import TensorFlow
extension Tensor where Scalar : FloatingPoint & Differentiable {
  @differentiable(wrt: (self))
  func hello() -> Tensor {
    return self
  }
}

SIL verification failed: generic function definition must have a generic environment: !FTy->isPolymorphic()
In function:
// AD__$s10TensorFlow0A0V8generic2s14DifferentiableRzSFRzrlE5helloACyxGyF__primal_src_0_wrt_0
sil hidden @AD__$s10TensorFlow0A0V8generic2s14DifferentiableRzSFRzrlE5helloACyxGyF__primal_src_0_wrt_0 : $@convention(method) <τ_0_0 where τ_0_0 : Differentiable, τ_0_0 : FloatingPoint, τ_0_0 : TensorFlowScalar> (@guaranteed Tensor<τ_0_0>) -> (@owned AD__$s10TensorFlow0A0V8generic2s14DifferentiableRzSFRzrlE5helloACyxGyF__Type__src_0_wrt_0, @owned Tensor<τ_0_0>) {
// %0                                             // users: %4, %2, %1
bb0(%0 : $Tensor<Scalar>):
  debug_value %0 : $Tensor<Scalar>, let, name "self", argno 1 // id: %1
  retain_value %0 : $Tensor<Scalar>               // id: %2
  %3 = struct $AD__$s10TensorFlow0A0V8generic2s14DifferentiableRzSFRzrlE5helloACyxGyF__Type__src_0_wrt_0 () // user: %4
  %4 = tuple (%3 : $AD__$s10TensorFlow0A0V8generic2s14DifferentiableRzSFRzrlE5helloACyxGyF__Type__src_0_wrt_0, %0 : $Tensor<Scalar>) // user: %5
  return %4 : $(AD__$s10TensorFlow0A0V8generic2s14DifferentiableRzSFRzrlE5helloACyxGyF__Type__src_0_wrt_0, Tensor<Scalar>) // id: %5
} // end sil function 'AD__$s10TensorFlow0A0V8generic2s14DifferentiableRzSFRzrlE5helloACyxGyF__primal_src_0_wrt_0'