<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/147010>147010</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang] Assertion `!Found.isAmbiguous() && "Cannot handle ambiguities here yet"` failed in `clang::NamedDecl* clang::Sema::FindFirstQualifierInScope(clang::Scope*, clang::NestedNameSpecifier*)`
        </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>
    Start from clang-15: https://godbolt.org/z/87Tjfrosv

Generated by fuzzer.

Reduced Test:

```c++
template <class T> struct Base {
 static void f();
};

struct X0 { };

template <class T> struct Derived: Base<int>, Base<char> {

  void g(X0 *t = h(t)) {
    t->Base::f(); 
 }
};

```

Stack Dump:

```
clang++: /root/llvm-project/llvm/tools/clang/lib/Sema/SemaCXXScopeSpec.cpp:367: clang::NamedDecl* clang::Sema::FindFirstQualifierInScope(clang::Scope*, clang::NestedNameSpecifier*): Assertion `!Found.isAmbiguous() && "Cannot handle ambiguities here yet"' 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>:10:15: current parser token '('
2.      <source>:7:20: parsing struct/union/class body 'Derived'
3.      <source>:9:24: parsing function body 'Derived::g'
4.      <source>:9:24: in compound statement ('{}')
 #0 0x0000000003f78848 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f78848)
 #1 0x0000000003f764d4 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f764d4)
 #2 0x0000000003ebb048 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007b5b4bc42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007b5b4bc969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007b5b4bc42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007b5b4bc287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007b5b4bc2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x00007b5b4bc39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x000000000683c7d3 (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x683c7d3)
#10 0x0000000006c51ba2 clang::Sema::ActOnMemberAccessExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, clang::tok::TokenKind, clang::CXXScopeSpec&, clang::SourceLocation, clang::UnqualifiedId&, clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c51ba2)
#11 0x00000000066a7077 clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66a7077)
#12 0x000000000669fdaa clang::Parser::ParseCastExpression(clang::CastParseKind, bool, bool&, clang::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x669fdaa)
#13 0x00000000066a1f47 clang::Parser::ParseCastExpression(clang::CastParseKind, bool, clang::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66a1f47)
#14 0x00000000066a1fd9 clang::Parser::ParseAssignmentExpression(clang::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66a1fd9)
#15 0x00000000066a6699 clang::Parser::ParseExpression(clang::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66a6699)
#16 0x000000000673a479 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x673a479)
#17 0x0000000006731e28 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 24u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6731e28)
#18 0x0000000006732c4d clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 24u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6732c4d)
#19 0x000000000673ab73 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x673ab73)
#20 0x000000000673b33a clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x673b33a)
