Allow a using directive to refer to the implicitly-defined namespace
"std", with a warning, to improve GCC compatibility. Fixes PR7517.
As a drive-by, add typo correction for using directives.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107172 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index fcf5e94..325add7 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -2120,6 +2120,7 @@
AttributeList *AttrList);
virtual void ActOnFinishNamespaceDef(DeclPtrTy Dcl, SourceLocation RBrace);
+ NamespaceDecl *getStdNamespace();
virtual DeclPtrTy ActOnUsingDirective(Scope *CurScope,
SourceLocation UsingLoc,
SourceLocation NamespcLoc,
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index c6f149e..66d0bf5 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -3452,6 +3452,21 @@
PopDeclContext();
}
+/// \brief Retrieve the special "std" namespace, which may require us to
+/// implicitly define the namespace.
+NamespaceDecl *Sema::getStdNamespace() {
+ if (!StdNamespace) {
+ // The "std" namespace has not yet been defined, so build one implicitly.
+ StdNamespace = NamespaceDecl::Create(Context,
+ Context.getTranslationUnitDecl(),
+ SourceLocation(),
+ &PP.getIdentifierTable().get("std"));
+ StdNamespace->setImplicit(true);
+ }
+
+ return StdNamespace;
+}
+
Sema::DeclPtrTy Sema::ActOnUsingDirective(Scope *S,
SourceLocation UsingLoc,
SourceLocation NamespcLoc,
@@ -3465,13 +3480,46 @@
assert(S->getFlags() & Scope::DeclScope && "Invalid Scope.");
UsingDirectiveDecl *UDir = 0;
-
+ NestedNameSpecifier *Qualifier = 0;
+ if (SS.isSet())
+ Qualifier = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
+
// Lookup namespace name.
LookupResult R(*this, NamespcName, IdentLoc, LookupNamespaceName);
LookupParsedName(R, S, &SS);
if (R.isAmbiguous())
return DeclPtrTy();
+ if (R.empty()) {
+ // Allow "using namespace std;" or "using namespace ::std;" even if
+ // "std" hasn't been defined yet, for GCC compatibility.
+ if ((!Qualifier || Qualifier->getKind() == NestedNameSpecifier::Global) &&
+ NamespcName->isStr("std")) {
+ Diag(IdentLoc, diag::ext_using_undefined_std);
+ R.addDecl(getStdNamespace());
+ R.resolveKind();
+ }
+ // Otherwise, attempt typo correction.
+ else if (DeclarationName Corrected = CorrectTypo(R, S, &SS, 0, false,
+ CTC_NoKeywords, 0)) {
+ if (R.getAsSingle<NamespaceDecl>() ||
+ R.getAsSingle<NamespaceAliasDecl>()) {
+ if (DeclContext *DC = computeDeclContext(SS, false))
+ Diag(IdentLoc, diag::err_using_directive_member_suggest)
+ << NamespcName << DC << Corrected << SS.getRange()
+ << FixItHint::CreateReplacement(IdentLoc, Corrected.getAsString());
+ else
+ Diag(IdentLoc, diag::err_using_directive_suggest)
+ << NamespcName << Corrected
+ << FixItHint::CreateReplacement(IdentLoc, Corrected.getAsString());
+ Diag(R.getFoundDecl()->getLocation(), diag::note_namespace_defined_here)
+ << Corrected;
+
+ NamespcName = Corrected.getAsIdentifierInfo();
+ }
+ }
+ }
+
if (!R.empty()) {
NamedDecl *Named = R.getFoundDecl();
assert((isa<NamespaceDecl>(Named) || isa<NamespaceAliasDecl>(Named))
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 97300f7..1801565 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -1207,20 +1207,11 @@
// "std" or "bad_alloc" as necessary to form the exception specification.
// However, we do not make these implicit declarations visible to name
// lookup.
- if (!StdNamespace) {
- // The "std" namespace has not yet been defined, so build one implicitly.
- StdNamespace = NamespaceDecl::Create(Context,
- Context.getTranslationUnitDecl(),
- SourceLocation(),
- &PP.getIdentifierTable().get("std"));
- StdNamespace->setImplicit(true);
- }
-
if (!StdBadAlloc) {
// The "std::bad_alloc" class has not yet been declared, so build it
// implicitly.
StdBadAlloc = CXXRecordDecl::Create(Context, TTK_Class,
- StdNamespace,
+ getStdNamespace(),
SourceLocation(),
&PP.getIdentifierTable().get("bad_alloc"),
SourceLocation(), 0);