SILGen: More subclass existential tests

Author: slavapestov

test/SILGen/subclass_existentials.swift

@@ -1,20 +1,42 @@
-// RUN: %target-swift-frontend -Xllvm -sil-full-demangle -emit-silgen -parse-as-library -enable-experimental-subclass-existentials %s | %FileCheck %s
+// RUN: %target-swift-frontend -Xllvm -sil-full-demangle -emit-silgen -parse-as-library -enable-experimental-subclass-existentials -primary-file %s -verify | %FileCheck %s
+// RUN: %target-swift-frontend -emit-ir -parse-as-library -enable-experimental-subclass-existentials -primary-file %s
+
+// Note: we pass -verify above to ensure there are no spurious
+// compiler warnings relating to casts.
 
 protocol Q {}
 
 class Base<T> : Q {
-  func classSelfReturn() -> Self {}
-  static func classSelfReturn() -> Self {}
+  required init(classInit: ()) {}
+  func classSelfReturn() -> Self {
+    return self
+  }
+  static func classSelfReturn() -> Self {
+    return self.init(classInit: ())
+  }
 }
 
 protocol P {
+  init(protocolInit: ())
   func protocolSelfReturn() -> Self
   static func protocolSelfReturn() -> Self
 }
 
 class Derived : Base<Int>, P {
-  func protocolSelfReturn() -> Self {}
-  static func protocolSelfReturn() -> Self {}
+  required init(protocolInit: ()) {
+    super.init(classInit: ())
+  }
+
+  required init(classInit: ()) {
+    super.init(classInit: ())
+  }
+
+  func protocolSelfReturn() -> Self {
+    return self
+  }
+  static func protocolSelfReturn() -> Self {
+    return self.init(classInit: ())
+  }
 }
 
 protocol R {}
@@ -128,7 +150,23 @@ func methodCalls(
   // CHECK: end_borrow [[BORROW]] from %0 : $Base<Int> & P
   let _: Base<Int> & P = baseAndP.protocolSelfReturn()
 
+  // CHECK: [[METATYPE:%.*]] = open_existential_metatype %1 : $@thick (Base<Int> & P).Type to $@thick (@opened("{{.*}}") (Base<Int> & P)).Type
+  // CHECK: [[METHOD:%.*]] = function_ref @_T021subclass_existentials4BaseC15classSelfReturnACyxGXDyFZ : $@convention(method) <τ_0_0> (@thick Base<τ_0_0>.Type) -> @owned Base<τ_0_0>
+  // CHECK: [[METATYPE_REF:%.*]] = upcast [[METATYPE]] : $@thick (@opened("{{.*}}") (Base<Int> & P)).Type to $@thick Base<Int>.Type
+  // CHECK: [[RESULT_REF2:%.*]] = apply [[METHOD]]<Int>([[METATYPE_REF]])
+  // CHECK: [[RESULT_REF:%.*]] = unchecked_ref_cast [[RESULT_REF2]] : $Base<Int> to $@opened("{{.*}}") (Base<Int> & P)
+  // CHECK: [[RESULT:%.*]] = init_existential_ref [[RESULT_REF]] : $@opened("{{.*}}") (Base<Int> & P) : $@opened("{{.*}}") (Base<Int> & P), $Base<Int> & P
+  // CHECK: destroy_value [[RESULT]]
   let _: Base<Int> & P = baseAndPType.classSelfReturn()
+
+  // CHECK: [[METATYPE:%.*]] = open_existential_metatype %1 : $@thick (Base<Int> & P).Type to $@thick (@opened("{{.*}}") (Base<Int> & P)).Type
+  // CHECK: [[METHOD:%.*]] = witness_method $@opened("{{.*}}") (Base<Int> & P), #P.protocolSelfReturn!1 : <Self where Self : P> (Self.Type) -> () -> @dynamic_self Self, [[METATYPE]] : $@thick (@opened("{{.*}}") (Base<Int> & P)).Type : $@convention(witness_method) <τ_0_0 where τ_0_0 : P> (@thick τ_0_0.Type) -> @out τ_0_0
+  // CHECK: [[RESULT:%.*]] = alloc_stack $@opened("{{.*}}") (Base<Int> & P)
+  // CHECK: apply [[METHOD]]<@opened("{{.*}}") (Base<Int> & P)>(%37, %35) : $@convention(witness_method) <τ_0_0 where τ_0_0 : P> (@thick τ_0_0.Type) -> @out τ_0_0
+  // CHECK: [[RESULT_REF:%.*]] = load [take] [[RESULT]] : $*@opened("{{.*}}") (Base<Int> & P)
+  // CHECK: [[RESULT_VALUE:%.*]] = init_existential_ref [[RESULT_REF]] : $@opened("{{.*}}") (Base<Int> & P) : $@opened("{{.*}}") (Base<Int> & P), $Base<Int> & P
+  // CHECK: destroy_value [[RESULT_VALUE]]
+  // CHECK: dealloc_stack [[RESULT]]
   let _: Base<Int> & P = baseAndPType.protocolSelfReturn()
 
