std.array : appender woes

[abad via Digitalmars-d-learn]

import std.array : appender;
import std.stdio : writeln;
void main() {
    auto app = appender!(char[]);
    app.put('x');
    auto foo = app.data;
    app.clear; // done, start a new array
    app.put('y');
    writeln(foo);
}

This prints out 'y'. It's not surprising because what I suppose 
app.data is doing is just returning a slice of the dynamic array. 
Clear() resets the counter of current position. But this behavior 
is confusing in practical use, IMHO.

Should calling clear in your opinion guarantee that a new array 
gets allocated?