#21 0x00000000066423c0 clang::Parser::ParseLexedMethodDef(clang::Parser::LexedMethod&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66423c0)
#22 0x00000000066420ad clang::Parser::ParseLexedMethodDefs(clang::Parser::ParsingClass&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66420ad)
#23 0x0000000006695159 clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6695159)
#24 0x0000000006697f10 clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6697f10)
#25 0x000000000666b4e0 clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*, clang::ImplicitTypenameContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x666b4e0)
#26 0x0000000006746cbc clang::Parser::ParseDeclarationAfterTemplate(clang::DeclaratorContext, clang::Parser::ParsedTemplateInfo&, clang::ParsingDeclRAIIObject&, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6746cbc)
#27 0x000000000675492f clang::Parser::ParseTemplateDeclarationOrSpecialization(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (.part.0) ParseTemplate.cpp:0:0
#28 0x0000000006754cda clang::Parser::ParseDeclarationStartingWithTemplate(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6754cda)
#29 0x00000000066721b0 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66721b0)
#30 0x000000000662f85c clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x662f85c)
#31 0x000000000663077d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x663077d)
#32 0x0000000006622aea clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6622aea)
#33 0x000000000492ed48 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x492ed48)
#34 0x0000000004c28c65 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c28c65)
#35 0x0000000004ba5ffe clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4ba5ffe)
#36 0x0000000004d1b441 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4d1b441)
#37 0x0000000000d8e81f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd8e81f)
#38 0x0000000000d853fa ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#39 0x0000000004995b49 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 0x0000000003ebb4e4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3ebb4e4)
#41 0x000000000499615f 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 0x0000000004957f8d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4957f8d)
#43 0x000000000495901e 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+++0x495901e)
#44 0x00000000049614d5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49614d5)
#45 0x0000000000d8accf clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd8accf)
#46 0x0000000000c41924 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc41924)
#47 0x00007b5b4bc29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#48 0x00007b5b4bc29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#49 0x0000000000d84ea5 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd84ea5)
