Don't allocate `inherent_impls_in_block` and `trait_impls_in_block` if its empty

3 files changed, 56 insertions, 35 deletions

diff --git a/crates/hir-ty/src/chalk_db.rs b/crates/hir-ty/src/chalk_db.rs
index f4fbace19e3..e81d4ced554 100644
--- a/crates/hir-ty/src/chalk_db.rs
+++ b/crates/hir-ty/src/chalk_db.rs
@@ -167,7 +167,7 @@ impl chalk_solve::RustIrDatabase<Interner> for ChalkContext<'_> {
                 }
             });
         })
-        .map(|block_id| self.db.trait_impls_in_block(block_id));
+        .filter_map(|block_id| self.db.trait_impls_in_block(block_id));
 
         let id_to_chalk = |id: hir_def::ImplId| id.to_chalk(self.db);
         let mut result = vec![];
@@ -183,7 +183,8 @@ impl chalk_solve::RustIrDatabase<Interner> for ChalkContext<'_> {
                 def_blocks
                     .into_iter()
                     .flatten()
-                    .for_each(|it| f(&self.db.trait_impls_in_block(it)));
+                    .filter_map(|it| self.db.trait_impls_in_block(it))
+                    .for_each(|it| f(&it));
             }
             fps => {
                 let mut f =
@@ -198,7 +199,8 @@ impl chalk_solve::RustIrDatabase<Interner> for ChalkContext<'_> {
                 def_blocks
                     .into_iter()
                     .flatten()
-                    .for_each(|it| f(&self.db.trait_impls_in_block(it)));
+                    .filter_map(|it| self.db.trait_impls_in_block(it))
+                    .for_each(|it| f(&it));
             }
         }
 
diff --git a/crates/hir-ty/src/db.rs b/crates/hir-ty/src/db.rs
index 410bcbf0356..ad790fa094d 100644
--- a/crates/hir-ty/src/db.rs
+++ b/crates/hir-ty/src/db.rs
@@ -34,6 +34,8 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::invoke(crate::infer::infer_query)]
     fn infer_query(&self, def: DefWithBodyId) -> Arc<InferenceResult>;
 
+    // region:mir
+
     #[salsa::invoke(crate::mir::mir_body_query)]
     #[salsa::cycle(crate::mir::mir_body_recover)]
     fn mir_body(&self, def: DefWithBodyId) -> Result<Arc<MirBody>, MirLowerError>;
@@ -61,20 +63,6 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::invoke(crate::mir::borrowck_query)]
     fn borrowck(&self, def: DefWithBodyId) -> Result<Arc<[BorrowckResult]>, MirLowerError>;
 
-    #[salsa::invoke(crate::lower::ty_query)]
-    #[salsa::cycle(crate::lower::ty_recover)]
-    fn ty(&self, def: TyDefId) -> Binders<Ty>;
-
-    #[salsa::invoke(crate::lower::value_ty_query)]
-    fn value_ty(&self, def: ValueTyDefId) -> Binders<Ty>;
-
-    #[salsa::invoke(crate::lower::impl_self_ty_query)]
-    #[salsa::cycle(crate::lower::impl_self_ty_recover)]
-    fn impl_self_ty(&self, def: ImplId) -> Binders<Ty>;
-
-    #[salsa::invoke(crate::lower::const_param_ty_query)]
-    fn const_param_ty(&self, def: ConstParamId) -> Ty;
-
     #[salsa::invoke(crate::consteval::const_eval_query)]
     #[salsa::cycle(crate::consteval::const_eval_recover)]
     fn const_eval(
@@ -92,6 +80,22 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::cycle(crate::consteval::const_eval_discriminant_recover)]
     fn const_eval_discriminant(&self, def: EnumVariantId) -> Result<i128, ConstEvalError>;
 
+    // endregion:mir
+
+    #[salsa::invoke(crate::lower::ty_query)]
+    #[salsa::cycle(crate::lower::ty_recover)]
+    fn ty(&self, def: TyDefId) -> Binders<Ty>;
+
+    #[salsa::invoke(crate::lower::value_ty_query)]
+    fn value_ty(&self, def: ValueTyDefId) -> Binders<Ty>;
+
+    #[salsa::invoke(crate::lower::impl_self_ty_query)]
+    #[salsa::cycle(crate::lower::impl_self_ty_recover)]
+    fn impl_self_ty(&self, def: ImplId) -> Binders<Ty>;
+
+    #[salsa::invoke(crate::lower::const_param_ty_query)]
+    fn const_param_ty(&self, def: ConstParamId) -> Ty;
+
     #[salsa::invoke(crate::lower::impl_trait_query)]
     fn impl_trait(&self, def: ImplId) -> Option<Binders<TraitRef>>;
 
