Choosing a proper wording for referring compiler errors

Question

Consider someone is writing a message (or a question at StackOverflow). The context is following:

In my code, I have the following line:
int foo = Bar();

However, the compiler returns an error:
line 42: Bar() is unknown function

I'm puzzled to choose a proper verb instead of "returns". I've seen people using various verbs for it, but I stuck every time I read it:

• "returns" can be confused with a function return value;
• "throws" is for exceptions;
• "prints" has a little sense as the compiler output is not always printed;
• "outs", "outputs", or "gives" do not sound professional;
• "the compiler complains" sounds a bit like personification of the compiler;

What is the proper verb in this situation?