Merge #3584

3584: Switch to dynamic dispatch r=matklad a=matklad

Benches are in https://github.com/rust-analyzer/rust-analyzer/issues/1987#issuecomment-598807185

TL;DR: 

* 33% faster release build
* slightly worse/same perf
* no changes for debug build
* slightly smaller binary

cc @flodiebold I genuinely don't know if it is a good idea or not.

Co-authored-by: Aleksey Kladov <[email protected]>

1 files changed, 2 insertions, 2 deletions

diff --git a/crates/ra_hir_def/src/docs.rs b/crates/ra_hir_def/src/docs.rs
index b29f142e3..0539a77d4 100644
--- a/crates/ra_hir_def/src/docs.rs
+++ b/crates/ra_hir_def/src/docs.rs
@@ -34,7 +34,7 @@ impl Documentation {
     }
 
     pub(crate) fn documentation_query(
-        db: &impl DefDatabase,
+        db: &dyn DefDatabase,
         def: AttrDefId,
     ) -> Option<Documentation> {
         match def {
@@ -60,7 +60,7 @@ impl Documentation {
                 docs_from_ast(&src.value[it.local_id])
             }
             AttrDefId::TraitId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-            AttrDefId::MacroDefId(it) => docs_from_ast(&it.ast_id?.to_node(db)),
+            AttrDefId::MacroDefId(it) => docs_from_ast(&it.ast_id?.to_node(db.upcast())),
             AttrDefId::ConstId(it) => docs_from_ast(&it.lookup(db).source(db).value),
             AttrDefId::StaticId(it) => docs_from_ast(&it.lookup(db).source(db).value),
             AttrDefId::FunctionId(it) => docs_from_ast(&it.lookup(db).source(db).value),