what is going on with cgcs.c:351?

[Vlad Levenfeld via Digitalmars-d-learn]

I'd also like to note that elsewhere in my code (in a unittest to 
be precise), I am using the full functionality of the Plot struct 
with no hiccups...

info.add (
	Plot (ℕ!24.map!(i => 0.8*i)
		.map!(x => τ(x, sin (x^^2))),
	gfx, txt)
		.title (`testing`)
		.y_axis (`output`, Plot.Range (-1, 1))
		.x_axis (`input`)
		.text_size (8)
		.color (blue * white),
	square (0.5).map!(v => v*vec(1.2,1))
)	.align_to (Alignment.top_right)
	.decorate ((Bounding_Box bounds){gfx.draw (blue.alpha (0.5), 
bounds);});

This compiles and runs without issues even though it is using 
even more of the thing that made the other examples fail, in the 
exact same sort of context.