diff --git a/clang/include/clang/AST/ASTImporter.h b/clang/include/clang/AST/ASTImporter.h
--- a/clang/include/clang/AST/ASTImporter.h
+++ b/clang/include/clang/AST/ASTImporter.h
@@ -183,7 +183,7 @@
     /// \return Error information (success or error).
     template <typename ImportT>
     LLVM_NODISCARD llvm::Error importInto(ImportT &To, const ImportT &From) {
-      auto ToOrErr = Import_New(From);
+      auto ToOrErr = Import(From);
       if (ToOrErr)
         To = *ToOrErr;
       return ToOrErr.takeError();
@@ -193,40 +193,29 @@
     /// context. A null type is imported as a null type (no error).
     ///
     /// \returns The equivalent type in the "to" context, or the import error.
-    llvm::Expected<QualType> Import_New(QualType FromT);
-    // FIXME: Remove this version.
-    QualType Import(QualType FromT);
+    llvm::Expected<QualType> Import(QualType FromT);
 
     /// Import the given type source information from the
     /// "from" context into the "to" context.
     ///
     /// \returns The equivalent type source information in the "to"
     /// context, or the import error.
-    llvm::Expected<TypeSourceInfo *> Import_New(TypeSourceInfo *FromTSI);
-    // FIXME: Remove this version.
-    TypeSourceInfo *Import(TypeSourceInfo *FromTSI);
+    llvm::Expected<TypeSourceInfo *> Import(TypeSourceInfo *FromTSI);
 
     /// Import the given attribute from the "from" context into the
     /// "to" context.
     ///
     /// \returns The equivalent attribute in the "to" context, or the import
     /// error.
-    llvm::Expected<Attr *> Import_New(const Attr *FromAttr);
-    // FIXME: Remove this version.
-    Attr *Import(const Attr *FromAttr);
+    llvm::Expected<Attr *> Import(const Attr *FromAttr);
 
     /// Import the given declaration from the "from" context into the
     /// "to" context.
     ///
     /// \returns The equivalent declaration in the "to" context, or the import
     /// error.
-    llvm::Expected<Decl *> Import_New(Decl *FromD);
-    llvm::Expected<const Decl *> Import_New(const Decl *FromD) {
-      return Import_New(const_cast<Decl *>(FromD));
-    }
-    // FIXME: Remove this version.
-    Decl *Import(Decl *FromD);
-    Decl *Import(const Decl *FromD) {
+    llvm::Expected<Decl *> Import(Decl *FromD);
+    llvm::Expected<const Decl *> Import(const Decl *FromD) {
       return Import(const_cast<Decl *>(FromD));
     }
 
@@ -251,28 +240,21 @@
     ///
     /// \returns The equivalent expression in the "to" context, or the import
     /// error.
-    llvm::Expected<Expr *> Import_New(Expr *FromE);
-    // FIXME: Remove this version.
-    Expr *Import(Expr *FromE);
+    llvm::Expected<Expr *> Import(Expr *FromE);
 
     /// Import the given statement from the "from" context into the
     /// "to" context.
     ///
     /// \returns The equivalent statement in the "to" context, or the import
     /// error.
-    llvm::Expected<Stmt *> Import_New(Stmt *FromS);
-    // FIXME: Remove this version.
-    Stmt *Import(Stmt *FromS);
+    llvm::Expected<Stmt *> Import(Stmt *FromS);
 
     /// Import the given nested-name-specifier from the "from"
     /// context into the "to" context.
     ///
     /// \returns The equivalent nested-name-specifier in the "to"
     /// context, or the import error.
-    llvm::Expected<NestedNameSpecifier *>
-    Import_New(NestedNameSpecifier *FromNNS);
-    // FIXME: Remove this version.
-    NestedNameSpecifier *Import(NestedNameSpecifier *FromNNS);
+    llvm::Expected<NestedNameSpecifier *> Import(NestedNameSpecifier *FromNNS);
 
     /// Import the given nested-name-specifier-loc from the "from"
     /// context into the "to" context.
@@ -280,42 +262,32 @@
     /// \returns The equivalent nested-name-specifier-loc in the "to"
     /// context, or the import error.
     llvm::Expected<NestedNameSpecifierLoc>
-    Import_New(NestedNameSpecifierLoc FromNNS);
-    // FIXME: Remove this version.
-    NestedNameSpecifierLoc Import(NestedNameSpecifierLoc FromNNS);
+    Import(NestedNameSpecifierLoc FromNNS);
 
     /// Import the given template name from the "from" context into the
     /// "to" context, or the import error.
-    llvm::Expected<TemplateName> Import_New(TemplateName From);
-    // FIXME: Remove this version.
-    TemplateName Import(TemplateName From);
+    llvm::Expected<TemplateName> Import(TemplateName From);
 
     /// Import the given source location from the "from" context into
     /// the "to" context.
     ///
     /// \returns The equivalent source location in the "to" context, or the
     /// import error.
-    llvm::Expected<SourceLocation> Import_New(SourceLocation FromLoc);
-    // FIXME: Remove this version.
-    SourceLocation Import(SourceLocation FromLoc);
+    llvm::Expected<SourceLocation> Import(SourceLocation FromLoc);
 
     /// Import the given source range from the "from" context into
     /// the "to" context.
     ///
     /// \returns The equivalent source range in the "to" context, or the import
     /// error.
-    llvm::Expected<SourceRange> Import_New(SourceRange FromRange);
-    // FIXME: Remove this version.
-    SourceRange Import(SourceRange FromRange);
+    llvm::Expected<SourceRange> Import(SourceRange FromRange);
 
     /// Import the given declaration name from the "from"
     /// context into the "to" context.
     ///
     /// \returns The equivalent declaration name in the "to" context, or the
     /// import error.
-    llvm::Expected<DeclarationName> Import_New(DeclarationName FromName);
-    // FIXME: Remove this version.
-    DeclarationName Import(DeclarationName FromName);
+    llvm::Expected<DeclarationName> Import(DeclarationName FromName);
 
     /// Import the given identifier from the "from" context
     /// into the "to" context.
@@ -329,46 +301,32 @@
     ///
     /// \returns The equivalent selector in the "to" context, or the import
     /// error.
-    llvm::Expected<Selector> Import_New(Selector FromSel);
-    // FIXME: Remove this version.
-    Selector Import(Selector FromSel);
+    llvm::Expected<Selector> Import(Selector FromSel);
 
     /// Import the given file ID from the "from" context into the
     /// "to" context.
     ///
     /// \returns The equivalent file ID in the source manager of the "to"
     /// context, or the import error.
-    llvm::Expected<FileID> Import_New(FileID, bool IsBuiltin = false);
-    // FIXME: Remove this version.
-    FileID Import(FileID, bool IsBuiltin = false);
+    llvm::Expected<FileID> Import(FileID, bool IsBuiltin = false);
 
