3 files changed, 7 insertions, 3 deletions
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 4a3ce0e0c30..f5e79c04d78 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1454,7 +1454,10 @@ pub enum ExprKind {
     Block(P<Block>, Option<Label>),
     /// An `async` block (`async move { ... }`),
     /// or a `gen` block (`gen move { ... }`)
-    Gen(CaptureBy, P<Block>, GenBlockKind),
+    ///
+    /// The span is the "decl", which is the header before the body `{ }`
+    /// including the `asyng`/`gen` keywords and possibly `move`.
+    Gen(CaptureBy, P<Block>, GenBlockKind, Span),
     /// An await expression (`my_future.await`). Span is of await keyword.
     Await(P<Expr>, Span),
 
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index a81c335aa23..27e781a5a63 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -1528,8 +1528,9 @@ pub fn noop_visit_expr<T: MutVisitor>(
             visit_opt(label, |label| vis.visit_label(label));
             vis.visit_block(blk);
         }
-        ExprKind::Gen(_capture_by, body, _kind) => {
+        ExprKind::Gen(_capture_by, body, _kind, decl_span) => {
             vis.visit_block(body);
+            vis.visit_span(decl_span);
         }
         ExprKind::Await(expr, await_kw_span) => {
             vis.visit_expr(expr);
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 0f3c30048ce..26cb04d4d47 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -1122,7 +1122,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) -> V
             visit_opt!(visitor, visit_label, opt_label);
             try_visit!(visitor.visit_block(block));
         }
-        ExprKind::Gen(_capt, body, _kind) => try_visit!(visitor.visit_block(body)),
+        ExprKind::Gen(_capt, body, _kind, _decl_span) => try_visit!(visitor.visit_block(body)),
         ExprKind::Await(expr, _span) => try_visit!(visitor.visit_expr(expr)),
         ExprKind::Assign(lhs, rhs, _span) => {
             try_visit!(visitor.visit_expr(lhs));