Rollup merge of #117871 - klensy:unused-pub, r=cjgillot

remove unused pub fns

This removes some unused `pub fn`; also fixes few obsoleted fn names or added fixmes with reminders to update them.

compiler/rustc_middle/src/ty/mod.rs

@@ -42,7 +42,6 @@ use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, StashKey};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, DocLinkResMap, LifetimeRes, Res};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LocalDefIdMap};
-use rustc_hir::Node;
 use rustc_index::IndexVec;
 use rustc_macros::HashStable;
 use rustc_query_system::ich::StableHashingContext;
@@ -1301,25 +1300,6 @@ impl<'tcx> Predicate<'tcx> {
         }
     }
 
-    pub fn to_opt_type_outlives(self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
-        let predicate = self.kind();
-        match predicate.skip_binder() {
-            PredicateKind::Clause(ClauseKind::TypeOutlives(data)) => Some(predicate.rebind(data)),
-            PredicateKind::Clause(ClauseKind::Trait(..))
-            | PredicateKind::Clause(ClauseKind::ConstArgHasType(..))
-            | PredicateKind::Clause(ClauseKind::Projection(..))
-            | PredicateKind::AliasRelate(..)
-            | PredicateKind::Subtype(..)
-            | PredicateKind::Coerce(..)
-            | PredicateKind::Clause(ClauseKind::RegionOutlives(..))
-            | PredicateKind::Clause(ClauseKind::WellFormed(..))
-            | PredicateKind::ObjectSafe(..)
-            | PredicateKind::Clause(ClauseKind::ConstEvaluatable(..))
-            | PredicateKind::ConstEquate(..)
-            | PredicateKind::Ambiguous => None,
-        }
-    }
-
     /// Matches a `PredicateKind::Clause` and turns it into a `Clause`, otherwise returns `None`.
     pub fn as_clause(self) -> Option<Clause<'tcx>> {
         match self.kind().skip_binder() {
@@ -2532,22 +2512,6 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 }
 
-/// Yields the parent function's `LocalDefId` if `def_id` is an `impl Trait` definition.
-pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<LocalDefId> {
-    let def_id = def_id.as_local()?;
-    if let Node::Item(item) = tcx.hir().get_by_def_id(def_id) {
-        if let hir::ItemKind::OpaqueTy(opaque_ty) = item.kind {
-            return match opaque_ty.origin {
-                hir::OpaqueTyOrigin::FnReturn(parent) | hir::OpaqueTyOrigin::AsyncFn(parent) => {
-                    Some(parent)
-                }
-                hir::OpaqueTyOrigin::TyAlias { .. } => None,
-            };
-        }
-    }
-    None
-}
-
 pub fn int_ty(ity: ast::IntTy) -> IntTy {
     match ity {
         ast::IntTy::Isize => IntTy::Isize,