<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/147127>147127</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang]Assertion `This && (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())` failed
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          Rush10233
      </td>
    </tr>
</table>

<pre>
    Generated by fuzzer that randomly removes member declarations from classes and unions.

Goes back to clang-12: https://godbolt.org/z/c8WTPhGjo

Test Input:

```c++
union A
{
  ;
  bool operator==(const A&) const = default;
};

A a { 42 };
bool b = a == a;
```

Stack　Dump：

```
clang++: /root/llvm-project/llvm/tools/clang/lib/AST/ExprConstant.cpp:6668: bool HandleFunctionCall(clang::SourceLocation, const clang::FunctionDecl*, const {anonymous}::LValue*, const clang::Expr*, llvm::ArrayRef<const clang::Expr*>, {anonymous}::CallRef, const clang::Stmt*, {anonymous}::EvalInfo&, clang::APValue&, const {anonymous}::LValue*): Assertion `ObjectArg && (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())' 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.      <source>:8:16: current parser token ';'
 #0 0x0000000003f7e5c8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f7e5c8)
 #1 0x0000000003f7b9f4 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f7b9f4)
 #2 0x0000000003ec0318 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007a4454242520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007a44542969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007a4454242476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007a44542287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007a445422871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x00007a4454239e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000007884fd8 HandleFunctionCall(clang::SourceLocation, clang::FunctionDecl const*, (anonymous namespace)::LValue const*, clang::Expr const*, llvm::ArrayRef<clang::Expr const*>, (anonymous namespace)::CallRef, clang::Stmt const*, (anonymous namespace)::EvalInfo&, clang::APValue&, (anonymous namespace)::LValue const*) ExprConstant.cpp:0:0
#10 0x00000000078cbb6d (anonymous namespace)::IntExprEvaluator::VisitCallExpr(clang::CallExpr const*) ExprConstant.cpp:0:0
#11 0x000000000786c051 clang::StmtVisitorBase<llvm::make_const_ptr, (anonymous namespace)::IntExprEvaluator, bool>::Visit(clang::Stmt const*) ExprConstant.cpp:0:0
#12 0x000000000785af76 Evaluate(clang::APValue&, (anonymous namespace)::EvalInfo&, clang::Expr const*) ExprConstant.cpp:0:0
#13 0x0000000007877ea5 EvaluateInPlace(clang::APValue&, (anonymous namespace)::EvalInfo&, (anonymous namespace)::LValue const&, clang::Expr const*, bool) (.part.0) ExprConstant.cpp:0:0
#14 0x00000000078bafa1 clang::Expr::EvaluateAsInitializer(clang::APValue&, clang::ASTContext const&, clang::VarDecl const*, llvm::SmallVectorImpl<std::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x78bafa1)
#15 0x00000000076d89a2 clang::VarDecl::evaluateValueImpl(llvm::SmallVectorImpl<std::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x76d89a2)
