IIRC the main one is that it could be confusing inside a list, e.g. [foo: bar] vs [foo:bar()]. Someone also mentioned that `foo. bar()` (with a space after the

IIRC the main one is that it could be confusing inside a list, e.g. [foo: bar] vs [foo:bar()]. Someone also mentioned that `foo. bar()` (with a space after the dot) is legal syntax, but `foo: bar()` wouldn't be. I guess you can always do `alias :foo, as: Foo`.