<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/124715>124715</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang] crash when combining CTAD+std::invocable+alias template
        </td>
    </tr>

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

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

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

<pre>
    Clang crashes when compiling the following code with `clang -std=c++20 main.cpp`.
Confirmed with clang-19.1.4 and trunk(84af3ee).

main.cpp:
```cpp
#include <functional>

template <class Ret, class... Args>
struct SomeLongStructName {
 SomeLongStructName(std::function<Ret(Args...)>, Args...) {}
};

template <class Lambda, class... Args>
    requires std::invocable<Lambda, Args...>
SomeLongStructName(Lambda lambda, Args... args) -> SomeLongStructName<std::invoke_result_t<Lambda, Args...>, Args...>;

template <class T, class... Ts>
using AliasName = SomeLongStructName<T, Ts...>;

auto main() -> int {
    AliasName([](int) {}, 0);
    return 0;
}
```

Crash dump:
```
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-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>:16:29: current parser token ';'
2.      <source>:15:20: parsing function body 'main'
3.      <source>:15:20: in compound statement ('{}')
 #0 0x0000000003ab3738 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ab3738)
 #1 0x0000000003ab187c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ab187c)
 #2 0x0000000003a00bb8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007b0685442520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x000000000782ea93 clang::TemplateArgument::containsUnexpandedParameterPack() const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x782ea93)
 #5 0x0000000006eda160 bool clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformTemplateArguments<clang::TemplateArgumentLoc const*>(clang::TemplateArgumentLoc const*, clang::TemplateArgumentLoc const*, clang::TemplateArgumentListInfo&, bool) (.constprop.0) SemaTemplateInstantiate.cpp:0:0
 #6 0x0000000006edafde clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformConceptSpecializationExpr(clang::ConceptSpecializationExpr*) SemaTemplateInstantiate.cpp:0:0
 #7 0x0000000006ec2243 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #8 0x0000000006ef0445 clang::Sema::SubstExpr(clang::Expr*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6ef0445)
 #9 0x0000000006e4260b (anonymous namespace)::BuildDeductionGuideForTypeAlias(clang::Sema&, clang::TypeAliasTemplateDecl*, clang::FunctionTemplateDecl*, clang::SourceLocation) SemaTemplateDeductionGuide.cpp:0:0
#10 0x0000000006e819c2 clang::Sema::DeclareImplicitDeductionGuides(clang::TemplateDecl*, clang::SourceLocation) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6e819c2)
#11 0x0000000006a7dd00 LookupDirect(clang::Sema&, clang::LookupResult&, clang::DeclContext const*) SemaLookup.cpp:0:0
#12 0x0000000006a69b94 clang::Sema::LookupQualifiedName(clang::LookupResult&, clang::DeclContext*, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6a69b94)
#13 0x0000000006a3de4c clang::Sema::DeduceTemplateSpecializationFromInitializer(clang::TypeSourceInfo*, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6a3de4c)
#14 0x00000000069259ab clang::Sema::BuildCXXTypeConstructExpr(clang::TypeSourceInfo*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x69259ab)
#15 0x000000000699b37d clang::Sema::ActOnCXXTypeConstructExpr(clang::OpaquePtr<clang::QualType>, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x699b37d)
#16 0x00000000063d6901 clang::Parser::ParseCXXTypeConstructExpression(clang::DeclSpec const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x63d6901)
#17 0x00000000063c5e01 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x63c5e01)
#18 0x00000000063c699a clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x63c699a)
#19 0x00000000063c6b69 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x63c6b69)
#20 0x00000000063cbe09 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x63cbe09)
#21 0x00000000064595a7 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x64595a7)
#22 0x000000000644cd37 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x644cd37)
#23 0x000000000644d72d clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x644d72d)
#24 0x000000000644ea44 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x644ea44)
#25 0x000000000644fbfa clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x644fbfa)
#26 0x000000000634b226 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x634b226)
#27 0x00000000063954ef clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x63954ef)
#28 0x00000000063437f7 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x63437f7)
#29 0x000000000634460e clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x634460e)
#30 0x000000000634df02 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x634df02)
#31 0x000000000634f798 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x634f798)
#32 0x000000000633ddfa clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x633ddfa)
#33 0x00000000044038f5 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x44038f5)
#34 0x00000000046db8d1 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x46db8d1)
#35 0x000000000465b2eb clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x465b2eb)
#36 0x00000000047c6973 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x47c6973)
#37 0x0000000000d106a1 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd106a1)
#38 0x0000000000d08e9d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#39 0x000000000444f159 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
#40 0x0000000003a00fe3 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a00fe3)
#41 0x000000000444f379 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
#42 0x000000000441351d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x441351d)
#43 0x00000000044144b1 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x44144b1)
#44 0x000000000441e83c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x441e83c)
#45 0x0000000000d0d331 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd0d331)
#46 0x0000000000bd3054 main (/opt/compiler-explorer/clang-trunk/bin/clang+++0xbd3054)
#47 0x00007b0685429d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#48 0x00007b0685429e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#49 0x0000000000d08935 _start (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd08935)
clang++: error: clang frontend command failed with exit code 139 (use -v to see invocation)
Compiler returned: 139
```

