less diff

Author: asukaminato0721

crates/hir-def/src/expr_store/lower.rs

@@ -1004,6 +1004,10 @@ impl<'db> ExprCollector<'db> {
         let coroutine = self.desugared_coroutine_expr(
             kind,
             coroutine_source,
+            // The default capture mode here is by-ref. Later on during upvar analysis,
+            // we will force the captured arguments to by-move, but for async closures,
+            // we want to make sure that we avoid unnecessarily moving captures, or else
+            // all async closures would default to `FnOnce` as their calling mode.
             CaptureBy::Ref,
             None,
             statements.into_boxed_slice(),