psalm/src/Psalm/Checker/FunctionLikeChecker.php

<?php
namespace Psalm\Checker;

use PhpParser\Node\Expr\Closure;
use PhpParser\Node\Stmt\ClassMethod;
use PhpParser\Node\Stmt\Function_;
use PhpParser;
use Psalm\CodeLocation;
use Psalm\Checker\Statements\ExpressionChecker;
use Psalm\Checker\TypeChecker;
use Psalm\Context;
use Psalm\EffectsAnalyser;
use Psalm\Exception\DocblockParseException;
use Psalm\FunctionLikeParameter;
use Psalm\Issue\DuplicateParam;
use Psalm\Issue\InvalidDocblock;
use Psalm\Issue\InvalidParamDefault;
use Psalm\Issue\InvalidReturnType;
use Psalm\Issue\InvalidToString;
use Psalm\Issue\MethodSignatureMismatch;
use Psalm\Issue\MissingReturnType;
use Psalm\Issue\MixedInferredReturnType;
use Psalm\IssueBuffer;
use Psalm\StatementsSource;
use Psalm\Type;

abstract class FunctionLikeChecker extends SourceChecker implements StatementsSource
{
    const RETURN_TYPE_REGEX = '/\\:\s+(\\??[A-Za-z0-9_\\\\]+)/';
    const PARAM_TYPE_REGEX = '/^(\\??[A-Za-z0-9_\\\\]+)\s/';

    /**
     * @var Closure|Function_|ClassMethod
     */
    protected $function;

    /**
     * @var string
     */
    protected $namespace;

    /**
     * @var bool
     */
    protected $is_static = false;

    /**
     * @var string
     */
    protected $fq_class_name;

    /**
     * @var StatementsChecker|null
     */
    protected $statements_checker;

    /**
     * @var StatementsSource
     */
    protected $source;

    /**
     * @var array<string, array<string, Type\Union>>
     */
    protected $return_vars_in_scope = [];

    /**
     * @var array<string, array<string,bool>>
     */
    protected $return_vars_possibly_in_scope = [];

    /**
     * @var string|null
     */
    protected $class_name;

    /**
     * @var string|null
     */
    protected $class_extends;

    /**
     * @var array<string, array>
     */
    protected static $no_effects_hashes = [];

    /**
     * @param Closure|Function_|ClassMethod $function
     * @param StatementsSource $source
     */
    public function __construct($function, StatementsSource $source)
    {
        $this->function = $function;
        $this->namespace = $source->getNamespace();
        $this->class_name = $source->getClassName();
        $this->class_extends = $source->getParentClass();
        $this->file_name = $source->getFileName();
        $this->file_path = $source->getFilePath();
        $this->include_file_name = $source->getIncludeFileName();
        $this->include_file_path = $source->getIncludeFilePath();
        $this->fq_class_name = $source->getFQCLN();
        $this->source = $source;
        $this->suppressed_issues = $source->getSuppressedIssues();
        $this->aliased_classes = $source->getAliasedClasses();
        $this->aliased_constants = $source->getAliasedConstants();
        $this->aliased_functions = $source->getAliasedFunctions();
    }

    /**
     * @param Context       $context
     * @param Context|null  $global_context
     * @return false|null
     */
    public function check(Context $context, Context $global_context = null)
    {
        $function_stmts = $this->function->getStmts() ?: [];

        $statements_checker = new StatementsChecker($this);

        $hash = null;

        $closure_return_type = null;
        $closure_return_type_location = null;

        if ($this instanceof MethodChecker) {
            if (ClassLikeChecker::getThisClass()) {
                $hash = $this->getMethodId() . json_encode([
                    $context->vars_in_scope,
                        $context->vars_possibly_in_scope
                    ]);

                // if we know that the function has no effects on vars, we don't bother rechecking
                if (isset(self::$no_effects_hashes[$hash])) {
                    list(
                        $context->vars_in_scope,
                        $context->vars_possibly_in_scope
                    ) = self::$no_effects_hashes[$hash];

                    return null;
                }
            } elseif ($context->self) {
                $context->vars_in_scope['$this'] = new Type\Union([new Type\Atomic($context->self)]);
            }

