<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/107047>107047</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang crashes on incorrect code with -std=c++20
        </td>
    </tr>

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

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

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

<pre>
    Reproducer: https://godbolt.org/z/Merf3f3Ms
```
struct A {
    static constexpr auto as_tuple_helper() {
        return std::tuple_size<decltype(static_cast<Tuple&>(*this)._data)>;
    }
 static constexpr int data_size = as_tuple_helper<1>();
};
```
Command to compile:
```
clang++ --std=c++20 main.cpp
```
```
clang++: /root/llvm-project/clang/lib/Sema/SemaOverload.cpp:13530: void AddOverloadedCallCandidate(clang::Sema&, clang::DeclAccessPair, clang::TemplateArgumentListInfo*, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool): Assertion `!KnownValid && "Explicit template arguments?"' 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 -std=c++20 <source>
1.      <source>:7:57: current parser token ')'
2.      <source>:1:1: parsing struct/union/class body 'A'
 #0 0x0000000003b1e5e8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3b1e5e8)
 #1 0x0000000003b1c2ac llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3b1c2ac)
 #2 0x0000000003a64768 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x000072e8a6042520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x000072e8a60969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x000072e8a6042476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x000072e8a60287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x000072e8a602871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x000072e8a6039e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000006fd38b9 AddOverloadedCallCandidate(clang::Sema&, clang::DeclAccessPair, clang::TemplateArgumentListInfo*, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool) SemaOverload.cpp:0:0
#10 0x0000000006fd3ae9 clang::Sema::AddOverloadedCallCandidates(clang::UnresolvedLookupExpr*, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fd3ae9)
#11 0x0000000006fd3dee clang::Sema::buildOverloadedCallSet(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::OverloadCandidateSet*, clang::ActionResult<clang::Expr*, true>*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fd3dee)
#12 0x0000000006fe0515 clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fe0515)
#13 0x0000000006b86e18 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b86e18)
#14 0x0000000006fe0072 FinishOverloadedCallExpr(clang::Sema&, clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, clang::OverloadCandidateSet*, clang::OverloadCandidate**, clang::OverloadingResult, bool) SemaOverload.cpp:0:0
#15 0x0000000006fe0704 clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fe0704)
#16 0x0000000006b86e18 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b86e18)
#17 0x0000000006b8937c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b8937c)
#18 0x000000000660ccad clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x660ccad)
#19 0x0000000006605a31 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6605a31)
#20 0x0000000006605c9e clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6605c9e)
#21 0x0000000006607b8a clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6607b8a)
