3 files changed, 33 insertions, 26 deletions

diff --git a/crates/hir_def/src/generics.rs b/crates/hir_def/src/generics.rs
index 5189c7e9f..81912a454 100644
--- a/crates/hir_def/src/generics.rs
+++ b/crates/hir_def/src/generics.rs
@@ -19,10 +19,10 @@ use crate::{
     db::DefDatabase,
     dyn_map::DynMap,
     keys,
-    src::HasChildSource,
     src::HasSource,
     type_ref::{LifetimeRef, TypeBound, TypeRef},
-    AdtId, GenericDefId, LocalTypeParamId, Lookup, TypeParamId,
+    AdtId, GenericDefId, LifetimeParamId, LocalLifetimeParamId, LocalTypeParamId, Lookup,
+    TypeParamId,
 };
 
 /// Data about a generic parameter (to a function, struct, impl, ...).
@@ -72,7 +72,11 @@ pub enum WherePredicateTypeTarget {
     // FIXME: ForLifetime(Vec<LifetimeParamId>, TypeRef)
 }
 
-type SourceMap = ArenaMap<LocalTypeParamId, Either<ast::Trait, ast::TypeParam>>;
+#[derive(Default)]
+pub struct SourceMaps {
+    pub type_params: ArenaMap<LocalTypeParamId, Either<ast::Trait, ast::TypeParam>>,
+    pub lifetime_params: ArenaMap<LocalLifetimeParamId, ast::LifetimeParam>,
+}
 
 impl GenericParams {
     pub(crate) fn generic_params_query(
@@ -129,9 +133,9 @@ impl GenericParams {
         Arc::new(generics)
     }
 
-    fn new(db: &dyn DefDatabase, def: GenericDefId) -> (GenericParams, InFile<SourceMap>) {
+    fn new(db: &dyn DefDatabase, def: GenericDefId) -> (GenericParams, InFile<SourceMaps>) {
         let mut generics = GenericParams::default();
-        let mut sm = ArenaMap::default();
+        let mut sm = SourceMaps::default();
 
         // FIXME: add `: Sized` bound for everything except for `Self` in traits
         let file_id = match def {
@@ -174,7 +178,7 @@ impl GenericParams {
                     default: None,
                     provenance: TypeParamProvenance::TraitSelf,
                 });
-                sm.insert(self_param_id, Either::Left(src.value.clone()));
+                sm.type_params.insert(self_param_id, Either::Left(src.value.clone()));
                 // add super traits as bounds on Self
                 // i.e., trait Foo: Bar is equivalent to trait Foo where Self: Bar
                 let self_param = TypeRef::Path(name![Self].into());
@@ -210,7 +214,7 @@ impl GenericParams {
     pub(crate) fn fill(
         &mut self,
         lower_ctx: &LowerCtx,
-        sm: &mut SourceMap,
+        sm: &mut SourceMaps,
         node: &dyn GenericParamsOwner,
     ) {
         if let Some(params) = node.generic_param_list() {
@@ -237,7 +241,7 @@ impl GenericParams {
     fn fill_params(
         &mut self,
         lower_ctx: &LowerCtx,
-        sm: &mut SourceMap,
+        sm: &mut SourceMaps,
         params: ast::GenericParamList,
     ) {
         for type_param in params.type_params() {
@@ -250,7 +254,7 @@ impl GenericParams {
                 provenance: TypeParamProvenance::TypeParamList,
             };
             let param_id = self.types.alloc(param);
-            sm.insert(param_id, Either::Right(type_param.clone()));
+            sm.type_params.insert(param_id, Either::Right(type_param.clone()));
 
             let type_ref = TypeRef::Path(name.into());
             self.fill_bounds(&lower_ctx, &type_param, Either::Left(type_ref));
@@ -260,7 +264,8 @@ impl GenericParams {
                 .lifetime_token()
                 .map_or_else(Name::missing, |tok| Name::new_lifetime(&tok));
             let param = LifetimeParamData { name: name.clone() };
-            let _param_id = self.lifetimes.alloc(param);
+            let param_id = self.lifetimes.alloc(param);
+            sm.lifetime_params.insert(param_id, lifetime_param.clone());
             let lifetime_ref = LifetimeRef::new_name(name);
             self.fill_bounds(&lower_ctx, &lifetime_param, Either::Right(lifetime_ref));
         }
@@ -340,27 +345,29 @@ impl GenericParams {
         })
     }
 }
-
-impl HasChildSource for GenericDefId {
-    type ChildId = LocalTypeParamId;
-    type Value = Either<ast::Trait, ast::TypeParam>;
-    fn child_source(&self, db: &dyn DefDatabase) -> InFile<SourceMap> {
-        let (_, sm) = GenericParams::new(db, *self);
-        sm
+impl GenericDefId {
+    // FIXME: Change HasChildSource's ChildId AssocItem to be a generic parameter instead
+    pub fn child_source(&self, db: &dyn DefDatabase) -> InFile<SourceMaps> {
+        GenericParams::new(db, *self).1
     }
 }
 
