<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/112660>112660</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang++] Frontend assertion failure in clang::InitializationSequence::Perform
        </td>
    </tr>

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

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

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

<pre>
    Hi there, clang++ crashes from an assertion failure on the following invalid test case:


```cpp
 a ( [] < -> > { struct { struct {} b [( { }} c
```


Tested version(s): 17.0.1 ~ trunk (assertions)

Example: https://godbolt.org/z/TsM7341G3

<details>
<summary>Stack dump</summary>

```
clang++: /root/llvm-project/clang/lib/Sema/SemaInit.cpp:7663: clang::ExprResult clang::InitializationSequence::Perform(clang::Sema&, const clang::InitializedEntity&, const clang::InitializationKind&, clang::MultiExprArg, clang::QualType*): Assertion `Kind.getKind() == InitializationKind::IK_Copy || Kind.isExplicitCast() || Kind.getKind() == InitializationKind::IK_DirectList' 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 <source>
1.      <eof> parser at end of file
2.      <source>:1:6: lambda expression parsing
3.      <source>:1:16: in compound statement ('{}')
 #0 0x0000000003bb1d58 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bb1d58)
 #1 0x0000000003bafa1c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bafa1c)
 #2 0x0000000003afcd68 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x000072a27ea42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x000072a27ea969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x000072a27ea42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x000072a27ea287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x000072a27ea2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x000072a27ea39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000006eb709a clang::InitializationSequence::Perform(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, clang::QualType*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6eb709a)
#10 0x0000000006acb90b BuildImplicitMemberInitializer(clang::Sema&, clang::CXXConstructorDecl*, ImplicitInitializerKind, clang::FieldDecl*, clang::IndirectFieldDecl*, clang::CXXCtorInitializer*&) (.constprop.0) SemaDeclCXX.cpp:0:0
#11 0x0000000006acc62c CollectFieldInitializer(clang::Sema&, (anonymous namespace)::BaseAndFieldInfo&, clang::FieldDecl*, clang::IndirectFieldDecl*) SemaDeclCXX.cpp:0:0
#12 0x0000000006b0227d clang::Sema::SetCtorInitializers(clang::CXXConstructorDecl*, bool, llvm::ArrayRef<clang::CXXCtorInitializer*>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b0227d)
#13 0x0000000006b570fa clang::Sema::DefineImplicitDefaultConstructor(clang::SourceLocation, clang::CXXConstructorDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b570fa)
#14 0x00000000067e0f81 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67e0f81)
#15 0x0000000006ea6035 PerformConstructorInitialization(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, clang::InitializationSequence::Step const&, bool&, bool, bool, clang::SourceLocation, clang::SourceLocation) SemaInit.cpp:0:0
#16 0x0000000006eb4c3a clang::InitializationSequence::Perform(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, clang::QualType*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6eb4c3a)
#17 0x0000000006a1a11b clang::Sema::ActOnUninitializedDecl(clang::Decl*) (.part.0) SemaDecl.cpp:0:0
#18 0x00000000066a00f8 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66a00f8)
#19 0x00000000066afb19 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66afb19)
