<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Issue</th>
<td>
<a href=https://github.com/llvm/llvm-project/issues/71682>71682</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>
Error when using iostream as module
</td>
</tr>
<tr>
<th>Labels</th>
<td>
new issue
</td>
</tr>
<tr>
<th>Assignees</th>
<td>
</td>
</tr>
<tr>
<th>Reporter</th>
<td>
miyoku157
</td>
</tr>
</table>
<pre>
Hi,
I'm trying to switch from using headers to using modules and i tried just to switch an `#include <iostream` to `import <iostream>;`
To do so, i'm building my program on c++23 with cmake 3.28.0-rc4, the ninja generator 1.11.1 and clang 16.0.6.
I added the compile option: -fmodules to look for modules and i got this error stack:
```
[main] Building folder: cppgame
[build] Starting build
[proc] Executing command: /usr/local/bin/cmake --build /Development/cppgame/build --config Debug --target all --
[build] [2/6 16% :: 0.451] Scanning /Development/cppgame/src/Hvulk.cpp for CXX dependencies
[build] FAILED: CMakeFiles/sdvulk.dir/src/Hvulk.cpp.o.ddi
[build] "/usr/bin/clang-scan-deps" -format=p1689 -- /usr/bin/clang++ -I/Development/cppgame/build/_deps/sdl-build/include -I/Development/cppgame/build/_deps/sdl-src/include -I/Development/cppgame/build/_deps/sdl-src/include/SDL3 -g -std=gnu++2b -fmodules -idirafter/Development/cppgame/build/_deps/sdl-src/src/video/khronos -x c++ /Development/cppgame/src/Hvulk.cpp -c -o CMakeFiles/sdvulk.dir/src/Hvulk.cpp.o -MT CMakeFiles/sdvulk.dir/src/Hvulk.cpp.o.ddi -MD -MF CMakeFiles/sdvulk.dir/src/Hvulk.cpp.o.ddi.d > CMakeFiles/sdvulk.dir/src/Hvulk.cpp.o.ddi
[build] LLVM ERROR: unexpected call to lookupModuleOutput
[build] PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
[build] #0 0x00007fd5dda1f503 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/libLLVM-16.so+0xe1f503)
[build] #1 0x00007fd5dda1c7bf llvm::sys::RunSignalHandlers() (/usr/lib/libLLVM-16.so+0xe1c7bf)
[build] #2 0x00007fd5dda1c90d (/usr/lib/libLLVM-16.so+0xe1c90d)
[build] #3 0x00007fd5dc65c710 (/usr/lib/libc.so.6+0x3e710)
[build] #4 0x00007fd5dc6ac83c (/usr/lib/libc.so.6+0x8e83c)
[build] #5 0x00007fd5dc65c668 gsignal (/usr/lib/libc.so.6+0x3e668)
[build] #6 0x00007fd5dc6444b8 abort (/usr/lib/libc.so.6+0x264b8)
[build] #7 0x00007fd5dd74d25f (/usr/lib/libLLVM-16.so+0xb4d25f)
[build] #8 0x00007fd5dd91f19e (/usr/lib/libLLVM-16.so+0xd1f19e)
[build] #9 0x00007fd5e7223bec (/usr/lib/libclang-cpp.so.16+0x2223bec)
[build] #10 0x00007fd5e725b9eb clang::tooling::dependencies::ModuleDepCollector::addOutputPaths(clang::CompilerInvocation&, clang::tooling::dependencies::ModuleDeps&) (/usr/lib/libclang-cpp.so.16+0x225b9eb)
[build] #11 0x00007fd5e72605f5 clang::tooling::dependencies::ModuleDepCollectorPP::handleTopLevelModule(clang::Module const*) (/usr/lib/libclang-cpp.so.16+0x22605f5)
[build] #12 0x00007fd5e7260a57 clang::tooling::dependencies::ModuleDepCollectorPP::EndOfMainFile() (/usr/lib/libclang-cpp.so.16+0x2260a57)
