<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/110301>110301</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang++] Frontend Crash in clang::Decl::castFromDeclContext
        </td>
    </tr>

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

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

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

<pre>
    Hello there, clang++ crashes on the following test case:

```cpp
a() { struct{[({ struct { b =
```

Tested version(s): 19.1.0, trunk.

Example: https://godbolt.org/z/nnj3sYKbP

Stack dump:

```
Stack dump:
0.      Program arguments: /opt/compiler-explorer/clang-19.1.0/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-14.2.0 -fcolor-diagnostics -fno-crash-diagnostics -emit-llvm -O3 <source>
1.      <eof> parser at end of file
2.      <source>:1:5: parsing function body 'a'
 #0 0x00000000036fdb08 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x36fdb08)
 #1 0x00000000036fbc74 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x36fbc74)
 #2 0x0000000003647be8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007a7aeb842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x0000000007196d90 clang::Decl::castFromDeclContext(clang::DeclContext const*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x7196d90)
 #5 0x00000000060a6b28 clang::Sema::checkTypeSupport(clang::QualType, clang::SourceLocation, clang::ValueDecl*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x60a6b28)
 #6 0x00000000062bae04 clang::Sema::ActOnFinishFunctionBody(clang::Decl*, clang::Stmt*, bool) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x62bae04)
 #7 0x0000000006028c0f clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x6028c0f)
 #8 0x0000000005f24740 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x5f24740)
 #9 0x0000000005f6d07e clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x5f6d07e)
#10 0x0000000005f1e817 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x5f1e817)
#11 0x0000000005f1f703 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x5f1f703)
#12 0x0000000005f27cd2 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x5f27cd2)
#13 0x0000000005f29ac8 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x5f29ac8)
#14 0x0000000005f2a100 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x5f2a100)
#15 0x0000000005f18742 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x5f18742)
#16 0x0000000003fce825 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x3fce825)
#17 0x0000000004274201 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x4274201)
#18 0x00000000041f699b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x41f699b)
#19 0x000000000435a843 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x435a843)
#20 0x0000000000c874dc cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0xc874dc)
#21 0x0000000000c8146d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#22 0x0000000004017309 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
#23 0x0000000003648013 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x3648013)
#24 0x0000000004017529 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
#25 0x0000000003fdd947 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x3fdd947)
