Using PHPStan for Static Analysis

Use the PHPStan CLI and a project config to check parameter contracts and return types as part of normal development.

What It Does

Native parameter and return types make contracts statically visible. Run analysis and inspect environmental diagnostics if setup fails.

Requirements and Compatibility

Use a supported PHP runtime and install any third-party tool or extension explicitly shown in the examples. Commands should be run from the project root unless stated otherwise.

Syntax, Inputs and Results

The examples separate configuration, the smallest working operation and a realistic follow-up task. Adapt file paths and dependency versions to your own project.

Example 1: Basic Use

Native parameter and return types make contracts statically visible.

<?php
function formatCount(int $count): string {
    return (string) $count;
}
echo formatCount(12);

Example 2: Another Case

Run analysis and inspect environmental diagnostics if setup fails.

vendor/bin/phpstan analyse src --level=5 --no-progress
vendor/bin/phpstan diagnose

Practical Example

Control the analysis target and treatment of PHPDoc annotations.

parameters:
  level: 5
  paths:
    - src
  treatPhpDocTypesAsCertain: true

For production, apply the compatibility and edge-case limits described below.

Important Behavior and Edge Cases

Fix the types identified by the analyzer rather than blanket-suppressing warnings.

Comparison with Related Functions and Tools

Subject	Key difference
Static analysis vs runtime tests	PHPStan checks source types without executing business behavior; tests confirm actual outcomes.

Common Beginner Mistakes

Mistake	Correct approach
Ignoring unknown or mixed types	Add valid PHPDoc element types or proper native declarations, then re-run the analyzer.
Skipping the prerequisite of this specific workflow	Install or configure the named tool and confirm the example can actually run.
Ignoring edge conditions	Fix the types identified by the analyzer rather than blanket-suppressing warnings.

Key Takeaways

Use the PHPStan CLI and a project config to check parameter contracts and return types as part of normal development.
Fix the types identified by the analyzer rather than blanket-suppressing warnings.
Keep application configuration, source code and validation tests under version control.

Use these examples as a starting point, then validate the result with the actual PHP build, dependencies and inputs used by your application.