<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/69470>69470</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang: Assertion 'idx < size()' failed. In function `clang::Sema::tryCaptureVariable`
        </td>
    </tr>

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

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

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

<pre>
    The link for quick verification: https://gcc.godbolt.org/z/Y8EWoxv13

The bug triggering program:
```
int (^a) (int i, int j) = ^(int i, int j)
{ return i / j; }/ j;
```

Stack dump is pasted below:
```
<source>:1:6: error: blocks support disabled - compile with -fblocks or pick a deployment target that supports them
    1 | int (^a) (int i, int j) = ^(int i, int j)
      |      ^
<source>:1:27: error: blocks support disabled - compile with -fblocks or pick a deployment target that supports them
    1 | int (^a) (int i, int j) = ^(int i, int j)
 |                           ^
<source>:2:20: error: use of undeclared identifier 'j'
    2 | { return i / j; }/ j;
      | ^
clang: /root/llvm-project/llvm/include/llvm/ADT/SmallVector.h:294: T& llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::operator[](llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::size_type) [with T = clang::sema::FunctionScopeInfo*; <template-parameter-1-2> = void; llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::reference = clang::sema::FunctionScopeInfo*&; llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::size_type = long unsigned int]: Assertion `idx < size()' 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 -S --gcc-toolchain=/opt/compiler-explorer/gcc-9.2.0 -fcolor-diagnostics -fno-crash-diagnostics -fopenmp-simd <source>
1.      <source>:2:21: current parser token ';'
 #0 0x00000000037346b8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x37346b8)
 #1 0x000000000373237c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x373237c)
 #2 0x000000000367ac28 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007fa357695420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007fa35715800b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #5 0x00007fa357137859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #6 0x00007fa357137729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
 #7 0x00007fa357148fd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #8 0x00000000063f5033 clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation, bool, clang::QualType&, clang::QualType&, unsigned int const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x63f5033)
 #9 0x00000000063f5411 clang::Sema::getCapturedDeclRefType(clang::ValueDecl*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x63f5411)
#10 0x0000000006428471 clang::Sema::BuildDeclarationNameExpr(clang::CXXScopeSpec const&, clang::DeclarationNameInfo const&, clang::NamedDecl*, clang::NamedDecl*, clang::TemplateArgumentListInfo const*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x6428471)
#11 0x0000000006560260 clang::TreeTransform<clang::Sema::CorrectDelayedTyposInExpr(clang::Expr*, clang::VarDecl*, bool, llvm::function_ref<clang::ActionResult<clang::Expr*, true> (clang::Expr*)>)::TyposReplace>::TransformDeclRefExpr(clang::DeclRefExpr*) SemaExprCXX.cpp:0:0
#12 0x0000000006562b08 clang::TreeTransform<clang::Sema::CorrectDelayedTyposInExpr(clang::Expr*, clang::VarDecl*, bool, llvm::function_ref<clang::ActionResult<clang::Expr*, true> (clang::Expr*)>)::TyposReplace>::TransformBinaryOperator(clang::BinaryOperator*) SemaExprCXX.cpp:0:0
