Hack Array Immutable Documentation

[Mujing Zhou]

Please complete the information below:

Where is the problem?

• "The section describing how Hack array works"
• https://docs.hhvm.com/hack/arrays-and-collections/vec-keyset-and-dict

What is the problem?

• It is confusing/wrong in this piece of the example code ("C\contains($items, 'a'); // true"). After modifying in above lines, it should be false
• When explaining the immutable characteristic, I suppose it means the modification does not occur at the same memory location referenced Hack array, but instead create a modifiable copy. Perhaps it can use an example so it first assign the array to another variable ($items2 = $items) and then modify the $items, and check the values for both $items and $items2

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Please don't change anything below this point.

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• Build ID: HHVM=HHVM-4.164.0:HSL=v4.108.1:2023-11-08T01:59:56+0000:1fa47f258c6b68f8ec01899aa82fd6ffa0957109
• Page requested: /hack/arrays-and-collections/vec-keyset-and-dict
• Page requested at: Thu, 09 Nov 2023 00:23:18 +0000
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