[clang-tidy] RenamerClangTidy now correctly renames `using namespace` decls

[njames93]

Summary

Fixes readability-identifier-naming doesn't rename using namespace correctly.

[njames93]

• Remove unnecessary include

[njames93]

Ping??

[aaron.ballman]

LGTM aside from a commenting nit.

clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp

276

Comments should be complete sentences with capitalization and punctuation (and you can remove the empty newline above).

[njames93]

• Fixed comment nit

clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp

if (const auto *MemberRef =
           Result.Nodes.getNodeAs<MemberExpr>("memberExpr")) {
     SourceRange Range = MemberRef->getMemberNameInfo().getSourceRange();
     addUsage(NamingCheckFailures, MemberRef->getMemberDecl(), Range,
              Result.SourceManager);
     return;
   }
 
   if (const auto *Decl = Result.Nodes.getNodeAs<NamedDecl>("decl")) {
+    // Fix using namespace declarations.
+    if (const auto *UsingNS = dyn_cast<UsingDirectiveDecl>(Decl))
+      addUsage(NamingCheckFailures, UsingNS->getNominatedNamespaceAsWritten(),
+               UsingNS->getIdentLocation());
+
     if (!Decl->getIdentifier() || Decl->getName().empty() || Decl->isImplicit())
       return;
 
     // Fix type aliases in value declarations.
     if (const auto *Value = Result.Nodes.getNodeAs<ValueDecl>("decl")) {
       if (const Type *TypePtr = Value->getType().getTypePtrOrNull()) {
         if (const auto *Typedef = TypePtr->getAs<TypedefType>())
           addUsage(NamingCheckFailures, Typedef->getDecl(),

clang-tools-extra/test/clang-tidy/checkers/readability-identifier-naming.cpp

 // CHECK-MESSAGES: :[[@LINE-1]]:59: warning: invalid case style for constant pointer parameter 'constant_ptr'
 // CHECK-FIXES: {{^}}void MyPoiterFunction(int * p_normal_pointer, int * const cp_ConstantPtr){{{$}}
     int * l_PointerA;
     int * const pointer_b = nullptr;
 // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: invalid case style for local constant pointer 'pointer_b'
 // CHECK-FIXES: {{^}}    int * const lc_PointerB = nullptr;{{$}}
 }
 
+using namespace FOO_NS;
+// CHECK-FIXES: {{^}}using namespace foo_ns;
+
+using namespace FOO_NS::InlineNamespace;
+// CHECK-FIXES: {{^}}using namespace foo_ns::inline_namespace;