#26 0x0000000003fde2fd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x3fde2fd)
#27 0x0000000003fe7d4c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0x3fe7d4c)
#28 0x0000000000c847f1 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0xc847f1)
#29 0x0000000000b5c2d4 main (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0xb5c2d4)
#30 0x00007a7aeb829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#31 0x00007a7aeb829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#32 0x0000000000c80f0e _start (/opt/compiler-explorer/clang-19.1.0/bin/clang+++0xc80f0e)
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzkWV1v2zgW_TXMCyGDomRJfvCD49Qzme2i3ToYYJ8MiqIcTilSS1Kps79-QUpORCV2W6xmgMUWbaPw85xzL--9oogx_CgZW4PlLVje3ZDOPiq9fn5u2U2pquf1r0wIBe0j0wzgLaSCyCPAtwDfQqqJeWQGKun6Ya2EUN-4PELLjIWUGAaSDUB3AJ3_z1D_l7Zt30IALgBeQZDfQmN1Ry3Ibx0UXLw2-d4SguRussx47QdmLKvgE9OGKwlwYQBegWQD49UiXiCH3epOfl2MJ304kaYVDiZ8tLY1Di_eAbw7qqpUwi6UPgK8-zfAOyn_SMw__1Z-Hs_fW0K_wqpr2ktML45DC4BWn7U6atJAoo9dw6R1ACDAO9VagHdUNS0XTEfs1AqlmXZtTv_ozGlXcnluHIwSHatvRNdRCqMjjJRbjbStW7OzbWcXBkaNEE8NjKJTkUXENJF5lpacQHLHpWUCRrVU0RPTpTLM9cNoD6PoSGlklRL0kXDpTHENpRscpwu8QDCqqRJKRxUnR6mM5dT0O3jvCZtZw23Ug_uUQJBsjeo0ZSD50GsWO81AsmWqBskH2BJtmIbEQiYrqGpYc8H6kXgY-bpAsolBslk6gd0856Z1J6nlSkLn6BDgnACc9_MhwAmC6ITOf5KsrkpUQIfO2TDZmGfTP3zWXFpv4QdNKAO4eB2kybeDMlYz0gCcOSfk0nqHd37_X9gZ4Ft0GkA5R39BHU9QlzRP30O9FYzIrv0k9_woiQC46KQPBRUUyu0yH0YHIcCIQ4xpXrICbp0_fGFUPTH93IP6lchKuK2KQbVgzFZJy0524YJJskH-38sWybBFTnLCyiLFS4wGQoKXAO9ORXbI0khw2Z2io-z6DrowapF54H5KADsdw87jVVat0BAQvaR3jIr-iRJjd1o1rmWACXAxGTp0QKqksQBvZpN8gBZgX46xZ4hkJS7G2PesIQP2R0a_Pjy3bN-1rdIT4P_oiHCdr7mgn-7P2UdFifXRN-j8nYiOeXFmJDlwCEhmAUlcEobS90luqP0kd1xy87gbosCtqp7fGslDDqnaxg6tpVJiPkI93oBQHloNFxTVYyyffQQcPZ_J7C2xzGWUH2X1ZqU9Vc7K2YwG8_ADfsWY37LGaZ6iH-J3x2ouee9rxWQCl0fHkWhilR6i7rU1qwfWtIJYdi9rdT6N12Z9JJb1MzfW6o983tM7yBDotAp1yiqUs6ucnAC_aNW1F-XZt4y-pfkq3EvYeiuDp83LzjLzs_K-HT-NHNccc6f0FyKP7F7ymSX3ir5I7tIoCiWPWRHn35X8kx456L20TPep9ecV_O6Iq2bcUMqMcX285k6H2YTyOgRCxROh6hwl3xXK-RhXMtDr4oGeXa6pj_2Jcjk1ArnwJOTltMJX5fpw6t1oJNtfI9F88cxxDERIJiKsCC2uivCg2o_siYk-eY3Zf2rJvzr22WqQbCeBzAfAL8y9K7wTd15qgb-rqhPsvnHFjs-bc2a9gVzAPp2wJzH6Ttbj2tj_ZQkcw0CC5SRoFHn69hRs9g8hUQ-4p9GXXjOXYAOQAGlQUyY1ZQVejpFuVcV-YXLjo1jf9OHEaGfZ0DRccMzyLtVvH-ALSsQU5ylG8RjfTrtELqt3AM4Jbdg5gBZUd2lcZ6tVGUrXb3YvjSWSsvfVu8xlRh8d0AXwg6IrTZakSIPENgB9ZfH0UsQU11jOGFsHVGPYOChcEC3ytKKQ0vjQELfG6HJiozV59sFhSx-Jfn0RdcFiC8M2vIVPildzou-xBeDjCfg4zSp4FnobP_jTPqKwb4gQvzNqlb5vWvEuEx8vXqe4NSav3t6PKs2fmH57m-BgBUk7RXGeoJWXY7Tu-TbpoL2ivrc_Yf31k78WEKIk9OuhlmGo7vce_GUbb1XTEFlND-u7ljN2GKdatztxGoz0sZrL45AAerO-TDgc6OkUx_0vJTGcHowfPqgYDHYNB6sJt-bcPVmOCOH8X-lRvxsyelP2rtNr7qcAnAvSlJW_d3uRChfnC6jfVPm-PZLJBVKB4mRkiveuifqeL53ck5qJ50DO66ab7ybM4wz8PZ061tIp9H_sGE7qRUu0dUJe8YBlmJarapXmF4XzFiNv8t9ZzSBcTya6AZfuBK4M3QRlyojbHEWAJxu40aRIqRiuq59V4zdVmstS_KbKj9zYQIprYfjF-i3hzvD-AvfH1Rtc5E_U0EkUaJiHGrK8SuklvHej56AMeCf_X9L-L9RwtvLTixKoVkwSdprXQ_l5rjfOqH3g2AzH_vvpeKYKw-EJAAdVHSqXFFcpdFDn2bFfcLzjy3ek4VMEXlWrn_wU4acEa8bTNVmK4OHgph2MJdoeRpR-eBeWhrvgiXFRjRjs15_LPm7J1z3PX01vqnVSrZIVuWHrOMd5usyTIr15XJcVwlmKsqwoqrhK0KompK4ylGeUlcVydcPXGOEUrXAe53GGk0VSVtmKkjzDyyVmbAlSxBrCxcK54ELp4w03pmPrOEYJim8EKZkw_ms4xgNcDJZ3N3rtJkRldzQgRYIba16XsNwK_wl9THB5B88vLP2HK8jlD38uuum0WE--SXP72JULqhpnOneA-h9Rq9UfjDpDeCoG4N3A5mmN_xMAAP__YTd2kw">