            $function_params = MethodChecker::getMethodParams((string)$this->getMethodId());

            if ($function_params === null) {
                throw new \InvalidArgumentException('Cannot get params for own method');
            }

            $method_id = (string)$this->getMethodId($context->self);

            $implemented_method_ids = MethodChecker::getOverriddenMethodIds($method_id);

            if ($implemented_method_ids) {
                $have_emitted = false;

                foreach ($implemented_method_ids as $implemented_method_id) {
                    if ($have_emitted) {
                        break;
                    }

                    if ($implemented_method_id === 'ArrayObject::__construct') {
                        continue;
                    }

                    $implemented_params = MethodChecker::getMethodParams($implemented_method_id);

                    if ($implemented_params === null) {
                        continue;
                    }

                    foreach ($implemented_params as $i => $implemented_param) {
                        if (!isset($function_params[$i])) {
                            $cased_method_id = MethodChecker::getCasedMethodId((string)$this->getMethodId());
                            $parent_method_id = MethodChecker::getCasedMethodId($implemented_method_id);

                            if (IssueBuffer::accepts(
                                new MethodSignatureMismatch(
                                    'Method ' . $cased_method_id .' has fewer arguments than parent method ' .
                                        $parent_method_id,
                                    new CodeLocation($this, $this->function)
                                )
                            )) {
                                return false;
                            }

                            $have_emitted = true;
                            break;
                        }

                        if ((string)$function_params[$i]->signature_type !==
                            (string)$implemented_param->signature_type
                        ) {
                            $cased_method_id = MethodChecker::getCasedMethodId((string)$this->getMethodId());
                            $parent_method_id = MethodChecker::getCasedMethodId($implemented_method_id);

                            if (IssueBuffer::accepts(
                                new MethodSignatureMismatch(
                                    'Argument ' . ($i + 1) . ' of ' . $cased_method_id .' has wrong type \'' .
                                        $function_params[$i]->signature_type . '\', expecting \'' .
                                        $implemented_param->signature_type . '\' as defined by ' .
                                        $parent_method_id,
                                    new CodeLocation($this, $this->function)
                                )
                            )) {
                                return false;
                            }

                            $have_emitted = true;
                            break;
                        }
                    }
                }
            }
        } elseif ($this instanceof FunctionChecker) {
            $function_params = FunctionChecker::getParams(strtolower((string)$this->getMethodId()), $this->file_path);
        } else { // Closure
            $function_params = [];
            $function_param_names = [];

            foreach ($this->function->getParams() as $param) {
                $param_array = self::getTranslatedParam(
                    $param,
                    $this
                );

                $function_params[] = $param_array;

                if (isset($function_param_names[$param->name])) {
                    if (IssueBuffer::accepts(
                        new DuplicateParam(
                            'Duplicate param $' . $param->name . ' in closure docblock',
                            new CodeLocation($this, $param, true)
                        ),
                        $this->suppressed_issues
                    )) {
                        return false;
                    }
                }

                $function_param_names[$param->name] = $param_array->type;
            }

            $doc_comment = $this->function->getDocComment();

            if ($this->function->returnType) {
                $parser_return_type = $this->function->returnType;

                $suffix = '';

                if ($parser_return_type instanceof PhpParser\Node\NullableType) {
                    $suffix = '|null';
                    $parser_return_type = $parser_return_type->type;
                }

                if (is_string($parser_return_type)) {
                    $return_type_string = $parser_return_type . $suffix;
                } else {
                    $fq_class_name = ClassLikeChecker::getFQCLNFromNameObject(
                        $parser_return_type,
                        $this->namespace,
                        $this->getAliasedClasses()
                    );

                    ClassLikeChecker::checkFullyQualifiedClassLikeName(
                        $fq_class_name,
                        $this->getFileChecker(),
                        new CodeLocation($this, $parser_return_type),
                        $this->suppressed_issues
                    );

                    $return_type_string = $fq_class_name . $suffix;
                }

                $closure_return_type = Type::parseString($return_type_string);

