Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 546 insertions, 0 deletions

diff --git a/gnu/llvm/clang/lib/AST/ExternalASTMerger.cpp b/gnu/llvm/clang/lib/AST/ExternalASTMerger.cpp
new file mode 100644
index 00000000000..88bbe90a4e9
--- /dev/null
+++ b/gnu/llvm/clang/lib/AST/ExternalASTMerger.cpp
@@ -0,0 +1,546 @@
+//===- ExternalASTMerger.cpp - Merging External AST Interface ---*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the ExternalASTMerger, which vends a combination of
+//  ASTs from several different ASTContext/FileManager pairs
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/ExternalASTMerger.h"
+
+using namespace clang;
+
+namespace {
+
+template <typename T> struct Source {
+  T t;
+  Source(T t) : t(t) {}
+  operator T() { return t; }
+  template <typename U = T> U &get() { return t; }
+  template <typename U = T> const U &get() const { return t; }
+  template <typename U> operator Source<U>() { return Source<U>(t); }
+};
+
+typedef std::pair<Source<NamedDecl *>, ASTImporter *> Candidate;
+
+/// For the given DC, return the DC that is safe to perform lookups on.  This is
+/// the DC we actually want to work with most of the time.
+const DeclContext *CanonicalizeDC(const DeclContext *DC) {
+  if (isa<LinkageSpecDecl>(DC))
+    return DC->getRedeclContext();
+  return DC;
+}
+
+Source<const DeclContext *>
+LookupSameContext(Source<TranslationUnitDecl *> SourceTU, const DeclContext *DC,
+                  ASTImporter &ReverseImporter) {
+  DC = CanonicalizeDC(DC);
+  if (DC->isTranslationUnit()) {
+    return SourceTU;
+  }
+  Source<const DeclContext *> SourceParentDC =
+      LookupSameContext(SourceTU, DC->getParent(), ReverseImporter);
+  if (!SourceParentDC) {
+    // If we couldn't find the parent DC in this TranslationUnit, give up.
+    return nullptr;
+  }
+  auto *ND = cast<NamedDecl>(DC);
+  DeclarationName Name = ND->getDeclName();
+  auto SourceNameOrErr = ReverseImporter.Import(Name);
+  if (!SourceNameOrErr) {
+    llvm::consumeError(SourceNameOrErr.takeError());
+    return nullptr;
+  }
+  Source<DeclarationName> SourceName = *SourceNameOrErr;
+  DeclContext::lookup_result SearchResult =
+      SourceParentDC.get()->lookup(SourceName.get());
+  size_t SearchResultSize = SearchResult.size();
+  if (SearchResultSize == 0 || SearchResultSize > 1) {
+    // There are two cases here.  First, we might not find the name.
+    // We might also find multiple copies, in which case we have no
+    // guarantee that the one we wanted is the one we pick.  (E.g.,
+    // if we have two specializations of the same template it is
+    // very hard to determine which is the one you want.)
+    //
+    // The Origins map fixes this problem by allowing the origin to be
+    // explicitly recorded, so we trigger that recording by returning
+    // nothing (rather than a possibly-inaccurate guess) here.
+    return nullptr;
+  } else {
+    NamedDecl *SearchResultDecl = SearchResult[0];
+    if (isa<DeclContext>(SearchResultDecl) &&
+        SearchResultDecl->getKind() == DC->getDeclKind())
+      return cast<DeclContext>(SearchResultDecl)->getPrimaryContext();
+    return nullptr; // This type of lookup is unsupported
+  }
+}
+
+/// A custom implementation of ASTImporter, for ExternalASTMerger's purposes.
+///
+/// There are several modifications:
+///
+/// - It enables lazy lookup (via the HasExternalLexicalStorage flag and a few
+///   others), which instructs Clang to refer to ExternalASTMerger.  Also, it
+///   forces MinimalImport to true, which is necessary to make this work.
+/// - It maintains a reverse importer for use with names.  This allows lookup of
+///   arbitrary names in the source context.
+/// - It updates the ExternalASTMerger's origin map as needed whenever a
+///   it sees a DeclContext.
