1 files changed, 118 insertions, 51 deletions

diff --git a/crates/ra_hir_def/src/adt.rs b/crates/ra_hir_def/src/adt.rs
index d04f54e15..c9f30923e 100644
--- a/crates/ra_hir_def/src/adt.rs
+++ b/crates/ra_hir_def/src/adt.rs
@@ -2,13 +2,17 @@
 
 use std::sync::Arc;
 
-use hir_expand::name::{AsName, Name};
-use ra_arena::Arena;
+use hir_expand::{
+    either::Either,
+    name::{AsName, Name},
+    Source,
+};
+use ra_arena::{map::ArenaMap, Arena};
 use ra_syntax::ast::{self, NameOwner, TypeAscriptionOwner};
 
 use crate::{
-    db::DefDatabase2, type_ref::TypeRef, AstItemDef, EnumId, LocalEnumVariantId,
-    LocalStructFieldId, StructOrUnionId,
+    db::DefDatabase, trace::Trace, type_ref::TypeRef, AstItemDef, EnumId, HasChildSource,
+    LocalEnumVariantId, LocalStructFieldId, StructOrUnionId, VariantId,
 };
 
 /// Note that we use `StructData` for unions as well!
@@ -30,13 +34,9 @@ pub struct EnumVariantData {
     pub variant_data: Arc<VariantData>,
 }
 
-/// Fields of an enum variant or struct
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct VariantData(VariantDataInner);
-
 #[derive(Debug, Clone, PartialEq, Eq)]
-enum VariantDataInner {
-    Struct(Arena<LocalStructFieldId, StructFieldData>),
+pub enum VariantData {
+    Record(Arena<LocalStructFieldId, StructFieldData>),
     Tuple(Arena<LocalStructFieldId, StructFieldData>),
     Unit,
 }
@@ -49,10 +49,7 @@ pub struct StructFieldData {
 }
 
 impl StructData {
-    pub(crate) fn struct_data_query(
-        db: &impl DefDatabase2,
-        id: StructOrUnionId,
-    ) -> Arc<StructData> {
+    pub(crate) fn struct_data_query(db: &impl DefDatabase, id: StructOrUnionId) -> Arc<StructData> {
         let src = id.source(db);
         let name = src.value.name().map(|n| n.as_name());
         let variant_data = VariantData::new(src.value.kind());
@@ -62,20 +59,12 @@ impl StructData {
 }
 
 impl EnumData {
-    pub(crate) fn enum_data_query(db: &impl DefDatabase2, e: EnumId) -> Arc<EnumData> {
+    pub(crate) fn enum_data_query(db: &impl DefDatabase, e: EnumId) -> Arc<EnumData> {
         let src = e.source(db);
         let name = src.value.name().map(|n| n.as_name());
-        let variants = src
-            .value
-            .variant_list()
-            .into_iter()
-            .flat_map(|it| it.variants())
-            .map(|var| EnumVariantData {
-                name: var.name().map(|it| it.as_name()),
-                variant_data: Arc::new(VariantData::new(var.kind())),
-            })
-            .collect();
-        Arc::new(EnumData { name, variants })
+        let mut trace = Trace::new_for_arena();
+        lower_enum(&mut trace, &src.value);
+        Arc::new(EnumData { name, variants: trace.into_arena() })
     }
 
     pub(crate) fn variant(&self, name: &Name) -> Option<LocalEnumVariantId> {
@@ -84,39 +73,117 @@ impl EnumData {
     }
 }
 
