Option<CoroutineKind>

compiler/rustc_ast_lowering/src/lib.rs

@@ -1359,13 +1359,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     generic_params,
                     unsafety: self.lower_unsafety(f.unsafety),
                     abi: self.lower_extern(f.ext),
-                    decl: self.lower_fn_decl(
-                        &f.decl,
-                        t.id,
-                        t.span,
-                        FnDeclKind::Pointer,
-                        CoroutineKind::None,
-                    ),
+                    decl: self.lower_fn_decl(&f.decl, t.id, t.span, FnDeclKind::Pointer, None),
                     param_names: self.lower_fn_params_to_names(&f.decl),
                 }))
             }
@@ -1800,7 +1794,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         fn_node_id: NodeId,
         fn_span: Span,
         kind: FnDeclKind,
-        coro: CoroutineKind,
+        coro: Option<CoroutineKind>,
     ) -> &'hir hir::FnDecl<'hir> {
         let c_variadic = decl.c_variadic();
 
@@ -1830,11 +1824,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }));
 
         let output = match coro {
-            CoroutineKind::Async { .. } | CoroutineKind::Gen { .. } => {
+            Some(coro) => {
                 let fn_def_id = self.local_def_id(fn_node_id);
                 self.lower_coroutine_fn_ret_ty(&decl.output, fn_def_id, coro, kind, fn_span)
             }
-            CoroutineKind::None => match &decl.output {
+            None => match &decl.output {
                 FnRetTy::Ty(ty) => {
                     let context = if kind.return_impl_trait_allowed() {
                         let fn_def_id = self.local_def_id(fn_node_id);
@@ -1911,9 +1905,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let opaque_ty_node_id = match coro {
             CoroutineKind::Async { return_impl_trait_id, .. }
             | CoroutineKind::Gen { return_impl_trait_id, .. } => return_impl_trait_id,
-            CoroutineKind::None => {
-                unreachable!("lower_coroutine_fn_ret_ty must be called with either Async or Gen")
-            }
         };
 
         let captured_lifetimes: Vec<_> = self
@@ -1971,7 +1962,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let (symbol, lang_item) = match coro {
             CoroutineKind::Async { .. } => (hir::FN_OUTPUT_NAME, hir::LangItem::Future),
             CoroutineKind::Gen { .. } => (hir::ITERATOR_ITEM_NAME, hir::LangItem::Iterator),
-            CoroutineKind::None => panic!("attemping to lower output type of non-coroutine fn"),
         };
 
         let future_args = self.arena.alloc(hir::GenericArgs {