Description:
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it often happen doing something similar to this assignment pattern:

$something = $something ?? ....whatever... ;

as a syntactic sugar it will be nice to have:

$something ??= ....whatever;

that will be interpreted as the original first line. Just simply syntactic sugar.

like the case of the operator:

$a = $a + 1;
$a++;





Expected result:
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if $something is set $something will be no operation or assigned itself, otherwise the RH operand will be assigned to $something.

Actual result:
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PHP Parse error:  syntax error, unexpected ?? (T_COALESCE) in php shell code on line 1