AST: Drop useless AnyObject requirement in ArchetypeType::getExistentialType()

Fixes rdar://problem/101917443.

Author: slavapestov

lib/AST/Type.cpp

@@ -3503,15 +3503,21 @@ Type ArchetypeType::getExistentialType() const {
   // Otherwise, compute it from scratch.
   SmallVector<Type, 4> constraintTypes;
 
+  bool hasExplicitAnyObject = requiresClass();
+
   if (auto super = getSuperclass()) {
+    hasExplicitAnyObject = false;
     constraintTypes.push_back(super);
   }
   for (auto proto : getConformsTo()) {
+    if (proto->requiresClass())
+      hasExplicitAnyObject = false;
     constraintTypes.push_back(proto->getDeclaredInterfaceType());
   }
+
   auto &ctx = const_cast<ArchetypeType*>(this)->getASTContext();
   auto constraint = ProtocolCompositionType::get(
-     ctx, constraintTypes, requiresClass());
+     ctx, constraintTypes, hasExplicitAnyObject);
 
   // If the archetype is only constrained to a class type,
   // return the class type directly.

test/ClangImporter/Inputs/objc_generics_upper_bound.h

@@ -0,0 +1,31 @@
+@import Foundation;
+
+@protocol P
+@end
+
+@interface C: NSObject
+@end
+
+@interface Base<T> : NSObject
+@end
+
+@interface Derived: Base
+@end
+
+@interface BaseWithProtocol<T: id<P>> : NSObject
+@end
+
+@interface DerivedWithProtocol: BaseWithProtocol
+@end
+
+@interface BaseWithClass<T: C *> : NSObject
+@end
+
+@interface DerivedWithClass: BaseWithClass
+@end
+
+@interface BaseWithBoth<T: C<P> *> : NSObject
+@end
+
+@interface DerivedWithBoth: BaseWithBoth
+@end

test/ClangImporter/objc_generics_upper_bound.swift

@@ -0,0 +1,19 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify %s -import-objc-header %S/Inputs/objc_generics_upper_bound.h
+
+// REQUIRES: objc_interop
+
+func upperBound(derived: Derived) -> Base<AnyObject> {
+  return derived
+}
+
+func upperBound(derived: DerivedWithProtocol) -> BaseWithProtocol<any P> {
+  return derived
+}
+
+func upperBound(derived: DerivedWithClass) -> BaseWithClass<C> {
+  return derived
+}
+
+func upperBound(derived: DerivedWithBoth) -> BaseWithBoth<any C & P> {
+  return derived
+}

test/IRGen/objc_extensions.swift

@@ -206,12 +206,12 @@ class SwiftSubGizmo : SwiftBaseGizmo {
 extension FungingArray {
   // CHECK-LABEL: define {{.*}} @"$sSo12FungingArrayC15objc_extensionsEyAByxGxcfC"
   // CHECK-SAME: (%objc_object* %0, %swift.type* swiftself %1)
-  // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_XlMD"{{.*}}!dbg
+  // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_pMD"{{.*}}!dbg
 
   // CHECK-LABEL: define {{.*}} @"$sSo12FungingArrayC15objc_extensionsEyAByxGxcfc"
   // CHECK-SAME: (%objc_object* %0, %TSo12FungingArrayC* swiftself %1)
   // CHECK: [[ALLOCA:%[^, =]+]] = alloca %Any, align 8
-  // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_XlMD"{{.*}}!dbg
+  // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_pMD"{{.*}}!dbg
   // CHECK: {{%[^, =]+}} = getelementptr inbounds %Any, %Any* [[ALLOCA]], i32 0, i32 0
   // CHECK: [[ANYBUF:%[^, =]+]] = getelementptr inbounds %Any, %Any* [[ALLOCA]], i32 0, i32 0
   // CHECK: [[BUFPTR:%[^, =]+]] = {{.*}} [[ANYBUF]]
@@ -225,12 +225,12 @@ extension FungingArray {
 
   // CHECK-LABEL: define {{.*}} @"$sSo12FungingArrayC15objc_extensionsE7pinningAByxGxm_tcfC"
   // CHECK-SAME: (%swift.type* %0, %swift.type* swiftself %1)
-  // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_XlMD"{{.*}}!dbg
+  // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_pMD"{{.*}}!dbg
 
   // CHECK-LABEL: define {{.*}} @"$sSo12FungingArrayC15objc_extensionsE7pinningAByxGxm_tcfc"
   // CHECK-SAME: (%swift.type* %0, %TSo12FungingArrayC* swiftself %1)
   // CHECK: [[ALLOCA:%[^, =]+]] = alloca %Any, align 8
-  // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_XlMD"{{.*}}!dbg
+  // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_pMD"{{.*}}!dbg
   // CHECK: [[OBJC_CLASS:%[^, =]+]] = call %objc_class* @swift_getObjCClassFromMetadata(%swift.type* %0)
   // CHECK: [[OBJC_CLASS_OBJ:%[^, =]+]] = bitcast %objc_class* [[OBJC_CLASS]]
   // CHECK: {{%[^, =]+}} = getelementptr inbounds %Any, %Any* [[ALLOCA]], i32 0, i32 0