                $closure_return_type_location = new CodeLocation(
                    $this->getSource(),
                    $this->function,
                    false,
                    self::RETURN_TYPE_REGEX
                );
            }

            if ($doc_comment) {
                try {
                    $docblock_info = CommentChecker::extractDocblockInfo(
                        (string)$doc_comment,
                        $doc_comment->getLine()
                    );
                } catch (DocblockParseException $e) {
                    if (IssueBuffer::accepts(
                        new InvalidDocblock(
                            'Invalid type passed in docblock for ' . $this->getMethodId(),
                            new CodeLocation($this, $this->function, true)
                        )
                    )) {
                        return false;
                    }
                }

                if ($docblock_info) {
                    $this->suppressed_issues = $docblock_info->suppress;

                    $config = \Psalm\Config::getInstance();

                    if ($config->use_docblock_types) {
                        if ($docblock_info->return_type) {
                            $closure_docblock_return_type =
                                Type::parseString(
                                    self::fixUpLocalType(
                                        (string)$docblock_info->return_type,
                                        null,
                                        $this->namespace,
                                        $this->getAliasedClasses()
                                    )
                                );

                            if (!$closure_return_type_location) {
                                $closure_return_type_location = new CodeLocation(
                                    $this->getSource(),
                                    $this->function,
                                    true
                                );
                            }

                            if ($closure_return_type &&
                                !TypeChecker::isContainedBy(
                                    $closure_return_type,
                                    $closure_docblock_return_type,
                                    $statements_checker->getFileChecker()
                                )
                            ) {
                                if (IssueBuffer::accepts(
                                    new InvalidDocblock(
                                        'Docblock return type does not match closure return type ' . $this->getMethodId(),
                                        new CodeLocation($this, $this->function, true)
                                    )
                                )) {
                                    return false;
                                }
                            } else {
                                $closure_return_type = $closure_docblock_return_type;
                            }

                            $closure_return_type_location->setCommentLine($docblock_info->return_type_line_number);
                        }

                        if ($docblock_info->params) {
                            $this->improveParamsFromDocblock(
                                $docblock_info->params,
                                $function_param_names,
                                $function_params,
                                new CodeLocation($this, $this->function, false)
                            );
                        }
                    }
                }
            }

            /** @var PhpParser\Node\Expr\Closure $this->function */
            $this->function->inferredType = new Type\Union([
                new Type\Fn(
                    'Closure',
                    $function_params,
                    $closure_return_type ?: Type::getMixed()
                )
            ]);
        }

        foreach ($function_params as $offset => $function_param) {
            $param_type = ExpressionChecker::fleshOutTypes(
                clone $function_param->type,
                [],
                $context->self,
                $this->getMethodId()
            );

            if (!$function_param->code_location) {
                throw new \UnexpectedValueException('We should know where this code is');
            }

            $parser_param = $this->function->getParams()[$offset];

            if ($parser_param->default) {
                $default_type = StatementsChecker::getSimpleType($parser_param->default);

                if ($default_type &&
                    !TypeChecker::isContainedBy(
                        $default_type,
                        $param_type,
                        $statements_checker->getFileChecker()
                    )
                ) {
                    $method_id = $this->getMethodId();
                    $cased_method_id = $method_id;

                    if ($cased_method_id) {
                        if ($this instanceof MethodChecker) {
                            $cased_method_id = MethodChecker::getCasedMethodId($cased_method_id);
                        } elseif ($this->function instanceof PhpParser\Node\Stmt\Function_) {
                            $cased_method_id = $this->function->name;
                        }
                    }

                    if (IssueBuffer::accepts(
                        new InvalidParamDefault(
                            'Default value for argument ' . ($offset + 1) . ' of method ' . $cased_method_id .
                                ' does not match the given type ' . $param_type,
                            $function_param->code_location
                        )
                    )) {
                        // fall through
                    }
                }
            }

            foreach ($param_type->types as $atomic_type) {
                if ($atomic_type->isObjectType()
                    && !$atomic_type->isObject()
                    && $this->function instanceof PhpParser\Node
                    && ClassLikeChecker::checkFullyQualifiedClassLikeName(
                        $atomic_type->value,
                        $this->getFileChecker(),
                        $function_param->code_location,
                        $this->suppressed_issues
                    ) === false
                ) {
                    return false;
                }
            }

            $context->vars_in_scope['$' . $function_param->name] = $param_type;

            $statements_checker->registerVariable(
                $function_param->name,
                $function_param->code_location->getLineNumber()
            );
        }