@@ -158,7 +162,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     fn inherent_impls_in_crate(&self, krate: CrateId) -> Arc<InherentImpls>;
 
     #[salsa::invoke(InherentImpls::inherent_impls_in_block_query)]
-    fn inherent_impls_in_block(&self, block: BlockId) -> Arc<InherentImpls>;
+    fn inherent_impls_in_block(&self, block: BlockId) -> Option<Arc<InherentImpls>>;
 
     /// Collects all crates in the dependency graph that have impls for the
     /// given fingerprint. This is only used for primitive types and types
@@ -175,7 +179,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     fn trait_impls_in_crate(&self, krate: CrateId) -> Arc<TraitImpls>;
 
     #[salsa::invoke(TraitImpls::trait_impls_in_block_query)]
-    fn trait_impls_in_block(&self, block: BlockId) -> Arc<TraitImpls>;
+    fn trait_impls_in_block(&self, block: BlockId) -> Option<Arc<TraitImpls>>;
 
     #[salsa::invoke(TraitImpls::trait_impls_in_deps_query)]
     fn trait_impls_in_deps(&self, krate: CrateId) -> Arc<[Arc<TraitImpls>]>;
diff --git a/crates/hir-ty/src/method_resolution.rs b/crates/hir-ty/src/method_resolution.rs
index 3b1697a07b0..06df30582aa 100644
--- a/crates/hir-ty/src/method_resolution.rs
+++ b/crates/hir-ty/src/method_resolution.rs
@@ -152,13 +152,20 @@ impl TraitImpls {
         Arc::new(Self::finish(impls))
     }
 
-    pub(crate) fn trait_impls_in_block_query(db: &dyn HirDatabase, block: BlockId) -> Arc<Self> {
+    pub(crate) fn trait_impls_in_block_query(
+        db: &dyn HirDatabase,
+        block: BlockId,
+    ) -> Option<Arc<Self>> {
         let _p = profile::span("trait_impls_in_block_query");
         let mut impls = FxHashMap::default();
 
         Self::collect_def_map(db, &mut impls, &db.block_def_map(block));
 
-        Arc::new(Self::finish(impls))
+        if impls.is_empty() {
+            None
+        } else {
+            Some(Arc::new(Self::finish(impls)))
+        }
     }
 
     pub(crate) fn trait_impls_in_deps_query(
@@ -276,7 +283,10 @@ impl InherentImpls {
         Arc::new(impls)
     }
 
-    pub(crate) fn inherent_impls_in_block_query(db: &dyn HirDatabase, block: BlockId) -> Arc<Self> {
+    pub(crate) fn inherent_impls_in_block_query(
+        db: &dyn HirDatabase,
+        block: BlockId,
+    ) -> Option<Arc<Self>> {
         let _p = profile::span("inherent_impls_in_block_query");
         let mut impls = Self { map: FxHashMap::default(), invalid_impls: Vec::default() };
 
@@ -284,7 +294,11 @@ impl InherentImpls {
         impls.collect_def_map(db, &block_def_map);
         impls.shrink_to_fit();
 
-        Arc::new(impls)
+        if impls.map.is_empty() && impls.invalid_impls.is_empty() {
+            None
+        } else {
+            Some(Arc::new(impls))
+        }
     }
 
     fn shrink_to_fit(&mut self) {
@@ -732,7 +746,7 @@ fn lookup_impl_assoc_item_for_trait_ref(
     let impls = db.trait_impls_in_deps(env.krate);
     let self_impls = match self_ty.kind(Interner) {
         TyKind::Adt(id, _) => {
-            id.0.module(db.upcast()).containing_block().map(|it| db.trait_impls_in_block(it))
+            id.0.module(db.upcast()).containing_block().and_then(|it| db.trait_impls_in_block(it))
         }
         _ => None,
     };
@@ -1249,17 +1263,18 @@ fn iterate_inherent_methods(
     };
 
     while let Some(block_id) = block {
-        let impls = db.inherent_impls_in_block(block_id);
-        impls_for_self_ty(
-            &impls,
-            self_ty,
-            table,
-            name,
-            receiver_ty,
-            receiver_adjustments.clone(),
-            module,
-            callback,
-        )?;
+        if let Some(impls) = db.inherent_impls_in_block(block_id) {
+            impls_for_self_ty(
+                &impls,
+                self_ty,
+                table,
+                name,
+                receiver_ty,
+                receiver_adjustments.clone(),
+                module,
+                callback,
+            )?;
+        }
 
         block = db.block_def_map(block_id).parent().and_then(|module| module.containing_block());
     }