`@var` annotation is ignored for class constants

[weirdan]

https://getpsalm.org/r/03a2f11ca3

<?php
  /** @param void ...$_p*/
  function type(...$_p): void {}

  class C {
    /** @var int[] */
    const N = [];
  }

  type(C::N);

Expected: should complain about array<mixed,int> provided
Actual: complains about array<empty,empty> provided

There's at least one usage of @var on constants in Psalm's tests:

psalm/tests/ConstantTest.php

Lines 66 to 69 in 0ef71a4

	/**
	* @var string[]
	*/
	protected const VALUES = [];

Additionally, psalm seems to ignore @var and const initialization contradiction:

<?php
class C {
  /** @var int */
  public const N = "aaaa"; // should produce issues, but doesn't
}

[vasily-kartashov]

Just as a side note, the words var and const clash semantically.

[sakshamsaxena]

Hey, @muglug. Is this still open ? Would like to start with this, looks interesting.

[muglug]

@sakshamsaxena

Sure!

Requirement:
Psalm currently does a lot of inference of constant types. If you provide your own type it should override that inference.

Nice-to-have:
Any classes that override a parent's constant value should be the same type as defined by the parent. You'd check for that in ClassAnalyzer::analyze, probably.

[sakshamsaxena]

@muglug Thanks! I'll try it out 😄

[bugreportuser]

When this is supported, it could be good for Psalm to only use the type for the rest of the analysis. That would resolve #2076.

[bdsl]

I just ran into this issue - reviewing a PR from a colleague using keys and values from two existing class constant arrays. I suggested typing the new constant using key-of and value-of to make sure they are spelled right. May need to change it from a constant to a property because of this issue.