Flutter Dart analyzer not applying my linter rules
Ah, so... the linter is working fine; it was just my assumptions that were broken.
avoid_empty_else does not check for empty {} blocks, but only for ; right after else, which is why it didn't trigger.
avoid_relative_lib_imports literally only checks for relative imports whose path contains /lib/ in the name, not for relative imports whose target resolves to some file inside lib/.
Bummer. I was hoping to forbid relative imports altogether, but that's still unimplemented.