Bug 18543 – Comments inside string mixin silently short-circuit code

I have recently stumbled upon the following wrong behaviour inside string mixins. If you use a single line style comment (//) inside a string mixin, this will silently short-circuit the code, leading to unexpected behaviour, as you can see in the example bellow: import std.stdio; void main(string[] args) { mixin("" ~"writeln(\"Hello\");" ~"// Some comment" ~"assert(0);" ); } The assert will never get triggered. If you use multi-line comments (/* */) those are correctly recognized and everything works as expected.

Just because you're mixin a single line. Adding \n will solve the problem import std.stdio; void main(string[] args) { mixin("" ~"writeln(\"Hello\");" ~"// Some comment\n" ~"assert(0);" ); } your code sounds like: void main() { writeln("hello"); // Some comment assert(0) }

Yeah, remember that string mixins are basically like pasting code in place. So, it's going to act like you pasted that code into your editor, and adding a comment with // is therefore going to have exactly the same effect as it would if you pasted code after a //, which means that it's going to be part of the comment.

Thank you both for explaining my mistake. I got confused by my own code. Cheers, Eduard