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/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index e5c16fb..8fd2634 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -459,6 +459,9 @@
"emitted in every translation unit">,
InGroup<DiagGroup<"weak-vtables">>, DefaultIgnore;
+def ext_using_undefined_std : ExtWarn<
+ "using directive refers to implicitly-defined namespace 'std'">;
+
// C++ exception specifications
def err_exception_spec_in_typedef : Error<
"exception specifications are not allowed in typedefs">;
@@ -3163,6 +3166,11 @@
"cannot find protocol declaration for %0; did you mean %1?">;
def note_base_class_specified_here : Note<
"base class %0 specified here">;
+def err_using_directive_suggest : Error<
+ "no namespace named %0; did you mean %1?">;
+def err_using_directive_member_suggest : Error<
+ "no namespace named %0 in %1; did you mean %2?">;
+def note_namespace_defined_here : Note<"namespace %0 defined here">;
} // end of sema category
} // end of sema component.
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);
diff --git a/test/FixIt/typo.cpp b/test/FixIt/typo.cpp
index 5b9e68b..9789a58 100644
--- a/test/FixIt/typo.cpp
+++ b/test/FixIt/typo.cpp
@@ -12,7 +12,8 @@
typedef basic_string<char> string; // expected-note 2{{'string' declared here}}
}
-namespace otherstd { // expected-note 2{{'otherstd' declared here}}
+namespace otherstd { // expected-note 2{{'otherstd' declared here}} \
+ // expected-note{{namespace 'otherstd' defined here}}
using namespace std;
}
@@ -29,6 +30,10 @@
return radious * pi; // expected-error{{did you mean 'radius'?}}
}
+using namespace othestd; // expected-error{{no namespace named 'othestd'; did you mean 'otherstd'?}}
+namespace blargh = otherstd; // expected-note{{namespace 'blargh' defined here}}
+using namespace ::blarg; // expected-error{{no namespace named 'blarg' in the global namespace; did you mean 'blargh'?}}
+
bool test_string(std::string s) {
basc_string<char> b1; // expected-error{{no template named 'basc_string'; did you mean 'basic_string'?}}
std::basic_sting<char> b2; // expected-error{{no template named 'basic_sting' in namespace 'std'; did you mean 'basic_string'?}}
diff --git a/test/SemaCXX/using-directive.cpp b/test/SemaCXX/using-directive.cpp
index 0d5c840..162f7fa 100644
--- a/test/SemaCXX/using-directive.cpp
+++ b/test/SemaCXX/using-directive.cpp
@@ -121,3 +121,8 @@
}
void f4() { f2(1); }
+
+// PR7517
+using namespace std; // expected-warning{{using directive refers to implicitly-defined namespace 'std'}}
+using namespace ::std; // expected-warning{{using directive refers to implicitly-defined namespace 'std'}}
+