<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/153731>153731</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [ObjC] Assertion failure when parsing constructor with invalid attribute syntax
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            crash,
            objective-c++
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          k-arrows
      </td>
    </tr>
</table>

<pre>
    Reproducer:
https://godbolt.org/z/K41cYoGvY
```cpp
struct S1 {
  int v{0};
};

struct S2 : S1 {
  S2(int a)
  [[a < 0]] : S2{a, a} {}

  int vc{0};
};
```

Backtrace:
```console
clang++: /root/llvm-project/llvm/include/llvm/Support/Casting.h:578: decltype(auto) llvm::cast(From*) [with To = clang::CXXConstructExpr; From = clang::Expr]: Assertion `isa<To>(Val) && "cast<Ty>() argument of incompatible type!"' 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++ -gdwarf-4 -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 -x objective-c++ <source>
1.      <source>:7:24: current parser token '{'
2.      <source>:5:1: parsing struct/union/class body 'S2'
 #0 0x0000000004022128 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4022128)
 #1 0x000000000401f554 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x401f554)
 #2 0x0000000003f63e08 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007ec3a3c42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007ec3a3c969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007ec3a3c42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007ec3a3c287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007ec3a3c2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x00007ec3a3c39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000006b1aacf clang::Sema::BuildDelegatingInitializer(clang::TypeSourceInfo*, clang::Expr*, clang::CXXRecordDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b1aacf)
#10 0x0000000006b25801 clang::Sema::BuildBaseInitializer(clang::QualType, clang::TypeSourceInfo*, clang::Expr*, clang::CXXRecordDecl*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b25801)
#11 0x0000000006b3852d clang::Sema::BuildMemInitializer(clang::Decl*, clang::Scope*, clang::CXXScopeSpec&, clang::IdentifierInfo*, clang::OpaquePtr<clang::QualType>, clang::DeclSpec const&, clang::SourceLocation, clang::Expr*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b3852d)
#12 0x00000000067314d7 clang::Parser::ParseMemInitializer(clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67314d7)
#13 0x0000000006733505 clang::Parser::ParseConstructorInitializer(clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6733505)
#14 0x00000000066f1208 clang::Parser::ParseLexedMethodDef(clang::Parser::LexedMethod&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66f1208)