 impl ChildBySource for GenericDefId {
     fn child_by_source(&self, db: &dyn DefDatabase) -> DynMap {
         let mut res = DynMap::default();
-        let arena_map = self.child_source(db);
-        let arena_map = arena_map.as_ref();
-        for (local_id, src) in arena_map.value.iter() {
+        let (_, sm) = GenericParams::new(db, *self);
+
+        let sm = sm.as_ref();
+        for (local_id, src) in sm.value.type_params.iter() {
             let id = TypeParamId { parent: *self, local_id };
             if let Either::Right(type_param) = src {
-                res[keys::TYPE_PARAM].insert(arena_map.with_value(type_param.clone()), id)
+                res[keys::TYPE_PARAM].insert(sm.with_value(type_param.clone()), id)
             }
         }
+        for (local_id, src) in sm.value.lifetime_params.iter() {
+            let id = LifetimeParamId { parent: *self, local_id };
+            res[keys::LIFETIME_PARAM].insert(sm.with_value(src.clone()), id);
+        }
         res
     }
 }
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index f7ce2e26d..2939c6b1e 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -2,7 +2,6 @@
 
 use std::{collections::hash_map::Entry, mem, sync::Arc};
 
-use arena::map::ArenaMap;
 use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, name::known, HirFileId};
 use smallvec::SmallVec;
 use syntax::{
@@ -607,7 +606,7 @@ impl Ctx {
         owner: GenericsOwner<'_>,
         node: &impl ast::GenericParamsOwner,
     ) -> GenericParamsId {
-        let mut sm = &mut ArenaMap::default();
+        let mut sm = &mut Default::default();
         let mut generics = GenericParams::default();
         match owner {
             GenericsOwner::Function(func) => {
@@ -630,7 +629,7 @@ impl Ctx {
                     default: None,
                     provenance: TypeParamProvenance::TraitSelf,
                 });
-                sm.insert(self_param_id, Either::Left(trait_def.clone()));
+                sm.type_params.insert(self_param_id, Either::Left(trait_def.clone()));
                 // add super traits as bounds on Self
                 // i.e., trait Foo: Bar is equivalent to trait Foo where Self: Bar
                 let self_param = TypeRef::Path(name![Self].into());
diff --git a/crates/hir_def/src/keys.rs b/crates/hir_def/src/keys.rs
index 40a5d92b5..9c585de2c 100644
--- a/crates/hir_def/src/keys.rs
+++ b/crates/hir_def/src/keys.rs
@@ -8,8 +8,8 @@ use syntax::{ast, AstNode, AstPtr};
 
 use crate::{
     dyn_map::{DynMap, Policy},
-    ConstId, EnumId, EnumVariantId, FieldId, FunctionId, ImplId, StaticId, StructId, TraitId,
-    TypeAliasId, TypeParamId, UnionId,
+    ConstId, EnumId, EnumVariantId, FieldId, FunctionId, ImplId, LifetimeParamId, StaticId,
+    StructId, TraitId, TypeAliasId, TypeParamId, UnionId,
 };
 
 pub type Key<K, V> = crate::dyn_map::Key<InFile<K>, V, AstPtrPolicy<K, V>>;
@@ -28,6 +28,7 @@ pub const VARIANT: Key<ast::Variant, EnumVariantId> = Key::new();
 pub const TUPLE_FIELD: Key<ast::TupleField, FieldId> = Key::new();
 pub const RECORD_FIELD: Key<ast::RecordField, FieldId> = Key::new();
 pub const TYPE_PARAM: Key<ast::TypeParam, TypeParamId> = Key::new();
+pub const LIFETIME_PARAM: Key<ast::LifetimeParam, LifetimeParamId> = Key::new();
 
 pub const MACRO: Key<ast::MacroCall, MacroDefId> = Key::new();