[modules] Enforce the rules that an explicit or partial specialization must be

declared before it is used. Because we don't use normal name lookup to find
these, the normal code to filter out non-visible names from name lookup results
does not apply.

llvm-svn: 268585

1 files changed, 63 insertions, 12 deletions

diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 66e3601f047..eaf44861d32 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -1482,6 +1482,35 @@ bool Sema::hasVisibleDefaultArgument(const NamedDecl *D,
                                      Modules);
 }
 
+bool Sema::hasVisibleMemberSpecialization(
+    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules) {
+  assert(isa<CXXRecordDecl>(D->getDeclContext()) &&
+         "not a member specialization");
+  for (auto *Redecl : D->redecls()) {
+    // If the specialization is declared at namespace scope, then it's a member
+    // specialization declaration. If it's lexically inside the class
+    // definition then it was instantiated.
+    //
+    // FIXME: This is a hack. There should be a better way to determine this.
+    // FIXME: What about MS-style explicit specializations declared within a
+    //        class definition?
+    if (Redecl->getLexicalDeclContext()->isFileContext()) {
+      auto *NonConstR = const_cast<NamedDecl*>(cast<NamedDecl>(Redecl));
+
+      if (isVisible(NonConstR))
+        return true;
+
+      if (Modules) {
+        Modules->push_back(getOwningModule(NonConstR));
+        const auto &Merged = Context.getModulesWithMergedDefinition(NonConstR);
+        Modules->insert(Modules->end(), Merged.begin(), Merged.end());
+      }
+    }
+  }
+
+  return false;
+}
+
 /// \brief Determine whether a declaration is visible to name lookup.
 ///
 /// This routine determines whether the declaration D is visible in the current
@@ -1586,18 +1615,36 @@ static NamedDecl *findAcceptableDecl(Sema &SemaRef, NamedDecl *D) {
     if (RD == D)
       continue;
 
-    if (auto ND = dyn_cast<NamedDecl>(RD)) {
-      // FIXME: This is wrong in the case where the previous declaration is not
-      // visible in the same scope as D. This needs to be done much more
-      // carefully.
-      if (LookupResult::isVisible(SemaRef, ND))
-        return ND;
-    }
+    auto ND = cast<NamedDecl>(RD);
+    // FIXME: This is wrong in the case where the previous declaration is not
+    // visible in the same scope as D. This needs to be done much more
+    // carefully.
+    if (LookupResult::isVisible(SemaRef, ND))
+      return ND;
   }
 
   return nullptr;
 }
 
+bool Sema::hasVisibleDeclarationSlow(const NamedDecl *D,
+                                     llvm::SmallVectorImpl<Module *> *Modules) {
+  assert(!isVisible(D) && "not in slow case");
+
+  for (auto *Redecl : D->redecls()) {
+    auto *NonConstR = const_cast<NamedDecl*>(cast<NamedDecl>(Redecl));
+    if (isVisible(NonConstR))
+      return true;
+
+    if (Modules) {
+      Modules->push_back(getOwningModule(NonConstR));
+      const auto &Merged = Context.getModulesWithMergedDefinition(NonConstR);
+      Modules->insert(Modules->end(), Merged.begin(), Merged.end());
+    }
+  }
+
+  return false;
+}
+
 NamedDecl *LookupResult::getAcceptableDeclSlow(NamedDecl *D) const {
   if (auto *ND = dyn_cast<NamespaceDecl>(D)) {
     // Namespaces are a bit of a special case: we expect there to be a lot of
@@ -4904,7 +4951,7 @@ static NamedDecl *getDefinitionToImport(NamedDecl *D) {
 }
 
 void Sema::diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
-                                 bool NeedDefinition, bool Recover) {
+                                 MissingImportKind MIK, bool Recover) {
   assert(!isVisible(Decl) && "missing import for non-hidden decl?");
 
   // Suggest importing a module providing the definition of this entity, if
@@ -4923,9 +4970,7 @@ void Sema::diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
   auto Merged = Context.getModulesWithMergedDefinition(Decl);
   OwningModules.insert(OwningModules.end(), Merged.begin(), Merged.end());
 
-  diagnoseMissingImport(Loc, Decl, Decl->getLocation(), OwningModules,
-                        NeedDefinition ? MissingImportKind::Definition
-                                       : MissingImportKind::Declaration,
+  diagnoseMissingImport(Loc, Decl, Decl->getLocation(), OwningModules, MIK,
                         Recover);
 }
 
@@ -4985,6 +5030,12 @@ void Sema::diagnoseMissingImport(SourceLocation UseLoc, NamedDecl *Decl,
   case MissingImportKind::DefaultArgument:
     DiagID = diag::note_default_argument_declared_here;
     break;
+  case MissingImportKind::ExplicitSpecialization:
+    DiagID = diag::note_explicit_specialization_declared_here;
+    break;
+  case MissingImportKind::PartialSpecialization:
+    DiagID = diag::note_partial_specialization_declared_here;
+    break;
   }
   Diag(DeclLoc, DiagID);
 
@@ -5020,7 +5071,7 @@ void Sema::diagnoseTypo(const TypoCorrection &Correction,
     assert(Decl && "import required but no declaration to import");
 
     diagnoseMissingImport(Correction.getCorrectionRange().getBegin(), Decl,
-                          /*NeedDefinition*/ false, ErrorRecovery);
+                          MissingImportKind::Declaration, ErrorRecovery);
     return;
   }