#15 0x00000000066f0d6d clang::Parser::ParseLexedMethodDefs(clang::Parser::ParsingClass&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66f0d6d)
#16 0x0000000006744761 clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6744761)
#17 0x0000000006747530 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+++0x6747530)
#18 0x000000000671a6ae 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+++0x671a6ae)
#19 0x00000000066d5068 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66d5068)
#20 0x00000000066d5a9f clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66d5a9f)
#21 0x00000000066dd8fa clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66dd8fa)
#22 0x00000000066de895 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66de895)
#23 0x00000000066d03fa clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66d03fa)
#24 0x00000000049c4218 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49c4218)
#25 0x0000000004cb8795 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4cb8795)
#26 0x0000000004c34aae clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c34aae)
#27 0x0000000004daa3b1 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4daa3b1)
#28 0x0000000000daf54f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xdaf54f)
#29 0x0000000000da61fa ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#30 0x0000000004a2bc09 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
#31 0x0000000003f642a4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f642a4)
#32 0x0000000004a2c21f 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
#33 0x00000000049ee4bd clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49ee4bd)
#34 0x00000000049ef54e 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+++0x49ef54e)
#35 0x00000000049f6f95 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49f6f95)
#36 0x0000000000daba05 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xdaba05)
#37 0x0000000000c5fa04 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc5fa04)
#38 0x00007ec3a3c29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#39 0x00007ec3a3c29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#40 0x0000000000da5ca5 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xda5ca5)
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/eJzkWs1y2zgSfhr4gqKKBPh78IGmolnPJJVs5JrKnFQgCEoYUwQXAB15nn4LIGX-SNbEU1b2sCmnTBNA4-uvG90NAkQpvq0ZuwXBHQiWN6TVOyFvHx0ipfiubnJRPN9-ZY0URUuZBDgFbrrTulHmEa0AWm1FkYtKL4TcArT6C6DVb75H_xC_PP0B3BSEbvdDmwa4qdKypRquPQiiO-CmEPJawycQ3bkgWgJs3g0PQ38EAU7Hw9YIoNiMJQAl9o3V4I5AgDPogmAJgmU3CIHojgCUQQKipRUQLTvp_ez0lemP0LvOd4Q-akko60gYFBO1EhUDbkorUm8BujM_OIUAraQQGqBVVT3tnUaKPxk9_gnQite0ags2vFi3TSOk6ZERpXm9XewAToMoNtIKRiv93DCAYtJqAVAC7TCcApxSojRA8UqKPUCpaQPB3Xeud_BBQICXsINm-2bfvmWi7oj9cGgkwHfQDJz3s23B0sydKsWk5qKGIHS5IgBnDwLgDwDFv5PKTodCgEIIELJQcPbw3LWbRiK37Z7VGooS8pqKfUM0zysGO308gBBAESwJr1ixAG765eOHdP0Bqjbfcw