+class LazyASTImporter : public ASTImporter {
+private:
+  ExternalASTMerger &Parent;
+  ASTImporter Reverse;
+  const ExternalASTMerger::OriginMap &FromOrigins;
+  /// @see ExternalASTMerger::ImporterSource::Temporary
+  bool TemporarySource;
+  /// Map of imported declarations back to the declarations they originated
+  /// from.
+  llvm::DenseMap<Decl *, Decl *> ToOrigin;
+  /// @see ExternalASTMerger::ImporterSource::Merger
+  ExternalASTMerger *SourceMerger;
+  llvm::raw_ostream &logs() { return Parent.logs(); }
+public:
+  LazyASTImporter(ExternalASTMerger &_Parent, ASTContext &ToContext,
+                  FileManager &ToFileManager,
+                  const ExternalASTMerger::ImporterSource &S,
+                  std::shared_ptr<ASTImporterSharedState> SharedState)
+      : ASTImporter(ToContext, ToFileManager, S.getASTContext(),
+                    S.getFileManager(),
+                    /*MinimalImport=*/true, SharedState),
+        Parent(_Parent),
+        Reverse(S.getASTContext(), S.getFileManager(), ToContext, ToFileManager,
+                /*MinimalImport=*/true),
+        FromOrigins(S.getOriginMap()), TemporarySource(S.isTemporary()),
+        SourceMerger(S.getMerger()) {}
+
+  llvm::Expected<Decl *> ImportImpl(Decl *FromD) override {
+    if (!TemporarySource || !SourceMerger)
+      return ASTImporter::ImportImpl(FromD);
+
+    // If we get here, then this source is importing from a temporary ASTContext
+    // that also has another ExternalASTMerger attached. It could be
+    // possible that the current ExternalASTMerger and the temporary ASTContext
+    // share a common ImporterSource, which means that the temporary
+    // AST could contain declarations that were imported from a source
+    // that this ExternalASTMerger can access directly. Instead of importing
+    // such declarations from the temporary ASTContext, they should instead
+    // be directly imported by this ExternalASTMerger from the original
+    // source. This way the ExternalASTMerger can safely do a minimal import
+    // without creating incomplete declarations originated from a temporary
+    // ASTContext. If we would try to complete such declarations later on, we
+    // would fail to do so as their temporary AST could be deleted (which means
+    // that the missing parts of the minimally imported declaration in that
+    // ASTContext were also deleted).
+    //
+    // The following code tracks back any declaration that needs to be
+    // imported from the temporary ASTContext to a persistent ASTContext.
+    // Then the ExternalASTMerger tries to import from the persistent
+    // ASTContext directly by using the associated ASTImporter. If that
+    // succeeds, this ASTImporter just maps the declarations imported by
+    // the other (persistent) ASTImporter to this (temporary) ASTImporter.
+    // The steps can be visualized like this:
+    //
+    //  Target AST <--- 3. Indirect import --- Persistent AST
+    //       ^            of persistent decl        ^
+    //       |                                      |
+    // 1. Current import           2. Tracking back to persistent decl
+    // 4. Map persistent decl                       |
+    //  & pretend we imported.                      |
+    //       |                                      |
+    // Temporary AST -------------------------------'
+
+    // First, ask the ExternalASTMerger of the source where the temporary
+    // declaration originated from.
+    Decl *Persistent = SourceMerger->FindOriginalDecl(FromD);
+    // FromD isn't from a persistent AST, so just do a normal import.
+    if (!Persistent)
+      return ASTImporter::ImportImpl(FromD);
+    // Now ask the current ExternalASTMerger to try import the persistent
+    // declaration into the target.
+    ASTContext &PersistentCtx = Persistent->getASTContext();
+    ASTImporter &OtherImporter = Parent.ImporterForOrigin(PersistentCtx);
+    // Check that we never end up in the current Importer again.
+    assert((&PersistentCtx != &getFromContext()) && (&OtherImporter != this) &&
+           "Delegated to same Importer?");
+    auto DeclOrErr = OtherImporter.Import(Persistent);
+    // Errors when importing the persistent decl are treated as if we
+    // had errors with importing the temporary decl.
+    if (!DeclOrErr)
+      return DeclOrErr.takeError();
+    Decl *D = *DeclOrErr;
+    // Tell the current ASTImporter that this has already been imported
+    // to prevent any further queries for the temporary decl.