     /// Import the given C++ constructor initializer from the "from"
     /// context into the "to" context.
     ///
     /// \returns The equivalent initializer in the "to" context, or the import
     /// error.
-    llvm::Expected<CXXCtorInitializer *>
-    Import_New(CXXCtorInitializer *FromInit);
-    // FIXME: Remove this version.
-    CXXCtorInitializer *Import(CXXCtorInitializer *FromInit);
+    llvm::Expected<CXXCtorInitializer *> Import(CXXCtorInitializer *FromInit);
 
     /// Import the given CXXBaseSpecifier from the "from" context into
     /// the "to" context.
     ///
     /// \returns The equivalent CXXBaseSpecifier in the source manager of the
     /// "to" context, or the import error.
-    llvm::Expected<CXXBaseSpecifier *>
-    Import_New(const CXXBaseSpecifier *FromSpec);
-    // FIXME: Remove this version.
-    CXXBaseSpecifier *Import(const CXXBaseSpecifier *FromSpec);
+    llvm::Expected<CXXBaseSpecifier *> Import(const CXXBaseSpecifier *FromSpec);
 
     /// Import the definition of the given declaration, including all of
     /// the declarations it contains.
-    LLVM_NODISCARD llvm::Error ImportDefinition_New(Decl *From);
-
-    // FIXME: Compatibility function.
-    // Usages of this should be changed to ImportDefinition_New.
-    void ImportDefinition(Decl *From);
+    LLVM_NODISCARD llvm::Error ImportDefinition(Decl *From);
 
     /// Cope with a name conflict when importing a declaration into the
     /// given context.
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -148,7 +148,7 @@
     // Use this to import pointers of specific type.
     template <typename ImportT>
     LLVM_NODISCARD Error importInto(ImportT *&To, ImportT *From) {
-      auto ToOrErr = Importer.Import_New(From);
+      auto ToOrErr = Importer.Import(From);
       if (ToOrErr)
         To = cast_or_null<ImportT>(*ToOrErr);
       return ToOrErr.takeError();
@@ -158,7 +158,7 @@
     // cast the return value to `T`.
     template <typename T>
     Expected<T *> import(T *From) {
-      auto ToOrErr = Importer.Import_New(From);
+      auto ToOrErr = Importer.Import(From);
       if (!ToOrErr)
         return ToOrErr.takeError();
       return cast_or_null<T>(*ToOrErr);
@@ -172,7 +172,7 @@
     // Call the import function of ASTImporter for type `T`.
     template <typename T>
     Expected<T> import(const T &From) {
-      return Importer.Import_New(From);
+      return Importer.Import(From);
     }
 
     template <class T>
@@ -1671,7 +1671,7 @@
 static Error setTypedefNameForAnonDecl(TagDecl *From, TagDecl *To,
                                        ASTImporter &Importer) {
   if (TypedefNameDecl *FromTypedef = From->getTypedefNameForAnonDecl()) {
-    if (ExpectedDecl ToTypedefOrErr = Importer.Import_New(FromTypedef))
+    if (ExpectedDecl ToTypedefOrErr = Importer.Import(FromTypedef))
       To->setTypedefNameForAnonDecl(cast<TypedefNameDecl>(*ToTypedefOrErr));
     else
       return ToTypedefOrErr.takeError();
@@ -5033,13 +5033,19 @@
         Importer.MapImported(D, PrevDecl->getDefinition());
         // Import those default field initializers which have been
         // instantiated in the "From" context, but not in the "To" context.
-        for (auto *FromField : D->fields())
-          Importer.Import(FromField);
+        for (auto *FromField : D->fields()) {
+          auto ToOrErr = import(FromField);
+          if (!ToOrErr)
+            return ToOrErr.takeError();
+        }
 
         // Import those methods which have been instantiated in the
         // "From" context, but not in the "To" context.
-        for (CXXMethodDecl *FromM : D->methods())
-          Importer.Import(FromM);
+        for (CXXMethodDecl *FromM : D->methods()) {
+          auto ToOrErr = import(FromM);
+          if (!ToOrErr)
+            return ToOrErr.takeError();
+        }
 
         // TODO Import instantiated default arguments.
         // TODO Import instantiated exception specifications.
@@ -7666,7 +7672,7 @@
   AddToLookupTable(ToD);
 }
 
-Expected<QualType> ASTImporter::Import_New(QualType FromT) {
+Expected<QualType> ASTImporter::Import(QualType FromT) {
   if (FromT.isNull())
     return QualType{};
 
@@ -7689,56 +7695,32 @@
 
   return ToContext.getQualifiedType(*ToTOrErr, FromT.getLocalQualifiers());
 }
-QualType ASTImporter::Import(QualType From) {
-  llvm::Expected<QualType> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return {};
-}
 
-Expected<TypeSourceInfo *> ASTImporter::Import_New(TypeSourceInfo *FromTSI) {
+Expected<TypeSourceInfo *> ASTImporter::Import(TypeSourceInfo *FromTSI) {
   if (!FromTSI)
     return FromTSI;
 
   // FIXME: For now we just create a "trivial" type source info based
   // on the type and a single location. Implement a real version of this.
-  ExpectedType TOrErr = Import_New(FromTSI->getType());
+  ExpectedType TOrErr = Import(FromTSI->getType());
   if (!TOrErr)
     return TOrErr.takeError();
-  ExpectedSLoc BeginLocOrErr = Import_New(FromTSI->getTypeLoc().getBeginLoc());
+  ExpectedSLoc BeginLocOrErr = Import(FromTSI->getTypeLoc().getBeginLoc());
   if (!BeginLocOrErr)
     return BeginLocOrErr.takeError();
 
   return ToContext.getTrivialTypeSourceInfo(*TOrErr, *BeginLocOrErr);
 }
-TypeSourceInfo *ASTImporter::Import(TypeSourceInfo *From) {
-  llvm::Expected<TypeSourceInfo *> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return nullptr;
-}
 
-Expected<Attr *> ASTImporter::Import_New(const Attr *FromAttr) {
+Expected<Attr *> ASTImporter::Import(const Attr *FromAttr) {
   Attr *ToAttr = FromAttr->clone(ToContext);
-  if (auto ToRangeOrErr = Import_New(FromAttr->getRange()))
+  if (auto ToRangeOrErr = Import(FromAttr->getRange()))
     ToAttr->setRange(*ToRangeOrErr);
   else
     return ToRangeOrErr.takeError();
 
   return ToAttr;
 }
-Attr *ASTImporter::Import(const Attr *From) {
-  llvm::Expected<Attr *> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return nullptr;
-}
 