#13 0x0000000006560ef8 clang::TreeTransform<clang::Sema::CorrectDelayedTyposInExpr(clang::Expr*, clang::VarDecl*, bool, llvm::function_ref<clang::ActionResult<clang::Expr*, true> (clang::Expr*)>)::TyposReplace>::TransformInitializer(clang::Expr*, bool) (.part.0) SemaExprCXX.cpp:0:0
#14 0x000000000656127c clang::TreeTransform<clang::Sema::CorrectDelayedTyposInExpr(clang::Expr*, clang::VarDecl*, bool, llvm::function_ref<clang::ActionResult<clang::Expr*, true> (clang::Expr*)>)::TyposReplace>::TransformReturnStmt(clang::ReturnStmt*) SemaExprCXX.cpp:0:0
#15 0x0000000006576cb4 clang::TreeTransform<clang::Sema::CorrectDelayedTyposInExpr(clang::Expr*, clang::VarDecl*, bool, llvm::function_ref<clang::ActionResult<clang::Expr*, true> (clang::Expr*)>)::TyposReplace>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaExprCXX.cpp:0:0
#16 0x000000000657973c clang::TreeTransform<clang::Sema::CorrectDelayedTyposInExpr(clang::Expr*, clang::VarDecl*, bool, llvm::function_ref<clang::ActionResult<clang::Expr*, true> (clang::Expr*)>)::TyposReplace>::TransformBlockExpr(clang::BlockExpr*) SemaExprCXX.cpp:0:0
#17 0x0000000006562b08 clang::TreeTransform<clang::Sema::CorrectDelayedTyposInExpr(clang::Expr*, clang::VarDecl*, bool, llvm::function_ref<clang::ActionResult<clang::Expr*, true> (clang::Expr*)>)::TyposReplace>::TransformBinaryOperator(clang::BinaryOperator*) SemaExprCXX.cpp:0:0
#18 0x000000000654f13d clang::Sema::CorrectDelayedTyposInExpr(clang::Expr*, clang::VarDecl*, bool, llvm::function_ref<clang::ActionResult<clang::Expr*, true> (clang::Expr*)>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x654f13d)
#19 0x000000000620d29c clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x620d29c)
#20 0x0000000005ed15e3 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5ed15e3)
#21 0x0000000005edecb0 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5edecb0)
#22 0x0000000005eac30b clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5eac30b)
#23 0x0000000005eaca3f clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (.part.0) Parser.cpp:0:0
#24 0x0000000005eb43e4 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5eb43e4)
#25 0x0000000005eb4c0d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5eb4c0d)
#26 0x0000000005eb5050 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5eb5050)
#27 0x0000000005ea7c82 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5ea7c82)
#28 0x00000000049a0c78 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x49a0c78)
#29 0x00000000042046a9 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x42046a9)
#30 0x0000000004185b4e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4185b4e)
#31 0x00000000042e382e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x42e382e)
#32 0x0000000000bf0b06 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbf0b06)
#33 0x0000000000be83ca ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#34 0x0000000003fe1d39 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
#35 0x000000000367b0d4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x367b0d4)
#36 0x0000000003fe232f 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
#37 0x0000000003faa4f5 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3faa4f5)
#38 0x0000000003faaf5d 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+0x3faaf5d)
#39 0x0000000003fb2e85 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3fb2e85)
#40 0x0000000000bedfac clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbedfac)
#41 0x0000000000ae8141 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xae8141)
