[clangd][clang] Crash in TryListConversion when performing code completion on rvalue reference to VLA parameter

This input is generated by a fuzzer.
Very likely related to https://github.com/llvm/llvm-project/issues/113088. However, this does not reproduce directly through fsyntax-only.
https://godbolt.org/z/8P875Ys5h
Seems to be introduced since clang20.

```cxx
templatevoid f(int(&&)[N],int);void a(){f<1>({},);}
```

```
-std=c++20 -fsyntax-only -Xclang -code-completion-at=example.cpp:1:62
```

```
clang++: warning: argument unused during compilation: '-S' [-Wunused-command-line-argument]
clang++: /root/llvm-project/clang/lib/Sema/SemaOverload.cpp:5545: clang::ImplicitConversionSequence TryListConversion(clang::Sema&, clang::InitListExpr*, clang::QualType, bool, bool, bool): Assertion `isa(AT) && "Expected incomplete array"' 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-20.1.0/bin/clang++ -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-14.2.0 -fcolor-diagnostics -fno-crash-diagnostics -std=c++20 -fsyntax-only -Xclang -code-completion-at=example.cpp:1:62
1. parser at end of file
2. :1:53: parsing function body 'a'
3. :1:53: in compound statement ('{}')
#0 0x0000000003e64af8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x3e64af8)
#1 0x0000000003e627b4 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x3e627b4)
#2 0x0000000003daec88 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#3 0x00007f0974845330 (/lib/x86_64-linux-gnu/libc.so.6+0x45330)
#4 0x00007f097489eb2c pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x9eb2c)
#5 0x00007f097484527e raise (/lib/x86_64-linux-gnu/libc.so.6+0x4527e)
#6 0x00007f09748288ff abort (/lib/x86_64-linux-gnu/libc.so.6+0x288ff)
#7 0x00007f097482881b (/lib/x86_64-linux-gnu/libc.so.6+0x2881b)
#8 0x00007f097483b517 (/lib/x86_64-linux-gnu/libc.so.6+0x3b517)
#9 0x00000000071222ef TryListConversion(clang::Sema&, clang::InitListExpr*, clang::QualType, bool, bool, bool) SemaOverload.cpp:0:0
#10 0x000000000712156b TryListConversion(clang::Sema&, clang::InitListExpr*, clang::QualType, bool, bool, bool) SemaOverload.cpp:0:0
#11 0x0000000007122362 TryCopyInitialization(clang::Sema&, clang::Expr*, clang::QualType, bool, bool, bool, bool) SemaOverload.cpp:0:0
#12 0x0000000007124f08 clang::Sema::AddOverloadCandidate(clang::FunctionDecl*, clang::DeclAccessPair, llvm::ArrayRef, clang::OverloadCandidateSet&, bool, bool, bool, bool, clang::CallExpr::ADLCallKind, llvm::MutableArrayRef, clang::OverloadCandidateParamOrder, bool, bool) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x7124f08)
#13 0x000000000712e8fd clang::Sema::AddTemplateOverloadCandidate(clang::FunctionTemplateDecl*, clang::DeclAccessPair, clang::TemplateArgumentListInfo*, llvm::ArrayRef, clang::OverloadCandidateSet&, bool, bool, bool, clang::CallExpr::ADLCallKind, clang::OverloadCandidateParamOrder, bool) (.constprop.1) SemaOverload.cpp:0:0
#14 0x000000000712f05b AddOverloadedCallCandidate(clang::Sema&, clang::DeclAccessPair, clang::TemplateArgumentListInfo*, llvm::ArrayRef, clang::OverloadCandidateSet&, bool, bool) SemaOverload.cpp:0:0
#15 0x000000000712f371 clang::Sema::AddOverloadedCallCandidates(clang::UnresolvedLookupExpr*, llvm::ArrayRef, clang::OverloadCandidateSet&, bool) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x712f371)
#16 0x0000000006b04763 clang::SemaCodeCompletion::ProduceCallSignatureHelp(clang::Expr*, llvm::ArrayRef, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x6b04763)
#17 0x00000000068b35b9 clang::QualType llvm::function_ref::callback_fn)::'lambda'()>(long) ParseExpr.cpp:0:0
#18 0x00000000068bc706 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68bc706)
#19 0x00000000068bc9ee clang::Parser::ParseExpressionList(llvm::SmallVectorImpl&, llvm::function_ref, bool, bool, bool*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68bc9ee)
#20 0x00000000068c16cc clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68c16cc)
#21 0x00000000068ba491 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68ba491)
#22 0x00000000068bc5f7 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68bc5f7)
#23 0x00000000068bc689 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68bc689)
#24 0x00000000068c11f9 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68c11f9)
#25 0x0000000006945929 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x6945929)
#26 0x000000000693bc9e clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x693bc9e)
#27 0x000000000693cbf0 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x693cbf0)
#28 0x000000000693dab5 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x693dab5)
#29 0x000000000693f2ba clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x693f2ba)
#30 0x0000000006850a53 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x6850a53)
#31 0x00000000068856ad clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68856ad)
#32 0x00000000068447be clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x68447be)
#33 0x0000000006844f79 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x6844f79)
#34 0x000000000684c723 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x684c723)
#35 0x000000000684d5fd clang::Parser::ParseTopLevelDecl(clang::OpaquePtr&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x684d5fd)
#36 0x000000000683fa5a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x683fa5a)
#37 0x0000000004abdd25 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x4abdd25)
#38 0x0000000004a407de clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x4a407de)
#39 0x0000000004babd8e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x4babd8e)
#40 0x0000000000cfe40f cc1_main(llvm::ArrayRef, char const*, void*) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0xcfe40f)
#41 0x0000000000cf5e9a ExecuteCC1Tool(llvm::SmallVectorImpl&, llvm::ToolContext const&) driver.cpp:0:0
#42 0x000000000483e749 void llvm::function_ref::callback_fn>, std::__cxx11::basic_string, std::allocator>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#43 0x0000000003daf134 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x3daf134)
#44 0x000000000483ed3f clang::driver::CC1Command::Execute(llvm::ArrayRef>, std::__cxx11::basic_string, std::allocator>*, bool*) const (.part.0) Job.cpp:0:0
#45 0x0000000004801bad clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x4801bad)
#46 0x0000000004802c2e clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl>&, bool) const (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x4802c2e)
#47 0x000000000480a765 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl>&) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0x480a765)
#48 0x0000000000cfb213 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0xcfb213)
#49 0x0000000000bc3694 main (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0xbc3694)
#50 0x00007f097482a1ca (/lib/x86_64-linux-gnu/libc.so.6+0x2a1ca)
#51 0x00007f097482a28b __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2a28b)
#52 0x0000000000cf5945 _start (/opt/compiler-explorer/clang-assertions-20.1.0/bin/clang+++0xcf5945)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```

Start with clang/lib/Sema/SemaOverload.cpp, especially TryListConversion, and reproduce the supplied C++20 example using the code-completion command shown. Trace the call from SemaCodeCompletion::ProduceCallSignatureHelp and compare the related issue; done means this input no longer triggers the assertion or crashes clang.

Written by the indexing model from the issue text.