https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122792
Bug ID: 122792
Summary: [15 regression] Link failure with modules
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
CC: jussi.pakkanen at mailbox dot org
Target Milestone: ---
Reported by Jussi Pakkanen.
This works with trunk (from y'day) and fails with 15.2.1 20251115, works with
15.2.0:
```
$ cat <<-EOF > unistd.cpp
import std;
int main(int, char**) {
std::print("Import STD is working.\n");
return 0;
}
EOF
$ g++-15 -std=c++23 -c -fmodules -fsearch-include-path bits/std.cc
$ g++-15 -std=c++23 -fmodules -c unistd.cpp -o useistd.cpp.o
$ g++-15 useistd.cpp.o std.o -o useistd -Wl,--as-needed -Wl,--no-undefined
/usr/lib/gcc/x86_64-pc-linux-gnu/15/../../../../x86_64-pc-linux-gnu/bin/ld:
useistd.cpp.o: warning: relocation against
`_ZNSt4spanIcLm18446744073709551615EE3__vILm12EEE' in read-only section
`.text._ZNSt4spanIcLm18446744073709551615EEC2ILm12EEERAT__c[_ZNSt4spanIcLm18446744073709551615EEC5ILm12EEERAT__c]'
/usr/lib/gcc/x86_64-pc-linux-gnu/15/../../../../x86_64-pc-linux-gnu/bin/ld:
useistd.cpp.o: in function `std::span<char,
18446744073709551615ul>::span<12ul>(char (&) [12ul])':
unistd.cpp:(.text._ZNSt4spanIcLm18446744073709551615EEC2ILm12EEERAT__c[_ZNSt4spanIcLm18446744073709551615EEC5ILm12EEERAT__c]+0x27):
undefined reference to `std::span<char, 18446744073709551615ul>::__v<12ul>'
/usr/lib/gcc/x86_64-pc-linux-gnu/15/../../../../x86_64-pc-linux-gnu/bin/ld:
useistd.cpp.o: in function `std::span<char,
18446744073709551615ul>::span<256ul>(char (&) [256ul])':
unistd.cpp:(.text._ZNSt4spanIcLm18446744073709551615EEC2ILm256EEERAT__c[_ZNSt4spanIcLm18446744073709551615EEC5ILm256EEERAT__c]+0x27):
undefined reference to `std::span<char, 18446744073709551615ul>::__v<256ul>'
/usr/lib/gcc/x86_64-pc-linux-gnu/15/../../../../x86_64-pc-linux-gnu/bin/ld:
read-only segment has dynamic relocations
collect2: error: ld returned 1 exit status
```
