Problem with passing ref parameters to properties

[SebastianA]

I had not tested the code with DMD. We need x64 support, so we 
need GDC for that at the moment. However, I tried compiling with 
DMD and it seems that the line

t.vPosition = (Clock.currStdTime % 2 == 0) ? Vec(2, 2) : Vec(3, 
3);

does not compile with the latest DMD compiler. I get the error:

test.d(23): Error: not a property t.vPosition

when trying that. If I remove the ternary operator and just 
assign Vec(2, 2) to the property, it works as expected. Am I 
missing something here? Why cannot I write the code as listed 
above?