Code Inspection: Disabled extension stubs
Reports the usages of classes, functions, and constants, for which the stubs for the corresponding PHP interpreter extensions are disabled.
You can configure the set of stubs under Settings | PHP | PHP Runtime.
See PhpStorm stubs (blog.jetbrains.com/phpstorm) for details.
Suppress an inspection in the editor
Place the caret at the highlighted line and press Alt+Enter or click .
Click the arrow next to the inspection you want to suppress and select the necessary suppress action.