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<?php $var1 = "1"; $var2 = "2"; $temp1 = "var" . "1"; $temp2 = "var" . "2"; var_dump(${$temp1} ?? ${$temp2});
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
string(1) "1"
Output for 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28
Parse error: syntax error, unexpected '?' in /in/lrSoc on line 7
Process exited with code 255.

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