Using a non-string value inside a string interpolation is not detected

UweKeim

This code:

<?php declare(strict_types = 1);

enum P
{
    case A;
    case B;
}

$p = P::A;

$s = "{$p}";

Above, the last line is detected by PHPStan as:

Part $p (P::A) of encapsed string cannot be cast to string.

PHP Tools does currently not detect it.

A similar example:

<?php declare(strict_types = 1);

class Test4
{
}

$d = new Test4();

$s = "{$d}";

Again, PHPStan detects this:

Part $d (Test4) of encapsed string cannot be cast to string.

My suggestion

Please also notify me when misusing something inside a string interpolation that is not allowed.

UweKeim

Yet another example, this time with an array:

<?php declare(strict_types = 1);

function Base64Encode(string $data) : string
{
    $r = base64_encode($data);
    if($r===FALSE)
    {
        $le = error_get_last();
        throw new Exception("Error $le while base64-decoding.");
    }

    return $r;
}

Above, the $le cannot be converted to string. PHPStan in fact detects two errors:

Strict comparison using === between string and false will always evaluate to false.

Part $le (array{type: int, message: string, file: string, line: int}|null) of encapsed string cannot be cast to string.

JakubMisek

thanks! checking types in string interpolation added.