Plus operator in class const not resolving type when referencing parent const

[AndrolGenhald]

Referencing self consts seem to work fine: https://psalm.dev/r/70beb89706
But referencing parent consts causes the type to become mixed: https://psalm.dev/r/cbc8e21d41
Broken for ints too: https://psalm.dev/r/6b0c9ee8fc

Concatenation seems to work ok, though it changes the type to string instead of resolving the literal concatenation: https://psalm.dev/r/b67a63d851

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/70beb89706

<?php

class A {
    public const FOO = ['foo' => true];
    public const BAR = self::FOO + ['bar' => true];
}

/** @psalm-trace $foo */
$foo = A::FOO;
/** @psalm-trace $bar */
$bar = A::BAR;

Psalm output (using commit a469c82):

INFO: Trace - 9:1 - $foo: array{foo: true}

INFO: Trace - 11:1 - $bar: array{bar: true, foo: true}

INFO: UnusedVariable - 9:1 - $foo is never referenced or the value is not used

INFO: UnusedVariable - 11:1 - $bar is never referenced or the value is not used

https://psalm.dev/r/cbc8e21d41

<?php
class A {
    /** @var array<string, true> */
    public const ARR = [
        'A' => true,
    ];
}

class B extends A {
    /** @var array<string, true> */
    public const ARR = parent::ARR + [
        'B' => true,
    ];
}

class C extends B {
    /** @var array<string, true> */
    public const ARR = parent::ARR + [
        'C' => true,
    ];
}

/** @psalm-trace $a */
$a = A::ARR;
/** @psalm-trace $b */
$b = B::ARR;
/** @psalm-trace $c */
$c = C::ARR;

Psalm output (using commit a469c82):

INFO: Trace - 24:1 - $a: array{A: true}

INFO: MixedAssignment - 26:1 - Unable to determine the type that $b is being assigned to

INFO: Trace - 26:1 - $b: mixed

INFO: MixedAssignment - 28:1 - Unable to determine the type that $c is being assigned to

INFO: Trace - 28:1 - $c: mixed

INFO: UnusedVariable - 24:1 - $a is never referenced or the value is not used

INFO: UnusedVariable - 26:1 - $b is never referenced or the value is not used

INFO: UnusedVariable - 28:1 - $c is never referenced or the value is not used

INFO: MixedOperand - 18:24 - Left operand cannot be mixed

https://psalm.dev/r/6b0c9ee8fc

<?php
class A {
    public const INT = 1;
}

class B extends A {
    public const INT = parent::INT + 2;
}

class C extends B {
    public const INT = parent::INT + 3;
}

/** @psalm-trace $a */
$a = A::INT;
/** @psalm-trace $b */
$b = B::INT;
/** @psalm-trace $c */
$c = C::INT;

Psalm output (using commit a469c82):

INFO: Trace - 15:1 - $a: 1

INFO: MixedAssignment - 17:1 - Unable to determine the type that $b is being assigned to

INFO: Trace - 17:1 - $b: mixed

INFO: MixedAssignment - 19:1 - Unable to determine the type that $c is being assigned to

INFO: Trace - 19:1 - $c: mixed

INFO: UnusedVariable - 15:1 - $a is never referenced or the value is not used

INFO: UnusedVariable - 17:1 - $b is never referenced or the value is not used

INFO: UnusedVariable - 19:1 - $c is never referenced or the value is not used

INFO: MixedOperand - 11:24 - Left operand cannot be mixed

https://psalm.dev/r/b67a63d851

<?php
class A {
    public const STR = 'a';
}

class B extends A {
    public const STR = parent::STR . 'b';
}

class C extends B {
    public const STR = parent::STR . 'c';
}

/** @psalm-trace $a */
$a = A::STR;
/** @psalm-trace $b */
$b = B::STR;
/** @psalm-trace $c */
$c = C::STR;

Psalm output (using commit a469c82):

INFO: Trace - 15:1 - $a: "a"

INFO: Trace - 17:1 - $b: string

INFO: Trace - 19:1 - $c: string

INFO: UnusedVariable - 15:1 - $a is never referenced or the value is not used

INFO: UnusedVariable - 17:1 - $b is never referenced or the value is not used

INFO: UnusedVariable - 19:1 - $c is never referenced or the value is not used