fixup add gen blocks

Author: oli-obk

compiler/rustc_ast_lowering/src/expr.rs

@@ -682,59 +682,32 @@ impl<'hir> LoweringContext<'_, 'hir> {
         &mut self,
         capture_clause: CaptureBy,
         closure_node_id: NodeId,
-        yield_ty: Option<hir::FnRetTy<'hir>>,
+        _yield_ty: Option<hir::FnRetTy<'hir>>,
         span: Span,
         // We re-use the async enum, because we have the same cases.
         // FIXME(oli-obk): rename the enum.
         gen_kind: hir::AsyncGeneratorKind,
         body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
     ) -> hir::ExprKind<'hir> {
-        let output = yield_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));
-
-        // Resume argument type: `ResumeTy`
-        let unstable_span =
-            self.mark_span_with_reason(DesugaringKind::Async, span, self.allow_gen_future.clone());
-        let resume_ty = hir::QPath::LangItem(hir::LangItem::ResumeTy, unstable_span, None);
-        let input_ty = hir::Ty {
-            hir_id: self.next_id(),
-            kind: hir::TyKind::Path(resume_ty),
-            span: unstable_span,
-        };
+        let output = hir::FnRetTy::DefaultReturn(self.lower_span(span));
 
         // The closure/generator `FnDecl` takes a single (resume) argument of type `input_ty`.
         let fn_decl = self.arena.alloc(hir::FnDecl {
-            inputs: arena_vec![self; input_ty],
+            inputs: &[],
             output,
             c_variadic: false,
             implicit_self: hir::ImplicitSelfKind::None,
             lifetime_elision_allowed: false,
         });
 
-        // Lower the argument pattern/ident. The ident is used again in the `.await` lowering.
-        let (pat, task_context_hid) = self.pat_ident_binding_mode(
-            span,
-            Ident::with_dummy_span(sym::_task_context),
-            hir::BindingAnnotation::MUT,
-        );
-        let param = hir::Param {
-            hir_id: self.next_id(),
-            pat,
-            ty_span: self.lower_span(span),
-            span: self.lower_span(span),
-        };
-        let params = arena_vec![self; param];
-
         let body = self.lower_body(move |this| {
             this.generator_kind = Some(hir::GeneratorKind::Iter(gen_kind));
 
-            let old_ctx = this.task_context;
-            this.task_context = Some(task_context_hid);
             let res = body(this);
-            this.task_context = old_ctx;
-            (params, res)
+            (&[], res)
         });
 
-        // `static |_task_context| -> <ret_ty> { body }`:
+        // `static |()| -> () { body }`:
         hir::ExprKind::Closure(self.arena.alloc(hir::Closure {
             def_id: self.local_def_id(closure_node_id),
             binder: hir::ClosureBinder::Default,