diff --git a/crates/hir-def/src/child_by_source.rs b/crates/hir-def/src/child_by_source.rs
index 6ee6d313e948..0438278ca270 100644
--- a/crates/hir-def/src/child_by_source.rs
+++ b/crates/hir-def/src/child_by_source.rs
@@ -215,7 +215,7 @@ impl ChildBySource for GenericDefId {
 
         let generic_params = db.generic_params(*self);
         let mut toc_idx_iter = generic_params.iter_type_or_consts().map(|(idx, _)| idx);
-        let lts_idx_iter = generic_params.lifetimes.iter().map(|(idx, _)| idx);
+        let lts_idx_iter = generic_params.iter_lt().map(|(idx, _)| idx);
 
         // For traits the first type index is `Self`, skip it.
         if let GenericDefId::TraitId(_) = *self {
diff --git a/crates/hir-def/src/generics.rs b/crates/hir-def/src/generics.rs
index fe9004fcc66d..1d880c9eeeb8 100644
--- a/crates/hir-def/src/generics.rs
+++ b/crates/hir-def/src/generics.rs
@@ -160,7 +160,7 @@ pub enum GenericParamDataRef<'a> {
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct GenericParams {
     type_or_consts: Arena<TypeOrConstParamData>,
-    pub lifetimes: Arena<LifetimeParamData>,
+    lifetimes: Arena<LifetimeParamData>,
     where_predicates: Box<[WherePredicate]>,
 }
 
diff --git a/crates/hir-def/src/item_tree/pretty.rs b/crates/hir-def/src/item_tree/pretty.rs
index ad260df80fbe..6283ae23b522 100644
--- a/crates/hir-def/src/item_tree/pretty.rs
+++ b/crates/hir-def/src/item_tree/pretty.rs
@@ -532,7 +532,7 @@ impl Printer<'_> {
 
         w!(self, "<");
         let mut first = true;
-        for (idx, lt) in params.lifetimes.iter() {
+        for (idx, lt) in params.iter_lt() {
             if !first {
                 w!(self, ", ");
             }
diff --git a/crates/hir-def/src/resolver.rs b/crates/hir-def/src/resolver.rs
index a8cedd7421e8..e5c1f93bbde6 100644
--- a/crates/hir-def/src/resolver.rs
+++ b/crates/hir-def/src/resolver.rs
@@ -775,7 +775,7 @@ impl Scope {
                         );
                     }
                 }
-                for (local_id, param) in params.lifetimes.iter() {
+                for (local_id, param) in params.iter_lt() {
                     let id = LifetimeParamId { parent, local_id };
                     acc.add(&param.name, ScopeDef::GenericParam(id.into()))
                 }
diff --git a/crates/hir-def/src/src.rs b/crates/hir-def/src/src.rs
index 278388945c7c..a0d2079e0d41 100644
--- a/crates/hir-def/src/src.rs
+++ b/crates/hir-def/src/src.rs
@@ -103,7 +103,7 @@ impl HasChildSource<LocalLifetimeParamId> for GenericDefId {
         db: &dyn DefDatabase,
     ) -> InFile<ArenaMap<LocalLifetimeParamId, Self::Value>> {
         let generic_params = db.generic_params(*self);
-        let idx_iter = generic_params.lifetimes.iter().map(|(idx, _)| idx);
+        let idx_iter = generic_params.iter_lt().map(|(idx, _)| idx);
 
         let (file_id, generic_params_list) = self.file_id_and_params_of(db);
 
diff --git a/crates/hir-ty/src/generics.rs b/crates/hir-ty/src/generics.rs
index 6d20791f6e55..7fc60c41d70b 100644
--- a/crates/hir-ty/src/generics.rs
+++ b/crates/hir-ty/src/generics.rs
@@ -163,7 +163,7 @@ impl Generics {
     fn find_lifetime(&self, lifetime: LifetimeParamId) -> Option<usize> {
         if lifetime.parent == self.def {
             let idx = lifetime.local_id.into_raw().into_u32() as usize;
-            debug_assert!(idx <= self.params.lifetimes.len());
+            debug_assert!(idx <= self.params.len_lifetimes());
             Some(self.params.len_type_or_consts() + idx)
         } else {
             debug_assert_eq!(self.parent_generics().map(|it| it.def), Some(lifetime.parent));
diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index 05047450af3c..72e79af75dfc 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs
@@ -539,7 +539,7 @@ fn write_generic_params(
     f: &mut HirFormatter<'_>,
 ) -> Result<(), HirDisplayError> {
     let params = f.db.generic_params(def);
-    if params.lifetimes.is_empty()
+    if params.iter_lt().next().is_none()
         && params.iter_type_or_consts().all(|it| it.1.const_param().is_none())
         && params
             .iter_type_or_consts()
@@ -559,7 +559,7 @@ fn write_generic_params(
             f.write_str(", ")
         }
     };
-    for (_, lifetime) in params.lifetimes.iter() {
+    for (_, lifetime) in params.iter_lt() {
         delim(f)?;
         write!(f, "{}", lifetime.name.display(f.db.upcast()))?;
     }
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 19d91f44a738..18a5325db6b0 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -665,7 +665,7 @@ impl Module {
                 }
                 let parent = impl_def.id.into();
                 let generic_params = db.generic_params(parent);
-                let lifetime_params = generic_params.lifetimes.iter().map(|(local_id, _)| {
+                let lifetime_params = generic_params.iter_lt().map(|(local_id, _)| {
                     GenericParamId::LifetimeParamId(LifetimeParamId { parent, local_id })
                 });
                 let type_params = generic_params
@@ -1540,8 +1540,7 @@ impl Adt {
         resolver
             .generic_params()
             .and_then(|gp| {
-                gp.lifetimes
-                    .iter()
+                gp.iter_lt()
                     // there should only be a single lifetime
                     // but `Arena` requires to use an iterator
                     .nth(0)
@@ -3141,8 +3140,7 @@ impl GenericDef {
     pub fn lifetime_params(self, db: &dyn HirDatabase) -> Vec<LifetimeParam> {
         let generics = db.generic_params(self.into());
         generics
-            .lifetimes
-            .iter()
+            .iter_lt()
             .map(|(local_id, _)| LifetimeParam {
                 id: LifetimeParamId { parent: self.into(), local_id },
             })
@@ -3548,7 +3546,7 @@ pub struct LifetimeParam {
 impl LifetimeParam {
     pub fn name(self, db: &dyn HirDatabase) -> Name {
         let params = db.generic_params(self.id.parent);
-        params.lifetimes[self.id.local_id].name.clone()
+        params[self.id.local_id].name.clone()
     }
 
     pub fn module(self, db: &dyn HirDatabase) -> Module {