Nullable<T>.GetValueOrDefault() should be implicit in a nullable context

[marinasundstrom]

One thing that bugs me:

Currently you have to call GetValueOrDefault() to cast a Nullable regardless whether nullable is enabled or not:

int? value = null;

if(value != null)
{
    int foo = value.GetValueOrDefault();
}

In a Nullable context, the GetValueOrDefault()call (the type cast) should be implicit (emitted by the compiler) when checked, just like with nullable reference types:

int? value = 42;

if(value != null)
{
    int foo = value;
}

This ensures consistency. I don't think that a change would break anything existing in a major way.

[YairHalberstadt]

Discussed here: #1865. Difficult to be sure, but I think https://github.com/dotnet/csharplang/blob/master/meetings/2018/LDM-2018-10-24.md#using-nullable-values-as-non-nullable-values implies they're not going to do this.