[build] #13 0x00007fd5e711e82e clang::FrontendAction::EndSourceFile() (/usr/lib/libclang-cpp.so.16+0x211e82e)
[build] #14 0x00007fd5e70c0d85 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/libclang-cpp.so.16+0x20c0d85)
[build] #15 0x00007fd5e725e50f (/usr/lib/libclang-cpp.so.16+0x225e50f)
[build] #16 0x00007fd5e7292d09 clang::tooling::ToolInvocation::run() (/usr/lib/libclang-cpp.so.16+0x2292d09)
[build] #17 0x00007fd5e72597d5 clang::tooling::dependencies::DependencyScanningWorker::computeDependencies(llvm::StringRef, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>> const&, clang::tooling::dependencies::DependencyConsumer&, clang::DiagnosticConsumer&, std::optional<llvm::StringRef>) (/usr/lib/libclang-cpp.so.16+0x22597d5)
[build] #18 0x00007fd5e7259d7c clang::tooling::dependencies::DependencyScanningWorker::computeDependencies(llvm::StringRef, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>> const&, clang::tooling::dependencies::DependencyConsumer&, std::optional<llvm::StringRef>) (/usr/lib/libclang-cpp.so.16+0x2259d7c)
[build] #19 0x00007fd5e725abb3 clang::tooling::dependencies::DependencyScanningTool::getP1689ModuleDependencyFile(clang::tooling::CompileCommand const&, llvm::StringRef, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>&) (/usr/lib/libclang-cpp.so.16+0x225abb3)
[build] #20 0x0000561ccd1c115c (/usr/bin/clang-scan-deps+0x1115c)
[build] #21 0x0000561ccd1c54b2 (/usr/bin/clang-scan-deps+0x154b2)
[build] #22 0x00007fd5dd9a59f4 llvm::ThreadPool::processTasks(llvm::ThreadPoolTaskGroup*) (/usr/lib/libLLVM-16.so+0xda59f4)
[build] #23 0x00007fd5dd9a63ea (/usr/lib/libLLVM-16.so+0xda63ea)
[build] #24 0x00007fd5dc6aa9eb (/usr/lib/libc.so.6+0x8c9eb)
[build] #25 0x00007fd5dc72e7cc (/usr/lib/libc.so.6+0x1107cc)
[build] [2/6 33% :: 0.478] Scanning /Development/cppgame/src/main.cpp for CXX dependencies
[build] FAILED: CMakeFiles/sdvulk.dir/src/main.cpp.o.ddi
[build] "/usr/bin/clang-scan-deps" -format=p1689 -- /usr/bin/clang++ -I/Development/cppgame/build/_deps/sdl-build/include -I/Development/cppgame/build/_deps/sdl-src/include -I/Development/cppgame/build/_deps/sdl-src/include/SDL3 -g -std=gnu++2b -fmodules -idirafter/Development/cppgame/build/_deps/sdl-src/src/video/khronos -x c++ /Development/cppgame/src/main.cpp -c -o CMakeFiles/sdvulk.dir/src/main.cpp.o -MT CMakeFiles/sdvulk.dir/src/main.cpp.o.ddi -MD -MF CMakeFiles/sdvulk.dir/src/main.cpp.o.ddi.d > CMakeFiles/sdvulk.dir/src/main.cpp.o.ddi
[build] LLVM ERROR: unexpected call to lookupModuleOutput
[build] PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
[build] #0 0x00007f9c5a61f503 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/libLLVM-16.so+0xe1f503)
[build] #1 0x00007f9c5a61c7bf llvm::sys::RunSignalHandlers() (/usr/lib/libLLVM-16.so+0xe1c7bf)
[build] #2 0x00007f9c5a61c90d (/usr/lib/libLLVM-16.so+0xe1c90d)
[build] #3 0x00007f9c5925c710 (/usr/lib/libc.so.6+0x3e710)
