diff --git a/crates/hir-def/src/data.rs b/crates/hir-def/src/data.rs
index 9c183c9332..a42d6bb337 100644
--- a/crates/hir-def/src/data.rs
+++ b/crates/hir-def/src/data.rs
@@ -19,7 +19,7 @@ use crate::{
     macro_call_as_call_id,
     nameres::{
         attr_resolution::ResolvedAttr,
-        diagnostics::DefDiagnostic,
+        diagnostics::{DefDiagnostic, DefDiagnostics},
         proc_macro::{parse_macro_name_and_helper_attrs, ProcMacroKind},
         DefMap, MacroSubNs,
     },
@@ -240,7 +240,7 @@ impl TraitData {
     pub(crate) fn trait_data_with_diagnostics_query(
         db: &dyn DefDatabase,
         tr: TraitId,
-    ) -> (Arc<TraitData>, Arc<[DefDiagnostic]>) {
+    ) -> (Arc<TraitData>, DefDiagnostics) {
         let tr_loc @ ItemLoc { container: module_id, id: tree_id } = tr.lookup(db);
         let item_tree = tree_id.item_tree(db);
         let tr_def = &item_tree[tree_id.value];
@@ -274,7 +274,7 @@ impl TraitData {
                 rustc_has_incoherent_inherent_impls,
                 fundamental,
             }),
-            diagnostics.into(),
+            DefDiagnostics::new(diagnostics),
         )
     }
 
@@ -340,7 +340,7 @@ impl ImplData {
     pub(crate) fn impl_data_with_diagnostics_query(
         db: &dyn DefDatabase,
         id: ImplId,
-    ) -> (Arc<ImplData>, Arc<[DefDiagnostic]>) {
+    ) -> (Arc<ImplData>, DefDiagnostics) {
         let _p = profile::span("impl_data_with_diagnostics_query");
         let ItemLoc { container: module_id, id: tree_id } = id.lookup(db);
 
@@ -367,7 +367,7 @@ impl ImplData {
                 is_unsafe,
                 attribute_calls,
             }),
-            diagnostics.into(),
+            DefDiagnostics::new(diagnostics),
         )
     }
 
diff --git a/crates/hir-def/src/data/adt.rs b/crates/hir-def/src/data/adt.rs
index 942fafe329..6e302aea65 100644
--- a/crates/hir-def/src/data/adt.rs
+++ b/crates/hir-def/src/data/adt.rs
@@ -21,7 +21,7 @@ use crate::{
     item_tree::{AttrOwner, Field, FieldAstId, Fields, ItemTree, ModItem, RawVisibilityId},
     lang_item::LangItem,
     lower::LowerCtx,
-    nameres::diagnostics::DefDiagnostic,
+    nameres::diagnostics::{DefDiagnostic, DefDiagnostics},
     src::HasChildSource,
     src::HasSource,
     trace::Trace,
@@ -187,7 +187,7 @@ impl StructData {
     pub(crate) fn struct_data_with_diagnostics_query(
         db: &dyn DefDatabase,
         id: StructId,
-    ) -> (Arc<StructData>, Arc<[DefDiagnostic]>) {
+    ) -> (Arc<StructData>, DefDiagnostics) {
         let loc = id.lookup(db);
         let krate = loc.container.krate;
         let item_tree = loc.id.item_tree(db);
@@ -232,7 +232,7 @@ impl StructData {
                 visibility: item_tree[strukt.visibility].clone(),
                 flags,
             }),
-            diagnostics.into(),
+            DefDiagnostics::new(diagnostics),
         )
     }
 
@@ -243,7 +243,7 @@ impl StructData {
     pub(crate) fn union_data_with_diagnostics_query(
         db: &dyn DefDatabase,
         id: UnionId,
-    ) -> (Arc<StructData>, Arc<[DefDiagnostic]>) {
+    ) -> (Arc<StructData>, DefDiagnostics) {
         let loc = id.lookup(db);
         let krate = loc.container.krate;
         let item_tree = loc.id.item_tree(db);
@@ -278,7 +278,7 @@ impl StructData {
                 visibility: item_tree[union.visibility].clone(),
                 flags,
             }),
-            diagnostics.into(),
+            DefDiagnostics::new(diagnostics),
         )
     }
 }
@@ -332,14 +332,14 @@ impl EnumVariantData {
     pub(crate) fn enum_variant_data_with_diagnostics_query(
         db: &dyn DefDatabase,
         e: EnumVariantId,
-    ) -> (Arc<EnumVariantData>, Option<Arc<Box<[DefDiagnostic]>>>) {
+    ) -> (Arc<EnumVariantData>, DefDiagnostics) {
         let loc = e.lookup(db);
         let krate = loc.container.krate;
         let item_tree = loc.id.item_tree(db);
         let cfg_options = db.crate_graph()[krate].cfg_options.clone();
         let variant = &item_tree[loc.id.value];
 
