When a linter returns a Lint with an invalid (NA) column_number, as has recently happened in some regex-based linters, the error message is extremely confusing:

Error in rep.int(character, length) : invalid 'times' value
Calls: <Anonymous> ... print.lint -> cat -> highlight_string -> fill_with -> paste0
Execution halted

IMO Lint() should do some mild verification during construction so that invalid Lint()s can't be created successfully.

Here are a bunch of checks we could add:

1. No NAs are allowed anywhere.
2. 1L <= column_number <= nchar(line) + 1L.
3. line_number >= 1L.
4. ranges is a list of length 2 integer(ish) vectors, or NULL.
5. 1L <= ranges[[i]][1L] <= ranges[[i]][2L] <= nchar(line) + 1L for all i.

WDYT?