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<base href="http://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - -Wunused-const-variable is too aggressive, shouldn't be part of "-Wall" anyway"
href="http://llvm.org/bugs/show_bug.cgi?id=19596">19596</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>-Wunused-const-variable is too aggressive, shouldn't be part of "-Wall" anyway
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>3.4
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Static Analyzer
</td>
</tr>
<tr>
<th>Assignee</th>
<td>kremenek@apple.com
</td>
</tr>
<tr>
<th>Reporter</th>
<td>arthur.j.odwyer@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>cat >type_safe_enum.h <<EOF
#pragma once
#define ENUM_CONST(a) a,
#define ENUM_COUNT(a) +1
#define ENUM_NAME(a) #a,
#define TYPE_SAFE_ENUM(NAME, TYPE, VALUES) \
enum class NAME : TYPE { VALUES(ENUM_CONST) }; \
static const TYPE EnumSize_##NAME = 0 VALUES(ENUM_COUNT); \
inline const char* EnumName(NAME a) { const char* names[] = {
VALUES(ENUM_NAME) }; return names[static_cast<TYPE>(a)]; }
EOF
cat >test.cc <<EOF
#include <string>
#include "type_safe_enum.h"
#define TABLE_ROLE_VALUES(F) \
F(Slave) \
F(Master)
TYPE_SAFE_ENUM(TableRole, int, TABLE_ROLE_VALUES);
TableRole g_foo = TableRole::Slave;
TableRole GetFoo() { return g_foo; }
std::string GetFooName() { return EnumName(g_foo); }
EOF
clang++ -std=c++11 -c test.cc -Wall
The above test case gives a spurious warning about the "unused const variable"
EnumSize_TableRole, even though there's nothing the programmer can do about
that.
I would like to see this warning either
(1) moved out of -Wall to preserve GCC-compatibility (I think the appropriate
place for it is -Weverything), and/or
(2) toned down so that it doesn't warn about variables generated by macro
expansions.
$ clang++ -std=c++11 -c test.cc -Wall
test.cc:7:1: warning: unused variable 'EnumSize_TableRole'
[-Wunused-const-variable]
TYPE_SAFE_ENUM(TableRole, int, TABLE_ROLE_VALUES);
^
./type_safe_enum.h:7:117: note: expanded from macro 'TYPE_SAFE_ENUM'
#define TYPE_SAFE_ENUM(NAME, TYPE, VALUES) enum class NAME : TYPE {
VALUES(ENUM_CONST) }; static const TYPE EnumSize_##NAME = 0 VALUES...
^
<scratch space>:159:1: note: expanded from here
EnumSize_TableRole
^
1 warning generated.
$ clang++ --version
Apple LLVM version 5.1 (clang-503.0.38) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin12.5.0
Thread model: posix</pre>
</div>
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