Null and Non-Null Patterns

[TonyValenti]

It would be great to be able to write this code:

if(x is null y){
    //x is null
    //y is the default value.  

} else {
    //x is not null
    //y is the non-null version of x.  For example if x is long? y is long.
}


if(x is !null y){
  //x is not null
  //y is the non-null version of x.  For example, long? => long.
} else {
  //x is null
  //y is the default value.
}

[Joe4evr]

Gafter said that property patterns will give you if (x is {} y).