+    MapImported(FromD, D);
+    return D;
+  }
+
+  /// Implements the ASTImporter interface for tracking back a declaration
+  /// to its original declaration it came from.
+  Decl *GetOriginalDecl(Decl *To) override {
+    auto It = ToOrigin.find(To);
+    if (It != ToOrigin.end())
+      return It->second;
+    return nullptr;
+  }
+
+  /// Whenever a DeclContext is imported, ensure that ExternalASTSource's origin
+  /// map is kept up to date.  Also set the appropriate flags.
+  void Imported(Decl *From, Decl *To) override {
+    ToOrigin[To] = From;
+
+    if (auto *ToDC = dyn_cast<DeclContext>(To)) {
+      const bool LoggingEnabled = Parent.LoggingEnabled();
+      if (LoggingEnabled)
+        logs() << "(ExternalASTMerger*)" << (void*)&Parent
+               << " imported (DeclContext*)" << (void*)ToDC
+               << ", (ASTContext*)" << (void*)&getToContext()
+               << " from (DeclContext*)" << (void*)llvm::cast<DeclContext>(From)
+               << ", (ASTContext*)" << (void*)&getFromContext()
+               << "\n";
+      Source<DeclContext *> FromDC(
+          cast<DeclContext>(From)->getPrimaryContext());
+      if (FromOrigins.count(FromDC) &&
+          Parent.HasImporterForOrigin(*FromOrigins.at(FromDC).AST)) {
+        if (LoggingEnabled)
+          logs() << "(ExternalASTMerger*)" << (void*)&Parent
+                 << " forced origin (DeclContext*)"
+                 << (void*)FromOrigins.at(FromDC).DC
+                 << ", (ASTContext*)"
+                 << (void*)FromOrigins.at(FromDC).AST
+                 << "\n";
+        Parent.ForceRecordOrigin(ToDC, FromOrigins.at(FromDC));
+      } else {
+        if (LoggingEnabled)
+          logs() << "(ExternalASTMerger*)" << (void*)&Parent
+                 << " maybe recording origin (DeclContext*)" << (void*)FromDC
+                 << ", (ASTContext*)" << (void*)&getFromContext()
+                 << "\n";
+        Parent.MaybeRecordOrigin(ToDC, {FromDC, &getFromContext()});
+      }
+    }
+    if (auto *ToTag = dyn_cast<TagDecl>(To)) {
+      ToTag->setHasExternalLexicalStorage();
+      ToTag->getPrimaryContext()->setMustBuildLookupTable();
+      assert(Parent.CanComplete(ToTag));
+    } else if (auto *ToNamespace = dyn_cast<NamespaceDecl>(To)) {
+      ToNamespace->setHasExternalVisibleStorage();
+      assert(Parent.CanComplete(ToNamespace));
+    } else if (auto *ToContainer = dyn_cast<ObjCContainerDecl>(To)) {
+      ToContainer->setHasExternalLexicalStorage();
+      ToContainer->getPrimaryContext()->setMustBuildLookupTable();
+      assert(Parent.CanComplete(ToContainer));
+    }
+  }
+  ASTImporter &GetReverse() { return Reverse; }
+};
+
+bool HasDeclOfSameType(llvm::ArrayRef<Candidate> Decls, const Candidate &C) {
+  if (isa<FunctionDecl>(C.first.get()))
+    return false;
+  return llvm::any_of(Decls, [&](const Candidate &D) {
+    return C.first.get()->getKind() == D.first.get()->getKind();
+  });
+}
+
+} // end namespace
+
+ASTImporter &ExternalASTMerger::ImporterForOrigin(ASTContext &OriginContext) {
+  for (const std::unique_ptr<ASTImporter> &I : Importers)
+    if (&I->getFromContext() == &OriginContext)
+      return *I;
+  llvm_unreachable("We should have an importer for this origin!");
+}
+
+namespace {
+LazyASTImporter &LazyImporterForOrigin(ExternalASTMerger &Merger,
+                                   ASTContext &OriginContext) {
+  return static_cast<LazyASTImporter &>(
+      Merger.ImporterForOrigin(OriginContext));
+}
+}
+
+bool ExternalASTMerger::HasImporterForOrigin(ASTContext &OriginContext) {
+  for (const std::unique_ptr<ASTImporter> &I : Importers)
