Somewhat opposite direction is languages features that increase the need for more debugging tools. As c++ is getting more and more features for compile time code evaluation it raises need for debugging them. One language that gets it right is Haxe. It allows executing arbitrary code at compile time for AST manipulation. Official implementation comes with a debugger that can debug it just like regular code.

Does anyone knows something similar in other languages or build systems? Does any of LISP environments provide such debugging functionality?