[Compiler Explorer Link](https://godbolt.org/z/GG7edsoe7)
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkW91ypLa2fhp8o-ouENDAhS9wezxncpwzc8beu3LXJSTRVgwSkYTHztPvkgRNg-m2M2GSVO1UptyAlvStT-tPQiCl2J5TeunFV158fYFa_SDkZS1-fUH48aIQ5OVyWyG-B1gi9UAV-PZAOcCibljF-B7oBwpKUVXim7nCglDwjekH4G18bOVWShMvvMYevPLgFfRBjRhf46bxNv7a8_Ot4CWTNSVOzgqtgmwdrCOAOAFatvzRg2kaoTKk1IOZkfL8_NBPaK68je_-N3f83IMh47hqCQVeuC1bjjUTHFVe-MFJa1o3FdL2Ma6QUuAr1R7cAnuxXq9BLvfKNVdatliDO1HTW8H3d_by_1BNgZdceX4-88SDqdU798K8H90Lt3aM1PS8Xq89mJn-4RYMN2yPybXBmFx74dUpsLeoLgg6gRcAACT9rWWSKnCAwfiTwKioqBduB_F-aCs4q4drC6qpCEBmQJiBlRd-mKMg3I7GfqQ7SVVb6Z0-hWB8dVr7-5Hi953arTImmFcMKTc54fU8LCt-Px0GtVpY4_RgelCLcd1PMgBD36aJdRgPpozro4mDW-Dbib06TIRuJQd-N46b295Y3chb41qAtPXUlj0__3L7Ib_7AFRb1EwDBIp2DyRthNRAC_CgdaOMELzx4M2e6Ye2WGNRe_Cmqp76P6tGil8p1h68YUq1VHnwxvpW7yLGia1_gwLhRy0RpkaRRtJGCkyVogQo0Up320gipQRmSFMCZMuBwpI12jjmnUb48UgX4-PZFyn2EtXGYtqacm0gAw_eiMZgcsGEyhV9biohqTT3bBjofP-mMJPi7rkwAlZ78g3JchWB1R6shOkMNY3pstVNq9cKrGqjOlitntPNCql6pV64Rs9eeM24phVYlVysnqgshKLmOVjdgdVqj_FKC1HhB2MI4fVZkKax4qhRD0KDVYlFJeSKMLTnQmmGlRvDEju-PQ2JxlUcvdaQA8PZ6F6YBxsvzI1d5QC3UlKuQYOkohJo8Ug58GBiLAwmnp_DOfnYyPtG3sgZT-njEjBR3nTgjN_0EJ7vgbkMIFpOgNJIUzOpwPpN0vtBYrzAN9Mc-sB_9vv_QlSESZgCa582OKgX5X58kYxra0D3zgTToZFE33ZCaUlR7cGNMcPe78yo329JHrzynztMA-JggjhIEzyHeFtRxNvmM79je5NdYNpym1AJqIQZYjF8BsGAD47x-X5RpMCGka8UiycqXxyg_0GcVGaYPkqN2mwF1_RZd0nUt_9c_2HXf1L4mzSOIhgbK7WaVKzw4M1zutltolXFePu82vPWPcBrJdYbC9mKDICjY8BJCinKQpfrHZH3XYzPuwjh7mLBNWJc_YvT5wZxQskXJFFNNZVfEH7sAjUWXOlFeO6ADbDjY9gbSlCw8UEhRDXCLim9l4irUsjaC7ceTBEX_KUWrQIc1VQ11pqzsaqfuNKIa4a0kM7DbF9dP1NClEt-p_i6Fdjx4MHcZtL0vY1dJl2iKVP6Ey9F556Gpc7-17aHRopmbUwC3NEavWaBztjhZsp_SegPp34rOKaNvmsoZqhivyMTJD88N3LM6plm-R_TMhlriSGMwh-u5WuFvgt7OsZe-lEUH2M3PXW_2kLpM6OOjOvnttLslj7Ras7MepPcLBVgO-CD42djtSK48QvwBu9XLavINSWtzaofW0bojZD3Lw21deNYbcuL85Tjme4b91pfU1y9Zuemy9znW93Z5H0rsLXM6bSOgU5m1qRAf0xBGmQYzs-sGR5J-qluKoaZHves5mPReyEvM7sWvJtdo9oovW9QQojvg1shHtvmmklbKb89V679V7ukef3U6Nfl16MA6qbASc5QDse4NlmRRfOUuy7-v0UVKxkl3Zrke9B1k3AUrv883w75wHc41iskNMKnTIm0mPZGMo6tN1LUnzjT9g6dhBHjOc56XA6aWtYgSD5wzfTLUQyZb2jH_F_GyajlUAT-3Gqzms6lRC9faTnOz31UM6l4KVItbQOpo5Jqk8E4Q8U8qTYwbX_5xXC0NbqYtfDrSPwWhVPn_C4y3uhxUTN0nAyMjau5LCvChMwzlmP9mb_N2OcG_dbSL1qO9TVuaSTfo_A_nUJL0kDhuCALySbzg2M4X-ya9Oj3HIlUKYs1nUQk4-7Lp3YHclBhXG2FOKZvqYDUSdjHjU07e22CxjAT_d9poDkWtRQhZRa_mr4WzZcjw6o7kJFOyNhkGfqxZPz9DBgdBwayKQPFJjvLQG63zE0p-h4eJnotp0SxyQ5KQH-iREH980r8ndANuAH6uBaL4ixGyZvQ7_pNp9Po7W9yp2t9KHQW0sBhHDQYV21RhEl4XoMD-s_Slc42duelpjLXWrKi1bZsHnLDXY2q6t8U25XccV4w-nWZOoStTQ_n4swMKWezybQEcPLHIGdHm7ZYinhL7UB8OCGeJJB8B_H_FKYXY8nwMLAUTViiKIrOh_hua_fA1pUgLx5MFy0sHI4BZTxBWRbl-UTUr4GnKCc1xQkbHlkFFg1d1k4N-kG3SdEUFRBu3qXbNS2ZWY7MRWnG970NC_keWxz2c0pxavFzLHWLNB28-ZYdlrDLpAHLwsDRpCrL4oiWZ_Uxyn-Uom1OUmPKyfmlryNt3jHfGeJOUvu6_buCatffjZBfEd9TswpdlG5L6ED3pO6LwqQ8n7MMbZ_lkWF-4ppK987jzyeIVy3OTmGOMVXKbg6UzHCwmE0aGgaSJqVhFG18-iZJXVIZcXXSiRenampbP44qQ8aBqnBSgEak9OEbVZwzn3Ee_gvoWYwAo-JAQDAhoEyy9CwB96Kx-9suSb1jV-EQ8OzmwEz5MWxf_CxIW9FPdSNkX70vuJ62ug2aj8vfMCRkJnPnd_cn91THK72lUFocA8pRrRhFfpiWo_cUW0HoR8rz7qSO23OhuNW0u-XeNS6BrRt9wDaq0KINKVIy2pG4kSZTcTIDbklYbuABVjyGFReQFmPK3EDuBRGm86yd1mM5m-zADdBHFVeU4E2WjN6odSAHDZ4O2Tk9p-FyAaQDNUAeFUA-CfwNCgDGwa47kjQsUY53CB-QHL_33YLxPbgFT4KRBZE7aAPwdAzcT2lGQE_wNri3Xj2_wvpUN9WsFpOtdtPH5GWKtR0i2ROVr1-kjF_fRVFUBnFmeTjqtD_-spOWSvvUudPhZSlGVVUg_Lgr-TgWu4E7I9kGW1HXiJOpZ85O2eFMnGj6I4nbI3K0ZHzfRXg3nweB3Q4_PweBuyiQYninbPOOwlFjc2OnJWLu5IB5POkOVZUxerfO7Z6bJvlk180RbkU8mPTHAJOBKpj2Z11-EsXryYj86WGVkoZH8zB3JMU9-dryO1TS6mXE5fl5W-zEjYV5sPIomFpUmIx22P7rLMIe7GiQ1O5Mx_zUwzFrQRgH5CRrdqrQqxTXUzmKzBNB0-DUmvZM03xyVmW5k0SdroP9TOqPIIqK4I8y8ZMo1GkafhLF5GzEcQh9HXUP094gZmbcnhB7P3Odbfw4_gxDA3_RhD-ahvgU1uuj36NMP5PiT_H-F_K3VFVpORkYiyd5mZhFipXqS4oesY0Ueefnb2fdRYoIC2cAOyrY_IKEfhzZw9iLjOb6G0ZLxscbYUayP3i80YoMHabTDmnkg93OyOyURlLvjnR59xA0Ohoim5ZZWRgD1_lCM2J6dOMdPwtzQKU0OSF31gPKrowHuLPpErGq_36DPjPtPgMJQmsqraJg9QS0AIpSwI4q7cx-_eHQdsfkqXEpI_n6kLwXXx0af-hUA7eMP7pT-JOT8IIUotJrIfcevPndgzcfPyaUKEETD2YX5DIkWZihC3oZJGHqR9km2Fw8XMIsLkiYFGEQFFEUpAWNM0gy6Bc0jgkJL9gl9GHsBzD1kzAMN-uEQlpGaRjHCMECF17k0xqxam3cyAx_YU_cXwYwSoL4okIFrZT92AbCjmXoxdcX8tIe1C_avfIiv2JKq6ELzXRlv9BxEvF1d1i__xSnYJzxPdje59cevJr54ANeoYohBfovKS5aWV1-_7cDnTJPl_A_AQAA__9N0hDP">