What is elm-make: Map.!: given key is not an element in the map

Question

when compiling with elm 0.18 I'm getting elm-make: Map.!: given key is not an element in the map, but I can not seem to find any error in any List.map.

edit: I have a fix (posted below), but I would still like to know what this error means and where it comes from.

Answer 1

deleting .elm-stuff and reinstalling packages fixes the issue.

Answer 2

There is a github issue: https://github.com/elm-lang/elm-package/issues/254. No answers there at the moment, but perhaps that's where they will appear ... ?

Answer 3

There is a problem with the 0.19 compiler. You can check the progress of the issue here: https://github.com/elm/compiler/pull/1850#issuecomment-509327575

Meanwhile, you could install the development version of the 0.19.1 compiler, use the fork here: https://github.com/CurrySoftware/compiler, or run your code without the --debug flag.