swift-mirror/test/AutoDiff/compiler_crashers_fixed/rdar84716758-differentiable-protocol-witness-missing-requirements.swift

// RUN: %target-build-swift %s

import _Differentiation

public protocol Layer: Differentiable {
  associatedtype Input: Differentiable
  associatedtype Output: Differentiable
  @differentiable(reverse, wrt: (self, input))
  @differentiable(reverse, wrt: input)
  func callAsFunction(_ input: Input) -> Output
}

// Test for explicitly declared `@differentiable` attributes.
public class Function1<Input: Differentiable, Output: Differentiable>: Layer {
  @noDerivative public let body: @differentiable(reverse) (Input) -> Output

  public init(_ body: @escaping @differentiable(reverse) (Input) -> Output) {
    self.body = body
  }

  @differentiable(reverse, wrt: (self, input))
  @differentiable(reverse, wrt: input)
  public func callAsFunction(_ input: Input) -> Output {
    body(input)
  }

  @differentiable(reverse, wrt: x where T: Differentiable)
  public func foo<T>(x: T) -> T {
    x
  }
}

// Test for implicitly generated `@differentiable` attributes.
class Function2<Input: Differentiable, Output: Differentiable>: Layer {
  @noDerivative let body: @differentiable(reverse) (Input) -> Output

  init(_ body: @escaping @differentiable(reverse) (Input) -> Output) {
    self.body = body
  }

  func callAsFunction(_ input: Input) -> Output {
    body(input)
  }
}