diff options
author | Ievgenii Meshcheriakov <ievgenii.meshcheriakov@qt.io> | 2021-10-11 14:27:17 +0200 |
---|---|---|
committer | Qt Cherry-pick Bot <cherrypick_bot@qt-project.org> | 2021-10-13 01:00:18 +0000 |
commit | 23c51da465ded21cc0dede98bfcc10a595caee5d (patch) | |
tree | 333a64d104700a1fdf956d0ab6d057dcfe57f1ca /src | |
parent | 13ea8bfcc3427b963240eda0a5fb459f163b23a2 (diff) |
Add suffixes to loop variables for Q_FOREACH
Currently using nested Q_FOREACH loops produces warnings about
shadowing local variables (if enabled). For example, this code:
QList<int> aList;
QList<int> bList;
foreach (int a, aList) {
Q_UNUSED(a);
foreach (int b, bList)
Q_UNUSED(b);
}
produces the following warning with MSVC:
warning C4456: declaration of '_container_' hides previous local
declaration
This is due to using variable _container_ as loop variable for both
loops.
This patch appends current line number to the name of the loop
variables so that most of the uses of Q_FOREACH will not result
in shadowing.
The patch originally by Benoit Regrain.
Fixes: QTBUG-79081
Change-Id: I55235e917e920171b138c8b3239a95dfe2ac7988
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 9940e4812ba3448a997cb8fb1b08187a84c797f2)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
Diffstat (limited to 'src')
-rw-r--r-- | src/corelib/global/qglobal.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h index b505e9d1cf..2faf6a4415 100644 --- a/src/corelib/global/qglobal.h +++ b/src/corelib/global/qglobal.h @@ -1244,10 +1244,15 @@ QForeachContainer<typename std::decay<T>::type> qMakeForeachContainer(T &&t) // Use C++17 if statement with initializer. User's code ends up in a else so // scoping of different ifs is not broken -#define Q_FOREACH(variable, container) \ -for (auto _container_ = QtPrivate::qMakeForeachContainer(container); \ - _container_.i != _container_.e; ++_container_.i) \ - if (variable = *_container_.i; false) {} else +#define Q_FOREACH_IMPL(variable, name, container) \ + for (auto name = QtPrivate::qMakeForeachContainer(container); name.i != name.e; ++name.i) \ + if (variable = *name.i; false) {} else + +#define Q_FOREACH_JOIN(A, B) Q_FOREACH_JOIN_IMPL(A, B) +#define Q_FOREACH_JOIN_IMPL(A, B) A ## B + +#define Q_FOREACH(variable, container) \ + Q_FOREACH_IMPL(variable, Q_FOREACH_JOIN(_container_, __LINE__), container) #endif // QT_NO_FOREACH #define Q_FOREVER for(;;) |