 Decl *ASTImporter::GetAlreadyImportedOrNull(const Decl *FromD) const {
   auto Pos = ImportedDecls.find(FromD);
@@ -7755,7 +7737,7 @@
   return FromDPos->second->getTranslationUnitDecl();
 }
 
-Expected<Decl *> ASTImporter::Import_New(Decl *FromD) {
+Expected<Decl *> ASTImporter::Import(Decl *FromD) {
   if (!FromD)
     return nullptr;
 
@@ -7794,20 +7776,12 @@
   updateFlags(FromD, ToD);
   return ToDOrErr;
 }
-Decl *ASTImporter::Import(Decl *From) {
-  llvm::Expected<Decl *> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return nullptr;
-}
 
 Expected<DeclContext *> ASTImporter::ImportContext(DeclContext *FromDC) {
   if (!FromDC)
     return FromDC;
 
-  ExpectedDecl ToDCOrErr = Import_New(cast<Decl>(FromDC));
+  ExpectedDecl ToDCOrErr = Import(cast<Decl>(FromDC));
   if (!ToDCOrErr)
     return ToDCOrErr.takeError();
   auto *ToDC = cast<DeclContext>(*ToDCOrErr);
@@ -7863,22 +7837,14 @@
   return ToDC;
 }
 
-Expected<Expr *> ASTImporter::Import_New(Expr *FromE) {
-  if (ExpectedStmt ToSOrErr = Import_New(cast_or_null<Stmt>(FromE)))
+Expected<Expr *> ASTImporter::Import(Expr *FromE) {
+  if (ExpectedStmt ToSOrErr = Import(cast_or_null<Stmt>(FromE)))
     return cast_or_null<Expr>(*ToSOrErr);
   else
     return ToSOrErr.takeError();
 }
-Expr *ASTImporter::Import(Expr *From) {
-  llvm::Expected<Expr *> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return nullptr;
-}
 
-Expected<Stmt *> ASTImporter::Import_New(Stmt *FromS) {
+Expected<Stmt *> ASTImporter::Import(Stmt *FromS) {
   if (!FromS)
     return nullptr;
 
@@ -7910,17 +7876,9 @@
   ImportedStmts[FromS] = *ToSOrErr;
   return ToSOrErr;
 }
-Stmt *ASTImporter::Import(Stmt *From) {
-  llvm::Expected<Stmt *> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return nullptr;
-}
 
 Expected<NestedNameSpecifier *>
-ASTImporter::Import_New(NestedNameSpecifier *FromNNS) {
+ASTImporter::Import(NestedNameSpecifier *FromNNS) {
   if (!FromNNS)
     return nullptr;
 
@@ -7935,14 +7893,14 @@
                                        Import(FromNNS->getAsIdentifier()));
 
   case NestedNameSpecifier::Namespace:
-    if (ExpectedDecl NSOrErr = Import_New(FromNNS->getAsNamespace())) {
+    if (ExpectedDecl NSOrErr = Import(FromNNS->getAsNamespace())) {
       return NestedNameSpecifier::Create(ToContext, Prefix,
                                          cast<NamespaceDecl>(*NSOrErr));
     } else
       return NSOrErr.takeError();
 
   case NestedNameSpecifier::NamespaceAlias:
-    if (ExpectedDecl NSADOrErr = Import_New(FromNNS->getAsNamespaceAlias()))
+    if (ExpectedDecl NSADOrErr = Import(FromNNS->getAsNamespaceAlias()))
       return NestedNameSpecifier::Create(ToContext, Prefix,
                                          cast<NamespaceAliasDecl>(*NSADOrErr));
     else
@@ -7952,7 +7910,7 @@
     return NestedNameSpecifier::GlobalSpecifier(ToContext);
 
   case NestedNameSpecifier::Super:
-    if (ExpectedDecl RDOrErr = Import_New(FromNNS->getAsRecordDecl()))
+    if (ExpectedDecl RDOrErr = Import(FromNNS->getAsRecordDecl()))
       return NestedNameSpecifier::SuperSpecifier(ToContext,
                                                  cast<CXXRecordDecl>(*RDOrErr));
     else
@@ -7961,7 +7919,7 @@
   case NestedNameSpecifier::TypeSpec:
   case NestedNameSpecifier::TypeSpecWithTemplate:
     if (Expected<QualType> TyOrErr =
-            Import_New(QualType(FromNNS->getAsType(), 0u))) {
+            Import(QualType(FromNNS->getAsType(), 0u))) {
       bool TSTemplate =
           FromNNS->getKind() == NestedNameSpecifier::TypeSpecWithTemplate;
       return NestedNameSpecifier::Create(ToContext, Prefix, TSTemplate,
@@ -7973,17 +7931,9 @@
 
   llvm_unreachable("Invalid nested name specifier kind");
 }
-NestedNameSpecifier *ASTImporter::Import(NestedNameSpecifier *From) {
-  llvm::Expected<NestedNameSpecifier *> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return nullptr;
-}
 
 Expected<NestedNameSpecifierLoc>
-ASTImporter::Import_New(NestedNameSpecifierLoc FromNNS) {
+ASTImporter::Import(NestedNameSpecifierLoc FromNNS) {
   // Copied from NestedNameSpecifier mostly.
   SmallVector<NestedNameSpecifierLoc , 8> NestedNames;
   NestedNameSpecifierLoc NNS = FromNNS;
@@ -8048,7 +7998,7 @@
       break;
 
     case NestedNameSpecifier::Super: {
-      auto ToSourceRangeOrErr = Import_New(NNS.getSourceRange());
+      auto ToSourceRangeOrErr = Import(NNS.getSourceRange());
       if (!ToSourceRangeOrErr)
         return ToSourceRangeOrErr.takeError();
 
@@ -8061,19 +8011,11 @@
 
   return Builder.getWithLocInContext(getToContext());
 }
-NestedNameSpecifierLoc ASTImporter::Import(NestedNameSpecifierLoc From) {
-  llvm::Expected<NestedNameSpecifierLoc> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return {};
-}
 
-Expected<TemplateName> ASTImporter::Import_New(TemplateName From) {
+Expected<TemplateName> ASTImporter::Import(TemplateName From) {
   switch (From.getKind()) {
   case TemplateName::Template:
-    if (ExpectedDecl ToTemplateOrErr = Import_New(From.getAsTemplateDecl()))
+    if (ExpectedDecl ToTemplateOrErr = Import(From.getAsTemplateDecl()))
       return TemplateName(cast<TemplateDecl>(*ToTemplateOrErr));
     else
       return ToTemplateOrErr.takeError();
@@ -8082,7 +8024,7 @@
     OverloadedTemplateStorage *FromStorage = From.getAsOverloadedTemplate();
     UnresolvedSet<2> ToTemplates;
     for (auto *I : *FromStorage) {
-      if (auto ToOrErr = Import_New(I))
+      if (auto ToOrErr = Import(I))
         ToTemplates.addDecl(cast<NamedDecl>(*ToOrErr));
       else
         return ToOrErr.takeError();
@@ -8093,11 +8035,11 @@
 
   case TemplateName::QualifiedTemplate: {
     QualifiedTemplateName *QTN = From.getAsQualifiedTemplateName();
-    auto QualifierOrErr = Import_New(QTN->getQualifier());
+    auto QualifierOrErr = Import(QTN->getQualifier());
     if (!QualifierOrErr)
       return QualifierOrErr.takeError();
 
