Syntax error using curly syntax in @class directive

Not sure if I'm doing this wrong or it's a known limitation when ussing curly syntax inside double quotes?

syntax error, unexpected identifier "primary", expecting "]"

@php
    $theme = (object)[
        'colors' => ['primary' => 'red']
    ];
@endphp

Works
<x-test @class(["text- " . $theme->colors['primary']]) />

Doesn't work with curly syntax
<x-test @class(["text-{$theme->colors['primary']}"]) />

Test component simple output the class

<div {{ $attributes }}>test</div>