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/eJzkW11z4ygW_TXkhbJLQt8PeVA78Wxme7Z729ndfnMhhGymZdAAyjj967cAOfqw4yRdcc9W7VRPtyPB5ZxzL5cLJlgptuGUXoPoA4hurnCrt0Jef2nV1vdQEFwVony8XmksNayk2EFSY76Z-REIcrjVulEgyAFaArTciLIQtZ4LuQFo-R2gZZrc_15JoR6AlwMv_4VyKrGmJSweYdV-_07l3L35QsuW0BLeU6WNPfsQxJ77QwD6YP54uaa7psaaQhAsSI2VgvcguIVKy5Zo-AErCkFiGkKlsWYEPghWwgqgFKAMBOYNSG66D17e9fvqmV5w-Ob8QDdUsgdaGgnMmCBYMK5BcAvQ4vCAbLE0PRwcg8hh2QCUmvFQriEIbuAWoFQbcCg7QIcQ6hkIbp2lHAR5TwCaBgbomMiTVO7HlcbkG7xpd82xmMDLrQs7TYMcArSUQmiAlnX9sJs1UvxOyeFHgJZaiFoBtOy6LWtWALRc0R3u_ll8_boioqGrhpI5acygQZwY066L5fAPvKPlDSU1QKPn1o79tGS8XDKp9D9bXLOKUXnHrV2A0mEH9yg3Yg_tU6VpaUYxMGx32ygzOHKlqNRMcGgUQP5StLycM5XvCrZpRaucwBCgGKAYAoQWmHOh4RbzsqYQ23ZMM6rglkoKH6kGCAGUwAqzmpYmjj9_vM1Xt1C1xY5piGHRbqCkjZAaajGdK0xv22JOxK7XeaI-U6qlRneIeQkZJ3VbUqi3FBKJ1RYWmHzTEhNqhGgkbaQgVClaQiVa6R6bnlgpQZiddrLlUBHJGj1_ipLyKUq8OfCyz1JsJN5BLDftjnKtuggRjcFExK5hNZUzum9qIY3ELixm-KCwmmnZ8m8ALQvG-6gxwQZnm_JPLKtZCGcbOBPGLm4aY73VTavnCs52RgU4m-3TeIbVbqYeucZ7ENwwrmkNZxUXswcqC6GoeQ9nKzibbQiZmSglW8w4CG7O4jWNFceN2goNZxURtZCzkuENF0ozotwYVuPRYxAsOmGDW-DlvlFr9CzIfc_8ZVMjaaWkXMMGS0Ul1OIb5RCgxAZaArwcnehv5gwyNmw3xjddwgFo2XImOjmVgiYpG2uHRGQtBicsmuhH4dBi1XJiZ8LUhp1FG2cqPGuKcWiENXPI5llqAgV2zJIPJjEZopnNVSjwoLf3Dv8FVZKmYQptzNsh1aNyHz5LxrUNynsX1mnfSOI_10JpSfHOztEFNBnXztj0naIToA_evoPXg_cn4OOwDE-BX9QU87b5xFdsw3ENUNpyu7KWsBZmiEtANWB6qGgElRaFF6ZwYeL4CyXigcpHh-1vNqdJgNJOw1GbheCa7nWXxz37v7MfdPaTIirCgoQoQl5Hyi0J-zRex-GsZrzdzza8dS_IXIl5bCHbLj3gcGwwi7OKwEZvJcXl-hur67dZt_1769EUbpjEcKOsBG-FHSZxbzgeG0ZpUgUQFybPv8ms7dibTY7M-sWbDfpFbzAdGwwymsVvM2i79AazYYDFaUCSMnjvqO7MukHN_Btlj5hEfoHR6fohJ_oT_43uCipzYpbC230jX1U7uIbTpyub_D4KgrXNvaOXWnxzH-5NZv874-WkwbAo6lLWa23_i__RVUDlXXnctyuiLpBSOnl78UfZL45x4iXJEMpnu7oNPn8WSldsbwSlSjHBV21Vsf3YC7ldgL5Q1dba1dcnHKFlaxeeC7B0PHqWaMwyq0qMz7JcYKV7imNy5p1tdIiJQoi6_3fqzPvHxppbmXX0uPlFvOwY9vyDiZf9Kjzv5R_i_1eTtrR60uER6TI7Szq3O2VT6jxHfULrMhzKrOcQTTjEcXaew1-I3GDrkccj5EmAw-Rl5KtDrTkGf9S2XOmd7uqYS5BxcHsyyYSMT1F6lswTkU_SJHMs7SqQV5rKXGvJilabnd-g_l3tcF3_mxIt5DhjGqpdxkRhaxPmNMW8oM_ZdWm6Jrr-Q5AnR5u2uIQPjMq9D9KJDxAJyx_wwf-K6JcQzEjSC5ZNZ2CRBOeTfrflexLugygfAUpdzr7ILCuSvhBE3gRwEQTnV-llt9OdAj5VSp33XVc2XiiQDZGe5qTkClFAvLPgPtI9LX-jeivKG1o9nxoH7S5ExYHtqaApFQ-fn5NjKup8mmd8s6ixulSCcXB7MpMiKYv86PyKtfj61W1GuvPIw-xOX7sNOPvymUT8dOhgt_Y_a9vg1Oi1mtRWWVL552PYOnJwbpu-Zad1VifD-vQW7DhD33eH_ne8Esft3Z5yAPJkaTu0ehj7dNb_SQulU7_3zaRmjIuQnvfNYHV8Iq-O0-jFRP5xcQ-JD2vai_2RKX2c8u92Tc0I06YQ5nhHL1g9Osl7h0xK4TAmBXmtQ2zJeFD02CemlZAvK_Qaz3Qp15j9kt_dfSrc1xQvHWy8qjw8HwIXWHOtyL0LJgV8FGaoOqvVQaqBKz65PI9r9v1Eon_JG5eSbd5gqecm2uAI-OR414iQTkUg5fn6apgYNJaa8c1_mN7-WDj-kAAXiAxLu4-McZUcJ8gvXp0tf3YEvNzip2w0nEhPEo6__oljVKXR-fx2u9dUclw_K-V7SDFIZ27luowWlm2vxaS4D7wkOV8R34vmI32gtSvehiJ8avAfLf2sJ1tT0_AXKdrmC61Obkz78_LfRNnW9G7XCHk4-LlMBWJp9iJMtgUIYXqcaPLV_aRUtvcN4uPTwkt4zUDqAY9K_zBDtAxH5zsLUdJfKHfH2oeDbEpaTbtHh8sF7wqzA9LDHFXdIUEpiaMhzKU0iYeXJ3BeCKHD0CMc1Z5hgaOqomMh3Zh3XGnMCT2t5fOULhK_Hc6exahgC0u_CEN__G2SxduTeRCn9n5HZC-Sgjp8PfpRreOVKU39ChLir3eYjY-_cinxo00j9jYTJIK70tlddBo_Qwt7v-kyJBzKnkM64RAFFYYH2Rf-vc0Lpw_yTKF_kpDNLH0XY6NbqA_tbHCVkj1QeVw-jb8cDbMsKsLMXfnqjR7uXqylVdW-PVztunVNCK7rApNv64qPE7sbuAudhb8Qux3m5XQWn_Se0l070ZjRsRFgII6WjG-65cK59qnDek32e993PxRYMbJWtvnhhtuwsXmw1hIzrfoLcKMWuK7NVHDHqd170ySffPfjBLddAEpqvCtMTZb0UqH0cKniV1EcOyP0plchQjq8tXHqwoN786XlK1zR-nGk5Xm_XeBqh0P8FPChPwmu2I9GG5T_u-CY7G1ORwEaqxYlVVo-q5r1Gj5aGQ9SjlL3pKNpMEgSizNjDJvmo3JmQOx9qwRLuw-lSTETZZ5P3yrKr6JQzyvyqyg-MqVHipzLxU8R0GAmu7u0bxCxC5OfIqURq5dyXHBlsR-W0XOwbwafRwXCicrgORf8RCkvUK1aeXrxoskajgnpUtqhEjmAt6kk7xLByyv0u9ceBlmPe1T9eST0MxRCg_i9B3am-4Gn98OyMnvj9TvbpTeYTg3S0IPrtemzVhpLvR7QevUQNBwMkU2cHFIcQWf8_f1kjLuhh--CHFIpzarSXTuHVbdpgKSLf3eFG_7J9BbSPTPhVFLoB6HB2CoKZw9QC6gohWxQzGfDa_VX5XVQZkGGr-i1n0R-7AdhElxtr-MkSz2Es6LE1K-qLA19nAVlHGdVWvhhccWukYciL_FCL_GTKJhXFYpIgMsojby48D0QenSHWT03sT8XcnNlr4Zf-2Hi-d5VjQtaK_v7Gwh1zBGIbq7ktb1RXrQbBUKvZkqr3oRmura_9OF6RDcXuyMfeweBmTU9SEZ_3e8ExN5VK-vrH7-U34n_cI3-GwAA__8JrsbA">