[build] #4 0x00007f9c592ac83c (/usr/lib/libc.so.6+0x8e83c)
[build] #5 0x00007f9c5925c668 gsignal (/usr/lib/libc.so.6+0x3e668)
[build] #6 0x00007f9c592444b8 abort (/usr/lib/libc.so.6+0x264b8)
[build] #7 0x00007f9c5a34d25f (/usr/lib/libLLVM-16.so+0xb4d25f)
[build] #8 0x00007f9c5a51f19e (/usr/lib/libLLVM-16.so+0xd1f19e)
[build] #9 0x00007f9c63e23bec (/usr/lib/libclang-cpp.so.16+0x2223bec)
[build] #10 0x00007f9c63e5b9eb clang::tooling::dependencies::ModuleDepCollector::addOutputPaths(clang::CompilerInvocation&, clang::tooling::dependencies::ModuleDeps&) (/usr/lib/libclang-cpp.so.16+0x225b9eb)
[build] #11 0x00007f9c63e605f5 clang::tooling::dependencies::ModuleDepCollectorPP::handleTopLevelModule(clang::Module const*) (/usr/lib/libclang-cpp.so.16+0x22605f5)
[build] #12 0x00007f9c63e60a57 clang::tooling::dependencies::ModuleDepCollectorPP::EndOfMainFile() (/usr/lib/libclang-cpp.so.16+0x2260a57)
[build] #13 0x00007f9c63d1e82e clang::FrontendAction::EndSourceFile() (/usr/lib/libclang-cpp.so.16+0x211e82e)
[build] #14 0x00007f9c63cc0d85 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/libclang-cpp.so.16+0x20c0d85)
[build] #15 0x00007f9c63e5e50f (/usr/lib/libclang-cpp.so.16+0x225e50f)
[build] #16 0x00007f9c63e92d09 clang::tooling::ToolInvocation::run() (/usr/lib/libclang-cpp.so.16+0x2292d09)
[build] #17 0x00007f9c63e597d5 clang::tooling::dependencies::DependencyScanningWorker::computeDependencies(llvm::StringRef, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>> const&, clang::tooling::dependencies::DependencyConsumer&, clang::DiagnosticConsumer&, std::optional<llvm::StringRef>) (/usr/lib/libclang-cpp.so.16+0x22597d5)
[build] #18 0x00007f9c63e59d7c clang::tooling::dependencies::DependencyScanningWorker::computeDependencies(llvm::StringRef, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>> const&, clang::tooling::dependencies::DependencyConsumer&, std::optional<llvm::StringRef>) (/usr/lib/libclang-cpp.so.16+0x2259d7c)
[build] #19 0x00007f9c63e5abb3 clang::tooling::dependencies::DependencyScanningTool::getP1689ModuleDependencyFile(clang::tooling::CompileCommand const&, llvm::StringRef, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>&) (/usr/lib/libclang-cpp.so.16+0x225abb3)
[build] #20 0x0000560280e3615c (/usr/bin/clang-scan-deps+0x1115c)
[build] #21 0x0000560280e3a4b2 (/usr/bin/clang-scan-deps+0x154b2)
[build] #22 0x00007f9c5a5a59f4 llvm::ThreadPool::processTasks(llvm::ThreadPoolTaskGroup*) (/usr/lib/libLLVM-16.so+0xda59f4)
[build] #23 0x00007f9c5a5a63ea (/usr/lib/libLLVM-16.so+0xda63ea)
[build] #24 0x00007f9c592aa9eb (/usr/lib/libc.so.6+0x8c9eb)
[build] #25 0x00007f9c5932e7cc (/usr/lib/libc.so.6+0x1107cc)
[build] ninja: build stopped: subcommand failed.
[proc] The command: /usr/local/bin/cmake --build /Development/cppgame/build --config Debug --target all -- exited with code: 1
[driver] Build completed: 00:00:00.513