   // Partial applications
@@ -137,10 +175,15 @@ func methodCalls(
 
   let _: () -> (Base<Int> & P) = baseAndPType.classSelfReturn
   let _: () -> (Base<Int> & P) = baseAndPType.protocolSelfReturn
+
+  let _: () -> (Base<Int> & P) = baseAndPType.init(classInit:)
+  let _: () -> (Base<Int> & P) = baseAndPType.init(protocolInit:)
+
+  // CHECK:      return
+  // CHECK-NEXT: }
 }
 
 // CHECK-LABEL: sil hidden @_T021subclass_existentials19functionConversionsyAA1P_AA4BaseCySiGXcyc07returnsE4AndP_AaC_AFXcXpyc0feG5PTypeAA7DerivedCyc0fI0AJmyc0fI4TypeAA1R_AJXcyc0fiG1RAaM_AJXcXpyc0fiG5RTypetF : $@convention(thin) (@owned @callee_owned () -> @owned Base<Int> & P, @owned @callee_owned () -> @thick (Base<Int> & P).Type, @owned @callee_owned () -> @owned Derived, @owned @callee_owned () -> @thick Derived.Type, @owned @callee_owned () -> @owned Derived & R, @owned @callee_owned () -> @thick (Derived & R).Type) -> () {
-
 func functionConversions(
   returnsBaseAndP: @escaping () -> (Base<Int> & P),
   returnsBaseAndPType: @escaping () -> (Base<Int> & P).Type,
@@ -166,4 +209,259 @@ func functionConversions(
 