0JzNstlMxwA7WAM_fjetfmC2o0PxI545sr1TIF0AqSuoA97VDvGKSSqB3MXyyLMthI4-2UKcUKqEQru9dmJFFKUE40K6Bsa6io5I02eNea0EdYtPum8w13AdzkixRbSfYv2qveJ0RjMBkWeMWkww5NJSST5p0h3yFHspWjZVs_ArTKeX1s7twLOtviO5Gl40NnCx1h5JKmMdJb3bR6oaCzNyxAxznEoUPU3lHPtSYHgJe81qyCTlkL54nJXChm2qGzho6zpdTRQlR0R3gN8PIiXtNZ1aRRO6GhU1JRCekUnGxroTSnqpvDcjx9fYAiN7bhT8yhvUYAZz3b-ANwU89QOHmH0wjgFPmGRtpKaRyqIVIxCbV4ZDUEKDKLG0XATdGZ4QHAqWdGm1G83sJuDQC0amsueoaVgibmGWEmxBhZECDsQvfgHv_5LkIeikfrTz2r7uGL5LW27vDQOVQ8dJLk-0YoLRnZ2-WSmejTLZ74nfwCoDv30MPr4yJA2JuC98og8M-BzypG6rb5XK_5tjbrOm5rmx4KWAkzxRWgWjADVDSGissQMzeGmfGgr4yKJyafO2z_InVRmRnjnsNJn0zUmh30wuQcnLr2fycf9_IjRjHB1EcBcnulKp4DtDrE4Sb0nYrX7cHZ1m3XQBdKLMIOshkyAPanApMwKSls9E4yUmweeVW9TbodP0gP5nD9KIRbZSl4K2w_CgfB4VQwiqMSQ5KbCPsmsXbgIDY6Eevlbxbo5YPAeCoQJywJ3ybQDhkEJmMHC3OPEFqOs96a7Un3dNfyqliyim2JycX3NdecVPwv63WjEQ_PDVvbMHNfl8Km3-wkj568zb59M94qiyWj1TFnv-_i6rXrdDdhwJ3qjoLY9S7ofkcUe1Xrf7ekerDpe6LWe5Exae4EfhSUaBunr8CU5WJgypsyheMAFReY-sT2rxL1ikpUGO7OEGFb1g2jfY4Ytd4XrNa85EyeJ_dzQ_7Tsi9aApydM5UpyCYDDDYzFTQ1rD6dcE78D5jyJ9jKWmOw1SRlhBH2_CIaI_pia4TR8w9Z6_1xd8gG3HiGGwducBH3S9Uu5P8Gv0E44Pcn-MPSQ258Ef9HdmDFJ6Z3oliycop73HnUz7rk-6vSgR1UCWaquEVYvEEV9bouX7pSMzOF5dWUMXAHZcKpX_l-FHqX_erbt09snzNpQgEv-XHpxj8aCS422imKVGvJ81Yz1UeZl8rS1m8nUelaPmzZGLiKZlxFAXYvc2UM2fM0X3taPPZJ0GxHfuN18RaejrH4NAqfgCge2L6piO5z7Lx_Ss3udQQyg7kQ1QWpx7n7uvlHLHgN2xj2B9vEU9t4JCTsIi1GCyItty_Kq9PweDWS_zm5x8BHNBvI_shNSp7n1_t9U3HKtUnoNdmzF6lXMIilfDDItHQOi8ANLwd8o_lnuWprauZbsvK-1kx2O8u_jxBv7sHr7ev2PbHXFQKxZeSFL-TO-SJJ-aMOPKGNm2w_j8hXYW3ubT-HNZIMmxTkzVgr4pJcZO3DoXOqEXs_h6lrcGG0HbhAMy5YnFwuER9E85E9sapLofHf7w1Mx1-kaJuvrLT7g5MtwMtO55Mo2ord7xsh9VoTza5Vz1g1BxLwjAQXn3GIdP0wK1gM7k6bY_Lrfl8DsIE0AJ4Uxn5CfeRN4mQmCvYLq1O7vI97KUZbzfpX3Vfz9_7U1gEZYE6KXp_mcTR1rpU0qaUuzuC8EsIOw4AwnCLEPplWAFk_532tNKm7g5lTLl9X6Sr-2-MctJjUmH5BCM696T7a4h2UeRLnKvATZa8Sgnp8A_pJFeYWpAz8ElLqbfbECBh93k6lJM82jGR0R-Txm0J6_OwweYcy-CR4cR0lOpSDDslMh9ArCTzSnnkPNi6MNFnvSVX9zuxGe99UZxWykWUYYmT0pdjoY0oCC8mfmJx9iAYIzw4UCMqpm1hKRkLLvgTYSMuqbe2WXnegYQ_-qion9HFT1tPA3k3cu07mZWK_J3UxX8Vnrad03080ZnZiCBiRoyWvt3266Ez7MmCzoYeD53V_5ERxulG2e0_hpLN5sdGScK2OzTNxpKrMUhBy1G66pEM0t-7TEW6HABRVZJ8XBKBooArFx_OLX0V-xhje7NTBR2R8QHLubKFr-drWa1Ky6nnC5WW7vb-_94hfHH56iuITRJE3qTz_75zDML5oiNQL93UvwNO8zZifF6-yZq1GTjLjkcpJ6J4NNB1e--J6oWs6KWdGir1vlWDVHlxpVsywMvDZW0n5VeTqdUZ-FbnZ6k4YuRSLXzygIdwY__QD0kUSezf5KVQasgYqpwVXUobltOAaw16OnicFwpnK4DUT_EQqr1CtWnoG8sJZDs_J8Wv5sRI5grehJO0Dwd9n6HevPQyyAfek-nNpUBLXhwbxe0_ciR4mnp2coqRI3njSbYcMApO5QOa7cLMxYzZKE6k3I7V-eArmD1P47szIASUB7IS_v52M8G7qcRtOIZPSZJW0cy9Y9psGSHv_7-4pQXu9ih24caeCQQ_7BmOrGHSeoBZQMQb5qJg3Mx2LeCiZbmXNzPIzI8f3yW6KW1wkOCE37NaLggAhnCTRze42YJ5PiR95BUGM0NKLMSVFkITUL4KwSG74LXJR4MZe4CIPe9GCBEnhJtilAUUIByXwXbYnvFqYZbEQcntjr0bdegGOsHdTkZxVyl4FRMhe27E3szKA0Ml9HdMSLG_krb1rlbdbBXy34kqrQbjmurI3Cz_nf2YgWI7ukRkOW8ng9x2rX-7j0OGAq2OX10-k4gUkxy8zsLvEdNPK6vafXwPr1X26Rf8NAAD__1WXlVo">