1 files changed, 36 insertions, 0 deletions

diff --git a/crates/ra_hir_def/src/src.rs b/crates/ra_hir_def/src/src.rs
new file mode 100644
index 000000000..499375b80
--- /dev/null
+++ b/crates/ra_hir_def/src/src.rs
@@ -0,0 +1,36 @@
+//! Utilities for mapping between hir IDs and the surface syntax.
+
+use hir_expand::InFile;
+use ra_arena::map::ArenaMap;
+use ra_syntax::AstNode;
+
+use crate::{db::DefDatabase, AssocItemLoc, ItemLoc};
+
+pub trait HasSource {
+    type Value;
+    fn source(&self, db: &impl DefDatabase) -> InFile<Self::Value>;
+}
+
+impl<N: AstNode> HasSource for AssocItemLoc<N> {
+    type Value = N;
+
+    fn source(&self, db: &impl DefDatabase) -> InFile<N> {
+        let node = self.ast_id.to_node(db);
+        InFile::new(self.ast_id.file_id, node)
+    }
+}
+
+impl<N: AstNode> HasSource for ItemLoc<N> {
+    type Value = N;
+
+    fn source(&self, db: &impl DefDatabase) -> InFile<N> {
+        let node = self.ast_id.to_node(db);
+        InFile::new(self.ast_id.file_id, node)
+    }
+}
+
+pub trait HasChildSource {
+    type ChildId;
+    type Value;
+    fn child_source(&self, db: &impl DefDatabase) -> InFile<ArenaMap<Self::ChildId, Self::Value>>;
+}