[build] Build finished with exit code 1
```
Am i doing something wrong here?
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsW1tPJKsW_jX4QqpSUF23Bx_Uts-eRLPNaM7Zb4YCupuxCipAefn3J0C1Wq012jM6t20y6bG5fHwsFgvWF5oYI1aS832QHYJsvkd6u1Z6vxV36qpHWbFXK3a3_5cA-AiCZA6Sg08AFy20-k7IFbQKmhth6RoutWphb1zhmhPGtXGVoaBVrG-4gUQyKKDVgjP4pTf2UXciIcgTgFMhadMzDkF6JJSxmpMW5IlrCfJEtJ3SdlSXHoP00HX15C4UZAoa5egKT7TuRcM8iTvYabXSpIVKQgrwIcCHOIU3wq4hbckVh2mMyziJNJ25_nbNoRTyC4ErLrkmVmmIYoRi5CdCGyJXEOVxEufxYBpIGOPM96Sq7UTDoeqsUBKkBzBabuxgFWyUuoJLpbdss1IW2rUwkGutNDSW0CuQHgT44TNPhn_ha3bYEiFBNoeHm6kuVcO4dmPSrluRlsP7tt4crvG5Jdq6xqFkU99pRV318S2nva-nqm2JZA4N4EVvNMCLRlHSALyohQR4EYwXRR7JNZrza96oruXSuurAwTX3DaKIKrkUKzjndb-CUWSJXnELSdPAKHrKFGSHGOBFDlEOcAadOdIDmMSzDPmJUCKlI_qVgY2mAC_-uu6bq5h2nTf80T__QMY7LhmXVHDzdODFwaeT47kb7OiUXPGFaLhxYMzjMKGfIscqZkw8Y26A8b31Bqs5_4kMJTJivDMAYxgtlW6JBem8Q3lZwSiCz3UKrgujTy-ZGuDFZcBeGNZEm7LNFtsZIEz2bboDvDifn6QwWsHIWAbS-Ur2w6asH-2VSDChydJy_U2jhc9rwbgCeHG11koqA6PbTQDYxWsiCiO1iy_A6PRiZ9-JTucwOl3s2i9mEKTHu_Z66qgnJ_89hcefP__92Tl-L_ltx6nlDFK3P4fI1Xenfnn-7m3X26cgZyfHB-fH0PR1Kywk0O1zzX3stgqure2M28Z4AfBiJey6r2OqWhdYmuvNf1Gn1RdO3ZIIY3o_oRAlB__zUVYTs4Y1oVdWE8rjp1QgwGkCk9skSZJiyTLGCFpmSQr9UD6WmDsT_jjTQtpzF3MvHBrA5UMjTW4uN2cOzv354tylggCXD3FR1OHTWTFCeexOosPklvshAa6e54e2-NGiXj7H73Mvz8VKkuYvIlnDtfFjv5aCQ32WAsAp3mZQJey1sFXCJmeWPsaleUYLlDyPS2Oj4txjprxAySTkbAxJaJnSFyFLXqZ0EjLbZpnnJVwZb-pXsM3zchI6H0PPZrO6hKT2t5gXgHE-q6eBi9GKFTOGs-WrVqz2TSdxyxFuhZao4q_CZb7pJG71CJcXGKc1n1o2fzC6EGVUjAZbhA5T7ouSMXpWV7wON7Swc6xSjdh8GZ36viREsznvjlTTcGqVDuWEsRDizohdu932CPIoXPD0J3mtKPGXvBAXvmFY47tObOTn7eGnOGkPNLZHnmTL7LvscXYWatY-8lyo7sQdmqHd2C6hDFIljQX4YMdpeaaT08Lb0yJZ8SbTOpbs7-UpEdIdnV-LqlOsSVZMsk5HrBHiJeaPWS-0kpZLdkCHVCEQOle9pvybCIUxJgnNRoQSmrBy5B0Prm0skZQPlHxKwAeWozXfmsGuzhwYTNLNtjY3z5KJUDexVVyHSfR8jF5hllSTPnWhVPNow4ebQS939xg_zCSnYmvGVcF22b7zTcndJjn6n9JXfAhqLjPtLZ8_7vb4pnNutZCrz3zpgpm_mrvS6yEsHt2XXF7S21uEwpeaGEEvje8K0iO6JnrU3RVcWk2ENZvq9HjUgjQuqwxjbOq_0uQH0_D_NkFtxzD_sBxHSpq-danMNsRckJVUxgq61eaeWBASSAPSo-fWyk1jtwPEOdWkB5bbHsgK-uGBf5wHvqN3sWL6urZ1GcxIXaff5V0uLoe6FbdnKC-r-7N-aDmco1ODDEfeURC7RmZ-yS9_kBfmP2nQ3ZbdreRkkrm5pWc5opQhilA2zgEmlLHD5Ba5tpPAaAs4m9X4tcCu7STwOC-uSFYtZ48c4mKtOWFn987XaUW5MRfEXI0j2kNDV_cfrfrua3fj7dTKjztJMt0imaecvBLXNZ3E3c60iUuqXsy06VfyEjzOtAvMC_py8o5QUtCJxd9owzBNx-JwUe4mDrdEyHfRhjfAH9LwHycN3_vM65ThB094lTC85Tiv1YXH3V4pC487_dtU4YpmJP-FVeHA72eqwgODN1eFK5pV-G1VYQ_5tqrwwPI9VGEP_R6qsFux9B1UYYebvYMqXNE85e-mCnv0D1V4bI8_TxUepvWbqcKONfuVVGFHiP4-qnDY3O-lCnv0X0wVDjP-UIX_SE3ut1CFBw_8UIX_RA_86apw8K4PVfhfpgonuEx4mr-9KhyAydurwj4b-tVV4UDy7VXhkGm_qSrsINPvVoX9q22QHoS3zdBY1XXcv2A2fT28Z4ZLIhrO4icvny_C4-0f-eYZ8lthORueoivmrtYQ3TNjWlxzff_C2z8tb7gNM0oSkB4MH3GG0qfWCJ2WQgqz3gziBvQj3Q_z3NvygxYKyJSQK2hUy-3a_XWjlX_jrzlIF3CP7aesSiuyx_dRXlWzLC0Q2lvvz5IszwinScbrZVahEiWzWVkuC5xnSVHne2IfJy4nTUo0w2WKYrbEVZbmNUYJq1Fdg1nCWyKa2G2YWOnVnlf89guUl3ivITVvjP_ZAsaS30BfCTAG2XxP73utsO5XBsySRhhrHlCssA3fP_YP7G_WXA4_Utj8ogASMzzKh3u9bva_XZf0RP8fAAD__7l37CY">