-    if (ExpectedDecl ToTemplateOrErr = Import_New(From.getAsTemplateDecl()))
+    if (ExpectedDecl ToTemplateOrErr = Import(From.getAsTemplateDecl()))
       return ToContext.getQualifiedTemplateName(
           *QualifierOrErr, QTN->hasTemplateKeyword(),
           cast<TemplateDecl>(*ToTemplateOrErr));
@@ -8107,7 +8049,7 @@
 
   case TemplateName::DependentTemplate: {
     DependentTemplateName *DTN = From.getAsDependentTemplateName();
-    auto QualifierOrErr = Import_New(DTN->getQualifier());
+    auto QualifierOrErr = Import(DTN->getQualifier());
     if (!QualifierOrErr)
       return QualifierOrErr.takeError();
 
@@ -8123,11 +8065,11 @@
   case TemplateName::SubstTemplateTemplateParm: {
     SubstTemplateTemplateParmStorage *Subst =
         From.getAsSubstTemplateTemplateParm();
-    ExpectedDecl ParamOrErr = Import_New(Subst->getParameter());
+    ExpectedDecl ParamOrErr = Import(Subst->getParameter());
     if (!ParamOrErr)
       return ParamOrErr.takeError();
 
-    auto ReplacementOrErr = Import_New(Subst->getReplacement());
+    auto ReplacementOrErr = Import(Subst->getReplacement());
     if (!ReplacementOrErr)
       return ReplacementOrErr.takeError();
 
@@ -8138,7 +8080,7 @@
   case TemplateName::SubstTemplateTemplateParmPack: {
     SubstTemplateTemplateParmPackStorage *SubstPack
       = From.getAsSubstTemplateTemplateParmPack();
-    ExpectedDecl ParamOrErr = Import_New(SubstPack->getParameterPack());
+    ExpectedDecl ParamOrErr = Import(SubstPack->getParameterPack());
     if (!ParamOrErr)
       return ParamOrErr.takeError();
 
@@ -8155,16 +8097,8 @@
 
   llvm_unreachable("Invalid template name kind");
 }
-TemplateName ASTImporter::Import(TemplateName From) {
-  llvm::Expected<TemplateName> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return {};
-}
 
-Expected<SourceLocation> ASTImporter::Import_New(SourceLocation FromLoc) {
+Expected<SourceLocation> ASTImporter::Import(SourceLocation FromLoc) {
   if (FromLoc.isInvalid())
     return SourceLocation{};
 
@@ -8172,22 +8106,14 @@
   bool IsBuiltin = FromSM.isWrittenInBuiltinFile(FromLoc);
 
   std::pair<FileID, unsigned> Decomposed = FromSM.getDecomposedLoc(FromLoc);
-  Expected<FileID> ToFileIDOrErr = Import_New(Decomposed.first, IsBuiltin);
+  Expected<FileID> ToFileIDOrErr = Import(Decomposed.first, IsBuiltin);
   if (!ToFileIDOrErr)
     return ToFileIDOrErr.takeError();
   SourceManager &ToSM = ToContext.getSourceManager();
   return ToSM.getComposedLoc(*ToFileIDOrErr, Decomposed.second);
 }
-SourceLocation ASTImporter::Import(SourceLocation From) {
-  llvm::Expected<SourceLocation> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return {};
-}
 
-Expected<SourceRange> ASTImporter::Import_New(SourceRange FromRange) {
+Expected<SourceRange> ASTImporter::Import(SourceRange FromRange) {
   SourceLocation ToBegin, ToEnd;
   if (Error Err = importInto(ToBegin, FromRange.getBegin()))
     return std::move(Err);
@@ -8196,16 +8122,8 @@
 
   return SourceRange(ToBegin, ToEnd);
 }
-SourceRange ASTImporter::Import(SourceRange From) {
-  llvm::Expected<SourceRange> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return {};
-}
 
-Expected<FileID> ASTImporter::Import_New(FileID FromID, bool IsBuiltin) {
+Expected<FileID> ASTImporter::Import(FileID FromID, bool IsBuiltin) {
   llvm::DenseMap<FileID, FileID>::iterator Pos = ImportedFileIDs.find(FromID);
   if (Pos != ImportedFileIDs.end())
     return Pos->second;
@@ -8218,10 +8136,10 @@
   FileID ToID;
   if (FromSLoc.isExpansion()) {
     const SrcMgr::ExpansionInfo &FromEx = FromSLoc.getExpansion();
-    ExpectedSLoc ToSpLoc = Import_New(FromEx.getSpellingLoc());
+    ExpectedSLoc ToSpLoc = Import(FromEx.getSpellingLoc());
     if (!ToSpLoc)
       return ToSpLoc.takeError();
-    ExpectedSLoc ToExLocS = Import_New(FromEx.getExpansionLocStart());
+    ExpectedSLoc ToExLocS = Import(FromEx.getExpansionLocStart());
     if (!ToExLocS)
       return ToExLocS.takeError();
     unsigned TokenLen = FromSM.getFileIDSize(FromID);
@@ -8229,7 +8147,7 @@
     if (FromEx.isMacroArgExpansion()) {
       MLoc = ToSM.createMacroArgExpansionLoc(*ToSpLoc, *ToExLocS, TokenLen);
     } else {
-      if (ExpectedSLoc ToExLocE = Import_New(FromEx.getExpansionLocEnd()))
+      if (ExpectedSLoc ToExLocE = Import(FromEx.getExpansionLocEnd()))
         MLoc = ToSM.createExpansionLoc(*ToSpLoc, *ToExLocS, *ToExLocE, TokenLen,
                                        FromEx.isExpansionTokenRange());
       else
@@ -8241,8 +8159,7 @@
 
     if (!IsBuiltin) {
       // Include location of this file.
-      ExpectedSLoc ToIncludeLoc =
-          Import_New(FromSLoc.getFile().getIncludeLoc());
+      ExpectedSLoc ToIncludeLoc = Import(FromSLoc.getFile().getIncludeLoc());
       if (!ToIncludeLoc)
         return ToIncludeLoc.takeError();
 
@@ -8284,31 +8201,22 @@
   ImportedFileIDs[FromID] = ToID;
   return ToID;
 }
-FileID ASTImporter::Import(FileID From, bool IsBuiltin) {
-  llvm::Expected<FileID> To = Import_New(From, IsBuiltin);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return {};
-}
 
