void main() {

    (new C).writeln("OK."); // Error: no property writeln for type test.C, did you mean std.stdio.writeln(T...)(T args)?

    S1 s1;

    s1.writeln("Hey?"); // It can be compiled and runs!

    S2 s2;

    //s2.writeln("OK."); //  Error: no property writeln for type S2, did you mean std.stdio.writeln(T...)(T args)?

}

​

mixin template T() {

    import std.stdio;

}

​

class C {

    mixin T;

}

struct S1 {

    mixin T;

}

struct S2 {

    private import std.stdio;

}