   let _: () -> P = returnsDerivedAndR
   let _: () -> P.Type = returnsDerivedAndRType
+
+  // CHECK:      return %
+  // CHECK-NEXT: }
+}
+
+// CHECK-LABEL: sil hidden @_T021subclass_existentials9downcastsyAA1P_AA4BaseCySiGXc8baseAndP_AA7DerivedC7derivedAaC_AFXcXp0eF5PTypeAIm0H4TypetF : $@convention(thin) (@owned Base<Int> & P, @owned Derived, @thick (Base<Int> & P).Type, @thick Derived.Type) -> () {
+func downcasts(
+  baseAndP: Base<Int> & P,
+  derived: Derived,
+  baseAndPType: (Base<Int> & P).Type,
+  derivedType: Derived.Type) {
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %0 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<Int> & P to $Derived
+  let _ = baseAndP as? Derived
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %0 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<Int> & P to $Derived
+  let _ = baseAndP as! Derived
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %0 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<Int> & P to $Derived & R
+  let _ = baseAndP as? (Derived & R)
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %0 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<Int> & P to $Derived & R
+  let _ = baseAndP as! (Derived & R)
+
+  // CHECK:      checked_cast_br %3 : $@thick Derived.Type to $@thick (Derived & R).Type
+  let _ = derivedType as? (Derived & R).Type
+
+  // CHECK:      unconditional_checked_cast %3 : $@thick Derived.Type to $@thick (Derived & R).Type
+  let _ = derivedType as! (Derived & R).Type
+
+  // CHECK:      checked_cast_br %2 : $@thick (Base<Int> & P).Type to $@thick Derived.Type
+  let _ = baseAndPType as? Derived.Type
+
+  // CHECK:      unconditional_checked_cast %2 : $@thick (Base<Int> & P).Type to $@thick Derived.Type
+  let _ = baseAndPType as! Derived.Type
+
+  // CHECK:      checked_cast_br %2 : $@thick (Base<Int> & P).Type to $@thick (Derived & R).Type
+  let _ = baseAndPType as? (Derived & R).Type
+
+  // CHECK:      unconditional_checked_cast %2 : $@thick (Base<Int> & P).Type to $@thick (Derived & R).Type
+  let _ = baseAndPType as! (Derived & R).Type
+
+  // CHECK:      return
+  // CHECK-NEXT: }
+}
+
+// CHECK-LABEL: sil hidden @_T021subclass_existentials16archetypeUpcastsyq_9baseTAndP_q0_0E7IntAndPq1_7derivedtAA4BaseCyxGRb_AA1PR_AGySiGRb0_AaIR0_AA7DerivedCRb1_r2_lF : $@convention(thin) <T, BaseTAndP, BaseIntAndP, DerivedT where BaseTAndP : Base<T>, BaseTAndP : P, BaseIntAndP : Base<Int>, BaseIntAndP : P, DerivedT : Derived> (@owned BaseTAndP, @owned BaseIntAndP, @owned DerivedT) -> () {
+func archetypeUpcasts<T,
+                      BaseTAndP : Base<T> & P,
+                      BaseIntAndP : Base<Int> & P,
+                      DerivedT : Derived>(
+  baseTAndP: BaseTAndP,
+  baseIntAndP : BaseIntAndP,
+  derived : DerivedT) {
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %0 : $BaseTAndP
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $BaseTAndP
+  // CHECK-NEXT: init_existential_ref [[COPIED]] : $BaseTAndP : $BaseTAndP, $Base<T> & P
+  let _: Base<T> & P = baseTAndP
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %1 : $BaseIntAndP
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $BaseIntAndP
+  // CHECK-NEXT: init_existential_ref [[COPIED]] : $BaseIntAndP : $BaseIntAndP, $Base<Int> & P
+  let _: Base<Int> & P = baseIntAndP
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %2 : $DerivedT
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $DerivedT
+  // CHECK-NEXT: init_existential_ref [[COPIED]] : $DerivedT : $DerivedT, $Base<Int> & P
+  let _: Base<Int> & P = derived
+
+  // CHECK:      return
+  // CHECK-NEXT: }
+}
+
