<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/166848>166848</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang crashes when using a class that has `dllexport`ed virtual explicitly defaulted destructor and user-defined constructor
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          kikairoya
      </td>
    </tr>
</table>

<pre>
    reproducer: https://godbolt.org/z/oT1e63436

version: clang HEAD
procedure: `clang --target=x86_64-win32 -fms-extensions test.cc`
(x86_64-mingw doesn't crash)

```
struct S {
    __declspec(dllexport) virtual ~S() = default; //< using `{}` or dropping virtual doesn't crash 
    S() {} //< using `= default;` doesn't crash
};

S s;
```

```
clang++: /root/llvm-project/llvm/tools/clang/lib/Sema/SemaDeclCXX.cpp:14519: void clang::Sema::DefineImplicitDestructor(clang::SourceLocation, clang::CXXDestructorDecl*): Assertion `(Destructor->isDefaulted() && !Destructor->doesThisDeclarationHaveABody() && !Destructor->isDeleted()) && "DefineImplicitDestructor - call it for implicit default dtor"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics --target=x86_64-win32 -fms-extensions <source>
1.      <source>:4:2: current parser token ';'
2.      <source>:1:1: parsing struct/union/class body 'S'
 #0 0x000000000424be68 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x424be68)
 #1 0x0000000004249294 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4249294)
 #2 0x000000000418d4f8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f9b57e42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007f9b57e969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007f9b57e42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007f9b57e287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007f9b57e2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x00007f9b57e39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000006e0d176 clang::Sema::DefineImplicitDestructor(clang::SourceLocation, clang::CXXDestructorDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6e0d176)
#10 0x0000000006e0df8c clang::Sema::ActOnFinishCXXNonNestedClass() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6e0df8c)
#11 0x00000000069ca29e clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69ca29e)
#12 0x00000000069cd060 clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69cd060)
#13 0x000000000699fa5e clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*, clang::ImplicitTypenameContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x699fa5e)
#14 0x000000000695afa8 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x695afa8)
#15 0x000000000695b9df clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x695b9df)
#16 0x0000000006963293 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6963293)
#17 0x00000000069641a5 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69641a5)
#18 0x0000000006964650 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6964650)
#19 0x0000000006945763 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6945763)
#20 0x0000000004b97858 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4b97858)
#21 0x0000000004e85d25 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4e85d25)
#22 0x0000000004e06bbe clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4e06bbe)
#23 0x0000000004f7e57d clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4f7e57d)
#24 0x0000000000dd0d90 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xdd0d90)
#25 0x0000000000dc790a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) driver.cpp:0:0
#26 0x0000000000dc7a8d int llvm::function_ref<int (llvm::SmallVectorImpl<char const*>&)>::callback_fn<clang_main(int, char**, llvm::ToolContext const&)::'lambda'(llvm::SmallVectorImpl<char const*>&)>(long, llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#27 0x0000000004c016d9 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#28 0x000000000418d994 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x418d994)
#29 0x0000000004c01cef clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#30 0x0000000004bc2742 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4bc2742)
