A PHP internals RFC discussion proposing to make PHP fully case-sensitive. Currently, PHP treats function names, class names, and method names case-insensitively (e.g., STRLEN() works the same as strlen()). The RFC author Jorg Sowa wants to deprecate case-insensitive behavior leading up to PHP 9.0. Community responses are mixed: supporters argue it simplifies the engine, static analysis tools, and LSPs by removing identifier normalization passes, and makes PHP consistent with other languages. Opponents raise concerns about PHP's own inconsistent built-in naming (DateTime vs PDO vs mysqli), the risk of breaking dynamic method calls in frameworks, and whether the practical benefit justifies the migration cost. The RFC author suggests a possible narrower scope covering only namespaces and class names rather than all identifiers.
