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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Add -Wobjc-self-assignment for "cannot assign to 'self'" warnings"
href="http://llvm.org/bugs/show_bug.cgi?id=15324">15324</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Add -Wobjc-self-assignment for "cannot assign to 'self'" warnings
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Frontend
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</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 >test.m <<EOF
#import <Foundation/Foundation.h>
@interface A : NSObject
+(void)classmethod;
-(void)instancemethod;
@end
@implementation A
+(void) classmethod {
self = nil;
}
-(void) instancemethod {
self = nil;
}
@end
EOF
clang -fobjc-arc -c test.m
test.m:9:10: error: cannot assign to 'self' in a class method
self = nil;
~~~~ ^
test.m:12:10: error: cannot assign to 'self' outside of a method in the
init family
self = nil;
~~~~ ^
2 errors generated.
clang -Weverything -c test.m
(no diagnostics produced)
I suggested over at <a class="bz_bug_link
bz_status_NEW "
title="NEW --- - add -Wunused-but-set-variable"
href="show_bug.cgi?id=9824">bug 9824</a> that warning on dead writes could suffice to
diagnose this problematic code in non-ARC mode. (There's a motivating example
over there as well.) However, it was suggested that I also file a new issue for
this potentially simpler fix.
I propose that Clang add a flag named something like "-Wobjc-self-assignment",
place both of the existing ARC diagnostics under that flag, and allow the user
to enable the flag in non-ARC mode (possibly, but not necessarily, combined
with -Werror).</pre>
</div>
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