Additional IP Rights Grant (Patents)

"This implementation" means the copyrightable works distributed by

Google as part of the Go project.

Google hereby grants to You a perpetual, worldwide, non-exclusive,

no-charge, royalty-free, irrevocable (except as stated in this section)

patent license to make, have made, use, offer to sell, sell, import,

transfer and otherwise run, modify and propagate the contents of this

implementation of Go, where such license applies only to those patent

claims, both currently owned or controlled by Google and acquired in

the future, licensable by Google that are necessarily infringed by this

implementation of Go.  This grant does not include claims that would be

infringed only as a consequence of further modification of this

implementation.  If you or your agent or exclusive licensee institute or

order or agree to the institution of patent litigation against any

entity (including a cross-claim or counterclaim in a lawsuit) alleging

that this implementation of Go or any code incorporated within this

implementation of Go constitutes direct or contributory patent

infringement, or inducement of patent infringement, then any patent

rights granted to you under this License for this implementation of Go

shall terminate as of the date such litigation is filed.