#31 0x0000000004bc36ee clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4bc36ee)
#32 0x0000000004bcae45 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4bcae45)
#33 0x0000000000dcd2b1 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xdcd2b1)
#34 0x0000000000c7c234 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc7c234)
#35 0x00007f9b57e29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#36 0x00007f9b57e29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#37 0x0000000000dc73a5 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xdc73a5)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkWk1z2zjS_jXwBUUXCVL8OPjASNZM5s1MUpHrLd9UINiUsKYALgAq8h72t28BpEyRlj12ysphNxWXaaLRePrpRqMBgmrNNwLgBs0-odniirZmK9XNA3-gXMlHelXI8vFGQaNk2TJQKMzx1phGozBHZInIciPLQtbmWqoNIst_IbKUdwHEYRTGyM-Rn-9BaS6F7clqKjb499t8gfy8UZJB2SqwLSj2u0bPM1RtwKBwcUjjdRx5P7gICfaqnfbgYEBYZRob0OaaMRT7dhSS9sI7LjY_cClBC0QSg5mieotI1kGx0t1_P9dGtczgFUbJJ-TnGGO8XpfAat0AQyQt6xoOjVQGkQzvuTItrfG_V4ik9gUKF7iEira1QeEn3FGBwjluNRcba45VmyxQ7GOpcKlk09iGo6IJQtwjeFLvOp9VOxrYqp8a6-d23PBTZ_IK6_75xPbJn455RD7Z_9YXZKmkNIgs63q_8xol_wHs-CciSyNlrRFZ9t2WNS8QWa5gR_tfC2D1_P7-mjUNCvMgmgWZ1buXvOxCwAZPmLse7mkBFRfwedfUnHGzgM43UiGSnsrLVjH4Ihk1Np7I_FTZ_P5-6GcBIJJbv4c5zrUGZbs4_kg6yHkovOV60dEJ5ZF8EiMSY0SCsaQl-m5r5VlNlQPxO91D_kmWj3_T1Xaq4WmIkSh5yXrsYUbrGnODK6kw7wWO7selY4ggkuCK8hrKa-Tn377c5qtbrNtixw2muGg3WIGNY2zkdOpys22LayZ3g3MnLudat2CdjakoMResbkvAZgt93BaUPRhFGVh3NC5PMNAaSqydt-xr25NqLRmnBkqsWoE1U7wxFu_KUPaAy3ZnQwX5uX-N_OybkhtFd5iqTbsDYXQflrKxmJjcNbwG5cGhqaUCdYxFjx49rT2jWvGAyLLgYghVG-HY22BPWm20aazO1jStudbY21nbsecd0tijeufpR2HoAYULLgzU2KuE9PagCqnBtmNvhT1vw5hnJwTbUi5QuHgVpRXWgjZ6Kw32KiZrqbyS042Q2nCmuzEcs-PXb0yKKJz3tIe3yM8Dy-XoXZhHKMyJy8WtUiAMbqjSoLCRDyAwIonNFiRBfk7O9A76H9fLZqQuVhFZtsLNScu01tiuGlbZqlOFEQl97B_847-IRAXEKXZB5-avftTdwzfFhXFRcdfFVToIKfpjLbVRQHdu-swxF6abTOkHhQcin_xDD69bNyz4YAI-I1l0Dvy8Bira5qtY8Y2gNSJpK9wCW-Ja2iEuAdWCGaCSEdQgLaMqxXMbUt-ByT2oxw7b71SUtR0x7TkcycylMHAwfQr33U-nP-z1J1VWzBKIyIz4vVHdQtBHaM1Fe_A2ou0a2LWW13EPeUb8AXA0VpjFWcVwY7YKaLl-4HX9Pu2u_6B9NoUbJTHeaEfBe2FHSTwojseKSZpUIaaFTbTvUus6DmqTZ2qD4t0Kg2JQmI4Vhhlk8fsUui6Dwuw0wGLwyyCJf_Wy_tGzqDejLxRJGPhTI6uUnTcyZ-arWHLB9XZ-f_-XFH-BNlDObR58qgo-HGyVsgHsKDvFGaMkg1Ow31yKP3me39__CbsC1KoBxit-pP7Nbnm10Q1R5sYoXrTGVg8uVT9lQpdvRj0u6NiOjYErMuGq9GP_da6sI3ueYBK6Rj50D3d29fw_Lsr38GStXrnNRnyOwVMQ5R3smpoa-Cwq-Vw-Z7boOgE5x4WU9Staj2P3ef4tHryEbyz7g2_CsW-yis5ej-OTSvzJeD120UVJ_nlye8kv1MBA9heujZsGI_lj_rx7bEDQHTxpvYBDHOWDQ6KxQ2a0ounfOuSrWraC2fEWUH0WBlRXCf19hni3BBebl_37zF8X4MsxMvA1m_BVZGX11gAe0cYFf56RL8LaNNp-CWuWl4G1eMxaHJIsfJW120MXVCfs_RqmLsCFs3bgIplwEQV09ioXd7L5AnuouyX0lISvDf1nC9-MQuF8khB_U7JtvkNlN3XPDB9Kmz9l2da2fpPK7sgMXGodcGYOJKRTEuLZ62v0kitt_kuYiGcnK-K41s6iWRI_nxr56m5SurmjuPi0DOh-XwCwg_QEmIx3-UWWpLPRijGXJfwGIneJrnt1ewDWGuhfXaRi7oEMMMf7eUhnJRlNs6Wyi6woz-C8EMIOw4BwvI0HPy4KGBPZjflZaEMFg_NcvmzSReK3xzlYMarooiqBWTI6Au7xDsbs5bm9yDNjL5KMe3wD-lH545elX2Y-ZixY76hVcHIwlStFH10ambMtVZhJ0ZVyNq3M8fgdmbuj8MsY0aEcbJiNbWBJ5lN8pH0e3Lm8cGLJakfr-v_Bbrdt4XnWIJdZhi5WR1-UHuUmEp-FUa3me_gO1VyYLhMPzfuqPz5b8hpWj9rAzo2T4VLxPajJKZQ1K56aRVO3sTwZtOrLqbVyfrGNP2Np1p18ojBntK4Lyh7WlTguJMdIOG5pt1Q5t-ZvYSjrGhFJarorSopI8tMASdqdL56O-tb-L7M8qkYi5gdxmXWfcV6k2bX2XzleIa5r6Abu5_g8mMvdjopymm7PTjNtejnZ2NFpPYqolVFcbPp1vZuDTx3Wa3Y4BEH3R0E1Z2vtxHuCRsL2xdooyo0-Nk_U0bq2OUuqk3Yrkg_LrpvnHe3nPD5xYYb_kMUZZ6TTg91sdAZ97vi2a_neihWtoH4ccfm63y6QXTvEQ2bKpsHFYLRZ-p8LDsv4dUOVufZfjILJZ5SCkSQiL7LmvEaflTBHKkdr7KSjFRhl87eJ5qO688Swjy3nnNlPoTT5PFOwMAZ4Lyl_yEK_zMgfsvjC9Uvr2_NM-xQBDeWqW33eQ2IfJr-ESkvWQCWZUEkhmr0Ee3HyPKrkzpRwL7ngF1J5gW2Fo2cgL5xUJSUpAvwBhcKHF4kO2YB7XOiyhJEwwhbxRw_cqR4GnnydI5mtsN_3tSs7LXeffZXLIPLxem37rLWhyqxPzHrzEBCdDJFMS8-QznCn_OP9ZJV3Q08u6YBSUg13qqp-d4dZH__djRD8g5sthgO34VQCDsLIYmw1YG-PjcQaAPOTXZcd6bjbwgpMqwTY6Wd7nt4auipvwjILM3oFN0ESkygO0zS72t7QAlKfhElFCGVxxMKAET9hYcFYUUEUXvEb4pNZEPgxCYLUz66rgM380g_itAhZlMxQ5MOO8vraTotrqTZX7hLKTRDHaZRe1bSAWrv7aoT0pBA0W1ypG3d3pWg3GkV-zbXRgwrDTQ03c8eVu18BGv_YgugvVlHc3VswW2rwlmqMYn-4ABb7UD7d3LLe5Iyb-vF4EQdKXA6Xdiz5rQblle7rZ5-JusarVtU3P38Hp2dgf0P-EwAA__8Jc0KN">