A customer asked for help to track down the cause of runtime warnings like

Could not convert to double for property left

I found 3 places which print this warning:

• https://github.com/qt/qtdeclarative/blob/v6.9.2/src/qml/qml/qqmlglobal.cpp#L399-L402
• https://github.com/qt/qtdeclarative/blob/v6.9.2/src/qml/qml/qqmlglobal.cpp#L454-L457
• https://github.com/qt/qtdeclarative/blob/v6.9.2/src/qml/qml/qqmlglobal.cpp#L535-L538

Suggestions

• Provide more details to help identify the offending write operation (Target object's name? Source object + property name? File and line number?)
• Fill in the missing source value (a bit like QTBUG-139735)
• Convert these from raw qWarning to qCWarning