To properly need to debug such a language, you would need to be aware of all of the possible rules, pitfalls, bugs, and race conditions of every language under its hood.
At a basic level, is your "if else" condition running on it's Java or C++ or C version? Does it catch exceptions? Where is data being handled in memory? Are buffer overruns possible in some of these languages?
No one human could possibly we simultaneously cognisant of all possible sources of error. Programs in such a language would be a security disaster waiting to happen.