+    if (&I->getFromContext() == &OriginContext)
+      return true;
+  return false;
+}
+
+template <typename CallbackType>
+void ExternalASTMerger::ForEachMatchingDC(const DeclContext *DC,
+                                          CallbackType Callback) {
+  if (Origins.count(DC)) {
+    ExternalASTMerger::DCOrigin Origin = Origins[DC];
+    LazyASTImporter &Importer = LazyImporterForOrigin(*this, *Origin.AST);
+    Callback(Importer, Importer.GetReverse(), Origin.DC);
+  } else {
+    bool DidCallback = false;
+    for (const std::unique_ptr<ASTImporter> &Importer : Importers) {
+      Source<TranslationUnitDecl *> SourceTU =
+          Importer->getFromContext().getTranslationUnitDecl();
+      ASTImporter &Reverse =
+          static_cast<LazyASTImporter *>(Importer.get())->GetReverse();
+      if (auto SourceDC = LookupSameContext(SourceTU, DC, Reverse)) {
+        DidCallback = true;
+        if (Callback(*Importer, Reverse, SourceDC))
+          break;
+      }
+    }
+    if (!DidCallback && LoggingEnabled())
+      logs() << "(ExternalASTMerger*)" << (void*)this
+             << " asserting for (DeclContext*)" << (const void*)DC
+             << ", (ASTContext*)" << (void*)&Target.AST
+             << "\n";
+    assert(DidCallback && "Couldn't find a source context matching our DC");
+  }
+}
+
+void ExternalASTMerger::CompleteType(TagDecl *Tag) {
+  assert(Tag->hasExternalLexicalStorage());
+  ForEachMatchingDC(Tag, [&](ASTImporter &Forward, ASTImporter &Reverse,
+                             Source<const DeclContext *> SourceDC) -> bool {
+    auto *SourceTag = const_cast<TagDecl *>(cast<TagDecl>(SourceDC.get()));
+    if (SourceTag->hasExternalLexicalStorage())
+      SourceTag->getASTContext().getExternalSource()->CompleteType(SourceTag);
+    if (!SourceTag->getDefinition())
+      return false;
+    Forward.MapImported(SourceTag, Tag);
+    if (llvm::Error Err = Forward.ImportDefinition(SourceTag))
+      llvm::consumeError(std::move(Err));
+    Tag->setCompleteDefinition(SourceTag->isCompleteDefinition());
+    return true;
+  });
+}
+
+void ExternalASTMerger::CompleteType(ObjCInterfaceDecl *Interface) {
+  assert(Interface->hasExternalLexicalStorage());
+  ForEachMatchingDC(
+      Interface, [&](ASTImporter &Forward, ASTImporter &Reverse,
+                     Source<const DeclContext *> SourceDC) -> bool {
+        auto *SourceInterface = const_cast<ObjCInterfaceDecl *>(
+            cast<ObjCInterfaceDecl>(SourceDC.get()));
+        if (SourceInterface->hasExternalLexicalStorage())
+          SourceInterface->getASTContext().getExternalSource()->CompleteType(
+              SourceInterface);
+        if (!SourceInterface->getDefinition())
+          return false;
+        Forward.MapImported(SourceInterface, Interface);
+        if (llvm::Error Err = Forward.ImportDefinition(SourceInterface))
+          llvm::consumeError(std::move(Err));
+        return true;
+      });
+}
+
+bool ExternalASTMerger::CanComplete(DeclContext *Interface) {
+  assert(Interface->hasExternalLexicalStorage() ||
+         Interface->hasExternalVisibleStorage());
+  bool FoundMatchingDC = false;
+  ForEachMatchingDC(Interface,
+                    [&](ASTImporter &Forward, ASTImporter &Reverse,
+                        Source<const DeclContext *> SourceDC) -> bool {
+                      FoundMatchingDC = true;
+                      return true;
+                    });
+  return FoundMatchingDC;
+}
+
+namespace {
+bool IsSameDC(const DeclContext *D1, const DeclContext *D2) {
+  if (isa<ObjCContainerDecl>(D1) && isa<ObjCContainerDecl>(D2))
+    return true; // There are many cases where Objective-C is ambiguous.
