Shortest Code to Legitimately Slack Off I'm a developer, and I don't feel like doing my work. I know from XKCD that the best excuse for slacking off is that your code's compiling. Because of this, I think I need some code that will compile forever! And because I'm lazy and don't want to have to type much, this has to be done with the shortest code possible.

So, your task is to write a program that is syntactically valid, but will cause the compiler to enter an infinite loop.

Specifications


You must use a language that has a compiler, obviously.
Specify the implementation used in each solution.
This is code-golf, so the shortest valid solution (in bytes) wins.
The compiler can terminate from running out of memory or stack space.
TikZ (pdfTeX 3.14159265-2.6-1.40.17), 85 79 74 24 22 21 bytes
A bunch of bytes saved thanks to wchargin
One byte saved thanks to Chris H
\input tikz
\tikz\pic

I actually encountered this one by accident when I was working on homework.  I spent quite a while waiting for it to compile before I realized what was happening.
This has two parts:
\input tikz

This loads the TikZ package
and:
\tikz\pic

This starts a \tikz environment and a draw command.
What is going on
The pdflatex compiler has trouble with \tikz\pic, and enters interactive mode causing it to stall indefinitely.