[Sema] Add test for references to restricted imports from frozen structs

Exporting types imported as non-public in @Frozen strucs is reported by
pre-existing mechanics using the access-levels system. This simply adds
a test to prevent regressions.

Author: xymus

test/Sema/access-level-import-inlinable.swift

@@ -1,19 +1,20 @@
-// Test use of decls restricted by an import access-level in inlinable code.
+// Test use of decls restricted by an import access-level in inlinable code
+// and frozen structs.
 
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
 /// Build the libraries.
 // RUN: %target-swift-frontend -emit-module %t/PublicLib.swift -o %t \
-// RUN:   -enable-library-evolution
+// RUN:   -swift-version 5 -enable-library-evolution
 // RUN: %target-swift-frontend -emit-module %t/PackageLib.swift -o %t \
-// RUN:   -enable-library-evolution
+// RUN:   -swift-version 5 -enable-library-evolution
 // RUN: %target-swift-frontend -emit-module %t/InternalLib.swift -o %t \
-// RUN:   -enable-library-evolution
+// RUN:   -swift-version 5 -enable-library-evolution
 // RUN: %target-swift-frontend -emit-module %t/FileprivateLib.swift -o %t \
-// RUN:   -enable-library-evolution
+// RUN:   -swift-version 5 -enable-library-evolution
 // RUN: %target-swift-frontend -emit-module %t/PrivateLib.swift -o %t \
-// RUN:   -enable-library-evolution
+// RUN:   -swift-version 5 -enable-library-evolution
 
 /// Check diagnostics.
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
@@ -52,6 +53,8 @@ public struct InternalImportType {
 }
 public func InternalFunc() {}
 
+@frozen public struct InternalImportFrozenType {}
+
 //--- FileprivateLib.swift
 public protocol FileprivateImportProto {
     associatedtype T
@@ -74,20 +77,21 @@ public struct PrivateImportType {
 public import PublicLib
 
 package import PackageLib
-// expected-note@-1 2 {{struct 'PackageImportType' imported as 'package' from 'PackageLib' here}}
+// expected-note@-1 4 {{struct 'PackageImportType' imported as 'package' from 'PackageLib' here}}
 
 internal import InternalLib
-// expected-note@-1 6 {{struct 'InternalImportType' imported as 'internal' from 'InternalLib' here}}
+// expected-note@-1 9 {{struct 'InternalImportType' imported as 'internal' from 'InternalLib' here}}
 // expected-note@-2 4 {{protocol 'InternalImportProto' imported as 'internal' from 'InternalLib' here}}
 // expected-note@-3 2 {{global function 'InternalFunc()' imported as 'internal' from 'InternalLib' here}}
+// expected-note@-4 2 {{struct 'InternalImportFrozenType' imported as 'internal' from 'InternalLib' here}}
 
 fileprivate import FileprivateLib
 // expected-note@-1 2 {{generic struct 'FileprivateImportWrapper' imported as 'fileprivate' from 'FileprivateLib' here}}
 // expected-note@-2 2 {{initializer 'init(wrappedValue:)' imported as 'fileprivate' from 'FileprivateLib' here}}
 // expected-note@-3 2 {{protocol 'FileprivateImportProto' imported as 'fileprivate' from 'FileprivateLib' here}}
 
 private import PrivateLib
-// expected-note@-1 4 {{struct 'PrivateImportType' imported as 'private' from 'PrivateLib' here}}
+// expected-note@-1 10 {{struct 'PrivateImportType' imported as 'private' from 'PrivateLib' here}}
  // expected-note@-2 2 {{initializer 'init()' imported as 'private' from 'PrivateLib' here}}
 
 public struct GenericType<T, U> {}
@@ -171,3 +175,87 @@ public struct GenericType<T, U> {}
   let _: GenericType<InternalImportType, PrivateImportType> // expected-error {{struct 'InternalImportType' is internal and cannot be referenced from an '@_alwaysEmitIntoClient' function}}
   // expected-error @-1 {{struct 'PrivateImportType' is private and cannot be referenced from an '@_alwaysEmitIntoClient' function}}
 }
+
+@frozen public struct BadFields1 {
+  private var field: PrivateImportType // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@_fixed_layout public struct FixedBadFields1 {
+// expected-warning@-1 {{'@frozen' attribute is now used for fixed-layout structs}}
+  private var field: PrivateImportType // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@frozen public struct BadFields2 {
+  private var field: PrivateImportType? // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@_fixed_layout public struct FixedBadFields2 {
+// expected-warning@-1 {{'@frozen' attribute is now used for fixed-layout structs}}
+  private var field: PrivateImportType? // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@frozen public struct BadFields3 {
+  internal var field: PackageImportType? // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@_fixed_layout public struct FixedBadFields3 {
+// expected-warning@-1 {{'@frozen' attribute is now used for fixed-layout structs}}
+  internal var field: PackageImportType? // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@frozen @usableFromInline struct BadFields4 {
+  internal var field: InternalImportType? // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@_fixed_layout @usableFromInline struct FixedBadFields4 {
+// expected-warning@-1 {{'@frozen' attribute is now used for fixed-layout structs}}
+  internal var field: InternalImportType? // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@frozen public struct BadFields5 {
+  private var field: PrivateImportType? { // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+    didSet {}
+  }
+}
+
+@_fixed_layout public struct FixedBadFields5 {
+// expected-warning@-1 {{'@frozen' attribute is now used for fixed-layout structs}}
+  private var field: PrivateImportType? { // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+    didSet {}
+  }
+}
+
+@frozen public struct BadFields6 {
+  private var field: InternalImportFrozenType? { // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+    didSet {}
+  }
+}
+
+@_fixed_layout public struct FixedBadFields6 {
+// expected-warning@-1 {{'@frozen' attribute is now used for fixed-layout structs}}
+  private var field: InternalImportFrozenType? { // expected-error {{type referenced from a stored property in a '@frozen' struct must be '@usableFromInline' or public}}
+    didSet {}
+  }
+}
+
+// expected-error@+1 {{the result of a '@usableFromInline' function must be '@usableFromInline' or public}}
+@usableFromInline func notReallyUsableFromInline() -> InternalImportType? { return nil }
+@frozen public struct BadFields7 {
+  private var field = notReallyUsableFromInline() // expected-error {{type referenced from a stored property with inferred type 'InternalImportType?' in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@_fixed_layout public struct FrozenBadFields7 {
+// expected-warning@-1 {{'@frozen' attribute is now used for fixed-layout structs}}
+  private var field = notReallyUsableFromInline() // expected-error {{type referenced from a stored property with inferred type 'InternalImportType?' in a '@frozen' struct must be '@usableFromInline' or public}}
+}
+
+@frozen public struct OKFields {
+  internal static var staticProp: InternalImportType?
+  private var computed: PrivateImportType? { return nil }
+}
+
+@_fixed_layout public struct FixedOKFields {
+// expected-warning@-1 {{'@frozen' attribute is now used for fixed-layout structs}}
+  internal static var staticProp: InternalImportType?
+  private var computed: PrivateImportType? { return nil }
+}