DisplayName should be consistent between `RuleFor.ForEach` and `RuleForEach`

System Details

• FluentValidation version: 8.4

Issue Description

https://github.com/JeremySkinner/FluentValidation/blob/2eb493886b3f2f630f6c82ae7fc1baf6f34ec496/src/FluentValidation/Validators/PropertyValidatorContext.cs#L31

        public class Foo
        {
            public List<int> Numbers { get; set; }
        }

        [Fact]
        public void Should_show_property_name()
        {
            var validator = new InlineValidator<Foo>();
            validator.RuleFor(x => x.Numbers).ForEach(x => x.GreaterThan(10));

            validator.ShouldHaveValidationErrorFor(x => x.Numbers, new List<int>() {2})
                     .WithErrorMessage("'Numbers[0]' must be greater than '10'.");
            
            validator = new InlineValidator<Foo>();
            validator.RuleForEach(x => x.Numbers).GreaterThan(10);

            validator.ShouldHaveValidationErrorFor(x => x.Numbers, new List<int>() {2})
                     .WithErrorMessage("'Numbers[0]' must be greater than '10'.");

        }

maybe because https://github.com/JeremySkinner/FluentValidation/blob/2eb493886b3f2f630f6c82ae7fc1baf6f34ec496/src/FluentValidation/DefaultValidatorExtensions.cs#L1091 using a InlineValidator<IEnumerable<TElement>>() with x=>x lambda, so the MemberInfo will be resolved as null.

[JeremySkinner]

Thanks for the updated example. This is technically the correct behaviour as the display name is the always the name of the property being validated. In this case, you’re not validating a property, so it will correctly be an empty string and you’re expected to provide a name using WithName.

However I agree that this isn’t particularly intuitive or useful so will look at the implications of changing this for a future version.

[JeremySkinner]

Implemented in 40dbb78 and will be part of 10.2.