2 files changed, 10 insertions, 20 deletions
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index bf648388f4e..d6c2bfacf66 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1311,7 +1311,7 @@ pub struct Closure {
     pub binder: ClosureBinder,
     pub capture_clause: CaptureBy,
     pub constness: Const,
-    pub coro_kind: CoroutineKind,
+    pub coro_kind: Option<CoroutineKind>,
     pub movability: Movability,
     pub fn_decl: P<FnDecl>,
     pub body: P<Expr>,
@@ -2417,8 +2417,6 @@ pub enum CoroutineKind {
     Async { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
     /// `gen`, which evaluates to `impl Iterator`
     Gen { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
-    /// Neither `async` nor `gen`
-    None,
 }
 
 impl CoroutineKind {
@@ -2430,14 +2428,12 @@ impl CoroutineKind {
         matches!(self, CoroutineKind::Gen { .. })
     }
 
-    /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
-    pub fn opt_return_id(self) -> Option<(NodeId, Span)> {
+    /// In this case this is an `async` or `gen` return, the `NodeId` for the generated `impl Trait`
+    /// item.
+    pub fn return_id(self) -> (NodeId, Span) {
         match self {
             CoroutineKind::Async { return_impl_trait_id, span, .. }
-            | CoroutineKind::Gen { return_impl_trait_id, span, .. } => {
-                Some((return_impl_trait_id, span))
-            }
-            CoroutineKind::None => None,
+            | CoroutineKind::Gen { return_impl_trait_id, span, .. } => (return_impl_trait_id, span),
         }
     }
 }
@@ -2842,7 +2838,7 @@ pub struct FnHeader {
     /// The `unsafe` keyword, if any
     pub unsafety: Unsafe,
     /// Whether this is `async`, `gen`, or nothing.
-    pub coro_kind: CoroutineKind,
+    pub coro_kind: Option<CoroutineKind>,
     /// The `const` keyword, if any
     pub constness: Const,
     /// The `extern` keyword and corresponding ABI string, if any
@@ -2854,7 +2850,7 @@ impl FnHeader {
     pub fn has_qualifiers(&self) -> bool {
         let Self { unsafety, coro_kind, constness, ext } = self;
         matches!(unsafety, Unsafe::Yes(_))
-            || !matches!(coro_kind, CoroutineKind::None)
+            || coro_kind.is_some()
             || matches!(constness, Const::Yes(_))
             || !matches!(ext, Extern::None)
     }
@@ -2862,12 +2858,7 @@ impl FnHeader {
 
 impl Default for FnHeader {
     fn default() -> FnHeader {
-        FnHeader {
-            unsafety: Unsafe::No,
-            coro_kind: CoroutineKind::None,
-            constness: Const::No,
-            ext: Extern::None,
-        }
+        FnHeader { unsafety: Unsafe::No, coro_kind: None, constness: Const::No, ext: Extern::None }
     }
 }
 
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index f9f767862f5..c6aa7a6ae37 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -878,7 +878,6 @@ pub fn noop_visit_coro_kind<T: MutVisitor>(coro_kind: &mut CoroutineKind, vis: &
             vis.visit_id(closure_id);
             vis.visit_id(return_impl_trait_id);
         }
-        CoroutineKind::None => {}
     }
 }
 
@@ -1173,7 +1172,7 @@ fn visit_const_item<T: MutVisitor>(
 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
     let FnHeader { unsafety, coro_kind, constness, ext: _ } = header;
     visit_constness(constness, vis);
-    vis.visit_coro_kind(coro_kind);
+    coro_kind.as_mut().map(|coro_kind| vis.visit_coro_kind(coro_kind));
     visit_unsafety(unsafety, vis);
 }
 
@@ -1416,7 +1415,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
         }) => {
             vis.visit_closure_binder(binder);
             visit_constness(constness, vis);
-            vis.visit_coro_kind(coro_kind);
+            coro_kind.as_mut().map(|coro_kind| vis.visit_coro_kind(coro_kind));
             vis.visit_capture_by(capture_clause);
             vis.visit_fn_decl(fn_decl);
             vis.visit_expr(body);