php - Class doesn't inherit - class not found -

i have troubles inheritance. have that

file a.php

namespace main; class a{     public function __construct(){ echo 'a->__construct'; } } 

and file b.php

namespace main; class b extends \main\a{     /* if write construct , remove extends class - works - need inherit */     public function __construct(){ $a = new \main\a(); }      public function something(){ echo 'b->something';} } 

are there cases when classes cannot inherited or inherit class?

i had similar problem driving me crazy.

as test, copied parent class, renamed (i.e. code of abstract class same apart file name , class names) , inherit problem 'fixed'. weird!.

in case found class had require_once class causing error (i.e. 'b' in original poster's example) , removing (e.g.) 'require_once b' fixed it. somehow must have introduced circular causing php not load class - have no idea why, if has ideas, i'd love increase knowledge.

anyway... have moved on using spl_autoload_register (definitely way go). using spl_autoload_register in conjunction removing require_once whenever find 1 seems have solved problem.

i know reply late original poster, hope helps else pulling hair out (like was) similar issue.