<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/96485>96485</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Friend-injecting a template function causes an ICE if you inject after trying to instantiate that function
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

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

<pre>
    The following causes an internal compiler error in Clang 18 and trunk: https://gcc.godbolt.org/z/r9vvWGnnY

GCC also segfaults here, while MSVC compiles and runs this successfully, calling `bar<10,20>()`.
```cpp
template <int X, int Y> void bar() {}

template <typename T>
struct Reader
{
    template <int X>
    friend void foo(Reader<T>);
};

template <typename T, int Y>
struct Writer
{
    template <int X>
    friend void foo(Reader<T>) {bar<X, Y>();}
};

int main()
{
 foo<10>(Reader<int>{});
    Writer<int, 20>{};
}
```
Clang says:
```
<source>:14:33: error: cannot compile this l-value expression yet
   14 |     friend void foo(Reader<T>) {bar<X, Y>();}
      | ^~~~~~~~~
```
And then spits out the stacktrace.

But if you e.g. try to `cout` `X` and `Y`, it doesn't print this error and immediately proceeds to the stacktrace.

<details>
<summary>Stack</summary>

```
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-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics <source>
1.      <eof> parser at end of file
2.      Per-file LLVM IR generation
3.      <source>:14:17: Generating code for declaration 'foo'
 #0 0x00000000037a10a8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x37a10a8)
 #1 0x000000000379f1f4 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x379f1f4)
 #2 0x00000000036e77c8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x000079f5cc442520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x0000000003e3b6e7 arrangeFreeFunctionLikeCall(clang::CodeGen::CodeGenTypes&, clang::CodeGen::CodeGenModule&, clang::CodeGen::CallArgList const&, clang::FunctionType const*, unsigned int, bool) CGCall.cpp:0:0
 #5 0x0000000003ed9879 clang::CodeGen::CodeGenFunction::EmitCall(clang::QualType, clang::CodeGen::CGCallee const&, clang::CallExpr const*, clang::CodeGen::ReturnValueSlot, llvm::Value*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ed9879)
 #6 0x0000000003edb237 clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*, clang::CodeGen::ReturnValueSlot) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3edb237)
 #7 0x0000000003f24c7a (anonymous namespace)::ScalarExprEmitter::VisitCallExpr(clang::CallExpr const*) CGExprScalar.cpp:0:0
 #8 0x0000000003f1b6a1 clang::StmtVisitorBase<std::add_pointer, (anonymous namespace)::ScalarExprEmitter, llvm::Value*>::Visit(clang::Stmt*) CGExprScalar.cpp:0:0
 #9 0x0000000003f20a92 clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3f20a92)
#10 0x0000000003ebce8e clang::CodeGen::CodeGenFunction::EmitAnyExpr(clang::Expr const*, clang::CodeGen::AggValueSlot, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ebce8e)
#11 0x0000000003ed750d clang::CodeGen::CodeGenFunction::EmitIgnoredExpr(clang::Expr const*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ed750d)
#12 0x0000000003acf3be clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3acf3be)
#13 0x0000000003ad5db9 clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ad5db9)
#14 0x0000000003b36a96 clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b36a96)
#15 0x0000000003b439f8 clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b439f8)
#16 0x0000000003b9b73b clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b9b73b)
#17 0x0000000003b971c5 clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b971c5)
#18 0x0000000003ba1e51 clang::CodeGen::CodeGenModule::EmitDeferred() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ba1e51)
#19 0x0000000003ba42a3 clang::CodeGen::CodeGenModule::Release() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ba42a3)
#20 0x000000000403fa7e (anonymous namespace)::CodeGeneratorImpl::HandleTranslationUnit(clang::ASTContext&) ModuleBuilder.cpp:0:0
#21 0x000000000403dac5 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x403dac5)
#22 0x0000000005f5e2ac clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5f5e2ac)
#23 0x000000000403e245 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x403e245)
#24 0x00000000042ddde1 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x42ddde1)
#25 0x00000000042616db clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x42616db)
#26 0x00000000043c4b13 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x43c4b13)
#27 0x0000000000c7467c cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xc7467c)
#28 0x0000000000c6e77d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#29 0x0000000004087889 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
#30 0x00000000036e7bf3 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x36e7bf3)
#31 0x0000000004087aa9 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
#32 0x000000000404d287 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x404d287)
#33 0x000000000404dc3d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x404dc3d)
#34 0x0000000004057d9c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4057d9c)
#35 0x0000000000c71b21 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xc71b21)
#36 0x0000000000b4d804 main (/opt/compiler-explorer/clang-trunk/bin/clang+++0xb4d804)
#37 0x000079f5cc429d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#38 0x000079f5cc429e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#39 0x0000000000c6e21e _start (/opt/compiler-explorer/clang-trunk/bin/clang+++0xc6e21e)
```
</details>

