Merge pull request swiftlang#63479 from xymus/opaque-safety

[Serialization] Evaluate the safety of opaque types

Author: xymus

lib/Serialization/Serialization.cpp

@@ -3192,7 +3192,6 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     // Note: There's likely room to report some of these as unsafe to prevent
     //       failures.
     if (isa<GenericTypeParamDecl>(decl) ||
-        isa<OpaqueTypeDecl>(decl) ||
         isa<ParamDecl>(decl) ||
         isa<EnumCaseDecl>(decl) ||
         isa<EnumElementDecl>(decl))
@@ -3215,7 +3214,10 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     // Write a human readable name to an identifier.
     SmallString<64> out;
     llvm::raw_svector_ostream outStream(out);
-    if (auto val = dyn_cast<ValueDecl>(decl)) {
+    if (auto opaque = dyn_cast<OpaqueTypeDecl>(decl)) {
+      outStream << "opaque ";
+      outStream << opaque->getOpaqueReturnTypeIdentifier();
+    } else if (auto val = dyn_cast<ValueDecl>(decl)) {
       outStream << val->getName();
     } else if (auto ext = dyn_cast<ExtensionDecl>(decl)) {
       outStream << "extension ";

test/Serialization/Safety/unsafe-decls.swift

@@ -4,7 +4,7 @@
 
 // RUN: %target-swift-frontend -emit-module %s \
 // RUN:   -enable-library-evolution -swift-version 5 \
-// RUN:   -Xllvm -debug-only=Serialization 2>&1 \
+// RUN:   -Xllvm -debug-only=Serialization 2>&1 | %swift-demangle --simplified \
 // RUN:   | %FileCheck --check-prefixes=SAFETY-PRIVATE,SAFETY-INTERNAL %s
 
 // RUN: %target-swift-frontend -emit-module %s \
@@ -53,6 +53,9 @@ public struct PublicStruct {
 // NO-SAFETY-INTERNAL: Serialization safety, safe: 'internalTypealias'
 // SAFETY-PRIVATE: Serialization safety, safe: 'localTypealias'
 
+// SAFETY-PRIVATE: Serialization safety, safe: 'opaque PublicStruct.opaqueTypeFunc()'
+// SAFETY-PRIVATE: Serialization safety, unsafe: 'opaque PublicStruct.opaqueFuncInternal()'
+
     public init(publicInit a: Int) {}
 // SAFETY-PRIVATE: Serialization safety, safe: 'init(publicInit:)'
     internal init(internalInit a: Int) {}
@@ -69,11 +72,19 @@ public struct PublicStruct {
 // SAFETY-PRIVATE: Serialization safety, safe: 'inlinableFunc()'
     public func publicFunc() {}
 // SAFETY-PRIVATE: Serialization safety, safe: 'publicFunc()'
-@available(SwiftStdlib 5.1, *) // for the `some` keyword.
+
+    @available(SwiftStdlib 5.1, *) // for the `some` keyword.
     public func opaqueTypeFunc() -> some PublicProto {
+// SAFETY-PRIVATE: Serialization safety, safe: 'opaqueTypeFunc()'
         return InternalStruct()
     }
-// SAFETY-PRIVATE: Serialization safety, safe: 'opaqueTypeFunc()'
+
+    @available(SwiftStdlib 5.1, *) // for the `some` keyword.
+    internal func opaqueFuncInternal() -> some PublicProto {
+// SAFETY-PRIVATE: Serialization safety, unsafe: 'opaqueFuncInternal()'
+        return InternalStruct()
+    }
+
     internal func internalFunc() {}
 // SAFETY-INTERNAL: Serialization safety, unsafe: 'internalFunc()'
 // NO-SAFETY-INTERNAL: Serialization safety, safe: 'internalFunc()'