Rollup merge of #125635 - fmease:mv-type-binding-assoc-item-constraint, r=compiler-errors

Rename HIR `TypeBinding` to `AssocItemConstraint` and related cleanup

Rename `hir::TypeBinding` and `ast::AssocConstraint` to `AssocItemConstraint` and update all items and locals using the old terminology.

Motivation: The terminology *type binding* is extremely outdated. "Type bindings" not only include constraints on associated *types* but also on associated *constants* (feature `associated_const_equality`) and on RPITITs of associated *functions* (feature `return_type_notation`). Hence the word *item* in the new name. Furthermore, the word *binding* commonly refers to a mapping from a binder/identifier to a "value" for some definition of "value". Its use in "type binding" made sense when equality constraints (e.g., `AssocTy = Ty`) were the only kind of associated item constraint. Nowadays however, we also have *associated type bounds* (e.g., `AssocTy: Bound`) for which the term *binding* doesn't make sense.

---

Old terminology (HIR, rustdoc):

```
`TypeBinding`: (associated) type binding
├── `Constraint`: associated type bound
└── `Equality`: (associated) equality constraint (?)
    ├── `Ty`: (associated) type binding
    └── `Const`: associated const equality (constraint)
```

Old terminology (AST, abbrev.):

```
`AssocConstraint`
├── `Bound`
└── `Equality`
    ├── `Ty`
    └── `Const`
```

New terminology (AST, HIR, rustdoc):

```
`AssocItemConstraint`: associated item constraint
├── `Bound`: associated type bound
└── `Equality`: associated item equality constraint OR associated item binding (for short)
    ├── `Ty`: associated type equality constraint OR associated type binding (for short)
    └── `Const`: associated const equality constraint OR associated const binding (for short)
```

r? compiler-errors

1 files changed, 4 insertions, 4 deletions

diff --git a/compiler/rustc_passes/src/hir_stats.rs b/compiler/rustc_passes/src/hir_stats.rs
index 6bb9cff5319..d49298781a2 100644
--- a/compiler/rustc_passes/src/hir_stats.rs
+++ b/compiler/rustc_passes/src/hir_stats.rs
@@ -477,9 +477,9 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
         hir_visit::walk_generic_args(self, ga)
     }
 
-    fn visit_assoc_type_binding(&mut self, type_binding: &'v hir::TypeBinding<'v>) {
-        self.record("TypeBinding", Id::Node(type_binding.hir_id), type_binding);
-        hir_visit::walk_assoc_type_binding(self, type_binding)
+    fn visit_assoc_item_constraint(&mut self, constraint: &'v hir::AssocItemConstraint<'v>) {
+        self.record("AssocItemConstraint", Id::Node(constraint.hir_id), constraint);
+        hir_visit::walk_assoc_item_constraint(self, constraint)
     }
 
     fn visit_attribute(&mut self, attr: &'v ast::Attribute) {
@@ -688,7 +688,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
         ast_visit::walk_path_segment(self, path_segment)
     }
 
-    // `GenericArgs` has one inline use (in `ast::AssocConstraint::gen_args`) and one
+    // `GenericArgs` has one inline use (in `ast::AssocItemConstraint::gen_args`) and one
     // non-inline use (in `ast::PathSegment::args`). The latter case is more
     // common, so we implement `visit_generic_args` and tolerate the double
     // counting in the former case.