Add a SILGen test case for a resilient enum protocol witness.

Tests rdar://108001491 (SIL verification failed: Found mutating
or consuming use of in_guaranteed parameter?!: !ImmutableAddressUseVerifier().isMutatingOrConsuming(fArg))

Author: atrick

test/SILGen/protocol_enum_witness.swift

@@ -1,5 +1,5 @@
 // RUN: %target-swift-emit-silgen %s | %FileCheck %s
-// RUN: %target-swift-emit-silgen %s -enable-library-evolution
+// RUN: %target-swift-emit-silgen %s -enable-library-evolution | %FileCheck %s --check-prefix=CHECK-LIB
 
 public protocol Foo {
   static var button: Self { get }
@@ -55,3 +55,27 @@ enum InternalEnumWithPublicStruct : Foo {
 
 // CHECK-LABEL: sil_witness_table [serialized] AnotherBar: AnotherFoo module protocol_enum_witness {
 // CHECK: method #AnotherFoo.bar: <Self where Self : AnotherFoo> (Self.Type) -> (Int) -> Self : @$s21protocol_enum_witness10AnotherBarOAA0D3FooA2aDP3bar3argxSi_tFZTW
+
+// -----------------------------------------------------------------------------
+// rdar://108001491 (SIL verification failed: Found mutating or consuming use of
+//                  an in_guaranteed parameter?!:
+//                  !ImmutableAddressUseVerifier().isMutatingOrConsuming(fArg))
+
+public struct EntityIdentifier {
+  public let value: Swift.UInt64
+}
+
+public protocol ObjectProtocol {
+  static func entityReference(_ id: EntityIdentifier) -> Self
+}
+
+public enum Object : ObjectProtocol {
+  case entityReference(EntityIdentifier)
+}
+
+// CHECK-LIB-LABEL: sil private [transparent] [thunk] [ossa] @$s21protocol_enum_witness6ObjectOAA0D8ProtocolA2aDP15entityReferenceyxAA16EntityIdentifierVFZTW : $@convention(witness_method: ObjectProtocol) (@in_guaranteed EntityIdentifier, @thick Object.Type) -> @out Object {
+// CHECK-LIB: bb0(%0 : $*Object, %1 : $*EntityIdentifier, %2 : $@thick Object.Type):
+// CHECK-LIB: [[TEMP:%.*]] = alloc_stack $EntityIdentifier
+// CHECK-LIB: copy_addr %1 to [init] %3 : $*EntityIdentifier
+// CHECK-LIB: apply %{{.*}}(%0, [[TEMP]], %{{.*}}) : $@convention(method) (@in EntityIdentifier, @thin Object.Type) -> @out Object
+// CHECK-LIB-LABEL: } // end sil function '$s21protocol_enum_witness6ObjectOAA0D8ProtocolA2aDP15entityReferenceyxAA16EntityIdentifierVFZTW'