Rollup merge of #94006 - pierwill:upvar-field, r=nikomatsakis

Use a `Field` in `ConstraintCategory::ClosureUpvar`

As part of #90317, we do not want `HirId` to implement `Ord`, `PartialOrd`. This line of code has made that difficult

1b27144afc/compiler/rustc_borrowck/src/region_infer/mod.rs (L2184)

since it sorts a [`ConstraintCategory::ClosureUpvar(HirId)`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/mir/enum.ConstraintCategory.html#variant.ClosureUpvar).

This PR makes that variant take a [`Field`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/mir/struct.Field.html) instead.

r? `@nikomatsakis`

compiler/rustc_middle/src/mir/query.rs

@@ -341,7 +341,7 @@ pub enum ConstraintCategory {
     /// like `Foo { field: my_val }`)
     Usage,
     OpaqueType,
-    ClosureUpvar(hir::HirId),
+    ClosureUpvar(Field),
 
     /// A constraint from a user-written predicate
     /// with the provided span, written on the item
@@ -363,7 +363,7 @@ pub enum ConstraintCategory {
 #[derive(TyEncodable, TyDecodable, HashStable)]
 pub enum ReturnConstraint {
     Normal,
-    ClosureUpvar(hir::HirId),
+    ClosureUpvar(Field),
 }
 
 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing