Use `dyn Trait` for working with databse

It improves compile time in `--release` mode quite a bit, it doesn't
really slow things down and, conceptually, it seems closer to what we
want the physical architecture to look like (we don't want to
monomorphise EVERYTHING in a single leaf crate).

1 files changed, 1 insertions, 1 deletions

diff --git a/crates/ra_hir_expand/src/hygiene.rs b/crates/ra_hir_expand/src/hygiene.rs
index cb554ae4b..dfbac494f 100644
--- a/crates/ra_hir_expand/src/hygiene.rs
+++ b/crates/ra_hir_expand/src/hygiene.rs
@@ -19,7 +19,7 @@ pub struct Hygiene {
 }
 
 impl Hygiene {
-    pub fn new(db: &impl AstDatabase, file_id: HirFileId) -> Hygiene {
+    pub fn new(db: &dyn AstDatabase, file_id: HirFileId) -> Hygiene {
         let def_crate = match file_id.0 {
             HirFileIdRepr::FileId(_) => None,
             HirFileIdRepr::MacroFile(macro_file) => match macro_file.macro_call_id {