-Expected<CXXCtorInitializer *>
-ASTImporter::Import_New(CXXCtorInitializer *From) {
-  ExpectedExpr ToExprOrErr = Import_New(From->getInit());
+Expected<CXXCtorInitializer *> ASTImporter::Import(CXXCtorInitializer *From) {
+  ExpectedExpr ToExprOrErr = Import(From->getInit());
   if (!ToExprOrErr)
     return ToExprOrErr.takeError();
 
-  auto LParenLocOrErr = Import_New(From->getLParenLoc());
+  auto LParenLocOrErr = Import(From->getLParenLoc());
   if (!LParenLocOrErr)
     return LParenLocOrErr.takeError();
 
-  auto RParenLocOrErr = Import_New(From->getRParenLoc());
+  auto RParenLocOrErr = Import(From->getRParenLoc());
   if (!RParenLocOrErr)
     return RParenLocOrErr.takeError();
 
   if (From->isBaseInitializer()) {
-    auto ToTInfoOrErr = Import_New(From->getTypeSourceInfo());
+    auto ToTInfoOrErr = Import(From->getTypeSourceInfo());
     if (!ToTInfoOrErr)
       return ToTInfoOrErr.takeError();
 
@@ -8321,11 +8229,11 @@
         ToContext, *ToTInfoOrErr, From->isBaseVirtual(), *LParenLocOrErr,
         *ToExprOrErr, *RParenLocOrErr, EllipsisLoc);
   } else if (From->isMemberInitializer()) {
-    ExpectedDecl ToFieldOrErr = Import_New(From->getMember());
+    ExpectedDecl ToFieldOrErr = Import(From->getMember());
     if (!ToFieldOrErr)
       return ToFieldOrErr.takeError();
 
-    auto MemberLocOrErr = Import_New(From->getMemberLocation());
+    auto MemberLocOrErr = Import(From->getMemberLocation());
     if (!MemberLocOrErr)
       return MemberLocOrErr.takeError();
 
@@ -8333,11 +8241,11 @@
         ToContext, cast_or_null<FieldDecl>(*ToFieldOrErr), *MemberLocOrErr,
         *LParenLocOrErr, *ToExprOrErr, *RParenLocOrErr);
   } else if (From->isIndirectMemberInitializer()) {
-    ExpectedDecl ToIFieldOrErr = Import_New(From->getIndirectMember());
+    ExpectedDecl ToIFieldOrErr = Import(From->getIndirectMember());
     if (!ToIFieldOrErr)
       return ToIFieldOrErr.takeError();
 
-    auto MemberLocOrErr = Import_New(From->getMemberLocation());
+    auto MemberLocOrErr = Import(From->getMemberLocation());
     if (!MemberLocOrErr)
       return MemberLocOrErr.takeError();
 
@@ -8345,7 +8253,7 @@
         ToContext, cast_or_null<IndirectFieldDecl>(*ToIFieldOrErr),
         *MemberLocOrErr, *LParenLocOrErr, *ToExprOrErr, *RParenLocOrErr);
   } else if (From->isDelegatingInitializer()) {
-    auto ToTInfoOrErr = Import_New(From->getTypeSourceInfo());
+    auto ToTInfoOrErr = Import(From->getTypeSourceInfo());
     if (!ToTInfoOrErr)
       return ToTInfoOrErr.takeError();
 
@@ -8357,28 +8265,20 @@
     return make_error<ImportError>();
   }
 }
-CXXCtorInitializer *ASTImporter::Import(CXXCtorInitializer *From) {
-  llvm::Expected<CXXCtorInitializer *> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return nullptr;
-}
 
 Expected<CXXBaseSpecifier *>
-ASTImporter::Import_New(const CXXBaseSpecifier *BaseSpec) {
+ASTImporter::Import(const CXXBaseSpecifier *BaseSpec) {
   auto Pos = ImportedCXXBaseSpecifiers.find(BaseSpec);
   if (Pos != ImportedCXXBaseSpecifiers.end())
     return Pos->second;
 
-  Expected<SourceRange> ToSourceRange = Import_New(BaseSpec->getSourceRange());
+  Expected<SourceRange> ToSourceRange = Import(BaseSpec->getSourceRange());
   if (!ToSourceRange)
     return ToSourceRange.takeError();
-  Expected<TypeSourceInfo *> ToTSI = Import_New(BaseSpec->getTypeSourceInfo());
+  Expected<TypeSourceInfo *> ToTSI = Import(BaseSpec->getTypeSourceInfo());
   if (!ToTSI)
     return ToTSI.takeError();
-  ExpectedSLoc ToEllipsisLoc = Import_New(BaseSpec->getEllipsisLoc());
+  ExpectedSLoc ToEllipsisLoc = Import(BaseSpec->getEllipsisLoc());
   if (!ToEllipsisLoc)
     return ToEllipsisLoc.takeError();
   CXXBaseSpecifier *Imported = new (ToContext) CXXBaseSpecifier(
@@ -8387,19 +8287,12 @@
   ImportedCXXBaseSpecifiers[BaseSpec] = Imported;
   return Imported;
 }
-CXXBaseSpecifier *ASTImporter::Import(const CXXBaseSpecifier *From) {
-  llvm::Expected<CXXBaseSpecifier *> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return nullptr;
-}
 
-Error ASTImporter::ImportDefinition_New(Decl *From) {
-  Decl *To = Import(From);
-  if (!To)
-    return llvm::make_error<ImportError>();
+Error ASTImporter::ImportDefinition(Decl *From) {
+  ExpectedDecl ToOrErr = Import(From);
+  if (!ToOrErr)
+    return ToOrErr.takeError();
+  Decl *To = *ToOrErr;
 
   auto *FromDC = cast<DeclContext>(From);
   ASTNodeImporter Importer(*this);
@@ -8438,12 +8331,7 @@
   return Importer.ImportDeclContext(FromDC, true);
 }
 
-void ASTImporter::ImportDefinition(Decl *From) {
-  Error Err = ImportDefinition_New(From);
-  llvm::consumeError(std::move(Err));
-}
-
-Expected<DeclarationName> ASTImporter::Import_New(DeclarationName FromName) {
+Expected<DeclarationName> ASTImporter::Import(DeclarationName FromName) {
   if (!FromName)
     return DeclarationName{};
 
