[clang] [Clang] Explain why a type trait evaluated to false. (PR #141238)

[Erich Keane via cfe-commits]

================
@@ -5590,69 +5590,8 @@ static bool isTriviallyEqualityComparableType(Sema &S, QualType Type, SourceLoca
       CanonicalType, /*CheckIfTriviallyCopyable=*/false);
 }
 
-static bool IsCXXTriviallyRelocatableType(Sema &S, const CXXRecordDecl *RD) {
-  if (std::optional<ASTContext::CXXRecordDeclRelocationInfo> Info =
-          S.getASTContext().getRelocationInfoForCXXRecord(RD))
-    return Info->IsRelocatable;
-  ASTContext::CXXRecordDeclRelocationInfo Info =
-      S.CheckCXX2CRelocatableAndReplaceable(RD);
-  S.getASTContext().setRelocationInfoForCXXRecord(RD, Info);
-  return Info.IsRelocatable;
-}
-
-bool Sema::IsCXXTriviallyRelocatableType(QualType Type) {
-
-  QualType BaseElementType = getASTContext().getBaseElementType(Type);
-
-  if (Type->isVariableArrayType())
-    return false;
-
-  if (BaseElementType.hasNonTrivialObjCLifetime())
-    return false;
-
-  if (BaseElementType.hasAddressDiscriminatedPointerAuth())
-    return false;
-
-  if (BaseElementType->isIncompleteType())
-    return false;
-
-  if (BaseElementType->isScalarType() || BaseElementType->isVectorType())
-    return true;
-
-  if (const auto *RD = BaseElementType->getAsCXXRecordDecl())
-    return ::IsCXXTriviallyRelocatableType(*this, RD);
-
-  return false;
-}
-
-static bool IsCXXReplaceableType(Sema &S, const CXXRecordDecl *RD) {
-  if (std::optional<ASTContext::CXXRecordDeclRelocationInfo> Info =
-          S.getASTContext().getRelocationInfoForCXXRecord(RD))
-    return Info->IsReplaceable;
-  ASTContext::CXXRecordDeclRelocationInfo Info =
-      S.CheckCXX2CRelocatableAndReplaceable(RD);
-  S.getASTContext().setRelocationInfoForCXXRecord(RD, Info);
-  return Info.IsReplaceable;
-}
-
-bool Sema::IsCXXReplaceableType(QualType Type) {
-  if (Type.isConstQualified() || Type.isVolatileQualified())
-    return false;
-
-  if (Type->isVariableArrayType())
-    return false;
-
-  QualType BaseElementType =
-      getASTContext().getBaseElementType(Type.getUnqualifiedType());
-  if (BaseElementType->isIncompleteType())
-    return false;
-  if (BaseElementType->isScalarType())
-    return true;
-  if (const auto *RD = BaseElementType->getAsCXXRecordDecl())
-    return ::IsCXXReplaceableType(*this, RD);
-  return false;
-}
-
+// FIXME : Move the type traits logic to SemaTypeTraits.h
----------------
erichkeane wrote:

There is no such file though?  its a little sad to not have this done here.

https://github.com/llvm/llvm-project/pull/141238