vimeo/psalm

Psalm is not complaining about false value from createFromFormat

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#9,223 opened on Feb 4, 2023

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Help wantedbuginternal stubs/callmap

Description

The example below should complain on both lines about calling method on false.

createFromFormat example

Contributor guide

Tech stack
None
Domain
backendtooling
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.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
PHPPsalm basicsDateTime type inference
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the Psalm type inference for \DateTime::createFromFormat. The method's return type is DateTime|false. Ensure that when the return value is false, calling methods on it is flagged as a false method call. Check the relevant type checker files in Psalm's source, such as src/Psalm/Internal/Analyzer/Statements/Expression/Call/MethodCallAnalyzer.php, and look for existing test cases for similar issues. The psalm.dev link may contain a specific example to reproduce.