AST: Return a SemanticAvailableAttr from Decl::getNoAsyncAttr().

Author: tshortli

include/swift/AST/Attr.h

@@ -3189,13 +3189,19 @@ class SemanticAvailableAttr final {
   const AvailableAttr *getParsedAttr() const { return attr; }
   const AvailabilityDomain getDomain() const { return domain; }
 
+  /// Returns the `message:` field of the attribute, or an empty string.
+  StringRef getMessage() const { return attr->Message; }
+
+  /// Returns the `rename:` field of the attribute, or an empty string.
+  StringRef getRename() const { return attr->Rename; }
+
   /// Returns the platform kind that the attribute applies to, or
   /// `PlatformKind::none` if the attribute is not platform specific.
   bool isPlatformSpecific() const { return getDomain().isPlatform(); }
 
   /// Returns the platform kind that the attribute applies to, or
   /// `PlatformKind::none` if the attribute is not platform specific.
-  PlatformKind getPlatformKind() const { return getDomain().getPlatformKind(); }
+  PlatformKind getPlatform() const { return getDomain().getPlatformKind(); }
 
   /// Whether this is a `noasync` attribute.
   bool isNoAsync() const { return attr->isNoAsync(); }

include/swift/AST/Decl.h

@@ -1428,7 +1428,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
 
   /// Returns the first @available attribute that indicates this decl is
   /// unavailable from asynchronous contexts, or `nullptr` otherwise.
-  const AvailableAttr *getNoAsyncAttr() const;
+  std::optional<SemanticAvailableAttr> getNoAsyncAttr() const;
 
   /// Returns true if the decl has been marked unavailable in the Swift language
   /// version that is currently active.

lib/AST/Availability.cpp

@@ -581,33 +581,26 @@ const AvailableAttr *Decl::getSoftDeprecatedAttr() const {
   return result;
 }
 
-const AvailableAttr *Decl::getNoAsyncAttr() const {
-  const AvailableAttr *bestAttr = nullptr;
+std::optional<SemanticAvailableAttr> Decl::getNoAsyncAttr() const {
+  std::optional<SemanticAvailableAttr> bestAttr;
 
-  for (auto semanticAttr :
-       getSemanticAvailableAttrs(/*includingInactive=*/false)) {
-    auto attr = semanticAttr.getParsedAttr();
-
-    if (!semanticAttr.isNoAsync())
+  for (auto attr : getSemanticAvailableAttrs(/*includingInactive=*/false)) {
+    if (!attr.isNoAsync())
       continue;
 
     if (!bestAttr) {
-      bestAttr = attr;
-      continue;
-    }
-
-    if (!bestAttr) {
-      // If there is no best attr selected  and the attr either has an active
+      // If there is no best attr selected and the attr either has an active
       // platform, or doesn't have one at all, select it.
-      bestAttr = attr;
-    } else if (bestAttr && attr->hasPlatform() && bestAttr->hasPlatform() &&
-               inheritsAvailabilityFromPlatform(attr->getPlatform(),
+      bestAttr.emplace(attr);
+    } else if (bestAttr && attr.isPlatformSpecific() &&
+               bestAttr->isPlatformSpecific() &&
+               inheritsAvailabilityFromPlatform(attr.getPlatform(),
                                                 bestAttr->getPlatform())) {
       // if they both have a viable platform, use the better one
-      bestAttr = attr;
-    } else if (attr->hasPlatform() && !bestAttr->hasPlatform()) {
+      bestAttr.emplace(attr);
+    } else if (attr.isPlatformSpecific() && !bestAttr->isPlatformSpecific()) {
       // Use the one more specific
-      bestAttr = attr;
+      bestAttr.emplace(attr);
     }
   }
   return bestAttr;

lib/Sema/TypeCheckAvailability.cpp

@@ -4201,14 +4201,14 @@ diagnoseDeclAsyncAvailability(const ValueDecl *D, SourceRange R,
   }
 
   // @available(noasync) spelling
-  if (const AvailableAttr *attr = D->getNoAsyncAttr()) {
+  if (auto attr = D->getNoAsyncAttr()) {
     SourceLoc diagLoc = call ? call->getLoc() : R.Start;
-    auto diag = ctx.Diags.diagnose(diagLoc, diag::async_unavailable_decl,
-                                   D, attr->Message);
+    auto diag = ctx.Diags.diagnose(diagLoc, diag::async_unavailable_decl, D,
+                                   attr->getMessage());
     diag.warnUntilSwiftVersion(6);
 
-    if (!attr->Rename.empty()) {
-      fixItAvailableAttrRename(diag, R, D, attr, call);
+    if (!attr->getRename().empty()) {
+      fixItAvailableAttrRename(diag, R, D, attr->getParsedAttr(), call);
     }
     return true;
   }