If only

s/empty/coffee/mug;
[download]

was valid syntax.

I just stumbled upon this, 8 years after it was written. Now the syntax is valid:

$ perl -Mstrict -Mwarnings -E '$_ = "empty"; s/empty/coffee/mug; say'
coffee
[download]

[In fact, as far as I can tell, it has been valid since 5.14]