Relax constructor type requirements

[GabeDeBacker]

This change allows deserialization into object where it contains a member property (or field) whose type is "assignable" instead to the constructor type. This address some of the ideas mentioned in #44428.

Previously a class a simple as this would not "round trip" through System.Text.Json (which is a common pattern for applications using data binding to WPF/XAML, etc.)

public class ClassWithConstructorArgumentTypeThatIsAssignableFromImmutablePropertyType
{
   public ReadOnlyObservableCollection<int> Values { get; }
   private readonly ObservableCollection<int> valueCollection;
 
   public ClassWithConstructorArgumentTypeThatIsAssignableFromImmutablePropertyType(IEnumerable<int> values)
    {
        this.valueCollection = new ObservableCollection<int>(values);
        this.Values = new ReadOnlyObservableCollection<int>(this.valueCollection);
    }
}

[ghost]

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Issue Details

---

This change allows deserialization into object where it contains a member property (or field) whose type is "assignable" instead to the constructor type. This address some of the ideas mentioned in #44428.

Previously a class a simple as this would not "round trip" through System.Text.Json (which is a common pattern for applications using data binding to WPF/XAML, etc.)

public class ClassWithConstructorArgumentTypeThatIsAssignableFromImmutablePropertyType
{
   public ReadOnlyObservableCollection<int> Values { get; }
   private readonly ObservableCollection<int> valueCollection;
 
   public ClassWithConstructorArgumentTypeThatIsAssignableFromImmutablePropertyType(IEnumerable<int> values)
    {
        this.valueCollection = new ObservableCollection<int>(values);
        this.Values = new ReadOnlyObservableCollection<int>(this.valueCollection);
    }
}

Author:	GabeDeBacker
Assignees:	-
Labels:	area-System.Text.Json
Milestone:	-

[dnfadmin]

All CLA requirements met.

[ericstj]

@eiriktsarpalis @layomia can you have a look?

[ericstj]

Ping. Reviewers, please have a look and provide next steps (other than rebase of course).

[layomia]

I chatted with @GabeDeBacker offline - I'll pick up the work here. Thanks for the effort!