@@ -8454,13 +8342,13 @@
   case DeclarationName::ObjCZeroArgSelector:
   case DeclarationName::ObjCOneArgSelector:
   case DeclarationName::ObjCMultiArgSelector:
-    if (auto ToSelOrErr = Import_New(FromName.getObjCSelector()))
+    if (auto ToSelOrErr = Import(FromName.getObjCSelector()))
       return DeclarationName(*ToSelOrErr);
     else
       return ToSelOrErr.takeError();
 
   case DeclarationName::CXXConstructorName: {
-    if (auto ToTyOrErr = Import_New(FromName.getCXXNameType()))
+    if (auto ToTyOrErr = Import(FromName.getCXXNameType()))
       return ToContext.DeclarationNames.getCXXConstructorName(
           ToContext.getCanonicalType(*ToTyOrErr));
     else
@@ -8468,7 +8356,7 @@
   }
 
   case DeclarationName::CXXDestructorName: {
-    if (auto ToTyOrErr = Import_New(FromName.getCXXNameType()))
+    if (auto ToTyOrErr = Import(FromName.getCXXNameType()))
       return ToContext.DeclarationNames.getCXXDestructorName(
           ToContext.getCanonicalType(*ToTyOrErr));
     else
@@ -8476,8 +8364,7 @@
   }
 
   case DeclarationName::CXXDeductionGuideName: {
-    if (auto ToTemplateOrErr =
-            Import_New(FromName.getCXXDeductionGuideTemplate()))
+    if (auto ToTemplateOrErr = Import(FromName.getCXXDeductionGuideTemplate()))
       return ToContext.DeclarationNames.getCXXDeductionGuideName(
           cast<TemplateDecl>(*ToTemplateOrErr));
     else
@@ -8485,7 +8372,7 @@
   }
 
   case DeclarationName::CXXConversionFunctionName: {
-    if (auto ToTyOrErr = Import_New(FromName.getCXXNameType()))
+    if (auto ToTyOrErr = Import(FromName.getCXXNameType()))
       return ToContext.DeclarationNames.getCXXConversionFunctionName(
           ToContext.getCanonicalType(*ToTyOrErr));
     else
@@ -8507,14 +8394,6 @@
 
   llvm_unreachable("Invalid DeclarationName Kind!");
 }
-DeclarationName ASTImporter::Import(DeclarationName From) {
-  llvm::Expected<DeclarationName> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return {};
-}
 
 IdentifierInfo *ASTImporter::Import(const IdentifierInfo *FromId) {
   if (!FromId)
@@ -8528,7 +8407,7 @@
   return ToId;
 }
 
-Expected<Selector> ASTImporter::Import_New(Selector FromSel) {
+Expected<Selector> ASTImporter::Import(Selector FromSel) {
   if (FromSel.isNull())
     return Selector{};
 
@@ -8546,14 +8425,6 @@
                                                 unsigned NumDecls) {
   return Name;
 }
-Selector ASTImporter::Import(Selector From) {
-  llvm::Expected<Selector> To = Import_New(From);
-  if (To)
-    return *To;
-  else
-    llvm::consumeError(To.takeError());
-  return {};
-}
 
 DiagnosticBuilder ASTImporter::ToDiag(SourceLocation Loc, unsigned DiagID) {
   if (LastDiagFromFrom)
@@ -8609,7 +8480,7 @@
   llvm::DenseMap<const Type *, const Type *>::iterator Pos =
       ImportedTypes.find(From.getTypePtr());
   if (Pos != ImportedTypes.end()) {
-    if (ExpectedType ToFromOrErr = Import_New(From)) {
+    if (ExpectedType ToFromOrErr = Import(From)) {
       if (ToContext.hasSameType(*ToFromOrErr, To))
         return true;
     } else {
diff --git a/clang/lib/AST/ExternalASTMerger.cpp b/clang/lib/AST/ExternalASTMerger.cpp
--- a/clang/lib/AST/ExternalASTMerger.cpp
+++ b/clang/lib/AST/ExternalASTMerger.cpp
@@ -56,7 +56,7 @@
   }
   auto *ND = cast<NamedDecl>(DC);
   DeclarationName Name = ND->getDeclName();
-  auto SourceNameOrErr = ReverseImporter.Import_New(Name);
+  auto SourceNameOrErr = ReverseImporter.Import(Name);
   if (!SourceNameOrErr) {
     llvm::consumeError(SourceNameOrErr.takeError());
     return nullptr;
@@ -233,7 +233,7 @@
     if (!SourceTag->getDefinition())
       return false;
     Forward.MapImported(SourceTag, Tag);
-    if (llvm::Error Err = Forward.ImportDefinition_New(SourceTag))
+    if (llvm::Error Err = Forward.ImportDefinition(SourceTag))
       llvm::consumeError(std::move(Err));
     Tag->setCompleteDefinition(SourceTag->isCompleteDefinition());
     return true;
@@ -253,7 +253,7 @@
         if (!SourceInterface->getDefinition())
           return false;
         Forward.MapImported(SourceInterface, Interface);
-        if (llvm::Error Err = Forward.ImportDefinition_New(SourceInterface))
+        if (llvm::Error Err = Forward.ImportDefinition(SourceInterface))
           llvm::consumeError(std::move(Err));
         return true;
       });
@@ -360,7 +360,7 @@
 template <typename DeclTy>
 static bool importSpecializations(DeclTy *D, ASTImporter *Importer) {
   for (auto *Spec : D->specializations()) {
-    auto ImportedSpecOrError = Importer->Import_New(Spec);
+    auto ImportedSpecOrError = Importer->Import(Spec);
     if (!ImportedSpecOrError) {
       llvm::consumeError(ImportedSpecOrError.takeError());
       return true;
@@ -395,7 +395,7 @@
   ForEachMatchingDC(DC,
                     [&](ASTImporter &Forward, ASTImporter &Reverse,
                         Source<const DeclContext *> SourceDC) -> bool {
-                      auto FromNameOrErr = Reverse.Import_New(Name);
+                      auto FromNameOrErr = Reverse.Import(Name);
                       if (!FromNameOrErr) {
                         llvm::consumeError(FromNameOrErr.takeError());
                         return false;
@@ -415,7 +415,7 @@
   for (const Candidate &C : Candidates) {
     Decl *LookupRes = C.first.get();
     ASTImporter *Importer = C.second;
-    auto NDOrErr = Importer->Import_New(LookupRes);
+    auto NDOrErr = Importer->Import(LookupRes);
     assert(NDOrErr);
     (void)static_cast<bool>(NDOrErr);
     NamedDecl *ND = cast_or_null<NamedDecl>(*NDOrErr);
@@ -440,7 +440,7 @@
                             Source<const DeclContext *> SourceDC) -> bool {
     for (const Decl *SourceDecl : SourceDC.get()->decls()) {
       if (IsKindWeWant(SourceDecl->getKind())) {
-        auto ImportedDeclOrErr = Forward.Import_New(SourceDecl);
+        auto ImportedDeclOrErr = Forward.Import(SourceDecl);
         if (ImportedDeclOrErr)
           assert(!(*ImportedDeclOrErr) ||
                  IsSameDC((*ImportedDeclOrErr)->getDeclContext(), DC));
diff --git a/clang/lib/CrossTU/CrossTranslationUnit.cpp b/clang/lib/CrossTU/CrossTranslationUnit.cpp
--- a/clang/lib/CrossTU/CrossTranslationUnit.cpp
+++ b/clang/lib/CrossTU/CrossTranslationUnit.cpp
@@ -398,7 +398,7 @@
   assert(hasBodyOrInit(D) && "Decls to be imported should have body or init.");
 