+// CHECK-LABEL: sil hidden @_T021subclass_existentials18archetypeDowncastsyx1s_q_1tq0_2ptq1_5baseTq2_0F3Intq3_0f6TAndP_C0q4_0fg5AndP_C0q5_08derived_C0AA1R_AA7DerivedCXc0ji2R_C0AA1P_AA4BaseCyq_GXc0fH10P_concreteAaO_AQySiGXc0fgi2P_M0tAaOR0_ARRb1_ATRb2_ARRb3_AaOR3_ATRb4_AaOR4_AMRb5_r6_lF : $@convention(thin) <S, T, PT, BaseT, BaseInt, BaseTAndP, BaseIntAndP, DerivedT where PT : P, BaseT : Base<T>, BaseInt : Base<Int>, BaseTAndP : Base<T>, BaseTAndP : P, BaseIntAndP : Base<Int>, BaseIntAndP : P, DerivedT : Derived> (@in S, @in T, @in PT, @owned BaseT, @owned BaseInt, @owned BaseTAndP, @owned BaseIntAndP, @owned DerivedT, @owned Derived & R, @owned Base<T> & P, @owned Base<Int> & P) -> () {
+func archetypeDowncasts<S,
+                        T,
+                        PT : P,
+                        BaseT : Base<T>,
+                        BaseInt : Base<Int>,
+                        BaseTAndP : Base<T> & P,
+                        BaseIntAndP : Base<Int> & P,
+                        DerivedT : Derived>(
+  s: S,
+  t: T,
+  pt: PT,
+  baseT : BaseT,
+  baseInt : BaseInt,
+
+  baseTAndP_archetype: BaseTAndP,
+  baseIntAndP_archetype : BaseIntAndP,
+  derived_archetype : DerivedT,
+  derivedAndR_archetype : Derived & R,
+
+  baseTAndP_concrete: Base<T> & P,
+  baseIntAndP_concrete: Base<Int> & P) {
+
+  // CHECK:      [[COPY:%.*]] = alloc_stack $S
+  // CHECK-NEXT: copy_addr %0 to [initialization] [[COPY]] : $*S
+  // CHECK-NEXT: [[RESULT:%.*]] = alloc_stack $Base<T> & P
+  // CHECK-NEXT: checked_cast_addr_br take_always S in [[COPY]] : $*S to Base<T> & P in [[RESULT]] : $*Base<T> & P
+  let _ = s as? (Base<T> & P)
+
+  // CHECK:      [[COPY:%.*]] = alloc_stack $S
+  // CHECK-NEXT: copy_addr %0 to [initialization] [[COPY]] : $*S
+  // CHECK-NEXT: [[RESULT:%.*]] = alloc_stack $Base<T> & P
+  // CHECK-NEXT: unconditional_checked_cast_addr take_always S in [[COPY]] : $*S to Base<T> & P in [[RESULT]] : $*Base<T> & P
+  let _ = s as! (Base<T> & P)
+
+  // CHECK:      [[COPY:%.*]] = alloc_stack $S
+  // CHECK-NEXT: copy_addr %0 to [initialization] [[COPY]] : $*S
+  // CHECK-NEXT: [[RESULT:%.*]] = alloc_stack $Base<Int> & P
+  // CHECK-NEXT: checked_cast_addr_br take_always S in [[COPY]] : $*S to Base<Int> & P in [[RESULT]] : $*Base<Int> & P
+  let _ = s as? (Base<Int> & P)
+
+  // CHECK:      [[COPY:%.*]] = alloc_stack $S
+  // CHECK-NEXT: copy_addr %0 to [initialization] [[COPY]] : $*S
+  // CHECK-NEXT: [[RESULT:%.*]] = alloc_stack $Base<Int> & P
+  // CHECK-NEXT: unconditional_checked_cast_addr take_always S in [[COPY]] : $*S to Base<Int> & P in [[RESULT]] : $*Base<Int> & P
+  let _ = s as! (Base<Int> & P)
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %5 : $BaseTAndP
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $BaseTAndP
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $BaseTAndP to $Derived & R
+  let _ = baseTAndP_archetype as? (Derived & R)
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %5 : $BaseTAndP
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $BaseTAndP
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $BaseTAndP to $Derived & R
+  let _ = baseTAndP_archetype as! (Derived & R)
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %9 : $Base<T> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<T> & P
+  // CHECK-NEXT: [[COPY:%.*]] = alloc_stack $Base<T> & P
+  // CHECK-NEXT: store [[COPIED]] to [init] [[COPY]] : $*Base<T> & P
+  // CHECK-NEXT: [[RESULT:%.*]] = alloc_stack $Optional<S>
+  // CHECK-NEXT: [[PAYLOAD:%.*]] = init_enum_data_addr [[RESULT]] : $*Optional<S>, #Optional.some
+  // CHECK-NEXT: checked_cast_addr_br take_always Base<T> & P in [[COPY]] : $*Base<T> & P to S in [[PAYLOAD]] : $*S
+  let _ = baseTAndP_concrete as? S
+
+  // CHECK:      [[COPY:%.*]] = alloc_stack $Base<T> & P
+  // CHECK-NEXT: [[BORROWED:%.*]] = begin_borrow %9 : $Base<T> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<T> & P
+  // CHECK-NEXT: store [[COPIED]] to [init] [[COPY]] : $*Base<T> & P
+  // CHECK-NEXT: [[RESULT:%.*]] = alloc_stack $S
+  // CHECK-NEXT: unconditional_checked_cast_addr take_always Base<T> & P in [[COPY]] : $*Base<T> & P to S in [[RESULT]] : $*S
+  let _ = baseTAndP_concrete as! S