#16 0x00000000076d8d51 clang::VarDecl::checkForConstantInitialization(llvm::SmallVectorImpl<std::pair<clang::SourceLocation, clang::PartialDiagnostic>>&) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x76d8d51)
#17 0x00000000069f692b clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69f692b)
#18 0x00000000069fe1db clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69fe1db)
#19 0x000000000666592a clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x666592a)
#20 0x0000000006674a89 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+++0x6674a89)
#21 0x000000000663337e clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x663337e)
#22 0x0000000006633b29 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6633b29)
#23 0x00000000066390e3 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66390e3)
#24 0x000000000663a55f clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x663a55f)
#25 0x000000000662e62a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x662e62a)
#26 0x00000000049360f8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49360f8)
#27 0x0000000004c2fff5 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c2fff5)
#28 0x0000000004bacb9e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4bacb9e)
#29 0x0000000004d22941 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4d22941)
#30 0x0000000000d908af cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd908af)
#31 0x0000000000d8748a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#32 0x000000000499cca9 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
#33 0x0000000003ec07b4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3ec07b4)
#34 0x000000000499d2bf 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
#35 0x000000000495f28d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x495f28d)
#36 0x000000000496031e 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+++0x496031e)
#37 0x0000000004968eb5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4968eb5)
#38 0x0000000000d8cd5f clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd8cd5f)
#39 0x0000000000c422e4 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc422e4)
#40 0x00007a4454229d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#41 0x00007a4454229e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#42 0x0000000000d86f35 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd86f35)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
```
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkWl9vo7oS_zTui0UE5v9DH2ja7O3RHm21qfY-RsaYhFPAXNv0pPvpr2wgYJK0m6NmH-5dZdUEe8a_-Xk8M7bBQhTbmtJb4N8B__4Gt3LH-O33VuwcG7nuTcqyt9svtKYcS5rB9A3m7c-flEO5wxJyXGesKt8gpxV7pQJWtEophxklJeZYFqwWMOesgqTEQlABcZ3BtlbPF8BOgJ18YVTAFJMXKJnqVW8tBwE3gTspGwHcBKAVQKsty1JWygXjW4BWPwFakejfz0-7L3-xTs8zFRI-1k0rlYx-BAK7-xCA7tTHTvTQUDeG6jeEwO3-poyVkDXKTsaBe68-KCKsFhImAAUAxbD7Bdx7mNEct6XshEF433-xkwRiCMI76CF4eKxVp1oOw041xL3EALGTXktMXsCDCyIbRPZ9WzXgYQXuliCemwTsRJPVW-YmEKAVZ0wCtCrL18pqOPuLkuEnQCvJWCkUb53YqixSgFbJ-hmg1cO-4UtlHK7lgjQNcJMgCCKlVoP_F66zkq7amqgpXeKyVNxoRW4C3GTNWk7oV0b0lAO07KmadBmE7ykpAUrGPiC8wzWr3yrWCk2Z6v31By5bavSb6FJw-zZtnH6YcI7fvtMcuMuzAu6Dkjk5ojJKSZ8aby0r2Y93UvbhFZePdc60myynkslTb0jw6wbHivZECMoVXxAE9rdUTWXCt1ArCiBA0Z_3FnAfCrFkzVuiV3FFa_ltcGAUKYcF4RKESzj0_ZO90nN99SeEOS5Kmqm1-fT1IVk_QNGmVSEhhmm7hZw2jEu1Umers5C7Nl0QVo3-NvPCQoiWKv_TIaCoSdlmFModhYRjsdMhQHJMqCKq4bThjFAhaAaFdi71WEliIRgpdDDibQ0F4UUjF8PagZlaMzoA2Atgx0-cbTmuIObbVtks-pXCGoWJsKopSsotum9KxikfloeFB_qFJXlbvwC0Sot6XD1q0UFrm_2NeW550NpCiym9uGmU9lY2rVwIaFWKBWhZ-yiwsKgs8VZLvAfufVFLWkIrr5n1SnnKBFXt0FpDy9oSYqnVSna4qHUcegev6ixq3Igdk9DKCSsZt7ICb2smZEFEN4bm2HgM3GVPrPsA7MRRbBnP3EStfydQjJGWc1pL2GAuVOxnL7SGAIUqiKFQxU-AXBvae3v45-Yh9Uk0WZ_iTXRfnnhRSz1bz918R2Mnjv_eMCE5xVW_Zopaak9WTvop0wbQnb3v4Smn78A7M_BpnHunwC9Liuu2-Vavi22NVRhsa51CM1gyNcQ1oCowI1RkQKXEdp0ILtUEf6eEvVL-1mHrgrZa3j2HRp8lqyXdD9He1v87_W6vP8Se53vIQz6ye6O6nLGPgk3gWWVRt3trW7ddA1kItgg0ZC0yAvZMhXEQ5wQ2cscpzjYvRVlepl3Lj9r9OVwvDOBWaAouhe2Fwag4MBWjKMxdiFMVAC9SqwVHteGRWie9WKGTjgojU6Eb0zi4TKEWGRXGUwcLo8jLs-iflACnk3-XBYd0iqJDLoQ1rqhodEiIp1nRkJhldaPtdDFwTqAvBt5HMC0LzILgEjt-tUC4lI4YnqjchrWsopptTiVJ0yD7aJTHWiqtCnPbFcPq6Y9CFFKx0dVS06kfnl4CzDGBBcT2nTnDekjG77CgwF2Ok1vhF7rRY20ayX-BtyOL0FLXtV2aG4yb-bM5xR8ahEyDfJyHAexHpKbqi-b8vOtcSrlrIgxDiv0Dwsf6qeyS8ScBvciVPzCtn60uty4azOXC_gWDPdPgFOfYOdoVHLArFhLxWBeywGXxk_L3uJg2rJ_7XHrOmh-YHwW-0ZvXFS7LH5RIxh-rplQ1mMy6pgYX3Ixg70bZJ8wV9vtDlaf9-6EHNFDYb0I-t0jp2e1yiOLeN7gPsijG6AQn3Q_a068Z1iRMa8L_DYI6CkaCgjlBmRkADYLIjpKXFTs4-8FLeyt_O1tXZCnzJ24UTlkK4jyIUWqkCVrhPgkpipasakqqHIkXOC3p_XgOZa7mgd0ucH6yFT3O0YpoZgV1sjNWJFk2iUDPrAM5RT49Pzl5IjIJlZ9slII9GmVUiUEQ-DHCM_cRlE--TyYjySXlw2_GkzpLpORF2koqjs3F_THFPK4ejZA906opdTbL2bloPJVaMf4d11uqOL-SL3TEHGhDtklb6OEo_pC2L5y1jUmMaivqrWpdN5Qc2zky16enUzwYvF_G73H_eTSZO-nvZl5zOzLvmMy7rhvSD5n_xse9S_5YS8q7Xf_lRH7Y493ZTAihQqi2Ii8UHVfgSzMy8oXmfKXoY0_tF7hBW6Ei2jwCX4W1ucf9HtZSNPEyd8ZabFP3XdYe9p1Tnc1V12LqGlwoa0cuvBkX2Pfzd7l4Zs1X-krL47T3rcH_aemTnBUwh-Co9_oPJ2LSIbX-ybK2VNUl43It9aYsuA4JysyRBN8kAdHgRJ7U1zDRHPe0Lr1eYu8gjYCNytSL3cDOoyngJcvoF1onenkP5QclraT9o_7u4XNh9kBGmEZp6BGU57lvnDlxlfbq7ATOKyHsMIwIjbLPSzFJY2oS2Y35qIt6Qk9zed6kq_hvj3O0wqjzvAyh2JvtojXe0ZjXQwEQvWfsVUJQj--A3ryUsLPYjnAOCXE2FS7MjdP0yHCHj84JzWdoCV9ZkV3HiA7laINj2hCFXoThQPvSedZx4d0t4LFBgXkIoXQcn2LEMOPFK-XHZyvmJYQXx4TgWFMyUZr3JcCGa1Z1a3_ZOBy8EVyWKSYvm7w2A3s3cO86S2fJqgrX2XwVn5y9w36XNWp0XBqHh2vJi3rbp4tuag8Cmw3Z7x2n-5FiUZCN0N17Co3O6sFGclxIMTTP1OGyVEuB8Um76jLZpiWHrXQnAlBY4irNMEDhSBWKhrulP1h6YjLc-Y1QmE4vr07d-3Qt39t6jXNavhlcvj9vV7jh6hCPDu_NnCtDqVE3_N85x-zc87QX-CZrfo6i7CxretbwUWYcqDRC90xQdTi3uX6na_I7jtl6s0dXmhUzge069FJS_mCpOM_IHyz9Wgjz8PeS4zh9OfvrJP62E8uerJHKcEZlRFP_HOz7yXejQDhRGZybgt9I5RWqVU3PSF40y-EkG7ZCQyUygNehJDm6JjiXoT-79tDIRtxG9WcTDyHqQYX4swfuVB8G9uzZNXmcxRe-haBFRoXOXCH1bLjZKJmNkJjLzcSsXx6CepMh0GySg9z1Yaf88-dJKe-Gnra5CaSc60vbzr1g3m8aIOn9v3vFC_5dyB2k-0K5U0ah43oKYysotF6hZFBQCotJMR9PXz-8yW7dLHZjfENvndB3gtiLvOhmdxvmPnVi4lCPYJQj4tq-G_t-4GUod7KQ3hS3yEa-Hdq-7fueHS0o8XxquwEmURx4eQA8m1a4KBfK9xeMb2_0q2O3jhc6KLwpcUpLod9XRai3HAH__obf6jfO0nYrgGeXhZBiVCELWeqXXDsJ_954v-55V4grv1oX2D3vNy0vb__523M9C6-36L8BAAD__9zOblc">