[clang-repl] Disambiguate global namespace identifiers

[Hahnfeld]

Summary

A double colon starts an identifier name in the global namespace and must be tentatively parsed as such.

[v.g.vassilev]

clang/test/Interpreter/global-namespace-disambiguate.cpp

6 ↗

(On Diff #548514)

Can we add this test to disambiguate-decl-stmt.cpp instead where we track these things?

[Hahnfeld]

clang/test/Interpreter/global-namespace-disambiguate.cpp

6 ↗

(On Diff #548514)

done

[v.g.vassilev]

LGTM!

clang/lib/Parse/ParseTentative.cpp

bool Parser::isCXXDeclarationStatement(
   case tok::kw_namespace:
     // using-declaration
     // using-directive
   case tok::kw_using:
     // static_assert-declaration
   case tok::kw_static_assert:
   case tok::kw__Static_assert:
     return true;
+  case tok::coloncolon:
   case tok::identifier: {
     if (DisambiguatingWithExpression) {
       RevertingTentativeParsingAction TPA(*this);
       // Parse the C++ scope specifier.
       CXXScopeSpec SS;
       ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
                                      /*ObjectHasErrors=*/false,
                                      /*EnteringContext=*/true);

clang/test/Interpreter/disambiguate-decl-stmt.cpp

 I x = 10;
 x.I::~I();
 x = 20;
 
 struct Dtor1 {~Dtor1();};
 Dtor1::~Dtor1() { printf("Dtor1\n"); }
 Dtor1 d1;
 
+struct Dtor2 { ~Dtor2(); };
+::Dtor2::~Dtor2() { printf("Dtor2\n"); }
+Dtor2 d2;
+
 struct ANestedDtor { struct A1 { struct A2 { ~A2(); }; }; };
 ANestedDtor::A1::A2::~A2() { printf("Dtor A::A1::A2::~A2\n"); }
 
 // Ctors
 
 // Deduction guide
 template<typename T> struct A { A(); A(T); };
 A() -> A<int>;