[Clang] Assertion `!BaseType->isDependentType()` failed in `clang::Sema::BuildMemberReferenceExpr`

***Generated by fuzzer.***
Clang assertions trunk crashed but trunk is fine.
Compiler Explorer: https://godbolt.org/z/5hMGnT13E

This test case also triggers an Internal Compiler Error (ICE) in GCC trunk.
See GCC Bugzilla: [PR123522](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123522)

## Program
```cpp
#include

struct MergedObject {
std::string str;
int value;

MergedObject(const std::string &s) : str(s), value(0) {}
};

int main() {
auto stage3 = [&](auto &&...args) {
auto stage3_1 = [&](auto &&...innerArgs) {
auto stage3_1_1 = [&](auto &&...innerInnerArgs) {
union {
MergedObject obj1;
MergedObject obj2;
};
::new (&obj1) MergedObject("Hello");
};
stage3_1_1();
};
stage3_1();
};
stage3();
}

```

## Stack Dump
```bash
clang++: /root/llvm-project/llvm/tools/clang/lib/Sema/SemaExprMember.cpp:898: clang::ExprResult clang::Sema::BuildMemberReferenceExpr(clang::Expr*, clang::QualType, clang::SourceLocation, bool, const clang::CXXScopeSpec&, clang::SourceLocation, clang::NamedDecl*, clang::LookupResult&, const clang::TemplateArgumentListInfo*, const clang::Scope*, bool, clang::Sema::ActOnMemberAccessExtraArgs*): Assertion `(SS.isEmpty() ? !BaseType->isDependentType() || computeDeclContext(BaseType) : !isDependentScopeSpecifier(SS) || computeDeclContext(SS)) && "dependent lookup context that isn't the current instantiation?"' 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++ -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
1. :25:14: current parser token ')'
2. :11:12: parsing function body 'main'
3. :11:12: in compound statement ('{}')
4. :12:19: instantiating function definition 'main()::(lambda)::operator()<>'
#0 0x0000000004308bd8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4308bd8)
#1 0x0000000004306004 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4306004)
#2 0x0000000004248d58 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#3 0x00007d4c90442520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#4 0x00007d4c904969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
#5 0x00007d4c90442476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
#6 0x00007d4c904287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
#7 0x00007d4c9042871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
#8 0x00007d4c90439e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#9 0x00000000070a452a clang::Sema::BuildMemberReferenceExpr(clang::Expr*, clang::QualType, clang::SourceLocation, bool, clang::CXXScopeSpec const&, clang::SourceLocation, clang::NamedDecl*, clang::LookupResult&, clang::TemplateArgumentListInfo const*, clang::Scope const*, bool, clang::Sema::ActOnMemberAccessExtraArgs*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x70a452a)
#10 0x00000000075c364c clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformMemberExpr(clang::MemberExpr*) SemaTemplateInstantiate.cpp:0:0
#11 0x0000000007593ec7 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#12 0x00000000075daf71 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformUnaryOperator(clang::UnaryOperator*) SemaTemplateInstantiate.cpp:0:0
#13 0x0000000007594090 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#14 0x00000000075b3a15 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitializer(clang::Expr*, bool) (.part.0) SemaTemplateInstantiate.cpp:0:0
#15 0x00000000075b3410 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl&, bool*) SemaTemplateInstantiate.cpp:0:0
#16 0x00000000075b7664 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCXXNewExpr(clang::CXXNewExpr*) SemaTemplateInstantiate.cpp:0:0
#17 0x0000000007593bdf clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#18 0x0000000007593df0 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#19 0x00000000075d0eb7 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt(clang::Stmt*, clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
#20 0x00000000075d1565 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#21 0x0000000007593485 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformLambdaExpr(clang::LambdaExpr*) SemaTemplateInstantiate.cpp:0:0
#22 0x00000000075943b9 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#23 0x00000000075b3a15 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitializer(clang::Expr*, bool) (.part.0) SemaTemplateInstantiate.cpp:0:0
#24 0x00000000075b4624 clang::Sema::SubstInitializer(clang::Expr*, clang::MultiLevelTemplateArgumentList const&, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x75b4624)
#25 0x00000000076213b7 clang::Sema::InstantiateVariableInitializer(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x76213b7)
#26 0x00000000076724c0 clang::Sema::BuildVariableInstantiation(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&, llvm::SmallVector*, clang::DeclContext*, clang::LocalInstantiationScope*, bool, clang::VarTemplateSpecializationDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x76724c0)
#27 0x000000000767efe7 clang::TemplateDeclInstantiator::VisitVarDecl(clang::VarDecl*, bool, llvm::ArrayRef*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x767efe7)
#28 0x00000000076851d4 void llvm::function_ref::callback_fn(long) SemaTemplateInstantiateDecl.cpp:0:0
#29 0x0000000008533d41 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x8533d41)
#30 0x000000000761f52a clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x761f52a)
#31 0x000000000758984a clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformDeclStmt(clang::DeclStmt*) SemaTemplateInstantiate.cpp:0:0
#32 0x00000000075d1565 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#33 0x0000000007593485 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformLambdaExpr(clang::LambdaExpr*) SemaTemplateInstantiate.cpp:0:0
#34 0x00000000075943b9 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#35 0x00000000075b3a15 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitializer(clang::Expr*, bool) (.part.0) SemaTemplateInstantiate.cpp:0:0
#36 0x00000000075b4624 clang::Sema::SubstInitializer(clang::Expr*, clang::MultiLevelTemplateArgumentList const&, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x75b4624)
#37 0x00000000076213b7 clang::Sema::InstantiateVariableInitializer(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x76213b7)
