses.0.1,
         context.config.brace_style(),
         Shape::legacy(where_budget, indent),
         false,
@@ -1609,7 +1641,7 @@ fn rewrite_ty<R: Rewrite>(
     if let Some(ty) = rhs {
         // If there's a where clause, add a newline before the assignment. Otherwise just add a
         // space.
-        let has_where = !generics.where_clause.predicates.is_empty();
+        let has_where = !before_where_predicates.is_empty();
         if has_where {
             result.push_str(&indent.to_string_with_newline(context.config));
         } else {
@@ -1619,7 +1651,7 @@ fn rewrite_ty<R: Rewrite>(
         let comment_span = context
             .snippet_provider
             .opt_span_before(span, "=")
-            .map(|op_lo| mk_sp(generics.where_clause.span.hi(), op_lo));
+            .map(|op_lo| mk_sp(where_clauses.0.1.hi(), op_lo));
 
         let lhs = match comment_span {
             Some(comment_span)
@@ -2176,7 +2208,7 @@ fn rewrite_fn_base(
     let generics_str = rewrite_generics(
         context,
         rewrite_ident(context, ident),
-        fn_sig.generics,
+        &fn_sig.generics,
         shape,
     )?;
     result.push_str(&generics_str);
@@ -2416,7 +2448,8 @@ fn rewrite_fn_base(
     }
     let where_clause_str = rewrite_where_clause(
         context,
-        where_clause,
+        &where_clause.predicates,
+        where_clause.span,
         context.config.brace_style(),
         Shape::indented(indent, context.config),
         true,
@@ -2692,7 +2725,8 @@ fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> O
 
 fn rewrite_where_clause_rfc_style(
     context: &RewriteContext<'_>,
-    where_clause: &ast::WhereClause,
+    predicates: &[ast::WherePredicate],
+    where_span: Span,
     shape: Shape,
     terminator: &str,
     span_end: Option<BytePos>,
@@ -2701,7 +2735,8 @@ fn rewrite_where_clause_rfc_style(
 ) -> Option<String> {
     let (where_keyword, allow_single_line) = rewrite_where_keyword(
         context,
-        where_clause,
+        predicates,
+        where_span,
         shape,
         span_end_before_where,
         where_clause_option,
@@ -2714,12 +2749,12 @@ fn rewrite_where_clause_rfc_style(
         .block_left(context.config.tab_spaces())?
         .sub_width(1)?;
     let force_single_line = context.config.where_single_line()
-        && where_clause.predicates.len() == 1
+        && predicates.len() == 1
         && !where_clause_option.veto_single_line;
 
     let preds_str = rewrite_bounds_on_where_clause(
         context,
-        where_clause,
+        predicates,
         clause_shape,
         terminator,
         span_end,
@@ -2743,7 +2778,8 @@ fn rewrite_where_clause_rfc_style(
 /// Rewrite `where` and comment around it.
 fn rewrite_where_keyword(
     context: &RewriteContext<'_>,
-    where_clause: &ast::WhereClause,
+    predicates: &[ast::WherePredicate],
+    where_span: Span,
     shape: Shape,
     span_end_before_where: BytePos,
     where_clause_option: WhereClauseOption,
@@ -2763,7 +2799,7 @@ fn rewrite_where_keyword(
     };
 
     let (span_before, span_after) =
-        missing_span_before_after_where(span_end_before_where, where_clause);
+        missing_span_before_after_where(span_end_before_where, predicates, where_span);
     let (comment_before, comment_after) =
         rewrite_comments_before_after_where(context, span_before, span_after, shape)?;
 
@@ -2789,22 +2825,22 @@ fn rewrite_where_keyword(
 /// Rewrite bounds on a where clause.
 fn rewrite_bounds_on_where_clause(
     context: &RewriteContext<'_>,
-    where_clause: &ast::WhereClause,
+    predicates: &[ast::WherePredicate],
     shape: Shape,
     terminator: &str,
     span_end: Option<BytePos>,
     where_clause_option: WhereClauseOption,
     force_single_line: bool,
 ) -> Option<String> {
-    let span_start = where_clause.predicates[0].span().lo();
+    let span_start = predicates[0].span().lo();
     // If we don't have the start of the next span, then use the end of the
     // predicates, but that means we miss comments.
-    let len = where_clause.predicates.len();
-    let end_of_preds = where_clause.predicates[len - 1].span().hi();
+    let len = predicates.len();
+    let end_of_preds = predicates[len - 1].span().hi();
     let span_end = span_end.unwrap_or(end_of_preds);
     let items = itemize_list(
         context.snippet_provider,
-        where_clause.predicates.iter(),
+        predicates.iter(),
         terminator,
         ",",
         |pred| pred.span().lo(),
@@ -2837,7 +2873,8 @@ fn rewrite_bounds_on_where_clause(
 
 fn rewrite_where_clause(
     context: &RewriteContext<'_>,
-    where_clause: &ast::WhereClause,
+    predicates: &[ast::WherePredicate],
+    where_span: Span,
     brace_style: BraceStyle,
     shape: Shape,
     on_new_line: bool,
@@ -2846,14 +2883,15 @@ fn rewrite_where_clause(
     span_end_before_where: BytePos,
     where_clause_option: WhereClauseOption,
 ) -> Option<String> {
-    if where_clause.predicates.is_empty() {
+    if predicates.is_empty() {
         return Some(String::new());
     }
 
     if context.config.indent_style() == IndentStyle::Block {
         return rewrite_where_clause_rfc_style(
             context,
-            where_clause,
+            predicates,
+            where_span,
             shape,
             terminator,
             span_end,
@@ -2873,15 +2911,15 @@ fn rewrite_where_clause(
     // be out by a char or two.
 
     let budget = context.config.max_width() - offset.width();
-    let span_start = where_clause.predicates[0].span().lo();
+    let span_start = predicates[0].span().lo();
     // If we don't have the start of the next span, then use the end of the
     // predicates, but that means we miss comments.
-    let len = where_clause.predicates.len();
-    let end_of_preds = where_clause.predicates[len - 1].span().hi();
+    let len = predicates.len();
+    let end_of_preds = predicates[len - 1].span().hi();
     let span_end = span_end.unwrap_or(end_of_preds);
     let items = itemize_list(
         context.snippet_provider,
-        where_clause.predicates.iter(),
+        predicates.iter(),
         terminator,
         ",",
         |pred| pred.span().lo(),
@@ -2936,12 +2974,13 @@ fn rewrite_where_clause(
 
 fn missing_span_before_after_where(
     before_item_span_end: BytePos,
-    where_clause: &ast::WhereClause,
+    predicates: &[ast::WherePredicate],
+    where_span: Span,
 ) -> (Span, Span) {
-    let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
+    let missing_span_before = mk_sp(before_item_span_end, where_span.lo());
     // 5 = `where`
-    let pos_after_where = where_clause.span.lo() + BytePos(5);
-    let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
+    let pos_after_where = where_span.lo() + BytePos(5);
+    let missing_span_after = mk_sp(pos_after_where, predicates[0].span().lo());
     (missing_span_before, missing_span_after)
 }
 
@@ -3030,7 +3069,8 @@ fn format_generics(
         }
         let where_clause_str = rewrite_where_clause(
             context,
-            &generics.where_clause,
+            &generics.where_clause.predicates,
+            generics.where_clause.span,
             brace_style,
             Shape::legacy(budget, offset.block_only()),
             true,