Auto merge of #141506 - matthiaskrgr:rollup-80f1geg, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #137323 (Guarantee behavior of transmuting `Option::<T>::None` subject to NPO)
 - #139254 (std: sys: net: uefi: Implement TCP4 connect)
 - #141432 (refactor `CanonicalVarKind`)
 - #141480 (document some -Z flags as living in the rustc-dev-guide)
 - #141486 (rustdoc book: add argument explanation for `html_playground_url`)
 - #141496 (Enable `[issue-links]` and `[no-mentions]` in triagebot)

r? `@ghost`
`@rustbot` modify labels: rollup

3 files changed, 9 insertions, 8 deletions

diff --git a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs
index c62f2e2e0e9..455a178595b 100644
--- a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs
@@ -360,15 +360,15 @@ where
         }
 
         let var_values = delegate.cx().mk_args_from_iter(
-            response.variables.iter().enumerate().map(|(index, info)| {
-                if info.universe() != ty::UniverseIndex::ROOT {
+            response.variables.iter().enumerate().map(|(index, var_kind)| {
+                if var_kind.universe() != ty::UniverseIndex::ROOT {
                     // A variable from inside a binder of the query. While ideally these shouldn't
                     // exist at all (see the FIXME at the start of this method), we have to deal with
                     // them for now.
-                    delegate.instantiate_canonical_var_with_infer(info, span, |idx| {
+                    delegate.instantiate_canonical_var_with_infer(var_kind, span, |idx| {
                         prev_universe + idx.index()
                     })
-                } else if info.is_existential() {
+                } else if var_kind.is_existential() {
                     // As an optimization we sometimes avoid creating a new inference variable here.
                     //
                     // All new inference variables we create start out in the current universe of the caller.
@@ -379,12 +379,13 @@ where
                     if let Some(v) = opt_values[ty::BoundVar::from_usize(index)] {
                         v
                     } else {
-                        delegate.instantiate_canonical_var_with_infer(info, span, |_| prev_universe)
+                        delegate
+                            .instantiate_canonical_var_with_infer(var_kind, span, |_| prev_universe)
                     }
                 } else {
                     // For placeholders which were already part of the input, we simply map this
                     // universal bound variable back the placeholder of the input.
-                    original_values[info.expect_placeholder_index()]
+                    original_values[var_kind.expect_placeholder_index()]
                 }
             }),
         );
diff --git a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
index 9a4b95903a9..dfabb94ebfc 100644
--- a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
@@ -91,7 +91,7 @@ where
 
     /// The variable info for the `var_values`, only used to make an ambiguous response
     /// with no constraints.
-    variables: I::CanonicalVars,
+    variables: I::CanonicalVarKinds,
 
     /// What kind of goal we're currently computing, see the enum definition
     /// for more info.
diff --git a/compiler/rustc_next_trait_solver/src/solve/mod.rs b/compiler/rustc_next_trait_solver/src/solve/mod.rs
index 8173146e2fe..2a641807154 100644
--- a/compiler/rustc_next_trait_solver/src/solve/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/mod.rs
@@ -354,7 +354,7 @@ where
 fn response_no_constraints_raw<I: Interner>(
     cx: I,
     max_universe: ty::UniverseIndex,
-    variables: I::CanonicalVars,
+    variables: I::CanonicalVarKinds,
     certainty: Certainty,
 ) -> CanonicalResponse<I> {
     ty::Canonical {