[clang] [APINotes] Upstream Sema logic to apply API Notes to decls (PR #73017)

[Egor Zhdan via cfe-commits]

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@@ -7539,74 +7559,65 @@ static NullabilityKind mapNullabilityAttrKind(ParsedAttr::Kind kind) {
   }
 }
 
-/// Applies a nullability type specifier to the given type, if possible.
-///
-/// \param state The type processing state.
-///
-/// \param type The type to which the nullability specifier will be
-/// added. On success, this type will be updated appropriately.
-///
-/// \param attr The attribute as written on the type.
-///
-/// \param allowOnArrayType Whether to accept nullability specifiers on an
-/// array type (e.g., because it will decay to a pointer).
-///
-/// \returns true if a problem has been diagnosed, false on success.
-static bool checkNullabilityTypeSpecifier(TypeProcessingState &state,
-                                          QualType &type,
-                                          ParsedAttr &attr,
-                                          bool allowOnArrayType) {
-  Sema &S = state.getSema();
-
-  NullabilityKind nullability = mapNullabilityAttrKind(attr.getKind());
-  SourceLocation nullabilityLoc = attr.getLoc();
-  bool isContextSensitive = attr.isContextSensitiveKeywordAttribute();
-
-  recordNullabilitySeen(S, nullabilityLoc);
+static bool CheckNullabilityTypeSpecifier(
+    Sema &S, TypeProcessingState *State, ParsedAttr *PAttr, QualType &QT,
+    NullabilityKind Nullability, SourceLocation NullabilityLoc,
+    bool IsContextSensitive, bool AllowOnArrayType, bool OverrideExisting) {
+  bool Implicit = (State == nullptr);
+  if (!Implicit)
+    recordNullabilitySeen(S, NullabilityLoc);
 
   // Check for existing nullability attributes on the type.
-  QualType desugared = type;
-  while (auto attributed = dyn_cast<AttributedType>(desugared.getTypePtr())) {
+  QualType Desugared = QT;
+  while (auto Attributed = dyn_cast<AttributedType>(Desugared.getTypePtr())) {
     // Check whether there is already a null
-    if (auto existingNullability = attributed->getImmediateNullability()) {
+    if (auto ExistingNullability = Attributed->getImmediateNullability()) {
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egorzhdan wrote:

This is a `std::optional<NullabilityKind>`, it doesn't fit in one line. Would you still prefer an explicit type?

https://github.com/llvm/llvm-project/pull/73017