#38 0x00000000076724c0 clang::Sema::BuildVariableInstantiation(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&, llvm::SmallVector*, clang::DeclContext*, clang::LocalInstantiationScope*, bool, clang::VarTemplateSpecializationDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x76724c0)
#39 0x000000000767efe7 clang::TemplateDeclInstantiator::VisitVarDecl(clang::VarDecl*, bool, llvm::ArrayRef*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x767efe7)
#40 0x00000000076851d4 void llvm::function_ref::callback_fn(long) SemaTemplateInstantiateDecl.cpp:0:0
#41 0x0000000008533d41 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x8533d41)
#42 0x000000000761f52a clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x761f52a)
#43 0x000000000758984a clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformDeclStmt(clang::DeclStmt*) SemaTemplateInstantiate.cpp:0:0
#44 0x00000000075d1565 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#45 0x00000000075da99d clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x75da99d)
#46 0x0000000007676cd0 clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x7676cd0)
#47 0x0000000008533d41 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x8533d41)
#48 0x00000000074cc2b2 clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x74cc2b2)
#49 0x0000000006f812b3 clang::Sema::DiagnoseUseOfDecl(clang::NamedDecl*, llvm::ArrayRef, clang::ObjCInterfaceDecl const*, bool, bool, clang::ObjCInterfaceDecl*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f812b3)
#50 0x0000000007331a87 CreateFunctionRefExpr(clang::Sema&, clang::FunctionDecl*, clang::NamedDecl*, clang::Expr const*, bool, clang::SourceLocation, clang::DeclarationNameLoc const&) SemaOverload.cpp:0:0
#51 0x0000000007377088 clang::Sema::BuildCallToObjectOfClassType(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x7377088)
#52 0x0000000006fceff4 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fceff4)
#53 0x0000000006fd3f4c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fd3f4c)
#54 0x0000000006ad1bb7 clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6ad1bb7)
#55 0x0000000006acaaca clang::Parser::ParseCastExpression(clang::CastParseKind, bool, bool&, clang::TypoCorrectionTypeBehavior, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6acaaca)
#56 0x0000000006accd27 clang::Parser::ParseCastExpression(clang::CastParseKind, bool, clang::TypoCorrectionTypeBehavior, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6accd27)
#57 0x0000000006accdb9 clang::Parser::ParseAssignmentExpression(clang::TypoCorrectionTypeBehavior) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6accdb9)
#58 0x0000000006ad1399 clang::Parser::ParseExpression(clang::TypoCorrectionTypeBehavior) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6ad1399)
#59 0x0000000006b56c69 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b56c69)
#60 0x0000000006b4e114 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::LabelDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b4e114)
#61 0x0000000006b4eaf6 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::LabelDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b4eaf6)
#62 0x0000000006b5743e clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b5743e)
#63 0x0000000006b57c8a clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b57c8a)
#64 0x0000000006a5e0db clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6a5e0db)
#65 0x0000000006a9454d 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+++0x6a9454d)
#66 0x0000000006a5123b clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6a5123b)
#67 0x0000000006a51a2f clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6a51a2f)
#68 0x0000000006a5985a clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6a5985a)
#69 0x0000000006a5a7f5 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6a5a7f5)
#70 0x0000000006a3b87a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6a3b87a)
#71 0x0000000004c6ae28 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c6ae28)
#72 0x0000000004f64215 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4f64215)
#73 0x0000000004ee404e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4ee404e)
#74 0x000000000505e8bd clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x505e8bd)
#75 0x0000000000de879e cc1_main(llvm::ArrayRef, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xde879e)
#76 0x0000000000ddf16a ExecuteCC1Tool(llvm::SmallVectorImpl&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr) driver.cpp:0:0
#77 0x0000000000ddf2ed int llvm::function_ref&)>::callback_fn&)>(long, llvm::SmallVectorImpl&) driver.cpp:0:0
#78 0x0000000004cdde69 void llvm::function_ref::callback_fn>, std::__cxx11::basic_string, std::allocator>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#79 0x00000000042491f4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x42491f4)
#80 0x0000000004cde47f clang::driver::CC1Command::Execute(llvm::ArrayRef>, std::__cxx11::basic_string, std::allocator>*, bool*) const (.part.0) Job.cpp:0:0
#81 0x0000000004c9ee12 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c9ee12)
#82 0x0000000004c9fdbe clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c9fdbe)
#83 0x0000000004ca7215 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4ca7215)
#84 0x0000000000de4b11 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xde4b11)
#85 0x0000000000c8ee04 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc8ee04)
#86 0x00007d4c90429d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#87 0x00007d4c90429e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#88 0x0000000000ddec05 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xddec05)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```

Compile the supplied reproducer with Clang assertions enabled, then trace the failure from clang::Sema::BuildMemberReferenceExpr in SemaExprMember.cpp through TemplateInstantiator::TransformMemberExpr in SemaTemplateInstantiate.cpp. Compare the dependent lookup context during nested lambda instantiation and add a regression test using the reported program. Done means the test no longer triggers the assertion or an internal compiler error.

Written by the indexing model from the issue text.