https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101704
Bug ID: 101704
Summary: "Already defined" error in case of many concept
conversion operators
Product: gcc
Version: 11.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: fchelnokov at gmail dot com
Target Milestone: ---
Example code:
```
template <auto =[]{}> class C;
template <typename, typename = C<>> concept x = true;
#include <iostream>
struct S {
operator x<C<>> auto() { return 42; }
operator x<C<>> auto() { return '+'; }
operator x<C<>> auto() { return 44LL; }
operator x<C<>> auto() { return 45.5; }
operator x<C<>> auto() { return 46.5f; }
operator x<C<>> auto() { return 47L; }
operator x<C<>> auto() { return 48ULL; }
operator x<C<>> auto() { return 49U; }
};
int main() {
S s;
std::cout << (int)s << "\n";
std::cout << (char)s << "\n";
std::cout << (long long)s << "\n";
std::cout << (double)s << "\n";
std::cout << (float)s << "\n";
std::cout << (long)s << "\n";
std::cout << (unsigned long long)s << "\n";
std::cout << (unsigned)s << "\n";
}
```
GCC 11 prints:
```
/tmp/ccfcrhcg.s: Assembler messages:
/tmp/ccfcrhcg.s:33: Error: symbol `_ZN1ScvDaEv' is already defined
/tmp/ccfcrhcg.s:55: Error: symbol `_ZN1ScvDaEv' is already defined
/tmp/ccfcrhcg.s:77: Error: symbol `_ZN1ScvDaEv' is already defined
/tmp/ccfcrhcg.s:101: Error: symbol `_ZN1ScvDaEv' is already defined
/tmp/ccfcrhcg.s:123: Error: symbol `_ZN1ScvDaEv' is already defined
/tmp/ccfcrhcg.s:145: Error: symbol `_ZN1ScvDaEv' is already defined
/tmp/ccfcrhcg.s:167: Error: symbol `_ZN1ScvDaEv' is already defined
Execution build compiler returned: 1
```
GCC (truck) crashes on this example:
```
<source>:29:1: internal compiler error: symtab_node::verify failed
0x1dabd49 internal_error(char const*, ...)
???:0
0xb68322 symtab_node::verify_symtab_nodes()
???:0
0xb844cf symbol_table::finalize_compilation_unit()
???:0
```
https://gcc.godbolt.org/z/KP8Wqhz96
