[PATCH] D53974: [clang-tidy] new checker: bugprone-too-small-loop-variable

[Tamás Zolnai via Phabricator via cfe-commits]

ztamas added a comment.

In https://reviews.llvm.org/D53974#1283833, @sberg wrote:

> > I run the new checker on LibreOffice project. I found ~25 false positives, which seems small enough to me. This false positives can be supressed easily.
>
> Do you have a link to such a false positive and how it got suppressed in the LibreOffice code base?  (If those are included in the referenced https://cgit.freedesktop.org/libreoffice/core/commit/?id=26ccd00bc96c585b7065af0dcce246b5bfaae5e1, I failed to spot them.)


I did not supress anything yet, since this checker is still work in progress. The final version might avoid those false postives.
One example in basic/source/runtime/dllmgr-x86.cxx
This line:
for (sal_uInt16 i = 1; i < (arguments == 0 ? 0 : arguments->Count()); ++i)

arguments->Count() returns a sal_uInt16 too, which is unsigned short, however "0" is an int literal so the "<>?<>:<>" expression will have an int type.
To supress that you can cast the literal:

for (sal_uInt16 i = 1; i < (arguments == 0 ? (sal_uInt16)0 : arguments->Count()); ++i)

Or cast the whole expression:

for (sal_uInt16 i = 1; i < (sal_uInt16)(arguments == 0 ? 0 : arguments->Count()); ++i)

Or use int for the loop variable:

for (int i = 1; i < (arguments == 0 ? 0 : arguments->Count()); ++i)


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D53974