What obscure syntax ruined your day?

syntax

When have you run into syntax that might be dated, never used or just plain obfuscated that you couldn't understand for the life of you.

For example, I never knew that comma is an actual operator in C. So when I saw the code

if(Foo(), Bar())

I just about blew a gasket trying to figure out what was going on there.

I'm curious what little never-dusted corners might exist in other languages.

Best Solution

C++'s syntax for a default constructor on a local variable. At first I wrote the following.

Student student();  // error
Student student("foo");  // compiles

This lead me to about an hour of reading through a cryptic C++ error message. Eventually a non-C++ newbie dropped by, laughed and pointed out my mistake.

Student student;