Bug 1073 – CTFE: mixin expression with a function argument doesn't work

This code checks if TEST is defined, and defines it if not. If using the line that's commented out instead of the one above it, it works as expected. --- const int TEST = 1; char[] def(char[] s) { if (!is(typeof(mixin(s)))) // doesn't detect that TEST is defined //if (!is(typeof(mixin("TEST")))) // this works fine return "const int " ~ s ~ " = 3;\n"; else return ""; } mixin(def("TEST")); void main() { } --- test.d: variable test.TEST conflicts with test.TEST at test.d(1) I tried to recreate this problem without CTFE, just with a static if, but it doesn't happen then.

What this code is trying to do is to dynamically change the parse, rather than the evaluated result, at compile time. This isn't going to work (should use templates for that). I'll put some clarifications in the spec about this.