final class ClassTangentPropertyNotStored: Differentiable {
  var x: Float = 0

  struct TangentVector: Differentiable, AdditiveArithmetic {
    var x: Float { 0 }
  }
  func move(along direction: TangentVector) {}
}

@differentiable
func testClassTangentPropertyNotStored(_ c: ClassTangentPropertyNotStored) -> Float {
  var tmp = c
  return tmp.x
}

Assertion failed: (!operand->getType().isTrivial(getFunction()) && "Should not be passing trivial values to this api. Use instead " "emitDestroyValueOperation"), function createDestroyValue ...

Stack dump:
0.  Program arguments: /Users/aefr/swiftdir/build/Ninja-ReleaseAssert+swift-DebugAssert/swift-macosx-x86_64/bin/swift-frontend -target x86_64-apple-macosx10.9 -module-cache-path /Users/aefr/swiftdir/build/Ninja-ReleaseAssert+swift-DebugAssert/swift-macosx-x86_64/swift-test-results/x86_64-apple-macosx10.9/clang-module-cache -sdk /Users/aefr/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.16.sdk -swift-version 4 -ignore-module-source-info -typo-correction-limit 10 -emit-sil -enable-experimental-forward-mode-differentiation -verify /Users/aefr/swiftdir/swift/test/AutoDiff/SILOptimizer/forward_mode_diagnostics.swift 
1.  Swift version 5.3-dev (LLVM 03a20a7d045e034, Swift 445675a718a7b92)
2.  While evaluating request ExecuteSILPipelineRequest(Run pipelines { Mandatory Diagnostic Passes + Enabling Optimization Passes } on SIL for forward_mode_diagnostics.forward_mode_diagnostics)
3.  While running pass #​1323 SILModuleTransform "Differentiation".
4.  While processing // differentiability witness for test_class_tangent_property_not_stored
sil_differentiability_witness hidden [parameters 0] [results 0] @test_class_tangent_property_not_stored : $@convention(thin) (@guaranteed ClassTangentPropertyNotStored) -> Float {
}

 on SIL function "@test_class_tangent_property_not_stored".
 for 'testClassTangentPropertyNotStored(_:)' (at /Users/aefr/swiftdir/swift/test/AutoDiff/SILOptimizer/forward_mode_diagnostics.swift:283:1)
5.  While generating JVP and differential for SIL function "@test_class_tangent_property_not_stored".
 for 'testClassTangentPropertyNotStored(_:)' (at /Users/aefr/swiftdir/swift/test/AutoDiff/SILOptimizer/forward_mode_diagnostics.swift:283:1)
0  swift-frontend           0x000000011361b885 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 37
1  swift-frontend           0x000000011361a838 llvm::sys::RunSignalHandlers() + 248
2  swift-frontend           0x000000011361be86 SignalHandler(int) + 262
3  libsystem_platform.dylib 0x00007fff70c1e5fd _sigtramp + 29
4  swift-frontend           0x00000001160bae28 cmark_strbuf__initbuf + 1301091
5  libsystem_c.dylib        0x00007fff70af4808 abort + 120
6  libsystem_c.dylib        0x00007fff70af3ac6 err + 0
7  swift-frontend           0x000000010e8e91da swift::SILBuilder::createDestroyValue(swift::SILLocation, swift::SILValue) + 234
8  swift-frontend           0x000000010e704ce2 swift::SILBuilder::emitDestroyValue(swift::SILLocation, swift::SILValue) + 450
9  swift-frontend           0x000000010dad2bb1 swift::autodiff::JVPCloner::Implementation::emitTangentForDestroyValueInst(swift::DestroyValueInst*) + 241
10 swift-frontend           0x000000010dabf8ca swift::autodiff::JVPCloner::Implementation::visitDestroyValueInst(swift::DestroyValueInst*) + 90