   ASTImporter &Importer = getOrCreateASTImporter(D->getASTContext());
-  auto ToDeclOrError = Importer.Import_New(D);
+  auto ToDeclOrError = Importer.Import(D);
   if (!ToDeclOrError) {
     handleAllErrors(ToDeclOrError.takeError(),
                     [&](const ImportError &IE) {
diff --git a/clang/lib/Frontend/ASTMerge.cpp b/clang/lib/Frontend/ASTMerge.cpp
--- a/clang/lib/Frontend/ASTMerge.cpp
+++ b/clang/lib/Frontend/ASTMerge.cpp
@@ -65,7 +65,7 @@
           if (II->isStr("__va_list_tag") || II->isStr("__builtin_va_list"))
             continue;
 
-      llvm::Expected<Decl *> ToDOrError = Importer.Import_New(D);
+      llvm::Expected<Decl *> ToDOrError = Importer.Import(D);
 
       if (ToDOrError) {
         DeclGroupRef DGR(*ToDOrError);
diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -100,7 +100,7 @@
     createVirtualFileIfNeeded(To, FromFileName,
                               From->getBufferForFile(FromFileName));
 
-    auto Imported = Importer.Import_New(Node);
+    auto Imported = Importer.Import(Node);
 
     if (Imported) {
       // This should dump source locations and assert if some source locations
@@ -369,7 +369,7 @@
     Decl *import(ASTImporterLookupTable &LookupTable, ASTUnit *ToAST,
                  Decl *FromDecl) {
       lazyInitImporter(LookupTable, ToAST);
-      if (auto ImportedOrErr = Importer->Import_New(FromDecl))
+      if (auto ImportedOrErr = Importer->Import(FromDecl))
         return *ImportedOrErr;
       else {
         llvm::consumeError(ImportedOrErr.takeError());
@@ -380,7 +380,7 @@
     QualType import(ASTImporterLookupTable &LookupTable, ASTUnit *ToAST,
                     QualType FromType) {
       lazyInitImporter(LookupTable, ToAST);
-      if (auto ImportedOrErr = Importer->Import_New(FromType))
+      if (auto ImportedOrErr = Importer->Import(FromType))
         return *ImportedOrErr;
       else {
         llvm::consumeError(ImportedOrErr.takeError());
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
@@ -1968,7 +1968,14 @@
     return QualType();
   }
 
-  return merger.ImporterForOrigin(from_context).Import(type);
+  if (llvm::Expected<QualType> type_or_error =
+          merger.ImporterForOrigin(from_context).Import(type)) {
+    return *type_or_error;
+  } else {
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
+    LLDB_LOG_ERROR(log, type_or_error.takeError(), "Couldn't import type: {0}");
+    return QualType();
+  }
 }
 
 clang::Decl *ClangASTSource::CopyDecl(Decl *src_decl) {
@@ -1981,7 +1988,16 @@
       return nullptr;
     }
 
-    return m_merger_up->ImporterForOrigin(from_context).Import(src_decl);
+    if (llvm::Expected<Decl *> decl_or_error =
+            m_merger_up->ImporterForOrigin(from_context).Import(src_decl)) {
+      return *decl_or_error;
+    } else {
+      Log *log =
+          lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
+      LLDB_LOG_ERROR(log, decl_or_error.takeError(),
+                     "Couldn't import decl: {0}");
+      return nullptr;
+    }
   } else {
     lldbassert(0 && "No mechanism for copying a decl!");
     return nullptr;
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
@@ -272,9 +272,15 @@
   merger.AddSources(importer_source);
   clang::ASTImporter &exporter = merger.ImporterForOrigin(source);
   CompleteAllDeclContexts(exporter, file, root);
-  clang::QualType ret = exporter.Import(root);
+  llvm::Expected<clang::QualType> ret_or_error = exporter.Import(root);
   merger.RemoveSources(importer_source);
-  return ret;
+  if (ret_or_error) {
+    return *ret_or_error;
+  } else {
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
+    LLDB_LOG_ERROR(log, ret_or_error.takeError(), "Couldn't import type: {0}");
+    return clang::QualType();
+  }
 }
 
 TypeFromUser ClangExpressionDeclMap::DeportType(ClangASTContext &target,
diff --git a/lldb/source/Symbol/ClangASTContext.cpp b/lldb/source/Symbol/ClangASTContext.cpp
--- a/lldb/source/Symbol/ClangASTContext.cpp
+++ b/lldb/source/Symbol/ClangASTContext.cpp
@@ -1415,7 +1415,14 @@
   FileManager file_manager(file_system_options);
   ASTImporter importer(*dst_ast, file_manager, *src_ast, file_manager, false);
 
-  return importer.Import(source_decl);
+  if (llvm::Expected<clang::Decl *> ret_or_error =
+          importer.Import(source_decl)) {
+    return *ret_or_error;
+  } else {
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
+    LLDB_LOG_ERROR(log, ret_or_error.takeError(), "Couldn't import decl: {0}");
+    return nullptr;
+  }
 }
 
 bool ClangASTContext::AreTypesSame(CompilerType type1, CompilerType type2,
diff --git a/lldb/source/Symbol/ClangASTImporter.cpp b/lldb/source/Symbol/ClangASTImporter.cpp
--- a/lldb/source/Symbol/ClangASTImporter.cpp
+++ b/lldb/source/Symbol/ClangASTImporter.cpp
@@ -62,10 +62,18 @@
 
   ASTImporterDelegate::CxxModuleScope std_scope(*delegate_sp, dst_ast);
 
-  if (delegate_sp)
-    return delegate_sp->Import(type);
-
-  return QualType();
+  if (!delegate_sp)
+    return QualType();
+
+  llvm::Expected<QualType> ret_or_error = delegate_sp->Import(type);
+  if (!ret_or_error) {
+    Log *log =
+      lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
+    LLDB_LOG_ERROR(log, ret_or_error.takeError(),
+        "Couldn't import type: {0}");
+    return QualType();
+  }
+  return *ret_or_error;
 }
 
 lldb::opaque_compiler_type_t
@@ -105,34 +113,33 @@
 
   ASTImporterDelegate::CxxModuleScope std_scope(*delegate_sp, dst_ast);
 
