diff --git a/lib/src/util/prop_errors.dart b/lib/src/util/prop_errors.dart
index 7c93d0656..15bd2921d 100644
--- a/lib/src/util/prop_errors.dart
+++ b/lib/src/util/prop_errors.dart
@@ -56,7 +56,7 @@ class PropError extends Error {
     if (_messagePrefix == requiredPrefix) {
       explanation = 'Prop $propName is required. ';
     } else if (_messagePrefix == invalidPrefix) {
-      explanation = 'Prop $propName set to ${Error.safeToString(invalidValue)}. ';
+      explanation = 'Prop $propName set to $invalidValue. ';
     } else if (_messagePrefix == combinationPrefix) {
       explanation = 'Prop $propName and prop $prop2Name are set to incompatible values. ';
     } else {