Add some tests for @testable and subclassing.

Inspired by the previous commit. These are things we expect to keep
working.

Author: jrose-apple

test/NameBinding/Inputs/has_accessibility.swift

@@ -39,3 +39,4 @@ public protocol HasDefaultImplementation {}
 extension HasDefaultImplementation {
   internal func foo() {}
 }
+internal class InternalBase {}

test/NameBinding/accessibility.swift

@@ -167,5 +167,9 @@ public protocol Fooable {
 #if !ACCESS_DISABLED
 internal struct FooImpl: Fooable, HasDefaultImplementation {} // expected-error {{type 'FooImpl' does not conform to protocol 'Fooable'}}
 public struct PublicFooImpl: Fooable, HasDefaultImplementation {} // expected-error {{type 'PublicFooImpl' does not conform to protocol 'Fooable'}}
-#endif
 // TESTABLE-NOT: method 'foo()'
+
+internal class TestableSub: InternalBase {} // expected-error {{undeclared type 'InternalBase'}}
+public class TestablePublicSub: InternalBase {} // expected-error {{undeclared type 'InternalBase'}}
+// TESTABLE-NOT: undeclared type 'InternalBase'
+#endif

test/SILGen/Inputs/TestableMultifileHelper.swift

@@ -2,3 +2,7 @@ public protocol HasDefaultFoo {}
 extension HasDefaultFoo {
   internal func foo() {}
 }
+
+internal class Base {
+  func foo() {}
+}

test/SILGen/testable-multifile-other.swift

@@ -30,3 +30,14 @@ func test(internalFoo: FooImpl, publicFoo: PublicFooImpl) {
 // CHECK: [[IMPL_2:%.+]] = function_ref @_TFE23TestableMultifileHelperPS_13HasDefaultFoo3foofT_T_
 // CHECK: = apply [[IMPL_2]]<PublicFooImpl>({{%.+}}) : $@convention(method) <τ_0_0 where τ_0_0 : HasDefaultFoo> (@in_guaranteed τ_0_0) -> ()
 // CHECK: {{^}$}}
+
+func test(internalSub: Sub, publicSub: PublicSub) {
+  internalSub.foo()
+  publicSub.foo()
+}
+
+// CHECK-LABEL: sil hidden @_TF4main4testFT11internalSubCS_3Sub9publicSubCS_9PublicSub_T_
+// CHECK: = class_method %0 : $Sub, #Sub.foo!1
+// CHECK: = class_method %1 : $PublicSub, #PublicSub.foo!1
+// CHECK: {{^}$}}
+

test/SILGen/testable-multifile.swift

@@ -28,6 +28,36 @@ public struct PublicFooImpl: Fooable, HasDefaultFoo {}
 // CHECK: function_ref @_TFE23TestableMultifileHelperPS_13HasDefaultFoo3foofT_T_
 // CHECK: {{^}$}}
 
+private class PrivateSub: Base {
+  fileprivate override func foo() {}
+}
+class Sub: Base {
+  internal override func foo() {}
+}
+public class PublicSub: Base {
+  public override func foo() {}
+}
+
+// CHECK-LABEL: sil_vtable PrivateSub {
+// CHECK-NEXT:   #Base.foo!1: _TFC4mainP33_F1525133BD493492AD72BF10FBCB1C5210PrivateSub3foofT_T_
+// CHECK-NEXT:   #Base.init!initializer.1: _TFC4mainP33_F1525133BD493492AD72BF10FBCB1C5210PrivateSubcfT_S0_
+// CHECK-NEXT:   #PrivateSub.deinit!deallocator: _TFC4mainP33_F1525133BD493492AD72BF10FBCB1C5210PrivateSubD
+// CHECK-NEXT: }
+
+// CHECK-LABEL: sil_vtable Sub {
+// CHECK-NEXT:   #Base.foo!1: _TFC4main3Sub3foofT_T_
+// CHECK-NEXT:   #Base.init!initializer.1: _TFC4main3SubcfT_S0_
+// CHECK-NEXT:   #Sub.deinit!deallocator: _TFC4main3SubD
+// CHECK-NEXT: }
+
+// CHECK-LABEL: sil_vtable PublicSub {
+// CHECK-NEXT:   #Base.foo!1: _TFC4main9PublicSub3foofT_T_
+// CHECK-NEXT:   #Base.init!initializer.1: _TFC4main9PublicSubcfT_S0_
+// CHECK-NEXT:   #PublicSub.deinit!deallocator: _TFC4main9PublicSubD
+// CHECK-NEXT: }
+
+
+
 // CHECK-LABEL: sil_witness_table FooImpl: Fooable module main {
 // CHECK-NEXT:  method #Fooable.foo!1: @_TTWV4main7FooImplS_7FooableS_FS1_3foofT_T_
 // CHECK-NEXT: }