        $statements_checker->check($function_stmts, $context, null, $global_context);

        if ($this->function instanceof Closure) {
            $closure_yield_types = [];

            $this->checkReturnTypes(
                false,
                $closure_return_type,
                $this->fq_class_name,
                $closure_return_type_location
            );

            if (!$closure_return_type || $closure_return_type->isMixed()) {
                $closure_yield_types = [];
                $closure_return_types = EffectsAnalyser::getReturnTypes(
                    $this->function->stmts,
                    $closure_yield_types,
                    true
                );

                if ($closure_return_types && $this->function->inferredType) {
                    /** @var Type\Fn */
                    $closure_atomic = $this->function->inferredType->types['Closure'];
                    $closure_atomic->return_type = new Type\Union($closure_return_types);
                }
            }
        }


        if (isset($this->return_vars_in_scope[''])) {
            $context->vars_in_scope = TypeChecker::combineKeyedTypes(
                $context->vars_in_scope,
                $this->return_vars_in_scope['']
            );
        }

        if (isset($this->return_vars_possibly_in_scope[''])) {
            $context->vars_possibly_in_scope = array_merge(
                $context->vars_possibly_in_scope,
                $this->return_vars_possibly_in_scope['']
            );
        }

        foreach ($context->vars_in_scope as $var => $type) {
            if (strpos($var, '$this->') !== 0) {
                unset($context->vars_in_scope[$var]);
            }
        }

        foreach ($context->vars_possibly_in_scope as $var => $type) {
            if (strpos($var, '$this->') !== 0) {
                unset($context->vars_possibly_in_scope[$var]);
            }
        }

        if ($hash && ClassLikeChecker::getThisClass() && $this instanceof MethodChecker) {
            self::$no_effects_hashes[$hash] = [
                $context->vars_in_scope,
                $context->vars_possibly_in_scope
            ];
        }

        return null;
    }

    /**
     * Adds return types for the given function
     *
     * @param   string  $return_type
     * @param   Context $context
     * @return  void
     */
    public function addReturnTypes($return_type, Context $context)
    {
        if (isset($this->return_vars_in_scope[$return_type])) {
            $this->return_vars_in_scope[$return_type] = TypeChecker::combineKeyedTypes(
                $context->vars_in_scope,
                $this->return_vars_in_scope[$return_type]
            );
        } else {
            $this->return_vars_in_scope[$return_type] = $context->vars_in_scope;
        }

        if (isset($this->return_vars_possibly_in_scope[$return_type])) {
            $this->return_vars_possibly_in_scope[$return_type] = array_merge(
                $context->vars_possibly_in_scope,
                $this->return_vars_possibly_in_scope[$return_type]
            );
        } else {
            $this->return_vars_possibly_in_scope[$return_type] = $context->vars_possibly_in_scope;
        }
    }

    /**
     * @param string|null $context_self
     * @return null|string
     */
    public function getMethodId($context_self = null)
    {
        if ($this->function instanceof ClassMethod) {
            $function_name = (string)$this->function->name;

            if (strtolower($function_name) === strtolower((string)$this->class_name)) {
                $function_name = '__construct';
            }

            return ($context_self ?: $this->fq_class_name) . '::' . strtolower($function_name);
        }

        if ($this->function instanceof Function_) {
            return ($this->namespace ? strtolower($this->namespace) . '\\' : '') . strtolower($this->function->name);
        }

        return null;
    }

    /**
     * @return string
     */
    public function getNamespace()
    {
        return $this->namespace;
    }

    /**
     * @return array<string, string>
     */
    public function getAliasedClassesFlipped()
    {
        if ($this->source instanceof NamespaceChecker || $this->source instanceof FileChecker || $this->source instanceof ClassLikeChecker) {
            return $this->source->getAliasedClassesFlipped();
        }

        return [];
    }

    /**
     * @return string
     */
    public function getFQCLN()
    {
        return $this->fq_class_name;
    }

    /**
     * @return null|string
     */
    public function getClassName()
    {
        return $this->class_name;
    }

    /**
     * @return mixed
     */
    public function getClassLikeChecker()
    {
        return $this->source->getClassLikeChecker();
    }

    /**
     * @return string|null
     */
    public function getParentClass()
    {
        return $this->class_extends;
    }