+impl HasChildSource for EnumId {
+    type ChildId = LocalEnumVariantId;
+    type Value = ast::EnumVariant;
+    fn child_source(&self, db: &impl DefDatabase) -> Source<ArenaMap<Self::ChildId, Self::Value>> {
+        let src = self.source(db);
+        let mut trace = Trace::new_for_map();
+        lower_enum(&mut trace, &src.value);
+        src.with_value(trace.into_map())
+    }
+}
+
+fn lower_enum(
+    trace: &mut Trace<LocalEnumVariantId, EnumVariantData, ast::EnumVariant>,
+    ast: &ast::EnumDef,
+) {
+    for var in ast.variant_list().into_iter().flat_map(|it| it.variants()) {
+        trace.alloc(
+            || var.clone(),
+            || EnumVariantData {
+                name: var.name().map(|it| it.as_name()),
+                variant_data: Arc::new(VariantData::new(var.kind())),
+            },
+        );
+    }
+}
+
 impl VariantData {
     fn new(flavor: ast::StructKind) -> Self {
-        let inner = match flavor {
-            ast::StructKind::Tuple(fl) => {
-                let fields = fl
-                    .fields()
-                    .enumerate()
-                    .map(|(i, fd)| StructFieldData {
+        let mut trace = Trace::new_for_arena();
+        match lower_struct(&mut trace, &flavor) {
+            StructKind::Tuple => VariantData::Tuple(trace.into_arena()),
+            StructKind::Record => VariantData::Record(trace.into_arena()),
+            StructKind::Unit => VariantData::Unit,
+        }
+    }
+
+    pub fn fields(&self) -> &Arena<LocalStructFieldId, StructFieldData> {
+        const EMPTY: &Arena<LocalStructFieldId, StructFieldData> = &Arena::new();
+        match &self {
+            VariantData::Record(fields) | VariantData::Tuple(fields) => fields,
+            _ => EMPTY,
+        }
+    }
+
+    pub fn is_unit(&self) -> bool {
+        match self {
+            VariantData::Unit => true,
+            _ => false,
+        }
+    }
+}
+
+impl HasChildSource for VariantId {
+    type ChildId = LocalStructFieldId;
+    type Value = Either<ast::TupleFieldDef, ast::RecordFieldDef>;
+
+    fn child_source(&self, db: &impl DefDatabase) -> Source<ArenaMap<Self::ChildId, Self::Value>> {
+        let src = match self {
+            VariantId::EnumVariantId(it) => {
+                // I don't really like the fact that we call into parent source
+                // here, this might add to more queries then necessary.
+                let src = it.parent.child_source(db);
+                src.map(|map| map[it.local_id].kind())
+            }
+            VariantId::StructId(it) => it.0.source(db).map(|it| it.kind()),
+        };
+        let mut trace = Trace::new_for_map();
+        lower_struct(&mut trace, &src.value);
+        src.with_value(trace.into_map())
+    }
+}
+
+enum StructKind {
+    Tuple,
+    Record,
+    Unit,
+}
+
+fn lower_struct(
+    trace: &mut Trace<
+        LocalStructFieldId,
+        StructFieldData,
+        Either<ast::TupleFieldDef, ast::RecordFieldDef>,
+    >,
+    ast: &ast::StructKind,
+) -> StructKind {
+    match ast {
+        ast::StructKind::Tuple(fl) => {
+            for (i, fd) in fl.fields().enumerate() {
+                trace.alloc(
+                    || Either::A(fd.clone()),
+                    || StructFieldData {
                         name: Name::new_tuple_field(i),
                         type_ref: TypeRef::from_ast_opt(fd.type_ref()),
-                    })
-                    .collect();
-                VariantDataInner::Tuple(fields)
+                    },
+                );
             }
-            ast::StructKind::Named(fl) => {
-                let fields = fl
-                    .fields()
-                    .map(|fd| StructFieldData {
+            StructKind::Tuple
+        }
+        ast::StructKind::Record(fl) => {
+            for fd in fl.fields() {
+                trace.alloc(
+                    || Either::B(fd.clone()),
+                    || StructFieldData {
                         name: fd.name().map(|n| n.as_name()).unwrap_or_else(Name::missing),
                         type_ref: TypeRef::from_ast_opt(fd.ascribed_type()),
-                    })
-                    .collect();
-                VariantDataInner::Struct(fields)
+                    },
+                );
             }
-            ast::StructKind::Unit => VariantDataInner::Unit,
-        };
-        VariantData(inner)
-    }
-
-    pub fn fields(&self) -> Option<&Arena<LocalStructFieldId, StructFieldData>> {
-        match &self.0 {
-            VariantDataInner::Struct(fields) | VariantDataInner::Tuple(fields) => Some(fields),
-            _ => None,
+            StructKind::Record
         }
+        ast::StructKind::Unit => StructKind::Unit,
     }
 }