There is no way to silence the warning without making a type non-aggregate. A simplified case from Boost.Proto: #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wdeprecated-copy" struct expr { int a, b; expr& operator=(const expr&) { return *this; } }; #pragma GCC diagnostic pop #include <type_traits> static_assert(std::is_aggregate_v<expr>); expr foo(expr e) { return e; } <source>: In function 'expr foo(expr)': <source>:15:12: error: implicitly-declared 'constexpr expr::expr(const expr&)' is deprecated [-Werror=deprecated-copy] 15 | return e; | ^ <source>:6:11: note: because 'expr' has user-provided 'expr& expr::operator=(const expr&)' 6 | expr& operator=(const expr&) { return *this; } | ^~~~~~~~
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>: https://gcc.gnu.org/g:620cd7861e1266991c9c2a82e1e2d5f4d723ec88 commit r12-1144-g620cd7861e1266991c9c2a82e1e2d5f4d723ec88 Author: Jason Merrill <jason@redhat.com> Date: Tue Apr 27 17:13:39 2021 -0400 c++: -Wdeprecated-copy and #pragma diagnostic [PR94492] -Wdeprecated-copy was depending only on the state of the warning at the point where we call the function, making it hard to use #pragma diagnostic to suppress the warning for a particular implicitly declared function. But checking whether the warning is enabled at the location of the implicit declaration turned out to be a bit complicated; option_enabled only tests whether it was enabled at the start of compilation, the actual test only existed in the middle of diagnostic_report_diagnostic. So this patch factors it out and adds a new warning_enabled function to diagnostic.h. gcc/ChangeLog: PR c++/94492 * diagnostic.h (warning_enabled_at): Declare. * diagnostic.c (diagnostic_enabled): Factor out from... (diagnostic_report_diagnostic): ...here. (warning_enabled_at): New. gcc/cp/ChangeLog: PR c++/94492 * decl2.c (cp_warn_deprecated_use): Check warning_enabled_at. gcc/testsuite/ChangeLog: PR c++/94492 * g++.dg/cpp0x/depr-copy4.C: New test.
Could this be backported? The issue affects every release with -Wdeprecated-copy, which are GCC 9+.
Fixed.