This D code gives no compilation errors with DMD 2.050:


public class Foo {
    public int x = 10;
}
public class Test : Foo {
    public int x = 20;
}
void main() {}



This is equivalent C# code:

public class Foo {
    public int x = 10;
}
public class Test : Foo {
    public int x = 20; // warning
    public static void Main() {}
}


The C# compiler shows this warning:

warning CS0108: `Test.x' hides inherited member `Foo.x'. Use the new keyword if hiding was intended


The following C# code gives no warnings:


public class Foo {
    public int x = 10;
}
public class Test : Foo {
    new public int x = 20; // OK
    public static void Main() {}
}


A similar error (or warning), with a similar "new" keyword solution, may be added to D, so unwanted hiding of attributes may be avoided.

This is related to using the obligatory "override" keyword:
bug 3836

And this warning that I think is better to become an error ASAP:
bug 4216