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzkWt9z2yoW_mvIC2OPBLJlPeTBUeLe3umd7TbZ3tsnDwJk6xaBBlAa78P-7TuA_APHSZuu7s7ObKZNbATnfN_H4XAkQYxpNpLzazC7AbPbK9LbrdLXvyixuxGEfi2JvaoU210_bDmslRDqWyM3kJLecAOJhI20XEsiIFVt1wiuIddaadhIWAoiNzBdQCIZtLqXXwFewq21nQF4CdAKoNWG0ulGsUoJO1V6A9DqnwCtdPH4-Ps7Kb-A5BYky_D7XVlCIoyChm9q0gtr4JZrDlAJv20bweFv95_LPQzjnepeGmi3jYGmp5QbU_dC7NwISoRwRMA8qYgGuEwTgEqUAHwH0AKgAsyT6eB9noR_tOtCi-VtJ4jlEOCykRb-4Sy6D18AvoOPqmHQGfV2IMhvQH57SuR0uN11XJKWwwfn2V82VvfUwk-cMK6HcflN-AAhhM-970e6q7VuuGQBRK0UQIvBEC69C1QAfLO3env8_BqyE3YRxN91Y_8SiE60MC1e2i_HWcEnYj6D71y1pJFD3zNczpWfZ2_s4LKR1rWEWTpRxyEdCIZOqIQhPkLXUxXjOAlfQ_QbsvPBfqkHwKVRvabcGcXLNAN4ibFbI34JuQ-USKnsPqhDKIvJIxE9h_yp09yYRkm44_YAOs0gyEs4otDeljcKZnf_Gn4uMlq6hb7lEpqusQaq3rqv0FhCv1pNKJ-eTtdNb2FTw53qIZ9uptDqHbTKLUmqegvmifv4h_vr1jKYJ1-cIxeMFjLFjQQot7DTbtq9MiHzuM5N23LWEMvFDnZaUc6ZcbZfQQNwybgljTCHYHUT1Lct0TuA7-7dMIBLgFbHxshArMXHD3fL-zto-qptLCSw6jdQ805p64CcZcHGbvtqSlUL0EqIx_2fSafVn5xagFaNMT03AK0CP0lFz7jnQzUxW1jtSTmBOs09a2M4g0OModKPJMYo6pTx2REaqpvODkJ4ipD1bXcIWZcEi49abTRpIdGbvuXSOuAQoJXqHLJ94p_wp04ozbVrc8E_CTkfrSq3JEMbQDcA3cDJhn0jup5kcLKBE-WMka5zJnvb9XZq4KR1AsDJ5GkxnxDTTsxOWvIE8K3bcQSc3MPJZEPpxCol6Natenz7KibX2UjSma2ycFJTJZSesIZspDK2oQZOaqkmXs2oOVqmXpTUiQJwyVXtEn5HtOEaEgvdalM1rBvBQ0_k5eN64prghw-ff4PvP8ENl1wT2ygZeuHB3rNskOZO6XdDd7fvKua2YQ0Zp4IEGxCg3K_ufFiuAOEEJk_J_gfnJE3IAvrAwkuAlyYkJbz86BaPn_aHEDuLYydNvq2VsZqTFqD5sAn4nOEyxM9PPkA3ydOA6ZCmHeg0Bl3UaZ1dAl0KTmTf_U3eNxtJBECLXvoqhkGhnJexIHoEEUQUQZzzPKcLWLqQ-cSpeuR6FzD9QiQTztNi0CzqUypp-ZOduoICLxP__-ACDy7yop5RmmVohpKBj2gqgFZPi_l6nk1EI_unyUb24QKdGjWde-B-SAQ7i2BzXM15DonWRG74SnO-6iV1ofSh-cpLIpykQY2gt2L8HZfRl4dd57KRD4vvdP1NsV7w7_UlQiz15kNj3G4njX3efw_Sud73Wbo-h9kfdulKKeE1f-esXlZ5FivCikVefI_IHkBovGsb-1yrv_dEOICvcvW4OH-JqLt699TpiORLxj5x22v52VUE90J5_scl45u9gZGWRBAqiq35mZIVwvnPKek4n0Xef6TEaJwdpYhzHnGuUUZz4pwRqeSuVb2BrnI2nU-pRYB3T4kg2rFxfH1Z6aeoMW9g74LaNQVjl0N7EYNLqzlJT0W7t631XpW-IYa7fceycIkwtu6Uv6VzSr-Z0eXg8_vZnmpM0WH5YWLFmeoJKdDbI-2IOobyLM72aWSUIApoj3clCKfxHs0ryhf87XSWcvcDXF4yu9xsotQxKudAKeKcniWLfJawt3N-v5FKc_Zd3qMlAAcz4hHXAYTWuPqJuQvRf74eook7Lqel1mT3idcAlycDltaeMB7u6cYgHThFpHFMms1Y9TN7pmo71UvmqP7e2K3q7T1VbseMa45jr2ifDBH6oxE9lhieayRGXFJVeE6K-dvF2LfcKLZ7NRJGIhJwRkTiSqjKcFEv3kZkuD_h7mJM4p1QFRG3nIo4lg_jX89O5bt9x_eyVidhMJYanmykRlzNVEWV4-oHC9zDpAbWe-i3vG5kE9j-iDahffTKLVCJuOZnXPOUzn6O6_8MR0ch4hgXQxVJ-Sx9K8dbXnOtOds_0B0FqkcSQS3OoGaI4LdA_cQFd_XcqCgdiFOUKKpasgTXJOffKxQHsC5JKP2-7URoDjfJD5pII_yTjH_I8_pwef8w3CwP6z4QvukbwfiFMtEhTM8QMhKH9Q2hX7lkpZKmb_dl-M9gGUPiAV8kcVRczOoZR4SeEvhItOHL-4ezDYO35GyPHLOaG3BEQPGZ0hxllxLI8nTTe-K0t3xoGi9UB-8RvGiLzhBjjEdrf6XddEp2Ad-YyILjCNksRjZP5-xslwm-3ktjiaT8snYvUxkxPgO4CH20R2aYZlUaJaoB55HEo6LkOeZnJMfbCQZQEepot0tons1zCilN18Mbo8uV9pacldcljNtQ6d-vjAg-QIuwL2Lsc57nDO5lLtMHv85PGNy3RIjPnB7S7QUi83hLdjaG9BYVWkw3jy9l2iJe_4t8sSjC26aj3Xoog9baC-qv7l8xDc8FKBGiIvTrupbxzU3wPURLmZaqbYlk5wv14sQdHmmoznknToMTfaxu5Mb3vBtm9TBgvaZPT2kavlTENHRtfPdBxaiza1hbTRpr9pfPzBEhXPQrfXLddTl5xOAjJ2juhwCUC9JWjACUH6VCi_3D7V9VdXE-zp76z3le1fhkKi49gx5Kh17ek5qLXSTn61M3Vo0RYJ6GO07P44qQ6Ebz_y4unNLTjmg7TV4NABQLlzG0yF8Uzk8Yebb17dWMcvXZQNfhpafXr3RdRvXJCbcRtn_PNYoifC4GxeytYvyqKvOyEr-q6tkLi9eS8GHyO9KcnCr4UfGGCPkLJaQ4eswVvzfKklnOCvoS3NuTz1EFcGHrf0n6_6KEY5WdXpNItNlZoZFWaCg796XGHrTPGstnT_pe2orHKS4cnAhvVM4lVcYWSeaP0YziMNiLHObxG05UsOKNbzj9kMjm4twmzxK4Xrtha2OJtusTRj_shWexl-K8DkMph8H-OLPjLR5dPjsvBNDq_JDKFbvGrMAFueLXaZ4WCGeLJL_aXmcoQ4s8oyxhlNSzLKtJMi9YVuQpwYThq-YaJShL5ihLcYpRPl1UBU3wfMZSxPOcEJAlvCWNmLrYnCq9ufKnUK6LebaYXQlScWH8wUGEJP8G_UWAEJjdXulrf36l6jcGZIlojDVHK7axgl-v_OmkSSP_5NQfbiDHc2P70uPkoOH78m5_WigMgaS2XEOrd26wVbDxNxK2cQbsltiDlatei-ufP3ET6D5eo38HAAD__-9YZmY">