lto=full + address sanitizer results in free/delete errors

[Oipo]

clang version: 19

When compiling with lto=full and address sanitizer, I get weird errors:

$ ../bin/CoroutineTests
... program executes as normal ...
free(): invalid size
Aborted (core dumped)

$ ../bin/CoroutineTests_sdevent
... program executes as normal ...
munmap_chunk(): invalid pointer
Aborted (core dumped)

$ ../bin/AsyncFileIOTests
... program executes as normal ...
=================================================================
==3074019==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 376 byte(s) in 1 object(s) allocated from:
    #0 0x3f2edd in operator new(unsigned long) crtstuff.c
    #1 0x6473c9 in Catch::Detail::unique_ptr<std::__cxx11::basic_ostringstream<char, std::char_traits<char>, std::allocator<char>>> Catch::Detail::make_unique<std::__cxx11::basic_ostringstream<char, std::char_traits<char>, std::allocator<char>>>() /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/../catch2/internal/catch_unique_ptr.hpp:111:30
    #2 0x6473c9 in Catch::StringStreams::add() /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/internal/catch_reusable_string_stream.cpp:26:38
    #3 0x6473c9 in Catch::ReusableStringStream::ReusableStringStream() /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/internal/catch_reusable_string_stream.cpp:43:57
    #4 0x57dd08 in Catch::TablePrinter::TablePrinter(std::ostream&, std::vector<Catch::ColumnInfo, std::allocator<Catch::ColumnInfo>>) /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/reporters/catch_reporter_console.cpp:305:5
    #5 0x57dd08 in Catch::Detail::unique_ptr<Catch::TablePrinter> Catch::Detail::make_unique<Catch::TablePrinter, std::ostream&, std::vector<Catch::ColumnInfo, std::allocator<Catch::ColumnInfo>>>(std::ostream&, std::vector<Catch::ColumnInfo, std::allocator<Catch::ColumnInfo>>&&) /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/../catch2/internal/catch_unique_ptr.hpp:111:34
    #6 0x57dd08 in Catch::ConsoleReporter::ConsoleReporter(Catch::ReporterConfig&&) /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/reporters/catch_reporter_console.cpp:381:20
    #7 0x63e291 in Catch::Detail::unique_ptr<Catch::ConsoleReporter> Catch::Detail::make_unique<Catch::ConsoleReporter, Catch::ReporterConfig>(Catch::ReporterConfig&&) /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/../catch2/internal/catch_unique_ptr.hpp:111:34
    #8 0x63e291 in Catch::ReporterFactory<Catch::ConsoleReporter>::create(Catch::ReporterConfig&&) const /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/../catch2/reporters/catch_reporter_registrars.hpp:48:20
    #9 0x5defab in Catch::ReporterRegistry::create(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>> const&, Catch::ReporterConfig&&) const /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/internal/catch_reporter_registry.cpp:62:28
    #10 0x5defab in Catch::(anonymous namespace)::createReporter(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>> const&, Catch::ReporterConfig&&) /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/catch_session.cpp:46:75
    #11 0x5dc174 in Catch::(anonymous namespace)::prepareReporters(Catch::Config const*) /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/catch_session.cpp:56:24
    #12 0x5dc174 in Catch::Session::runInternal() /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/catch_session.cpp:320:29
    #13 0x5db471 in Catch::Session::run() /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/catch_session.cpp:269:24
    #14 0x56ad1b in int Catch::Session::run<char>(int, char const* const*) /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/../catch2/catch_session.hpp:41:30
    #15 0x56ad1b in main /home/githubrunner/actions-runner/_work/Ichor/Ichor/build/src/catch2/internal/catch_main.cpp:36:29
    #16 0x7f0733b8ed8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16

SUMMARY: AddressSanitizer: 376 byte(s) leaked in 1 allocation(s).

All of these errors disappear if I remove either lto or address sanitizer.

Source file compilation:

/usr/bin/clang++-19 -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_SANITIZE_VECTOR -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_FAST -D__SANITIZE_ADDRESS__ -I/home/oipo/Programming/Ichor/external/Catch2/src/catch2/.. -I/home/oipo/Programming/Ichor/build/external/Catch2/generated-includes -O3 -ggdb3 -DNDEBUG -flto=full -ffile-prefix-map=/home/oipo/Programming/Ichor/external/Catch2/= -fsanitize=address,undefined -fno-omit-frame-pointer -fno-sanitize=vptr -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3 -std=c++2b -MD -MT external/Catch2/src/CMakeFiles/Catch2.dir/catch2/matchers/catch_matchers_templated.cpp.o -MF external/Catch2/src/CMakeFiles/Catch2.dir/catch2/matchers/catch_matchers_templated.cpp.o.d -o external/Catch2/src/CMakeFiles/Catch2.dir/catch2/matchers/catch_matchers_templated.cpp.o -c /home/oipo/Programming/Ichor/external/Catch2/src/catch2/matchers/catch_matchers_templated.cpp

Linking:

/usr/bin/clang++-19 -O3 -ggdb3 -DNDEBUG -flto=full   -Wl,--exclude-libs,ALL -fsanitize=address,undefined -no-pie -Wl,-z,nodlopen -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -Wl,--as-needed -Wl,--no-copy-dt-needed-entries test/CMakeFiles/AsyncFileIOTests.dir/AsyncFileIOTests.cpp.o -o /home/githubrunner/actions-runner/_work/Ichor/Ichor/bin/AsyncFileIOTests  /home/githubrunner/actions-runner/_work/Ichor/Ichor/bin/libichor.a  /home/githubrunner/actions-runner/_work/Ichor/Ichor/bin/libCatch2Main.a  -lsystemd  -ldl  -lrt  /home/githubrunner/actions-runner/_work/Ichor/Ichor/bin/libCatch2.a

I don't really know how to make a minimally reproducible case here, as I can't trigger this without the combination of Catch2 and my source code. If I leave out Catch2, it doesn't trigger either. Please let me know what I could do to improve this report.