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<?php function foo(array &$x = array()){} $x = array(); foo($x[]); foo($x[]); foo($x[]); foo($x[]); var_dump($x);
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Fatal error: Uncaught TypeError: foo(): Argument #1 ($x) must be of type array, null given, called in /in/ik1HB on line 6 and defined in /in/ik1HB:2 Stack trace: #0 /in/ik1HB(6): foo(NULL) #1 {main} thrown in /in/ik1HB on line 2
Process exited with code 255.
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33
Fatal error: Uncaught TypeError: Argument 1 passed to foo() must be of the type array, null given, called in /in/ik1HB on line 6 and defined in /in/ik1HB:2 Stack trace: #0 /in/ik1HB(6): foo(NULL) #1 {main} thrown in /in/ik1HB on line 2
Process exited with code 255.
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.35, 5.6.0 - 5.6.28
Catchable fatal error: Argument 1 passed to foo() must be of the type array, null given, called in /in/ik1HB on line 6 and defined in /in/ik1HB on line 2
Process exited with code 255.
Output for 5.2.3 - 5.2.17, 5.3.0 - 5.3.29
Catchable fatal error: Argument 1 passed to foo() must be an array, null given, called in /in/ik1HB on line 6 and defined in /in/ik1HB on line 2
Process exited with code 255.
Output for 5.2.0 - 5.2.2
<br /> <b>Catchable fatal error</b>: Argument 1 passed to foo() must be an array, null given, called in /in/ik1HB on line 6 and defined in <b>/in/ik1HB</b> on line <b>2</b><br />
Process exited with code 255.
Output for 5.1.0 - 5.1.6
<br /> <b>Fatal error</b>: Argument 1 passed to foo() must not be null, called in /in/ik1HB on line 6 and defined in <b>/in/ik1HB</b> on line <b>2</b><br />
Process exited with code 255.
Output for 5.0.0 - 5.0.5
<br /> <b>Parse error</b>: parse error, unexpected T_ARRAY, expecting '&' or T_VARIABLE in <b>/in/ik1HB</b> on line <b>2</b><br />
Process exited with code 255.
Output for 4.4.2 - 4.4.9
<br /> <b>Parse error</b>: syntax error, unexpected T_ARRAY, expecting ')' in <b>/in/ik1HB</b> on line <b>2</b><br />
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1
<br /> <b>Parse error</b>: parse error, unexpected T_ARRAY, expecting ')' in <b>/in/ik1HB</b> on line <b>2</b><br />
Process exited with code 255.
Output for 4.3.2 - 4.3.4
<br /> <b>Parse error</b>: parse error, expecting `')'' in <b>/in/ik1HB</b> on line <b>2</b><br />
Process exited with code 255.

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