#42 0x00007fa357139083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#43 0x0000000000be7eae _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbe7eae)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsm19z27gRwD8N_YKRhgT4Tw9-UGTr6mvapLYmTZ80ILiUEZMEDwAd-z59ByAlEzSlOHe669w0nsRDEeBi94fF7oKCqVJ8VwNcetE7L7q6oK2-F_LyKwepRX2Rifz5cnMPqOT1AyqERL-0nD2gR5C84IxqLmqPLNG91o3yyNLDaw-vd4zNdyLPRKnnQu48vP7Vw-v_pNf_Fk-PAfH8K89fdr-N7KzdIS35bgeS1zvUSLGTtDLSuo6x3_-zH3mtkYdTL7qmHl6YS3OHe3iFzMUXe5NcIS-6nmrrZSbvkATdyhpx5OE1-uKRd8hLrvbXk0N3v-80ZQ8ob6sGcYUaqjTkKINSfD2mskdWSrSSgUeuPbIMPLKMDTWQUkhzkZWCPSik2qYRUqOcK5qVkKMZYqJqeAnoK9f3aFb0HYVEjZkGinJoSvFcQa2RpnIHGul7qveSFNL3UHVKIIRQgLykQ_G7CSL7Y8R1F9H1UVtx8pc39mDn5M8x47H57zvGtwqQKFBb58BKKiFHPIda84KDRB5Ovng4eTEB24Hf6KwvM3LQh5W03plhPbyWQmgPr8vysZo1UnwBtv_o4TWvWdnm8HJjebXx8PquomX5CZgWcn5vjFmERtrGwzGyHcnSI8tBrw1UTUk1rERVmciw2hiYHlnpvmHWUEkr0CBnwQx75Bp1qDyyFA1IqoXsIpGH07OPoPivsNXPDdhJj95ZP9vY6d-TMr2got3Vuq2ZiXB3TDRwUxfCw0uL_vRoV-hR8Nx0PLsFEgqQUDP4TqVx_IeocwBq1SlFvUNtbRNKblaQmUayREulQBqVkBf7PH8ywpF51KxLvPBwggrKS8jnndd-fH-9vLtGqs0qrhG1-UGCDRZajFMN1_dtNmeievHdkYtzpVpQZq3Q2qhlPd3ECsQkVfcoo-xBS8rA2N1IaKRgoBTkqF_LeGWfpEoJxqmJ9rKtkWKSN3o-zgmHHODPPX_xsctliMpda-KW6hejaIxmfbyTM3hqSiFBmntmTmd0j0zNtGzrBw-vM17vm9Fsl3-lspiFaLZDM2Ek0qYxclvdtHqu0OwOzWY7xmZaiJLdU1575OrkwKbzYo7nPpoVTJRCznJOd7VQmjOFZkUtZpbX6LZooK6ameJVjpzwZyEEBsJUVDR5AbFWShPMGyoVSKTFA9QmCJqQdgiDHiY-8p_8_Q9JSBhn6cCZ1bPqLj5KXms7FZtuPgchRNKvW6G0BFqZ1dCF-D4j_O4J8fA7_6lXbJA0MAlGmmOSsCnNVyXQum0-1Hd8V9PSw-lhHZlVdW49jRqOntjRM04owylamem-BSYeQT53iv2N1nlphkt7ek6flag1POk5a8wy8O3_wxCkHyIpKImSeBGF2EfbrQSlhYSt1L2FJc88vH5K420czkpet0-zXd12DY2-l0DzuRJz39oShCH2HUtCZ5ggSn0_Q5JyBW-Qz4zk2EoOie9njuTIlUySNFogmok3aT6QjHEaLRzJ8VhycpjvN8tMsCszcWWGaZHH3yeTkCKPHZnp0EtiUkQ-IcMkdHdIQlo-r2ijWwmfqOSmvvNwOuj5iZYtXAErbXJaOUJsqHgv-s3FqPEwwuYwwt95nX9TRiZEOer0r5aWG1sMxKdbhikNMVErbbU-45LsWTqwF2PYYRBMo9iB7lHkBuktFJ3yvxH4me0Kg-Bl24VJ4ATzOMRpmByx613LS2sRlVa1f9IKrp8a6Vq2-vzZljp3DbD97IwndCTEVEXHupr2fBrUiaZ9EbXs8_x7rvRwlOWLD54Tb0fPwetknDiKfRz7jqYSYCNprQohK4-sJsmvhJTA9BWU9BnyzXMj1E39Gn13Z8ziE5UDSPuF95L0ir5A3UooXAWW9v4tqLbUbstgJC1bsEXotCoLU2SY39ZYo_ktNCXdFx-WQG99v1he2-U02JVu0JiPq8-fX2c3gx2PsOPMT39gn8T-jtdUPn_Y7_YceeO2t8EnY5-H4gf8afg3NdeclvxXOG7XIE7NGyq1qbXeMAvhaBYCnLAfszA5C7f2bc6drrQra3j_ba4fudCTmGXhD-iT0FeiakRb56-xuy3OGvjmBMSjCVgk5IfXHwn8pWAPr60a3H6bzyc_cu3_Lte6e8AoLAKST5fvf33CZ6zUO1BOpe5u8LCf4wWbJrnM80He3oiOzLhifQ1xOqefyaJO4aFF2NnaRZAHETjvBz7a93yD68G-bFlokPvPQi7rfKm15FmrQb22lfY-O969vRoh3-_MTu35hk-thbyl9Q4M8HNv83skDrNgxAxY5n-T2U9StI1LxbTxemdazU74-B5YyP413RQEB_pYwvhFwdjd_kSMhpKDEbsYKSN-9k2MH-T-y5IrKG5qDbJ79_pdVN7W4-TULBkDpUyb_R7wzLAsCwcWGcOipHjrOnWYcROVjCv84cjGvjaNbLBd6WyYzGE4dO3PQgLhSfuvnzrfGHD4c2w-qyNYOx1HiMYgmJ-fBLERzXt4hPJ1BvrQ0F9a-Kilm3MP0erW5OnriaByyHL_EHlbwk3VCKnvNNXd69czE2C-k4RxPCIQ-dHp8LvmUum_OgZjpYMhGUWEhKX4FYbl3cY11irdmbKv0M5eZ_TKONo6NWi4oD5LnA3ASuTwE9RdJbgvhYC1Gvpb9nvn8-nYq-Do6FR3IfbDmC6GOq6lycJ1PqHk2dXrRh-q536lGgZplIWARltiM-BNrTStzdZiiuJxe87ss72GjgmBSxhIisGtfq2yL5Y8HiqX8ebfsfTMcbfXzFHdqVb8rPAzP0aMBduKmqcHX1svpaTPt90e557Kl-8TTBBZIfceXnUnT85sQaefYwBxDYCUMIr2wFfBxkaB6QM8N1VTTloTuzs8I6OvVAd1-wLlkj8eSezESeykgCAnC4vk-M7RtvYHUfbbZ0bLMqPsYVvUbhjvxu79ZhWsRFXROh8v3snZU7rvJxozOjUMBny05PWuTw7d1B4e2G7Z01MQdB8yqjjbKtu9p-h0Nje2WlKu1b55JI6WpVkHQg7aTZfBNtG6T8fcPuLhpKRVllMPJy-ocLo_mvCzyKbnIxodK8j8PBxMxdThgf5FaFvf0QLKZwfn6ak76xmJTlfH5-ORc2GCnar5_845RhX3US9IXHCUhkV0FJydNfoqJ-5pOqF79KDpcGyLf6Lr0ilhBradyZU6gx1XSsdEiij_XiI_i0wdx_GzyN5zpR0cp8LxwQMays3k2-M9byfYu8kfzbGInOrdPSNBigxDetSzrgbXTmkwURMc4_8ncjxnMOvADMmF_iiB5wXtXz7ua5C95jaILPsQ8O30fL6qw-rkKO1UfD6FNAgDZNQ936idUGdUPDqdtfBTgrbbkmcm1lKptwMV3npeK_RT5z1gOK6oEqCAOvnnZGrEHsbde-XL8XR7BxV9LY9Y75_d8dzuXD48cTPjOaCAhEa1VgGaPSItkAJAfFBmL0Z_DXGRX5J8QRb0Ai6DeJHEoe8ni4v7y4z4LA8znGZBACQLE0jCxI9JTPyYpRG74JfYxyTwgzQIwyBYzKNFERY0yiKAqKBp7oU-VJSXc-OhcyF3F_bY72W8CBP_oqQZlMr-jQvGPQ7sRVcX8tIeFs7anfJCv-RKqxcJmusSLg-QBseYcXLyGDO6qdG-VkFe7E_u8yeOyMX-RSvLy99-wtla-98AAAD__5qt4no">