Stack overflow with alias this

[rainers]

This code causes a stack overflow in the TypeReferenceFinder:

module bmp;

struct BMPInfoV3
{
    int width;
    int height;
}

struct BMPInfoV4
{
    BMPInfoV3 base;
    alias base this;
}

struct BMPInfoV5
{
    BMPInfoV4   base;
    alias base this;
}