[Proposal] infer backing variable from definition

[banjouuid]

Currently we have to write a backing variable for the property:

private bool _isEditing; public bool IsEditing { get => _isEditing; }

I think the _isEditing variable can be inferred by the compiler as it is being stated in the getter so the resulting code would be like:

public bool IsEditing { get => _isEditing; }

Sometimes the viewmodels have dozens of properties like this so it'll help make it much more readable, specially if we have long variable names.

[HaloFour]

Why would this be preferable to auto-implemented properties?

public bool IsEditing { get; private set; }

[kxxt]

I think this feature is useless as we can write or use a tool to complete the property defination,and ofcourse,without the tools,it's also easy to do in VS2017.(With Ctrl+.)

[banjouuid]

Because sometimes we have thins like NotifyPropertyChanged inside the setters in the ViewModels:

private bool _isEditing; public bool IsEditing { get => _isEditing; set => RaisePropertyChanged(ref _isEditing, value); }

So you cannot relay on the auto-implemented properties:

public bool IsEditing { get => _isEditing; set => RaisePropertyChanged(ref _isEditing, value); }

[HaloFour]

C# is not the kind of language that will infer the existence of a field or local based on usage. Declaration is necessary. There are proposals to allow for either scoped backing fields:

public bool IsEditing {
    // field is scoped within the property only
    bool _isEditing;
    get => _isEditing;
    set => RaisePropertyChanged(ref _isEditing, value);
}

Or proposals to allow for an inferred backing field:

// field is a contextual keyword just like value
public bool IsEditing {
    get => field;
    set => RaisePropertyChanged(ref field, value);
}

[banjouuid]

That last option would be just fine in most of scenarios

[jnm2]

Yes, see #140 which I want really bad.

Even further, we should be able to do:

// field is a contextual keyword just like value
public bool IsEditing { get; set => RaisePropertyChanged(ref field, value); }