+  if (auto *T1 = dyn_cast<TagDecl>(D1))
+    if (auto *T2 = dyn_cast<TagDecl>(D2))
+      if (T1->getFirstDecl() == T2->getFirstDecl())
+        return true;
+  return D1 == D2 || D1 == CanonicalizeDC(D2);
+}
+}
+
+void ExternalASTMerger::MaybeRecordOrigin(const DeclContext *ToDC,
+                                          DCOrigin Origin) {
+  LazyASTImporter &Importer = LazyImporterForOrigin(*this, *Origin.AST);
+  ASTImporter &Reverse = Importer.GetReverse();
+  Source<const DeclContext *> FoundFromDC =
+      LookupSameContext(Origin.AST->getTranslationUnitDecl(), ToDC, Reverse);
+  const bool DoRecord = !FoundFromDC || !IsSameDC(FoundFromDC.get(), Origin.DC);
+  if (DoRecord)
+    RecordOriginImpl(ToDC, Origin, Importer);
+  if (LoggingEnabled())
+    logs() << "(ExternalASTMerger*)" << (void*)this
+             << (DoRecord ? " decided " : " decided NOT")
+             << " to record origin (DeclContext*)" << (void*)Origin.DC
+             << ", (ASTContext*)" << (void*)&Origin.AST
+             << "\n";
+}
+
+void ExternalASTMerger::ForceRecordOrigin(const DeclContext *ToDC,
+                                          DCOrigin Origin) {
+  RecordOriginImpl(ToDC, Origin, ImporterForOrigin(*Origin.AST));
+}
+
+void ExternalASTMerger::RecordOriginImpl(const DeclContext *ToDC, DCOrigin Origin,
+                                         ASTImporter &Importer) {
+  Origins[ToDC] = Origin;
+  Importer.ASTImporter::MapImported(cast<Decl>(Origin.DC), const_cast<Decl*>(cast<Decl>(ToDC)));
+}
+
+ExternalASTMerger::ExternalASTMerger(const ImporterTarget &Target,
+                                     llvm::ArrayRef<ImporterSource> Sources) : LogStream(&llvm::nulls()), Target(Target) {
+  SharedState = std::make_shared<ASTImporterSharedState>(
+      *Target.AST.getTranslationUnitDecl());
+  AddSources(Sources);
+}
+
+Decl *ExternalASTMerger::FindOriginalDecl(Decl *D) {
+  assert(&D->getASTContext() == &Target.AST);
+  for (const auto &I : Importers)
+    if (auto Result = I->GetOriginalDecl(D))
+      return Result;
+  return nullptr;
+}
+
+void ExternalASTMerger::AddSources(llvm::ArrayRef<ImporterSource> Sources) {
+  for (const ImporterSource &S : Sources) {
+    assert(&S.getASTContext() != &Target.AST);
+    // Check that the associated merger actually imports into the source AST.
+    assert(!S.getMerger() || &S.getMerger()->Target.AST == &S.getASTContext());
+    Importers.push_back(std::make_unique<LazyASTImporter>(
+        *this, Target.AST, Target.FM, S, SharedState));
+  }
+}
+
+void ExternalASTMerger::RemoveSources(llvm::ArrayRef<ImporterSource> Sources) {
+  if (LoggingEnabled())
+    for (const ImporterSource &S : Sources)
+      logs() << "(ExternalASTMerger*)" << (void *)this
+             << " removing source (ASTContext*)" << (void *)&S.getASTContext()
+             << "\n";
+  Importers.erase(
+      std::remove_if(Importers.begin(), Importers.end(),
+                     [&Sources](std::unique_ptr<ASTImporter> &Importer) -> bool {
+                       for (const ImporterSource &S : Sources) {
+                         if (&Importer->getFromContext() == &S.getASTContext())
+                           return true;
+                       }
+                       return false;
+                     }),
+      Importers.end());
+  for (OriginMap::iterator OI = Origins.begin(), OE = Origins.end(); OI != OE; ) {
+    std::pair<const DeclContext *, DCOrigin> Origin = *OI;
+    bool Erase = false;
+    for (const ImporterSource &S : Sources) {
+      if (&S.getASTContext() == Origin.second.AST) {
+        Erase = true;
+        break;
+      }
+    }
+    if (Erase)
+      OI = Origins.erase(OI);
+    else
+      ++OI;
+  }
+}
+
+template <typename DeclTy>
+static bool importSpecializations(DeclTy *D, ASTImporter *Importer) {
+  for (auto *Spec : D->specializations()) {
+    auto ImportedSpecOrError = Importer->Import(Spec);
+    if (!ImportedSpecOrError) {
+      llvm::consumeError(ImportedSpecOrError.takeError());
+      return true;
+    }
+  }
+  return false;
+}
+
+/// Imports specializations from template declarations that can be specialized.
