Ghci has a built in debugger with the expected features (breakpoints, single step, inspect local variables, tracing execution and time travel) but it isn't very

Ghci has a built in debugger with the expected features (breakpoints, single step, inspect local variables, tracing execution and time travel) but it isn't very useful because haskell is lazy. Execution can just pinball around seemingly at random making it hard to figure out what is happening. It is possible to go lower level and just throw gdb at it but a lot of compiled functional code depends on multiple source locations and dwarf can't represent that. On the other hand, for pure code the distinction between repl, debugger and test suite kinda blur anyway.