Using ${expr} (variable variables) in strings is deprecated, use {${expr}} instead¶

Description¶

The interpolation syntax ${expression} is deprecated. It takes an expression (here, a concatenation) to build the name of the variable that is used in the end. It is recommended to update the syntax with a compatible one or use concatenation, before the syntax is removed.

Example¶

<?php

$foo = 'bar';
$bar = 'xyz';
var_dump("foo is $\{$foo}");

?>

Solutions¶

Use {} instead.
Use concatenation instead.

Changed Behavior¶

This error may appear following an evolution in behavior, in previous versions. See dollar_curly_expression.

Changed Behavior¶

This error may appear following an evolution in behavior, in previous versions. See dollar_curly_expression.