Move ChildbySource and HasSource impls to their corresponding modules

crates/hir-def/src/src.rs

@@ -1,10 +1,15 @@
 //! Utilities for mapping between hir IDs and the surface syntax.
 
+use either::Either;
 use hir_expand::InFile;
 use la_arena::ArenaMap;
 use syntax::ast;
 
-use crate::{db::DefDatabase, item_tree::ItemTreeNode, ItemTreeLoc, Lookup, UseId};
+use crate::{
+    data::adt::lower_struct, db::DefDatabase, item_tree::ItemTreeNode, trace::Trace, GenericDefId,
+    ItemTreeLoc, LocalFieldId, LocalLifetimeParamId, LocalTypeOrConstParamId, Lookup, UseId,
+    VariantId,
+};
 
 pub trait HasSource {
     type Value;
@@ -49,3 +54,105 @@ impl HasChildSource<la_arena::Idx<ast::UseTree>> for UseId {
         )
     }
 }
+
+impl HasChildSource<LocalTypeOrConstParamId> for GenericDefId {
+    type Value = Either<ast::TypeOrConstParam, ast::TraitOrAlias>;
+    fn child_source(
+        &self,
+        db: &dyn DefDatabase,
+    ) -> InFile<ArenaMap<LocalTypeOrConstParamId, Self::Value>> {
+        let generic_params = db.generic_params(*self);
+        let mut idx_iter = generic_params.type_or_consts.iter().map(|(idx, _)| idx);
+
+        let (file_id, generic_params_list) = self.file_id_and_params_of(db);
+
+        let mut params = ArenaMap::default();
+
+        // For traits and trait aliases the first type index is `Self`, we need to add it before
+        // the other params.
+        match *self {
+            GenericDefId::TraitId(id) => {
+                let trait_ref = id.lookup(db).source(db).value;
+                let idx = idx_iter.next().unwrap();
+                params.insert(idx, Either::Right(ast::TraitOrAlias::Trait(trait_ref)));
+            }
+            GenericDefId::TraitAliasId(id) => {
+                let alias = id.lookup(db).source(db).value;
+                let idx = idx_iter.next().unwrap();
+                params.insert(idx, Either::Right(ast::TraitOrAlias::TraitAlias(alias)));
+            }
+            _ => {}
+        }
+
+        if let Some(generic_params_list) = generic_params_list {
+            for (idx, ast_param) in idx_iter.zip(generic_params_list.type_or_const_params()) {
+                params.insert(idx, Either::Left(ast_param));
+            }
+        }
+
+        InFile::new(file_id, params)
+    }
+}
+
+impl HasChildSource<LocalLifetimeParamId> for GenericDefId {
+    type Value = ast::LifetimeParam;
+    fn child_source(
+        &self,
+        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 (file_id, generic_params_list) = self.file_id_and_params_of(db);
+
+        let mut params = ArenaMap::default();
+
+        if let Some(generic_params_list) = generic_params_list {
+            for (idx, ast_param) in idx_iter.zip(generic_params_list.lifetime_params()) {
+                params.insert(idx, ast_param);
+            }
+        }
+
+        InFile::new(file_id, params)
+    }
+}
+
+impl HasChildSource<LocalFieldId> for VariantId {
+    type Value = Either<ast::TupleField, ast::RecordField>;
+
+    fn child_source(&self, db: &dyn DefDatabase) -> InFile<ArenaMap<LocalFieldId, Self::Value>> {
+        let item_tree;
+        let (src, fields, container) = match *self {
+            VariantId::EnumVariantId(it) => {
+                let lookup = it.lookup(db);
+                item_tree = lookup.id.item_tree(db);
+                (
+                    lookup.source(db).map(|it| it.kind()),
+                    &item_tree[lookup.id.value].fields,
+                    lookup.parent.lookup(db).container,
+                )
+            }
+            VariantId::StructId(it) => {
+                let lookup = it.lookup(db);
+                item_tree = lookup.id.item_tree(db);
+                (
+                    lookup.source(db).map(|it| it.kind()),
+                    &item_tree[lookup.id.value].fields,
+                    lookup.container,
+                )
+            }
+            VariantId::UnionId(it) => {
+                let lookup = it.lookup(db);
+                item_tree = lookup.id.item_tree(db);
+                (
+                    lookup.source(db).map(|it| it.kind()),
+                    &item_tree[lookup.id.value].fields,
+                    lookup.container,
+                )
+            }
+        };
+        let mut trace = Trace::new_for_map();
+        lower_struct(db, &mut trace, &src, container.krate, &item_tree, fields);
+        src.with_value(trace.into_map())
+    }
+}