[... ]The first word of each simple command, if unquoted, is checked to see if it has an alias[...] The characters [...] and any of the shell metacharacters or quoting characters listed above may not appear in an alias name.
So aliases can only be a single word without any quoting characters.
-i in a call to rm also doesn't make much sense because they are somewhat contradictory(rm(1)):
ignore nonexistent files and arguments, never prompt
-i prompt before every removal
But here's the good thing - your alias to
rm is actually used even when you're calling
rm -r, because the first word -
rm - has an alias -
rm -i, so it gets replaced by that!
$ alias rm
bash: alias: rm: not found
$ alias rm='rm -i'
$ mkdir test
$ rm -r test
rm: remove directory ‘test’?
Raphael Ahrens also mentioned in the comments that using
-f (force) is not neceessary to remove directories (as can be already seen in my example),
-r (recursive) enough is alone:
-r, -R, --recursive
remove directories and their contents recursively