@unsafe attribute is not propagated through type alias declarations

[Xazax-hun]

Description

When a typealias is created in a non-strictly-safe module to a @unsafe construct, the alias can be used without triggering a warning in a strictly-safe module.

Reproduction

Apply the following diff and run tests:

diff --git a/test/Unsafe/Inputs/unsafe_swift_decls.swift b/test/Unsafe/Inputs/unsafe_swift_decls.swift
index 7c92bd6203f..c0996e6a183 100644
--- a/test/Unsafe/Inputs/unsafe_swift_decls.swift
+++ b/test/Unsafe/Inputs/unsafe_swift_decls.swift
@@ -1,5 +1,7 @@
 @unsafe public struct PointerType { } // expected-note{{'PointerType' declared here}}

+public typealias UnsafeTypeAlias = PointerType
+
 public func getPointers() -> [PointerType] { [] }

 public struct HasAPointerType {
diff --git a/test/Unsafe/unsafe_imports.swift b/test/Unsafe/unsafe_imports.swift
index 0b80943f303..fabc78c5554 100644
--- a/test/Unsafe/unsafe_imports.swift
+++ b/test/Unsafe/unsafe_imports.swift
@@ -1,9 +1,13 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature AllowUnsafeAttribute -enable-experimental-feature WarnUnsafe -I %S/Inputs
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module-path %t/unsafe_swift_decls.swiftmodule %S/Inputs/unsafe_swift_decls.swift -enable-experimental-feature AllowUnsafeAttribute
+
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature AllowUnsafeAttribute -enable-experimental-feature WarnUnsafe -I %S/Inputs  -I %t

 // REQUIRES: swift_feature_AllowUnsafeAttribute
 // REQUIRES: swift_feature_WarnUnsafe

 import unsafe_decls
+import unsafe_swift_decls

 func testUnsafe(_ ut: UnsafeType) { // expected-warning{{reference to unsafe struct 'UnsafeType'}}
   unsafe_c_function() // expected-warning{{call to unsafe global function 'unsafe_c_function'}}
@@ -12,3 +16,7 @@ func testUnsafe(_ ut: UnsafeType) { // expected-warning{{reference to unsafe str
   print_ints(&array, CInt(array.count))
   // expected-warning@-1{{call to global function 'print_ints' involves unsafe type 'UnsafeMutablePointer<Int32>'}}
 }
+
+
+func testUnsafe2(_ ut: UnsafeTypeAlias) { // expected-warning{{reference to unsafe type alias 'UnsafeTypeAlias'}}
+}

Expected behavior

Warning is produced for func testUnsafe2(_ ut: UnsafeTypeAlias)

Environment

Swift version 6.2-dev (LLVM be8c96d78337932, Swift 7867657)
Target: arm64-apple-macosx15.0

Additional information

No response