#20 0x00000000066b8437 clang::Parser::ParseSimpleDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, bool, clang::Parser::ForRangeInit*, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66b8437)
#21 0x00000000066b88f9 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66b88f9)
#22 0x0000000006764f72 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6764f72)
#23 0x0000000006765ca0 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6765ca0)
#24 0x0000000006766b75 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6766b75)
#25 0x00000000067060f2 clang::Parser::ParseLambdaExpressionAfterIntroducer(clang::LambdaIntroducer&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67060f2)
#26 0x00000000067071bb clang::Parser::ParseLambdaExpression() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67071bb)
#27 0x00000000066e6795 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e6795)
#28 0x00000000066e7147 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e7147)
#29 0x00000000066e71d9 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e71d9)
#30 0x00000000066e753e clang::Parser::ParseExpressionList(llvm::SmallVectorImpl<clang::Expr*>&, llvm::function_ref<void ()>, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e753e)
#31 0x00000000066a05b1 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66a05b1)
#32 0x00000000066afb19 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66afb19)
#33 0x000000000666fb8e clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x666fb8e)
#34 0x000000000667034e clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x667034e)
#35 0x0000000006677ae3 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6677ae3)
#36 0x00000000066789cd clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66789cd)
#37 0x0000000006678e70 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6678e70)
#38 0x000000000666aeb2 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x666aeb2)
#39 0x0000000004526408 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4526408)
#40 0x00000000047e0629 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47e0629)
#41 0x000000000475f1ae clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x475f1ae)
#42 0x00000000048c5dce clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x48c5dce)
#43 0x0000000000cdce6f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcdce6f)
#44 0x0000000000cd4b7a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#45 0x000000000456a119 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
#46 0x0000000003afd214 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3afd214)
#47 0x000000000456a70f 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
#48 0x000000000453000d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x453000d)
#49 0x00000000045310fd 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+++0x45310fd)
#50 0x0000000004538a25 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4538a25)
#51 0x0000000000cd9d3f clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd9d3f)
#52 0x0000000000ba9264 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xba9264)
#53 0x000072a27ea29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#54 0x000072a27ea29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#55 0x0000000000cd462e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd462e)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```
</details>

The test case was generated by a fuzzer.
