diff --git a/src/BenchmarkDotNet/Attributes/Validators/ParamsAllValuesValidator.cs b/src/BenchmarkDotNet/Validators/ParamsAllValuesValidator.cs
similarity index 98%
rename from src/BenchmarkDotNet/Attributes/Validators/ParamsAllValuesValidator.cs
rename to src/BenchmarkDotNet/Validators/ParamsAllValuesValidator.cs
index 6f84d3a0d7..a0a65d33ec 100644
--- a/src/BenchmarkDotNet/Attributes/Validators/ParamsAllValuesValidator.cs
+++ b/src/BenchmarkDotNet/Validators/ParamsAllValuesValidator.cs
@@ -24,7 +24,7 @@ class ParamsAllValuesValidator : IValidator
                 .SelectMany(type => type.GetTypeMembersWithGivenAttribute<ParamsAllValuesAttribute>(reflectionFlags))
                 .Distinct()
                 .Select(member => GetErrorOrDefault(member.ParameterType))
-                .Where(error => error != default);
+                .Where(error => error != null);
 
         private bool IsBool(Type paramType) => paramType == typeof(bool);
         private bool IsEnum(Type paramType) => paramType.GetTypeInfo().IsEnum;