-  if (delegate_sp) {
-    clang::Decl *result = delegate_sp->Import(decl);
-
-    if (!result) {
-      Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
+  if (!delegate_sp)
+    return nullptr;
 
-      if (log) {
-        lldb::user_id_t user_id = LLDB_INVALID_UID;
-        ClangASTMetadata *metadata = GetDeclMetadata(decl);
-        if (metadata)
-          user_id = metadata->GetUserID();
-
-        if (NamedDecl *named_decl = dyn_cast<NamedDecl>(decl))
-          log->Printf("  [ClangASTImporter] WARNING: Failed to import a %s "
-                      "'%s', metadata 0x%" PRIx64,
-                      decl->getDeclKindName(),
-                      named_decl->getNameAsString().c_str(), user_id);
-        else
-          log->Printf("  [ClangASTImporter] WARNING: Failed to import a %s, "
-                      "metadata 0x%" PRIx64,
-                      decl->getDeclKindName(), user_id);
-      }
+  llvm::Expected<clang::Decl *> result = delegate_sp->Import(decl);
+  if (!result) {
+    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
+    LLDB_LOG_ERROR(log, result.takeError(), "Couldn't import decl: {0}");
+    if (log) {
+      lldb::user_id_t user_id = LLDB_INVALID_UID;
+      ClangASTMetadata *metadata = GetDeclMetadata(decl);
+      if (metadata)
+        user_id = metadata->GetUserID();
+
+      if (NamedDecl *named_decl = dyn_cast<NamedDecl>(decl))
+        log->Printf("  [ClangASTImporter] WARNING: Failed to import a %s "
+                    "'%s', metadata 0x%" PRIx64,
+                    decl->getDeclKindName(),
+                    named_decl->getNameAsString().c_str(), user_id);
+      else
+        log->Printf("  [ClangASTImporter] WARNING: Failed to import a %s, "
+                    "metadata 0x%" PRIx64,
+                    decl->getDeclKindName(), user_id);
     }
-
-    return result;
+    return nullptr;
   }
 
-  return nullptr;
+  return *result;
 }
 
 class DeclContextOverride {
@@ -624,6 +631,8 @@
   if (!RequireCompleteType(type))
     return false;
 
+  Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
+
   if (const TagType *tag_type = type->getAs<TagType>()) {
     TagDecl *tag_decl = tag_type->getDecl();
 
@@ -641,7 +650,12 @@
     TagDecl *origin_tag_decl = llvm::dyn_cast<TagDecl>(decl_origin.decl);
 
     for (Decl *origin_child_decl : origin_tag_decl->decls()) {
-      delegate_sp->Import(origin_child_decl);
+      llvm::Expected<Decl *> imported_or_err =
+          delegate_sp->Import(origin_child_decl);
+      if (!imported_or_err)
+        // FIXME return with false?
+        LLDB_LOG_ERROR(log, imported_or_err.takeError(),
+                       "Couldn't import decl: {0}");
     }
 
     if (RecordDecl *record_decl = dyn_cast<RecordDecl>(origin_tag_decl)) {
@@ -666,7 +680,12 @@
           llvm::dyn_cast<ObjCInterfaceDecl>(decl_origin.decl);
 
       for (Decl *origin_child_decl : origin_interface_decl->decls()) {
-        delegate_sp->Import(origin_child_decl);
+        llvm::Expected<Decl *> imported_or_err =
+            delegate_sp->Import(origin_child_decl);
+        if (!imported_or_err)
+          // FIXME return with false?
+          LLDB_LOG_ERROR(log, imported_or_err.takeError(),
+                         "Couldn't import decl: {0}");
       }
 
       return true;
@@ -919,7 +938,13 @@
       to_cxx_record->startDefinition();
   */
 
-  ImportDefinition(from);
+  Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
+
+  if (llvm::Error err = ImportDefinition(from)) {
+    LLDB_LOG_ERROR(log, std::move(err),
+                   "[ClangASTImporter] Error during importing definition: {0}");
+    return;
+  }
 
   if (clang::TagDecl *to_tag = dyn_cast<clang::TagDecl>(to)) {
     if (clang::TagDecl *from_tag = dyn_cast<clang::TagDecl>(from)) {
@@ -949,13 +974,17 @@
       if (!from_superclass)
         break;
 
-      Decl *imported_from_superclass_decl = Import(from_superclass);
+      llvm::Expected<Decl *> imported_from_superclass_decl =
+          Import(from_superclass);
 
-      if (!imported_from_superclass_decl)
+      if (!imported_from_superclass_decl) {
+        LLDB_LOG_ERROR(log, imported_from_superclass_decl.takeError(),
+                       "Couldn't import decl: {0}");
         break;
+      }
 
       ObjCInterfaceDecl *imported_from_superclass =
-          dyn_cast<ObjCInterfaceDecl>(imported_from_superclass_decl);
+          dyn_cast<ObjCInterfaceDecl>(*imported_from_superclass_decl);
 
       if (!imported_from_superclass)
         break;
diff --git a/lldb/source/Symbol/CxxModuleHandler.cpp b/lldb/source/Symbol/CxxModuleHandler.cpp
--- a/lldb/source/Symbol/CxxModuleHandler.cpp
+++ b/lldb/source/Symbol/CxxModuleHandler.cpp
@@ -9,6 +9,7 @@
 #include "lldb/Symbol/CxxModuleHandler.h"
 
 #include "lldb/Symbol/ClangASTContext.h"
+#include "lldb/Utility/Log.h"
 #include "clang/Sema/Lookup.h"
 #include "llvm/Support/Error.h"
 
@@ -214,13 +215,15 @@
   // Import the foreign template arguments.
   llvm::SmallVector<TemplateArgument, 4> imported_args;
 
+  Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
+
   // If this logic is changed, also update templateArgsAreSupported.
   for (const TemplateArgument &arg : foreign_args.asArray()) {
     switch (arg.getKind()) {
     case TemplateArgument::Type: {
-      llvm::Expected<QualType> type = m_importer->Import_New(arg.getAsType());
+      llvm::Expected<QualType> type = m_importer->Import(arg.getAsType());
       if (!type) {
-        llvm::consumeError(type.takeError());
+        LLDB_LOG_ERROR(log, type.takeError(), "Couldn't import type: {0}");
         return {};
       }
       imported_args.push_back(TemplateArgument(*type));
@@ -229,9 +232,9 @@
     case TemplateArgument::Integral: {
       llvm::APSInt integral = arg.getAsIntegral();
       llvm::Expected<QualType> type =
-          m_importer->Import_New(arg.getIntegralType());
+          m_importer->Import(arg.getIntegralType());
       if (!type) {
-        llvm::consumeError(type.takeError());
+        LLDB_LOG_ERROR(log, type.takeError(), "Couldn't import type: {0}");
         return {};
       }
       imported_args.push_back(