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsW0tz2zjy_zT0BSUVX-Lj4IMsWzOZSSr5x_7v5qYCyaaMDQhwANCRctjPvgWQlAjqYXvGys7uTiq2JbLR6P71A90ggaUkawZw7cxunNntFW7UIxfX220NVxkvttc_E6QeQYDjL1BOMVs7_o3j36BcYPkIEpWCVwgzhKUEoQhnqMSENgIQZ3okKjml_Btha0TYE6akQAqkQjmW4ARzx711XPt35Lb_87puryCMHD9BrYTICRZo4gR3yPzEN0gq0eRq9NGJb1FmhuiR8Q1y4lt9LR9Ncjj_A0gFBXoCIQlnjp9Ix0-dYI68eOpOPfRPpETDvmqRdjobkgGPuw2uaqr1Q49K1VIr6i8df7nmRcapmnKxdvzld8dfPsgPcRB6PwWWJMGiAIUJlU5wt7skm6rCYusEd_cK519R0VS1Eywcf7m_cxTJ9uvAelowx18KzpXjLyl9qia14P-AXH_t6JaUZI6_vIcKd3_eMaKm2irBPI6iQDNpaYO5E8zvNrX4DLKhanhVjyGYku9Y43QPvzXAcmjvfQJRclE5fjIY0M4XGXfjTB5nBsUdU0RtnyU0s_5KWNFT7mk-NFQRLfRc28K69X8Npg_bGhx_3tl-vvNuJ3I1v-kaVMs3cfwUOcGtE9yiI_O28vy6WvB6i5x44cQLZBgQebepKcmJWmCpej4DgtfOcEsE5Oo90cxiE4VQTFvTf3p_N7-_Q7LJKqIQRlmzRgJqLhRSfOyiRD022TTnVecahx5CpGxAOv4SYVYgwnLaFGCC3WQFlOH8qxI4N0mjFlALnoOUUCDJG9Fe1iOxlDwnWIebaBiSuSC16kQeunjnz-7UcdNPgq8FrhAW66YCpmTny7w2vsurmlAQE9jUlAsQvT9P9rE6MfHr-MuMsL27m6Q2WRffsCgnIZqs0YRrvriuNfdG1Y2aSjSpNBZoMtkk0QTLaiK3TOGNE9wSpoCiScn45AlExiXo-2hyjyaTdZ5PFOc0f8SEaUuek1cTS4Zr-cgVmpQ5p1xMCoLXjEtFctnOYZC2LusM0cLbpwFPA-YEC-ClTpY1FhIEwgoBKxAvUUkotJR-R7lnEMw9J5hHGl2Kq6zACDa1AKmTouFE2LodG5wY65nBhCGtJG9YgaTCCrTRkHHquM3T-kOfPpHjBy5yN27_L8gyr5glyDii8XS5lV36EIQp4yYPra8leyKBv624VAJw1UU-YcqEkZ74TZzF8W_cTSeeJb9ny49L7OXH5F9QwKypP7J7smaYOn7SMLMYF4hyPcsFpDXCWNL6lrS4zIsoQQvtXJ8h508gtq14P2NWUD1p0iFp0Sw4U7DpVwfX_OymCLopYh_7MeDQn_lup1q7xmySaBWFE0pYs5msWdPeyKeSTyMjuBliiR3aPNMoLXNUq0cBuFh9JZS-bgIz3ppgNhY6jCO0lgaL1wofxpHFO7J5-0lcBghnOh2_irMZaHGODzh72at5epnFM7F5Bimk0et4miEWz3TodRFksZviNysbzhQMbalwhnC3rFqU--j90CicUZgLgbefoXSCxagE0jVDcHe2oHjrsO7w29egfuBZSTTCeZa6GbppCC3eVW3V8QGqDMQeIfESQBdfviw0LrrM5uIWcmpUWqCe64BfW7xYw5cEaDEYZVmgMPXLGRI9ueK2yHMjo4F0aixWC15Pda5AWgPNaPHly2Fe0hh5I4zyyM_RglPai_EScHQbwDjbVryRiOEKZG0Wo7SlvMES5qzo2JX8ENJXY_ICzaykHmWu78cFGsvffVIjTKWt6kmLZ5xTOzaOB8Vxq-kQeftAaDW1AiGwoZjFbomPQ3ELJWHQO_ItlLihaqD7yAVMtfOe5yZjvCxMLqCw0cdSOLQUjsEtE--4wqJhfyfq8b4pS5IT6Iqp-9Z_z-u6N3rZsFxfXQlj-CdOilbL9EI2bjWyVJ7ZqwmO3GCGumViYAc7yf8nrR_nlsN7BbU1WRuY0TBG-78v9d_xzTblDPr_Ub6JRst5mAd_Led_YDnX-FkeHttLlYc9Lzse1PNcfWT_z8geqjb9DNG1E9K0xkLZS-ZxKyeWEBF23TIZCvHJ9JeDz5oVFsYG81KB6L9zMWfFXClBskaBPBSuJTq068EMxQNUNcUK9Np6yhuGo5ZcfMZsDdpDLmS-FhjLfOkIuTLz0meR-0nwprax-dT23frufQ35oap78LqO7BgUFvSvg_iQfpwqxjXMDwdfYzsE37dL4ShLwiA-q_E9qWo6dN5TDnoc4zEiRxF-3gaHFEey-Fl0n7PTBdA34Froe2P0k_J51_9z4f5vQDEpbR-2C_o4CsvYP-_D_VbbRzHOwlbi3S-F9xWm9G9gKl1rGbxXVe9Pgd-Y1fD5pKEHvcxMRxPG6810gULToGyZIRiZYZZj93eY4c-C-yUw05BYmI36kSjK4tlZHRbddvEOuxtebB0_adPfJWTWIlky2w1F7EZueT7c3pst8rvdDrkJtHdMCV40-Xj3oCUe3r2M_xqxLb2ikV6xl2Wv0qt_GPXmompJLFHtijeCKE6fcRsslSXoCWJNZ773-1N2k3QuxHTNr4cbzzwcepnFwGhuQTOqwyH2wvMFzR-G5k-Fh1bXwiM9wKM4X2LMzUsPOrW8BJWRlpdRqbDW-8AdqzQL4KxKe0XaB8DHF5h3VU1P97jRq3Z2xta-CC6zACxcvHELOsu8v1rQYy3oLLP2yOznfH-1oD-0BQ3sujGKyiw5H84axI9i2UXgLZTvmALRPiV-45bmWYPO8xyk1PdISTQiF4DMIGJBZpeNUewG4fOQdZFuIWd2wo7m97cGbux3PwI4g4sF3GwEXIwheGbpaF3rZON9KbAuAYfW1oIjGsGRpHlxFo4HXr-HJ6CH26Yfa_xbA5_UqE_bJUqzgXykS9tvzn7gRUPhXVVz0ZcTFyn9WzUtHOIxDhCfb12XREj1XwIGxFZPGowq6AhDdtjfze8fTj6UuHjpY0SyZLaq3HDmR6Fr7b4veAE_AZubvNcXd5A3CrpLF2ndOkGGkoZW8RrG4Ea-VWoshS4MWHFE1AsJ2cpgCenZQs5KD4MNZzvtOyYV3j2sGiN6WquL-HInp6WIVdiFST4rcrDfyzUi7_V52hVKyTl9L5KhO_ksBaziyM2LHKIS5bm3qjCxt8qGj-keseiL7d0TOuuav0C6ZbmMHq2UlhrhSI0wizHqwV94DyZTnG_LDnQadWSaR1dUDxqNFBWCPIE4-tAunNlpI8KelxpgXtzpGZIcU5rh_OuqZHbCb-fufGjhLXhV4f6l5H1QH7WhVB0dr_XsWGMwwEcJwtbdMtIaeDdgtco3G89rv2RYknwlDXmHokWsL6yUwETJ_vaIHaZUx0S7Advd1yTz0V5Gi7kZ4vhx-1qseXt11xQn_Zubv_DsuD2i0fuWhe-FA1Mce6uyvfO5Yfe4BLq14PzRr190ElueH49dLHZL9L_sIqOn6id9IbGBC1zXLU4CZ2yHD1bMHk0rmY8GaoJTOxNnSOdWsTPQ7W0LCKO25VCjUifw3PLVuPzCM3kalF949p5IdeKtkMPUvPODGhPtAuYd6Jfj2DnLD0FTgzVEc-aO0EywPzsl-e3gs1U4HKkYTlnhB6J5gXLWwGPh540W9rQIuvTWVyi9_CatzLuk8Pyy_eY1iZbMEt2qDd0Mp34UIi30W8_dsrbmHr3176dF-sq3_s0Qi2c45gmhi1YrPWwlFRZqNVDuxbNAaM8yG1dykQ-o5f_2NtPMd7MPbwdzBELoBac7ZofKrsNAeRcR7Rkv9I2oRwQbor2rAOQFoRazkYAmT0hxJAEQGZT93WR9xY8EqEYwKMwhxyA8fkLSnDM8OJTYnph8hP2ZTvQNS7QGBsKc68q2CKOy-f4dxPSquA6KNEjxFVx7sZ96QeJ53tXj9SyJwxRDEnqFl7hlgmdRGkAaRmFeFnFcXJFr3_VDz_ViN3STwJuWSeBGYeGGmZcA4MIJXagwoVMddVMu1lfmjNq15_lR5F5RnAGV_RlXcW3Os2XNWjqhS4lUcj9OEUXNadihLWa3qG_vjhx0JeyV7zpeNYJe__5Td51ST9f-vwIAAP__UvplzA">