+static bool importSpecializationsIfNeeded(Decl *D, ASTImporter *Importer) {
+  if (!isa<TemplateDecl>(D))
+    return false;
+  if (auto *FunctionTD = dyn_cast<FunctionTemplateDecl>(D))
+    return importSpecializations(FunctionTD, Importer);
+  else if (auto *ClassTD = dyn_cast<ClassTemplateDecl>(D))
+    return importSpecializations(ClassTD, Importer);
+  else if (auto *VarTD = dyn_cast<VarTemplateDecl>(D))
+    return importSpecializations(VarTD, Importer);
+  return false;
+}
+
+bool ExternalASTMerger::FindExternalVisibleDeclsByName(const DeclContext *DC,
+                                                       DeclarationName Name) {
+  llvm::SmallVector<NamedDecl *, 1> Decls;
+  llvm::SmallVector<Candidate, 4> Candidates;
+
+  auto FilterFoundDecl = [&Candidates](const Candidate &C) {
+   if (!HasDeclOfSameType(Candidates, C))
+     Candidates.push_back(C);
+  };
+
+  ForEachMatchingDC(DC,
+                    [&](ASTImporter &Forward, ASTImporter &Reverse,
+                        Source<const DeclContext *> SourceDC) -> bool {
+                      auto FromNameOrErr = Reverse.Import(Name);
+                      if (!FromNameOrErr) {
+                        llvm::consumeError(FromNameOrErr.takeError());
+                        return false;
+                      }
+                      DeclContextLookupResult Result =
+                          SourceDC.get()->lookup(*FromNameOrErr);
+                      for (NamedDecl *FromD : Result) {
+                        FilterFoundDecl(std::make_pair(FromD, &Forward));
+                      }
+                      return false;
+                    });
+
+  if (Candidates.empty())
+    return false;
+
+  Decls.reserve(Candidates.size());
+  for (const Candidate &C : Candidates) {
+    Decl *LookupRes = C.first.get();
+    ASTImporter *Importer = C.second;
+    auto NDOrErr = Importer->Import(LookupRes);
+    NamedDecl *ND = cast<NamedDecl>(llvm::cantFail(std::move(NDOrErr)));
+    assert(ND);
+    // If we don't import specialization, they are not available via lookup
+    // because the lookup result is imported TemplateDecl and it does not
+    // reference its specializations until they are imported explicitly.
+    bool IsSpecImportFailed =
+        importSpecializationsIfNeeded(LookupRes, Importer);
+    assert(!IsSpecImportFailed);
+    (void)IsSpecImportFailed;
+    Decls.push_back(ND);
+  }
+  SetExternalVisibleDeclsForName(DC, Name, Decls);
+  return true;
+}
+
+void ExternalASTMerger::FindExternalLexicalDecls(
+    const DeclContext *DC, llvm::function_ref<bool(Decl::Kind)> IsKindWeWant,
+    SmallVectorImpl<Decl *> &Result) {
+  ForEachMatchingDC(DC, [&](ASTImporter &Forward, ASTImporter &Reverse,
+                            Source<const DeclContext *> SourceDC) -> bool {
+    for (const Decl *SourceDecl : SourceDC.get()->decls()) {
+      if (IsKindWeWant(SourceDecl->getKind())) {
+        auto ImportedDeclOrErr = Forward.Import(SourceDecl);
+        if (ImportedDeclOrErr)
+          assert(!(*ImportedDeclOrErr) ||
+                 IsSameDC((*ImportedDeclOrErr)->getDeclContext(), DC));
+        else
+          llvm::consumeError(ImportedDeclOrErr.takeError());
+      }
+    }
+    return false;
+  });
+}
+