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %9 : $Base<T> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<T> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<T> & P to $BaseT
+  let _ = baseTAndP_concrete as? BaseT
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %9 : $Base<T> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<T> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<T> & P to $BaseT
+  let _ = baseTAndP_concrete as! BaseT
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %9 : $Base<T> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<T> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<T> & P to $BaseInt
+  let _ = baseTAndP_concrete as? BaseInt
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %9 : $Base<T> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<T> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<T> & P to $BaseInt
+  let _ = baseTAndP_concrete as! BaseInt
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %9 : $Base<T> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<T> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<T> & P to $BaseTAndP
+  let _ = baseTAndP_concrete as? BaseTAndP
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %9 : $Base<T> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<T> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<T> & P to $BaseTAndP
+  let _ = baseTAndP_concrete as! BaseTAndP
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %6 : $BaseIntAndP
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $BaseIntAndP
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $BaseIntAndP to $Derived & R
+  let _ = baseIntAndP_archetype as? (Derived & R)
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %6 : $BaseIntAndP
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $BaseIntAndP
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $BaseIntAndP to $Derived & R
+  let _ = baseIntAndP_archetype as! (Derived & R)
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: [[COPY:%.*]] = alloc_stack $Base<Int> & P
+  // CHECK-NEXT: store [[COPIED]] to [init] [[COPY]] : $*Base<Int> & P
+  // CHECK-NEXT: [[RESULT:%.*]] = alloc_stack $Optional<S>
+  // CHECK-NEXT: [[PAYLOAD:%.*]] = init_enum_data_addr [[RESULT]] : $*Optional<S>, #Optional.some
+  // CHECK-NEXT: checked_cast_addr_br take_always Base<Int> & P in [[COPY]] : $*Base<Int> & P to S in [[PAYLOAD]] : $*S
+  let _ = baseIntAndP_concrete as? S
+
+  // CHECK:      [[COPY:%.*]] = alloc_stack $Base<Int> & P
+  // CHECK-NEXT: [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: store [[COPIED]] to [init] [[COPY]] : $*Base<Int> & P
+  // CHECK-NEXT: [[RESULT:%.*]] = alloc_stack $S
+  // CHECK-NEXT: unconditional_checked_cast_addr take_always Base<Int> & P in [[COPY]] : $*Base<Int> & P to S in [[RESULT]] : $*S
+  let _ = baseIntAndP_concrete as! S
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<Int> & P to $DerivedT
+  let _ = baseIntAndP_concrete as? DerivedT
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<Int> & P to $DerivedT
+  let _ = baseIntAndP_concrete as! DerivedT
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<Int> & P to $BaseT
+  let _ = baseIntAndP_concrete as? BaseT
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<Int> & P to $BaseT
+  let _ = baseIntAndP_concrete as! BaseT
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<Int> & P to $BaseInt
+  let _ = baseIntAndP_concrete as? BaseInt
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<Int> & P to $BaseInt
+  let _ = baseIntAndP_concrete as! BaseInt
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: checked_cast_br [[COPIED]] : $Base<Int> & P to $BaseTAndP
+  let _ = baseIntAndP_concrete as? BaseTAndP
+
+  // CHECK:      [[BORROWED:%.*]] = begin_borrow %10 : $Base<Int> & P
+  // CHECK-NEXT: [[COPIED:%.*]] = copy_value [[BORROWED]] : $Base<Int> & P
+  // CHECK-NEXT: unconditional_checked_cast [[COPIED]] : $Base<Int> & P to $BaseTAndP
+  let _ = baseIntAndP_concrete as! BaseTAndP
+
+  // CHECK:      return
+  // CHECK-NEXT: }
 }