vimeo/psalm

array_walk_recursive changes variable type to incorrect

Open

#5,767 opened on May 14, 2021

View on GitHub
 (2 comments) (1 reaction) (0 assignees)PHP (668 forks)batch import
good first issuetype providers

Repository metrics

Stars
 (5,369 stars)
PR merge metrics
 (Avg merge 3d 12h) (5 merged PRs in 30d)

Description

I have an array array<int, array<int, int>>, that I pass to array_walk_recursive.

The first parameter in the callback function int &$id I take by reference, then I change the value to a different type. (e.g.: string) Though I define the @param-out string $id annotation, the inferred type is not what it expected.

Expected: array<int, array<int, string>> Inferred: array<array-key, mixed>

https://psalm.dev/r/097021124e

Contributor guide

Research direction
Investigate how Psalm handles the type inference for array walk recursive when the callback modifies a by reference parameter. Trace through the code that processes function calls and type narrowing.
Tech stack
php
Domain
devtools
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
PHP
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60