Auto merge of #147138 - jackh726:split-canonical-bound, r=lcnr

Split Bound index into Canonical and Bound

See [#t-types/trait-system-refactor > perf `async-closures/post-mono-higher-ranked-hang.rs`](https://rust-lang.zulipchat.com/#narrow/channel/364551-t-types.2Ftrait-system-refactor/topic/perf.20.60async-closures.2Fpost-mono-higher-ranked-hang.2Ers.60/with/541535613) for context

Things compile and tests pass, but not sure if this actually solves the perf issue (edit: it does). Opening up this to do a perf (and maybe crater) run.

r? lcnr

8 files changed, 35 insertions, 10 deletions

diff --git a/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.stderr b/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.current.stderr
index 486e5f94165..f3938ff606f 100644
--- a/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.stderr
+++ b/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.current.stderr
@@ -1,5 +1,5 @@
-error: reached the recursion limit while instantiating `ToChain::<'_, '_>::perm_pairs::<{async closure@$DIR/post-mono-higher-ranked-hang.rs:43:45: 43:67}>`
-  --> $DIR/post-mono-higher-ranked-hang.rs:43:21
+error: reached the recursion limit while instantiating `ToChain::<'_, '_>::perm_pairs::<{async closure@$DIR/post-mono-higher-ranked-hang.rs:47:45: 47:67}>`
+  --> $DIR/post-mono-higher-ranked-hang.rs:47:21
    |
 LL | /                     self.perm_pairs(l, &mut async move |left_pair| {
 LL | |
@@ -8,7 +8,7 @@ LL | |                     })
    | |______________________^
    |
 note: `ToChain::<'env, 'db>::perm_pairs` defined here
-  --> $DIR/post-mono-higher-ranked-hang.rs:34:5
+  --> $DIR/post-mono-higher-ranked-hang.rs:38:5
    |
 LL | /     fn perm_pairs<'l>(
 LL | |         &'l self,
diff --git a/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.next.stderr b/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.next.stderr
new file mode 100644
index 00000000000..f3938ff606f
--- /dev/null
+++ b/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.next.stderr
@@ -0,0 +1,21 @@
+error: reached the recursion limit while instantiating `ToChain::<'_, '_>::perm_pairs::<{async closure@$DIR/post-mono-higher-ranked-hang.rs:47:45: 47:67}>`
+  --> $DIR/post-mono-higher-ranked-hang.rs:47:21
+   |
+LL | /                     self.perm_pairs(l, &mut async move |left_pair| {
+LL | |
+LL | |                         self.perm_pairs(r, yield_chain).await
+LL | |                     })
+   | |______________________^
+   |
+note: `ToChain::<'env, 'db>::perm_pairs` defined here
+  --> $DIR/post-mono-higher-ranked-hang.rs:38:5
+   |
+LL | /     fn perm_pairs<'l>(
+LL | |         &'l self,
+LL | |         perm: &'l SymPerm<'db>,
+LL | |         yield_chain: &'l mut impl AsyncFnMut(&SymPerm<'db>),
+LL | |     ) -> Pin<Box<dyn std::future::Future<Output = ()> + 'l>> {
+   | |____________________________________________________________^
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs b/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs
index f6ebf787f81..55d7cc30ec9 100644
--- a/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs
+++ b/tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs
@@ -2,6 +2,10 @@
 //@ aux-build:block-on.rs
 //@ edition:2021
 
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
 // Regression test for <https://github.com/rust-lang/rust/issues/135780>.
 
