Auto merge of rust-lang#120926 - fmease:astconv-no-mo, r=oli-obk

[MCP 723] Rename `astconv::AstConv` and related items

See rust-lang/compiler-team#723.
Corresponding rustc-dev-guide PR: rust-lang/rustc-dev-guide#1916.

Please consult the following *normative* list of changes here:
https://fmease.dev/rustc-dev/astconv-no-mo.html ([2024-03-22 archive link](https://web.archive.org/web/20240322054711/https://fmease.dev/rustc-dev/astconv-no-mo.html)).

Author: bors

compiler/rustc_hir_analysis/src/check/region.rs

@@ -760,7 +760,7 @@ impl<'tcx> RegionResolutionVisitor<'tcx> {
 
     fn enter_node_scope_with_dtor(&mut self, id: hir::ItemLocalId) {
         // If node was previously marked as a terminating scope during the
-        // recursive visit of its parent node in the AST, then we need to
+        // recursive visit of its parent node in the HIR, then we need to
         // account for the destruction scope representing the scope of
         // the destructors that run immediately after it completes.
         if self.terminating_scopes.contains(&id) {

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -272,7 +272,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) -> Result<()
                 }
                 Some(ty::ImplPolarity::Negative) => {
                     let ast::ImplPolarity::Negative(span) = impl_.polarity else {
-                        bug!("impl_polarity query disagrees with impl's polarity in AST");
+                        bug!("impl_polarity query disagrees with impl's polarity in HIR");
                     };
                     // FIXME(#27579): what amount of WF checking do we need for neg impls?
                     if let hir::Defaultness::Default { .. } = impl_.defaultness {
@@ -1866,7 +1866,7 @@ fn check_variances_for_type_defn<'tcx>(
             .iter()
             .filter_map(|predicate| match predicate {
                 hir::WherePredicate::BoundPredicate(predicate) => {
-                    match icx.to_ty(predicate.bounded_ty).kind() {
+                    match icx.lower_ty(predicate.bounded_ty).kind() {
                         ty::Param(data) => Some(Parameter(data.index)),
                         _ => None,
                     }