[cxx2a] P0641R2: (Some) type mismatches on defaulted functions only
render the function deleted instead of rendering the program ill-formed.
This change also adds an enabled-by-default warning for the case where
an explicitly-defaulted special member function of a non-template class
is implicitly deleted by the type checking rules. (This fires either due
to this language change or due to pre-C++20 reasons for the member being
implicitly deleted). I've tested this on a large codebase and found only
bugs (where the program means something that's clearly different from
what the programmer intended), so this is enabled by default, but we
should revisit this if there are problems with this being enabled by
default.
llvm-svn: 343285
diff --git a/clang/test/SemaCXX/cxx17-compat.cpp b/clang/test/SemaCXX/cxx17-compat.cpp
index 9d628da..93e052f 100644
--- a/clang/test/SemaCXX/cxx17-compat.cpp
+++ b/clang/test/SemaCXX/cxx17-compat.cpp
@@ -1,5 +1,5 @@
// RUN: %clang_cc1 -fsyntax-only -std=c++17 -pedantic -verify %s
-// RUN: %clang_cc1 -fsyntax-only -std=c++2a -Wc++17-compat-pedantic -verify %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++2a -Wc++17-compat-pedantic -verify %s -Wno-defaulted-function-deleted
struct A {};
int (A::*pa)() const&;
@@ -42,3 +42,15 @@
#else
// expected-warning@-4 {{assignment of lambda is incompatible with C++ standards before C++2a}}
#endif
+
+struct DefaultDeleteWrongTypeBase {
+ DefaultDeleteWrongTypeBase(DefaultDeleteWrongTypeBase&);
+};
+struct DefaultDeleteWrongType : DefaultDeleteWrongTypeBase {
+ DefaultDeleteWrongType(const DefaultDeleteWrongType&) = default;
+#if __cplusplus <= 201703L
+ // expected-error@-2 {{a member or base requires it to be non-const}}
+#else
+ // expected-warning@-4 {{explicitly defaulting this copy constructor with a type different from the implicit type is incompatible with C++ standards before C++2a}}
+#endif
+};