Raised when there are conflicting gem specs loaded

Methods
N
Attributes
[R] conflicts

A Hash mapping conflicting specifications to the dependencies that caused the conflict
[R] target

The specification that had the conflict
Class Public methods
new(target, conflicts)

Source: show | on GitHub 

# File lib/rubygems/errors.rb, line 38
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