psalm.xml

<?xml version="1.0"?>
<psalm
    totallyTyped="false"
    requireVoidReturnType="false"
    allowPhpStormGenerics="true"
    errorBaseline="psalm-baseline.xml"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="https://getpsalm.org/schema/config"
    xsi:schemaLocation="https://getpsalm.org/schema/config https://raw.githubusercontent.com/vimeo/psalm/master/config.xsd"
>
    <projectFiles>
        <directory name="src" />
        <ignoreFiles>
            <directory name="vendor" />
        </ignoreFiles>
    </projectFiles>

    <issueHandlers>
        <DeprecatedMethod errorLevel="info" />
        <DeprecatedProperty errorLevel="info" />
        <DeprecatedClass errorLevel="info" />
        <DeprecatedConstant errorLevel="info" />
        <DeprecatedInterface errorLevel="info" />
        <DeprecatedTrait errorLevel="info" />

        <MissingClosureReturnType errorLevel="suppress" />
        <MissingPropertyType errorLevel="suppress" />

        <PropertyNotSetInConstructor errorLevel="suppress" />
        <MissingConstructor errorLevel="info" />
        <MissingClosureParamType errorLevel="suppress" />

        <DocblockTypeContradiction errorLevel="suppress" />
        <RedundantConditionGivenDocblockType errorLevel="suppress" />

        <!-- Doing an include to Moodle -->
        <UnresolvableInclude errorLevel="info">
            <errorLevel type="suppress">
                <file name="src/Bridge/Moodle.php"/>
            </errorLevel>
        </UnresolvableInclude>

        <!-- Invalid PHPDoc on Symfony process helper -->
        <PossiblyInvalidArgument>
            <errorLevel type="suppress">
                <file name="src/Process/Execute.php"/>
            </errorLevel>
        </PossiblyInvalidArgument>

        <!-- These are due to how PhpParser classes work with properties -->
        <PossiblyNullOperand>
            <errorLevel type="suppress">
                <file name="src/Parser/StatementFilter.php"/>
            </errorLevel>
        </PossiblyNullOperand>

        <!-- Psalm is not finding inherited PHPDoc -->
        <MissingReturnType>
            <errorLevel type="suppress">
                <directory name="src/PluginValidate/Requirements"/>
                <file name="src/Command/CodeFixerCommand.php"/>
            </errorLevel>
        </MissingReturnType>

        <!-- CodeSniffer has some bad PHPDoc -->
        <InvalidPropertyAssignmentValue>
            <errorLevel type="suppress">
                <file name="src/Bridge/CodeSnifferCLI.php"/>
            </errorLevel>
        </InvalidPropertyAssignmentValue>

        <!-- CodeSniffer has some bad PHPDoc -->
        <NullArgument>
            <errorLevel type="suppress">
                <file name="src/Command/CodeFixerCommand.php"/>
                <file name="src/Command/CodeCheckerCommand.php"/>
            </errorLevel>
        </NullArgument>

        <!-- It is defined in Moodle itself -->
        <UndefinedClass>
            <errorLevel type="suppress">
                <file name="src/Bridge/Moodle.php"/>
            </errorLevel>
        </UndefinedClass>
    </issueHandlers>
</psalm>