diff --git a/pkg/compiler/lib/src/kernel/transformations/async_lowering.dart b/pkg/compiler/lib/src/kernel/transformations/async_lowering.dart
index 8f60070..1f5e31b 100644
--- a/pkg/compiler/lib/src/kernel/transformations/async_lowering.dart
+++ b/pkg/compiler/lib/src/kernel/transformations/async_lowering.dart
@@ -11,6 +11,7 @@
 class _FunctionData {
   final List<AwaitExpression> awaits = [];
   final Set<ReturnStatement> returnStatements = {};
+  bool hasAsyncLoop = false;
 
   _FunctionData();
 
@@ -34,7 +35,7 @@
   AsyncLowering(this._coreTypes);
 
   bool _shouldTryAsyncLowering(FunctionNode node) =>
-      node.asyncMarker == AsyncMarker.Async;
+      node.asyncMarker == AsyncMarker.Async && !_functions.last.hasAsyncLoop;
 
   void enterFunction(FunctionNode node) {
     _functions.add(_FunctionData());
@@ -134,4 +135,10 @@
   void visitReturnStatement(ReturnStatement statement) {
     _functions.last.returnStatements.add(statement);
   }
+
+  void visitForInStatement(ForInStatement statement) {
+    if (statement.isAsync && _functions.isNotEmpty) {
+      _functions.last.hasAsyncLoop = true;
+    }
+  }
 }
diff --git a/pkg/compiler/lib/src/kernel/transformations/lowering.dart b/pkg/compiler/lib/src/kernel/transformations/lowering.dart
index ba289ae..b90f526 100644
--- a/pkg/compiler/lib/src/kernel/transformations/lowering.dart
+++ b/pkg/compiler/lib/src/kernel/transformations/lowering.dart
@@ -107,4 +107,11 @@
     statement.transformChildren(this);
     return statement;
   }
+
+  @override
+  TreeNode visitForInStatement(ForInStatement statement) {
+    _asyncLowering?.visitForInStatement(statement);
+    statement.transformChildren(this);
+    return statement;
+  }
 }
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart
index bbef654..e19523f 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart
@@ -8,7 +8,14 @@
   return (await 6) + 3;
 }
 
+Future<void> foo3() async {
+  await for (final x in Stream.empty()) {
+    break;
+  }
+}
+
 void main() {
   foo1();
   foo2();
+  foo3();
 }
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.strong.expect b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.strong.expect
index eb616ff..f3422b1 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.strong.expect
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.strong.expect
@@ -9,7 +9,14 @@
 static method foo2() → asy::Future<core::int> async /* futureValueType= core::int */ {
   return (await 6).{core::num::+}(3){(core::num) → core::int};
 }
+static method foo3() → asy::Future<void> async /* futureValueType= void */ {
+  #L1:
+  await for (final dynamic x in new asy::_EmptyStream::•<dynamic>()) {
+    break #L1;
+  }
+}
 static method main() → void {
   self::foo1();
   self::foo2();
+  self::foo3();
 }
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.strong.transformed.expect b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.strong.transformed.expect
index eb616ff..f3422b1 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.strong.transformed.expect
@@ -9,7 +9,14 @@
 static method foo2() → asy::Future<core::int> async /* futureValueType= core::int */ {
   return (await 6).{core::num::+}(3){(core::num) → core::int};
 }
+static method foo3() → asy::Future<void> async /* futureValueType= void */ {
+  #L1:
+  await for (final dynamic x in new asy::_EmptyStream::•<dynamic>()) {
+    break #L1;
+  }
+}
 static method main() → void {
   self::foo1();
   self::foo2();
+  self::foo3();
 }
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.textual_outline.expect b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.textual_outline.expect
index 06a5c0d..c9ebdd9 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.textual_outline.expect
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.textual_outline.expect
@@ -1,3 +1,4 @@
 Future<void> foo1() async {}
 Future<int> foo2() async {}
+Future<void> foo3() async {}
 void main() {}
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.textual_outline_modelled.expect
index 4ab99eed..4ab2b8a 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.textual_outline_modelled.expect
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.textual_outline_modelled.expect
@@ -1,3 +1,4 @@
 Future<int> foo2() async {}
 Future<void> foo1() async {}
+Future<void> foo3() async {}
 void main() {}
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.expect b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.expect
index eb616ff..f3422b1 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.expect
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.expect
@@ -9,7 +9,14 @@
 static method foo2() → asy::Future<core::int> async /* futureValueType= core::int */ {
   return (await 6).{core::num::+}(3){(core::num) → core::int};
 }
+static method foo3() → asy::Future<void> async /* futureValueType= void */ {
+  #L1:
+  await for (final dynamic x in new asy::_EmptyStream::•<dynamic>()) {
+    break #L1;
+  }
+}
 static method main() → void {
   self::foo1();
   self::foo2();
+  self::foo3();
 }
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.modular.expect b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.modular.expect
index eb616ff..f3422b1 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.modular.expect
@@ -9,7 +9,14 @@
 static method foo2() → asy::Future<core::int> async /* futureValueType= core::int */ {
   return (await 6).{core::num::+}(3){(core::num) → core::int};
 }
+static method foo3() → asy::Future<void> async /* futureValueType= void */ {
+  #L1:
+  await for (final dynamic x in new asy::_EmptyStream::•<dynamic>()) {
+    break #L1;
+  }
+}
 static method main() → void {
   self::foo1();
   self::foo2();
+  self::foo3();
 }
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.outline.expect b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.outline.expect
index 85b14b9..0c508d4 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.outline.expect
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.outline.expect
@@ -7,5 +7,7 @@
   ;
 static method foo2() → asy::Future<core::int> async 
   ;
+static method foo3() → asy::Future<void> async 
+  ;
 static method main() → void
   ;
diff --git a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.transformed.expect b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.transformed.expect
index eb616ff..f3422b1 100644
--- a/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/dart2js/async_lowering/no_transform.dart.weak.transformed.expect
@@ -9,7 +9,14 @@
 static method foo2() → asy::Future<core::int> async /* futureValueType= core::int */ {
   return (await 6).{core::num::+}(3){(core::num) → core::int};
 }
+static method foo3() → asy::Future<void> async /* futureValueType= void */ {
+  #L1:
+  await for (final dynamic x in new asy::_EmptyStream::•<dynamic>()) {
+    break #L1;
+  }
+}
 static method main() → void {
   self::foo1();
   self::foo2();
+  self::foo3();
 }