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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - clang -frewrite-includes fails to remove __has_include if behind a macro."
href="https://bugs.llvm.org/show_bug.cgi?id=43982">43982</a>
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<th>Summary</th>
<td>clang -frewrite-includes fails to remove __has_include if behind a macro.
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>9.0
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>-New Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>emilio@crisal.io
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<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=22801" name="attach_22801" title="test-case.cpp">attachment 22801</a> <a href="attachment.cgi?id=22801&action=edit" title="test-case.cpp">[details]</a></span>
test-case.cpp
Minimal test-case attached. STR:
$ touch t.h
$ clang -frewrite-includes -E test-case.cpp > pre-processed.cpp
$ rm t.h
$ clang pre-processed.cpp
t.cpp:10:3: error: use of undeclared identifier 'std'
std::cout << "Hello world" << std::endl;
^
t.cpp:10:33: error: use of undeclared identifier 'std'
std::cout << "Hello world" << std::endl;
This is because:
* The __has_include check is not removed when expanding, and...
* The second <iostream> expansion is suppressed.
This is causing problems when building Firefox on Linux with distributed
compilers, because glibc has started using this pattern:
<a href="https://sourceware.org/ml/libc-alpha/2019-06/msg00254.html">https://sourceware.org/ml/libc-alpha/2019-06/msg00254.html</a>
I plan to try and submit a glibc workaround, but it'd be great if it wasn't
needed :)</pre>
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