user-documentation icon indicating copy to clipboard operation
user-documentation copied to clipboard

Published 20 hours ago • verified publisher icon hhvm

No good examples for parameter variance in method overrides

Open stevendesu opened this issue 2 years ago • 0 comments

Please complete the information below:

Where is the problem?

"Classes: Inheritance"

What is the problem?

It does not provide an example of an overridden method with parameters. Specifically I was interested in three things, two of which were not covered:

  • Can the overriding method have a broader parameter type? (contravariance)
  • Can the overriding method have a stricter return type? (covariance) -- It can :white_check_mark:
  • Can the overriding method parameters have different names so long as the types are the same? (name invariance)

The examples provided only gave an example of covariance (get(): num is overridden with get(): float), but did not show if contravariance or name invariance is supported.

Please don't change anything below this point.

  • Build ID: HHVM=HHVM-4.154.0:HSL=v4.108.1:2022-06-02T01:16:10+0000:1fa47f258c6b68f8ec01899aa82fd6ffa0957109
  • Page requested: /hack/classes/inheritance
  • Page requested at: Mon, 06 Jun 2022 17:42:17 +0000

stevendesu avatar Jun 06 '22 17:06 stevendesu