[Sema] Prevent using member declaration diagnostic if the base class is invalid.
Summary:
Once a base class has been made invalid (by a static_assert for example) all using-member declarations in the derived classes will result in a "not a base class" diagnostic. This diagnostic is very misleading and should not be emitted.
This change is needed to help libc++ produce reasonable diagnostics in `std::optional` and `std::variant`.
Reviewers: rsmith, majnemer, aaron.ballman
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D25430
llvm-svn: 283755
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 0f7f0ff..7eca6c1 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -9470,11 +9470,13 @@
return true;
}
- Diag(SS.getRange().getBegin(),
- diag::err_using_decl_nested_name_specifier_is_not_base_class)
- << SS.getScopeRep()
- << cast<CXXRecordDecl>(CurContext)
- << SS.getRange();
+ if (!cast<CXXRecordDecl>(NamedContext)->isInvalidDecl()) {
+ Diag(SS.getRange().getBegin(),
+ diag::err_using_decl_nested_name_specifier_is_not_base_class)
+ << SS.getScopeRep()
+ << cast<CXXRecordDecl>(CurContext)
+ << SS.getRange();
+ }
return true;
}
diff --git a/clang/test/SemaCXX/using-decl-templates.cpp b/clang/test/SemaCXX/using-decl-templates.cpp
index d766bb3..3b2b8e1 100644
--- a/clang/test/SemaCXX/using-decl-templates.cpp
+++ b/clang/test/SemaCXX/using-decl-templates.cpp
@@ -92,3 +92,12 @@
template struct APtr<int>; // expected-error{{elaborated type refers to a type alias template}}
}
+
+namespace DontDiagnoseInvalidTest {
+template <bool Value> struct Base {
+ static_assert(Value, ""); // expected-error {{static_assert failed}}
+};
+struct Derived : Base<false> { // expected-note {{requested here}}
+ using Base<false>::Base; // OK. Don't diagnose that 'Base' isn't a base class of Derived.
+};
+} // namespace DontDiagnoseInvalidTest