    /**
     * @return bool
     */
    public function isStatic()
    {
        return $this->is_static;
    }

    /**
     * @return StatementsSource
     */
    public function getSource()
    {
        return $this->source;
    }

    /**
     * @param   bool                $update_docblock
     * @param   Type\Union|null     $return_type
     * @param   string              $fq_class_name
     * @param   CodeLocation|null   $return_type_location
     * @param   CodeLocation|null   $secondary_return_type_location
     * @return  false|null
     */
    public function checkReturnTypes(
        $update_docblock = false,
        Type\Union $return_type = null,
        $fq_class_name = null,
        CodeLocation $return_type_location = null,
        CodeLocation $secondary_return_type_location = null
    ) {
        if (!$this->function->getStmts() &&
            ($this->function instanceof ClassMethod &&
                ($this->getSource() instanceof InterfaceChecker || $this->function->isAbstract())
            )
        ) {
            return null;
        }

        $is_to_string = $this->function instanceof ClassMethod && strtolower($this->function->name) === '__tostring';

        if ($this->function instanceof ClassMethod &&
            substr($this->function->name, 0, 2) === '__' &&
            !$is_to_string
        ) {
            // do not check __construct, __set, __get, __call etc.
            return null;
        }

        $method_id = (string)$this->getMethodId();

        $cased_method_id = $this instanceof MethodChecker
            ? MethodChecker::getCasedMethodId($method_id)
            : ($this instanceof FunctionChecker ? $this->function->name : null);

        if (!$return_type_location) {
            $return_type_location = new CodeLocation($this, $this->function, true);
        }

        if (!$return_type && !$update_docblock && !$is_to_string) {
            if (IssueBuffer::accepts(
                new MissingReturnType(
                    'Method ' . $cased_method_id . ' does not have a return type',
                    new CodeLocation($this, $this->function, true)
                ),
                $this->suppressed_issues
            )) {
                // fall through
            }

            return null;
        }

        $inferred_yield_types = [];
        $inferred_return_types = EffectsAnalyser::getReturnTypes(
            $this->function->getStmts(),
            $inferred_yield_types,
            true
        );

        $inferred_return_type = $inferred_return_types ? Type::combineTypes($inferred_return_types) : Type::getVoid();
        $inferred_yield_type = $inferred_yield_types ? Type::combineTypes($inferred_yield_types) : null;

        $inferred_generator_return_type = null;

        if ($inferred_yield_type) {
            $inferred_generator_return_type = $inferred_return_type;
            $inferred_return_type = $inferred_yield_type;
        }

        if ($is_to_string) {
            if (!$inferred_return_type->isMixed() && (string)$inferred_return_type !== 'string') {
                if (IssueBuffer::accepts(
                    new InvalidToString(
                        '__toString methods must return a string',
                        $secondary_return_type_location ?: $return_type_location
                    )
                )) {
                    return false;
                }
            }

            if (!$return_type && !$update_docblock) {
                return null;
            }
        }

        if (!$return_type) {
            if ($inferred_return_type && !$inferred_return_type->isMixed()) {
                FileChecker::addDocblockReturnType(
                    $this->file_name,
                    $this->function->getLine(),
                    (string)$this->function->getDocComment(),
                    $inferred_return_type->toNamespacedString(
                        $this->getAliasedClassesFlipped(),
                        $this->getFQCLN(),
                        false
                    ),
                    $inferred_return_type->toNamespacedString(
                        $this->getAliasedClassesFlipped(),
                        $this->getFQCLN(),
                        true
                    )
                );
            }

            return null;
        }

        // passing it through fleshOutTypes eradicates errant $ vars
        $declared_return_type = ExpressionChecker::fleshOutTypes(
            $return_type,
            [],
            $fq_class_name ?: $this->fq_class_name,
            $method_id
        );

        if (!$inferred_return_types && !$inferred_yield_types) {
            if ($declared_return_type->isVoid()) {
                return null;
            }

            if (ScopeChecker::onlyThrows($this->function->getStmts())) {
                // if there's a single throw statement, it's presumably an exception saying this method is not to be
                // used
                return null;
            }