-        let (var_data, field_diagnostics) = lower_fields(
+        let (var_data, diagnostics) = lower_fields(
             db,
             krate,
             loc.id.file_id(),
@@ -355,11 +355,7 @@ impl EnumVariantData {
                 name: variant.name.clone(),
                 variant_data: Arc::new(var_data),
             }),
-            if field_diagnostics.is_empty() {
-                None
-            } else {
-                Some(Arc::new(field_diagnostics.into_boxed_slice()))
-            },
+            DefDiagnostics::new(diagnostics),
         )
     }
 }
diff --git a/crates/hir-def/src/db.rs b/crates/hir-def/src/db.rs
index 2b1d0bca28..186a8cf2d9 100644
--- a/crates/hir-def/src/db.rs
+++ b/crates/hir-def/src/db.rs
@@ -19,7 +19,7 @@ use crate::{
     import_map::ImportMap,
     item_tree::{AttrOwner, ItemTree},
     lang_item::{self, LangItem, LangItemTarget, LangItems},
-    nameres::{diagnostics::DefDiagnostic, DefMap},
+    nameres::{diagnostics::DefDiagnostics, DefMap},
     visibility::{self, Visibility},
     AttrDefId, BlockId, BlockLoc, ConstBlockId, ConstBlockLoc, ConstId, ConstLoc, DefWithBodyId,
     EnumId, EnumLoc, EnumVariantId, EnumVariantLoc, ExternBlockId, ExternBlockLoc, ExternCrateId,
@@ -121,14 +121,13 @@ pub trait DefDatabase: InternDatabase + ExpandDatabase + Upcast<dyn ExpandDataba
     fn struct_data(&self, id: StructId) -> Arc<StructData>;
 
     #[salsa::invoke(StructData::struct_data_with_diagnostics_query)]
-    fn struct_data_with_diagnostics(&self, id: StructId)
-        -> (Arc<StructData>, Arc<[DefDiagnostic]>);
+    fn struct_data_with_diagnostics(&self, id: StructId) -> (Arc<StructData>, DefDiagnostics);
 
     #[salsa::invoke(StructData::union_data_query)]
     fn union_data(&self, id: UnionId) -> Arc<StructData>;
 
     #[salsa::invoke(StructData::union_data_with_diagnostics_query)]
-    fn union_data_with_diagnostics(&self, id: UnionId) -> (Arc<StructData>, Arc<[DefDiagnostic]>);
+    fn union_data_with_diagnostics(&self, id: UnionId) -> (Arc<StructData>, DefDiagnostics);
 
     #[salsa::invoke(EnumData::enum_data_query)]
     fn enum_data(&self, e: EnumId) -> Arc<EnumData>;
@@ -140,19 +139,19 @@ pub trait DefDatabase: InternDatabase + ExpandDatabase + Upcast<dyn ExpandDataba
     fn enum_variant_data_with_diagnostics(
         &self,
         id: EnumVariantId,
-    ) -> (Arc<EnumVariantData>, Option<Arc<Box<[DefDiagnostic]>>>);
+    ) -> (Arc<EnumVariantData>, DefDiagnostics);
 
     #[salsa::invoke(ImplData::impl_data_query)]
     fn impl_data(&self, e: ImplId) -> Arc<ImplData>;
 
     #[salsa::invoke(ImplData::impl_data_with_diagnostics_query)]
-    fn impl_data_with_diagnostics(&self, e: ImplId) -> (Arc<ImplData>, Arc<[DefDiagnostic]>);
+    fn impl_data_with_diagnostics(&self, e: ImplId) -> (Arc<ImplData>, DefDiagnostics);
 
     #[salsa::invoke(TraitData::trait_data_query)]
     fn trait_data(&self, e: TraitId) -> Arc<TraitData>;
 
     #[salsa::invoke(TraitData::trait_data_with_diagnostics_query)]
-    fn trait_data_with_diagnostics(&self, tr: TraitId) -> (Arc<TraitData>, Arc<[DefDiagnostic]>);
+    fn trait_data_with_diagnostics(&self, tr: TraitId) -> (Arc<TraitData>, DefDiagnostics);
 
     #[salsa::invoke(TraitAliasData::trait_alias_query)]
     fn trait_alias_data(&self, e: TraitAliasId) -> Arc<TraitAliasData>;
diff --git a/crates/hir-def/src/nameres/diagnostics.rs b/crates/hir-def/src/nameres/diagnostics.rs
index 9cffb3c9f3..0a3f7bf7ec 100644
--- a/crates/hir-def/src/nameres/diagnostics.rs
+++ b/crates/hir-def/src/nameres/diagnostics.rs
@@ -40,6 +40,23 @@ pub enum DefDiagnosticKind {
     MacroDefError { ast: AstId<ast::Macro>, message: String },
 }
 
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct DefDiagnostics(Option<triomphe::Arc<Box<[DefDiagnostic]>>>);
+
+impl DefDiagnostics {
+    pub fn new(diagnostics: Vec<DefDiagnostic>) -> Self {
+        Self(if diagnostics.is_empty() {
+            None
+        } else {
+            Some(triomphe::Arc::new(diagnostics.into_boxed_slice()))
+        })
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &DefDiagnostic> {
+        self.0.as_ref().into_iter().flat_map(|it| &***it)
+    }
+}
+
 #[derive(Debug, PartialEq, Eq)]
 pub struct DefDiagnostic {
     pub in_module: LocalModuleId,
diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs
index 69d8046524..749ca43fba 100644
--- a/crates/hir-ty/src/mir/lower.rs
+++ b/crates/hir-ty/src/mir/lower.rs
@@ -69,6 +69,7 @@ struct MirLowerCtx<'a> {
     drop_scopes: Vec<DropScope>,
 }
 
+// FIXME: Make this smaller, its stored in database queries
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum MirLowerError {
     ConstEvalError(Box<str>, Box<ConstEvalError>),
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 5e133bf5c7..246fc231b4 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -584,11 +584,8 @@ impl Module {
                         Adt::Enum(e) => {
                             for v in e.variants(db) {
                                 acc.extend(ModuleDef::Variant(v).diagnostics(db));
-                                if let Some(diags) = &db.enum_variant_data_with_diagnostics(v.id).1
-                                {
-                                    for diag in &***diags {
-                                        emit_def_diagnostic(db, acc, diag);
-                                    }
+                                for diag in db.enum_variant_data_with_diagnostics(v.id).1.iter() {
+                                    emit_def_diagnostic(db, acc, diag);
                                 }
                             }
                         }