#22 0x0000000006607d29 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6607d29)
#23 0x00000000065e5e61 clang::Parser::ParseCXXMemberInitializer(clang::Decl*, bool, clang::SourceLocation&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x65e5e61)
#24 0x00000000065f8d47 clang::Parser::ParseCXXClassMemberDeclaration(clang::AccessSpecifier, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::ParsingDeclRAIIObject*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x65f8d47)
#25 0x00000000065f9e75 clang::Parser::ParseCXXClassMemberDeclarationWithPragmas(clang::AccessSpecifier&, clang::ParsedAttributes&, clang::TypeSpecifierType, clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x65f9e75)
#26 0x00000000065fb9c7 clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x65fb9c7)
#27 0x00000000065fe170 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+++0x65fe170)
#28 0x00000000065d2a50 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+++0x65d2a50)
#29 0x000000000658f594 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x658f594)
#30 0x000000000658ffee clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x658ffee)
#31 0x0000000006596637 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6596637)
#32 0x000000000659750d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x659750d)
#33 0x00000000065979b0 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x65979b0)
#34 0x000000000658a9c2 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x658a9c2)
#35 0x0000000004469918 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4469918)
#36 0x00000000046f8ee9 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x46f8ee9)
#37 0x000000000467c4de clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x467c4de)
#38 0x00000000047e2dce clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47e2dce)
#39 0x0000000000caa52f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcaa52f)
#40 0x0000000000ca377a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#41 0x00000000044acd09 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
#42 0x0000000003a64c14 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a64c14)
#43 0x00000000044ad2ff 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
#44 0x00000000044732a5 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x44732a5)
#45 0x0000000004473d0d 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+++0x4473d0d)
#46 0x000000000447b955 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x447b955)
#47 0x0000000000ca7925 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xca7925)
#48 0x0000000000b7b664 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xb7b664)
#49 0x000072e8a6029d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#50 0x000072e8a6029e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#51 0x0000000000ca322e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xca322e)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsm19z46iywD-N8kI5JaF_1kMePE68N7uZmtQ4d---uRBq2dzIoAso4-ynvwWSHSE7zmRPNHXO7KYmE1uCpvvXDbQAEaXYmgNcefEnL76-II3eCHm11PIRLnJRPF99hVqKoqEgvXCGNlrXygtnHl54eLEWRS4qfSnk2sOLPz28-AyyDMvws_L8a8-feYnf_bNflZYN1WiGvPRTewUhhJQmmlFEBVcadrVEpNECEbXSTV3BagNVDdLDUw9nbkXzI0E3kiOlC6NVOGvrKPYneOG8AFrp5xo8PG0bWVGitBfOH0wpDydeeGMFz_SGKQ9nl6uCaOLhzNwIe0156XX35UhbxjUytWyjyAuvj1QP58G-oewg1Ug8fHYxzcV2S3iBtEBUbGtWgbHtVElaEb728CcPf0KTiYVwTdvv2EdbwvglreuTVV-XZPzs4YUUQnt4UVVP20ktxf8CNV-7couK5R5eLGFLuj9fnkBWghS2wXAWhHHoG0lPghVoVhT7-1DMSVXNCS9YQbRxTSvSeq-Vl3h4jnpXr4FWM0pBqXvC5ODmA2zrimiYyXWzBa7vmNK3vBQenpmSRv224ExK8vwVSi-c96rf7Gppihr_OHL3-h40XYLuVMuFqF7-ZsbKmVIgNRMcGaI4-I2Lb_x3UrEC2UoJ8jC-2dUVo0wj3emMSKe08sKFh7GHU1QSVkFx2Xrl_u5mtrxBqsm3TCOC8maNJNRCahMcg87I9KbJL6nYdl47dh5TqgHl4QUy4cU4rZoCkN4AopKoDcoJfdSSUDDW1dL0fEMdCqREI9vLpiZRSlBGNBRINhwpKlmtO5WXmtBHVDTb-hC0_qXnZ_dSrCXZ9k22YSZqG1ZtnMsJ7OpKSNPf21CbkD1ZNdGy4Y8eXuSMv0RiG_vr4huR5SRCkzWaCCOX1LWR3ui60ZcKTbaGBZpMdtNkQtR2op65JjsvvGZcQ4UmJReTJ5C5UGDuo8kSTSZrSidaiIpuCONeeH1WX1NYcVKrjdBoUlJRCTkpGFlzoTSjqm3DknYvD_utF8473uFNSzAwBJ3L4Sz1wlls_kO0kRK4RjWRCiTS4hE48nBqYhOnrQR8QkLQ_dqKjK9ROz57eNFwJjrGSiEzDxh5s4M05OHQR_7O3_-EeQAxTHvdTT2r9sO9ZFzbqHhoQ2v6UkiSbyuhtASy7foW49qO82aw_JDY8PAnf9epZ4Ac9A8G-lNM6Cn95xUQ3tRf-JKtOak8PG24nTQLVAnTyhjaGmUcbbGjLUmiNJmiuYmlr0DFE8jnVr3_Iryo7HTZkXTKzAXXsNPdGO3b30MTYddEimFKEj_CsYlFa1o72u-mySqJJhXjzW6y5k17g14qcZlYxW0VR-3IlZklWUlRrTcSSLF6ZFX1vgZsfaeBeKh0lCZorSyL9yofpYkjO3Fl42lahojkZvR9l2Rb0ZGcHkkO8nfLDHJH5tSVGWaQJe-Taas4MrN-1CVlEU7z7OeezNGJXKbXT8y44Q-hEMjQ0O5Wy1dJKRfVf3MJSlRPUNwJ8djUe0NGtfnDx62OxSGCDKxgCKsAOA0rb1g1wGU1dkKKCpPNzwam9nC9F-rnRpO8gneyXdpZ9E5Qou1E-R3gh9rNqKn6FVRT6dOt4jnSsrFztfk2irsKAMdd2HUX-HEQn3bXp2N3tYqP4a-z6Ed1Zk-J4Ujx4e6wtB13hI478mkCwfSMOz7ACT8v3paegzcaRrufYrRgnKnNm5F9cnL7qeL93UPaUSlb5LVSjK-70e9ds2889FnqR_-MUD9shEr9yOlCyT8j1JgjVDrAm4UpfSXXpPoL_w_GOwZOQ8vBOXVwJj6lpOhrc29XUHqf74XSJdsZLUEpJviyKUu2c_m-L5X7eENbOxxDs4GhMQmDs4bOidIvVrr29Qubcvb7b4wXx51iOCH2qz4817aZpbZTw7DqKDHQWt5Hg_0hGprB3xQNzZzsHwcDNGk-JeOi-bfiYcx1eOAhjwJnZ3nM7HbaFvh3URlYOYpJBXaex7H7RBFDDMkbA8Mff3yGbQ7yljPNSMX-hMH0cg20GsyQZ0b_ZAxDWzscQ93cPi6nRZS-Zei8Ikq11hqjiOx0dgd7Ckota6CsZDBcwLKSipnWkuWNXeY51-3b0vtFr3ah61R5xtdGn6-z29svebuXM0oXaCk5GOMBxgzS-K9h_B-mN_eSrLdEvUH0JLKzUE1POgh4sDu-R4uOozEzSBxmyYBZntE3Q6_F1dlAT8Td2Szq7M1X8B12MexGwY_DZWg4uNIBLghS_zwuE1-9eOlj0uKxCwnxCHw_3XwvKmO4Efyvd9sTw8Qbc96-7W6P5nucOIZ7DH3HPW7OHBeYxOfd0-vzB_vV8ZQxGue_zrcreUc0vPC-Y-rEWsfttt3LN4MNJ1s4SB3BJxa54xM3vY-nZZxFb_rki1w03D6qXEN5yzXIdjvz_dPXmyW6Ceu0i49cNgIyS6SPzN2uNgVKOJ_298LYIcdMHnQyrftocMdbBj8CXOluCbj75EmcJUl4fja72bWh9WoKNRasEXBYax0ceIAjjf3zSwgPor6DJ6jaSbXP4UtN_q-Bey3dRQNT8BcpmtousdycWGU-LPp8FkVTwe22FnL_FDHOtGDNdDiEQw5Zfn5aWDCp9E8CI8ud8TgcPGxMSUbxEYzZ8uHVPYSxlxZblRydncw-ipIsc1du56KAX4C3i1v75SygjYbuUnci82M17RRxNHXy6Sgpp-BuuC-kmXx5cULVkZRsdXCUTF0lUxoV4OJsm73lShNO4TTR160aJZY7PR1DnHwvSgEXFNwVW6vyiz1P4tTzypG9o4zQnX6OAU5y5FNCYlwiSoPVlhgZ09MnKjZEtod6e2vYzjU8t2dZx7Gj1bJvRuQPzAjTlKA9_HnwYEeKnjHLLamq34FqIU1yetKmxF3PNzK6xHVfzkZZIdkTyJP7b1HgDhuEFn7WHvJ9kVt22dJKWrb27v74801bhJKqygl9XJXcHfDbtrsYmgfdWehhpz7pw8MhcFGb1olh0OOjpd1ytNNI6-BDhdWK7nZB0H7JiWJ0pWzxjqJT2FxYaUmYVvvbA3GkqkyfELJ3vzvF4SxhtsxtFQ-nFdnmBbHnNveo8HR_xPBXkZ_2x9HBQBpEPVecOv7X3vna8CUpoXp2cJ533QhnHVuNncgPByFW4LJEf-cQMdAvayL1pX82FiIXXBpiEr8KzvqOHM2Ye5rOYD6oaN9OeBkw5mfa6BedDY6fHWz72ATCmu0EVDzkUrg5-_dw-VXk6nUov4r8jintQDk3NB_ioCbMhMDxGtxZjl2w_BiahZv5R8mAZp7Fr0bZde-zkzicyBhe88IPpDlCOmvxOPzSwcSeZrjjt89Q9vrbYWV2dGbxtWn7w3MSo5mjupMb-nmaJ0lkXzP66LZb0U7b2eDMdFZk7zyebqv0Zcb-UCZEPlqtTLWV0kTqVc-4724FIreVYJjJYQyolf_xPjPCD633b4czBFIK-xqfvY7K7gkD0a5HtO8eoW9MbxDsmImuAlAQRkbNRgGaPCEtkAJArJf2Z4fX1qz63Tt5YPqkqTx43-yiuAqLLMzIBVwFKY7DME3j-GJzhaGIcTQtiizKM0jyMIv9PC2TeJoH0zDJL9gV9nHkZ37oRzgL4suoiPI08yOMsR-QaexFPmwJqy5NX7kUcn1h33i6CvzUj9KLiuRQKfuqI8YdGuzF1xfyyr4olTdr5UV-xZRWLyI00xVczS0x-_IOKCQ4YpwKKYF2kCyz4Zs8F42srv76W1qd2k9X-P8DAAD__zLXrqA">