Raised when there are conflicting gem specs loaded
# File rubygems/errors.rb, line 84
def initialize target, conflicts
@target = target
@conflicts = conflicts
@name = target.name
reason = conflicts.map { |act, dependencies|
"#{act.full_name} conflicts with #{dependencies.join(", ")}"
}.join ", "
# TODO: improve message by saying who activated `con`
super("Unable to activate #{target.full_name}, because #{reason}")
end