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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - ICE on use of alias template resulting in array type nested within class template" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24212&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=MmwxEhd6n-m47g-xRqMjMc1E9wQrYrKuhdT2TUE-jKQ&s=og7EcGWeKxYNEwINfGXjB6whsS93VsGPjxcmSuaDA20&e=">24212</a>
</td>
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<th>Summary</th>
<td>ICE on use of alias template resulting in array type nested within class template
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>3.7
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>C++11
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>ed@catmur.co.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following program crashes clang++ (versions up to 3.7):
template<int I>
struct S {
template<int J> using T = int[J];
using U = T<I>;
};
S<3>::U a;
UNREACHABLE executed!
0 libLLVM-3.4.so 0x00007f7e80d695d2 llvm::sys::PrintStackTrace(_IO_FILE*) +
34
1 libLLVM-3.4.so 0x00007f7e80d69dfa
2 libpthread.so.0 0x00007f7e7fbc8710
3 libc.so.6 0x00007f7e7e87e625 gsignal + 53
4 libc.so.6 0x00007f7e7e87fe05 abort + 373
5 libLLVM-3.4.so 0x00007f7e80d549c4 llvm::llvm_unreachable_internal(char
const*, char const*, unsigned int) + 356
6 clang 0x00000000007aaa1f
clang::CodeGen::CodeGenTypes::ConvertType(clang::QualType) + 415
7 clang 0x00000000007ab30e
clang::CodeGen::CodeGenTypes::ConvertTypeForMem(clang::QualType) + 30
8 clang 0x0000000000759d0b
clang::CodeGen::CodeGenModule::EmitNullConstant(clang::QualType) + 187
9 clang 0x0000000000790c8f
clang::CodeGen::CodeGenModule::EmitGlobalVarDefinition(clang::VarDecl const*) +
1487
10 clang 0x000000000079613f
clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl) + 159
11 clang 0x000000000079668d
clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) + 941
12 clang 0x000000000079699b
clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) + 299
13 clang 0x000000000073c0bb
14 clang 0x000000000073b349
15 clang 0x00000000008c9e67 clang::ParseAST(clang::Sema&, bool, bool)
+ 487
16 clang 0x000000000073ab46 clang::CodeGenAction::ExecuteAction() +
70
17 clang 0x00000000005bccf2 clang::FrontendAction::Execute() + 210
18 clang 0x00000000005982cd
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 285
19 clang 0x000000000057dc5a
clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 1642
20 clang 0x0000000000573bc0 cc1_main(char const**, char const**, char
const*, void*) + 1184
21 clang 0x000000000057c264 main + 7636
22 libc.so.6 0x00007f7e7e86ad5d __libc_start_main + 253
23 clang 0x0000000000573529
Interestingly, supplying an equivalent alias template at (any) namespace scope
suppresses the bug:
namespace magic { template<int I> using unused = int[I]; }
template<int I>
struct S {
template<int J> using T = int[J];
using U = T<I>;
};
S<3>::U a; // OK</pre>
</div>
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