copy TypeName.type when we clone the AST

lib/src/compiler/reify_coercions.dart

Index: lib/src/compiler/reify_coercions.dart
diff --git a/lib/src/compiler/reify_coercions.dart b/lib/src/compiler/reify_coercions.dart
index 5d91aefdb57081dcabb07d0a2483c7d6437c2329..67fbefee912717348f50cb4aee1ae1684b1043ec 100644
--- a/lib/src/compiler/reify_coercions.dart
+++ b/lib/src/compiler/reify_coercions.dart
@@ -163,4 +163,13 @@ class _TreeCloner extends analyzer.AstCloner {
         (node as FunctionBodyImpl).localVariableInfo;
     return clone;
   }
+
+  // TODO(jmesserly): workaround for
+  // https://github.com/dart-lang/sdk/issues/26368
+  @override
+  TypeName visitTypeName(TypeName node) {
+    var clone = super.visitTypeName(node);
+    clone.type = node.type;
+    return clone;
+  }
 }