Return type declarations can't be used until the minimum PHP model is PHP 7.Zero or increased. Property kind declarations cannot be used until the minimum PHP version is PHP 7.Four or increased. Namespace declarations should have exactly one blank line earlier than the declaration and at the least one blank line after. Ternary operators are fine, however at all times have them take a look at if the assertion is true, not false. Namespace declarations using curly brace syntax should not allowed. This leaves, for now, only unconditionally declared functions in the worldwide namespace, private class strategies, and code new to Core, as candidates for adding kind declarations. Using the "pre" model is slightly extra performant and may forestall future bugs when code will get moved around. It is a good strategy to prefix a lot of your code to prevent naming conflicts with different plugins, themes and/or WordPress Core.