 extern crate block_on;
diff --git a/tests/ui/higher-ranked/trait-bounds/issue-59311.stderr b/tests/ui/higher-ranked/trait-bounds/issue-59311.stderr
index a26c617dc93..f8f64dcc545 100644
--- a/tests/ui/higher-ranked/trait-bounds/issue-59311.stderr
+++ b/tests/ui/higher-ranked/trait-bounds/issue-59311.stderr
@@ -37,7 +37,7 @@ error: higher-ranked lifetime error
 LL |     v.t(|| {});
    |         ^^^^^
    |
-   = note: could not prove `for<'a> &'a V: 'b`
+   = note: could not prove `for<'a> &'a V: '_`
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/higher-ranked/trait-bounds/trivial-does-not-hold.stderr b/tests/ui/higher-ranked/trait-bounds/trivial-does-not-hold.stderr
index 9e0d7e4b7be..a04c6d770d7 100644
--- a/tests/ui/higher-ranked/trait-bounds/trivial-does-not-hold.stderr
+++ b/tests/ui/higher-ranked/trait-bounds/trivial-does-not-hold.stderr
@@ -4,7 +4,7 @@ error: higher-ranked lifetime error
 LL |     || {};
    |     ^^^^^
    |
-   = note: could not prove `for<'a> &'a (): 'b`
+   = note: could not prove `for<'a> &'a (): '_`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/lifetimes/re-empty-in-error.stderr b/tests/ui/lifetimes/re-empty-in-error.stderr
index 554bcb5451f..b3b6d3d269c 100644
--- a/tests/ui/lifetimes/re-empty-in-error.stderr
+++ b/tests/ui/lifetimes/re-empty-in-error.stderr
@@ -4,7 +4,7 @@ error: higher-ranked lifetime error
 LL |     foo(&10);
    |     ^^^^^^^^
    |
-   = note: could not prove `for<'b> &'b (): 'a`
+   = note: could not prove `for<'b> &'b (): '_`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/nll/user-annotations/dump-fn-method.rs b/tests/ui/nll/user-annotations/dump-fn-method.rs
index 26714b6ffe3..ec349e36839 100644
--- a/tests/ui/nll/user-annotations/dump-fn-method.rs
+++ b/tests/ui/nll/user-annotations/dump-fn-method.rs
@@ -31,7 +31,7 @@ fn main() {
     // Here: we only want the `T` to be given, the rest should be variables.
     //
     // (`T` refers to the declaration of `Bazoom`)
-    let x = <_ as Bazoom<u32>>::method::<_>; //~ ERROR [^0, u32, ^1]
+    let x = <_ as Bazoom<u32>>::method::<_>; //~ ERROR [^c_0, u32, ^c_1]
     x(&22, 44, 66);
 
     // Here: all are given and definitely contain no lifetimes, so we
@@ -48,7 +48,7 @@ fn main() {
     //
     // (`U` refers to the declaration of `Bazoom`)
     let y = 22_u32;
-    y.method::<u32>(44, 66); //~ ERROR [^0, ^1, u32]
+    y.method::<u32>(44, 66); //~ ERROR [^c_0, ^c_1, u32]
 
     // Here: nothing is given, so we don't have any annotation.
     let y = 22_u32;
diff --git a/tests/ui/nll/user-annotations/dump-fn-method.stderr b/tests/ui/nll/user-annotations/dump-fn-method.stderr
index 8e847b464e1..f00fb0013df 100644
--- a/tests/ui/nll/user-annotations/dump-fn-method.stderr
+++ b/tests/ui/nll/user-annotations/dump-fn-method.stderr
@@ -4,7 +4,7 @@ error: user args: UserArgs { args: [&'static u32], user_self_ty: None }
 LL |     let x = foo::<&'static u32>;
    |             ^^^^^^^^^^^^^^^^^^^
 
-error: user args: UserArgs { args: [^0, u32, ^1], user_self_ty: None }
+error: user args: UserArgs { args: [^c_0, u32, ^c_1], user_self_ty: None }
   --> $DIR/dump-fn-method.rs:34:13
    |
 LL |     let x = <_ as Bazoom<u32>>::method::<_>;
@@ -16,7 +16,7 @@ error: user args: UserArgs { args: [u8, &'static u16, u32], user_self_ty: None }
 LL |     let x = <u8 as Bazoom<&'static u16>>::method::<u32>;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: user args: UserArgs { args: [^0, ^1, u32], user_self_ty: None }
+error: user args: UserArgs { args: [^c_0, ^c_1, u32], user_self_ty: None }
   --> $DIR/dump-fn-method.rs:51:5
    |
 LL |     y.method::<u32>(44, 66);