divergence!

gistfile1.txt

scala> implicitly[Bijection[String, Int]]
bijection.this.Bijection.identity is not a valid implicit value for com.twitter.bijection.Bijection[String,Int] because:
type mismatch;
 found   : com.twitter.bijection.Bijection[Any,Any]
 required: com.twitter.bijection.Bijection[String,Int]
Note: Any >: String, but trait Bijection is invariant in type A.
You may wish to define A as -A instead. (SLS 4.5)
Note: Any >: Int, but trait Bijection is invariant in type B.
You may wish to define B as -B instead. (SLS 4.5)
bijection.this.Bijection.identity is not a valid implicit value for com.twitter.bijection.Bijection[Int,String] because:
type mismatch;
 found   : com.twitter.bijection.Bijection[Any,Any]
 required: com.twitter.bijection.Bijection[Int,String]
Note: Any >: Int, but trait Bijection is invariant in type A.
You may wish to define A as -A instead. (SLS 4.5)
Note: Any >: String, but trait Bijection is invariant in type B.
You may wish to define B as -B instead. (SLS 4.5)
bijection.this.Bijection.identity is not a valid implicit value for com.twitter.bijection.Bijection[String,Int] because:
type mismatch;
 found   : com.twitter.bijection.Bijection[Any,Any]
 required: com.twitter.bijection.Bijection[String,Int]
Note: Any >: String, but trait Bijection is invariant in type A.
You may wish to define A as -A instead. (SLS 4.5)
Note: Any >: Int, but trait Bijection is invariant in type B.
You may wish to define B as -B instead. (SLS 4.5)
<console>:9: error: diverging implicit expansion for type com.twitter.bijection.Bijection[String,Int]
starting with method inverseOf in trait LowPriorityBijections
              implicitly[Bijection[String, Int]]
                        ^
bijection.this.Bijection.identity is not a valid implicit value for Unit => com.twitter.bijection.Bijection[String,Int] because:
type mismatch;
 found   : Unit
 required: com.twitter.bijection.Bijection[String,Int]
bijection.this.Bijection.inverseOf is not a valid implicit value for Unit => com.twitter.bijection.Bijection[String,Int] because:
type mismatch;
 found   : Unit
 required: com.twitter.bijection.Bijection[Int,String]
bijection.this.Bijection.identity is not a valid implicit value for => Unit => com.twitter.bijection.Bijection[String,Int] because:
type mismatch;
 found   : Unit
 required: com.twitter.bijection.Bijection[String,Int]
bijection.this.Bijection.inverseOf is not a valid implicit value for => Unit => com.twitter.bijection.Bijection[String,Int] because:
type mismatch;
 found   : Unit
 required: com.twitter.bijection.Bijection[Int,String]