            if (IssueBuffer::accepts(
                new InvalidReturnType(
                    'No return statements were found for method ' . $cased_method_id .
                        ' but return type \'' . $declared_return_type . '\' was expected',
                    $secondary_return_type_location ?: $return_type_location
                )
            )) {
                return false;
            }

            return null;
        }

        if ($inferred_return_type && !$declared_return_type->isMixed()) {
            if ($inferred_return_type->isVoid() && $declared_return_type->isVoid()) {
                return null;
            }

            if ($inferred_return_type->isMixed() || $inferred_return_type->isEmpty()) {
                if (IssueBuffer::accepts(
                    new MixedInferredReturnType(
                        'Could not verify return type \'' . $declared_return_type . '\' for ' .
                            $cased_method_id,
                        $secondary_return_type_location ?: $return_type_location
                    ),
                    $this->getSuppressedIssues()
                )) {
                    return false;
                }

                return null;
            }

            $inferred_return_type = ExpressionChecker::fleshOutTypes(
                $inferred_return_type,
                [],
                $this->fq_class_name,
                ''
            );

            if (!TypeChecker::hasIdenticalTypes(
                $declared_return_type,
                $inferred_return_type,
                $this->getFileChecker()
            )) {
                if ($update_docblock) {
                    if (!in_array('InvalidReturnType', $this->getSuppressedIssues())) {
                        FileChecker::addDocblockReturnType(
                            $this->file_name,
                            $this->function->getLine(),
                            (string)$this->function->getDocComment(),
                            $inferred_return_type->toNamespacedString(
                                $this->getAliasedClassesFlipped(),
                                $this->getFQCLN(),
                                false
                            ),
                            $inferred_return_type->toNamespacedString(
                                $this->getAliasedClassesFlipped(),
                                $this->getFQCLN(),
                                true
                            )
                        );
                    }

                    return null;
                }

                if (IssueBuffer::accepts(
                    new InvalidReturnType(
                        'The given return type \'' . $declared_return_type . '\' for ' . $cased_method_id .
                            ' is incorrect, got \'' . $inferred_return_type . '\'',
                        $secondary_return_type_location ?: $return_type_location
                    ),
                    $this->getSuppressedIssues()
                )) {
                    return false;
                }
            }
        }

        return null;
    }

    /**
     * @param  array<array{type:string,name:string,line_number:int}>  $docblock_params
     * @param  array<string,Type\Union>               $function_param_names
     * @param  array<\Psalm\FunctionLikeParameter>    &$function_signature
     * @param  CodeLocation                           $code_location
     * @return false|null
     */
    protected function improveParamsFromDocblock(
        array $docblock_params,
        array $function_param_names,
        array &$function_signature,
        CodeLocation $code_location
    ) {
        $docblock_param_vars = [];

        $method_id = $cased_method_id = $this->getMethodId();

        if ($method_id) {
            $cased_method_id = $this instanceof MethodChecker
                ? MethodChecker::getCasedMethodId($method_id)
                : FunctionChecker::getCasedFunctionId($method_id, $this->file_path);
        }

        foreach ($docblock_params as $docblock_param) {
            $param_name = $docblock_param['name'];
            $line_number = $docblock_param['line_number'];

            if (!array_key_exists($param_name, $function_param_names)) {
                $code_location->setCommentLine($line_number);
                if (IssueBuffer::accepts(
                    new InvalidDocblock(
                        'Parameter $' . $param_name .' does not appear in the argument list for ' .
                            $cased_method_id,
                        $code_location
                    )
                )) {
                    return false;
                }

                continue;
            }

            $docblock_param_vars[$param_name] = true;

            $new_param_type = Type::parseString(
                self::fixUpLocalType(
                    $docblock_param['type'],
                    null,
                    $this->namespace,
                    $this->getAliasedClasses()
                )
            );

            if ($function_param_names[$param_name] && !$function_param_names[$param_name]->isMixed()) {
                if (!TypeChecker::isContainedBy(
                    $new_param_type,
                    $function_param_names[$param_name],
                    $this->getFileChecker()
                )
                ) {
                    $code_location->setCommentLine($line_number);
                    if (IssueBuffer::accepts(
                        new InvalidDocblock(
                            'Parameter $' . $param_name .' has wrong type \'' . $new_param_type . '\', should be \'' .
                                $function_param_names[$param_name] . '\'',
                            $code_location
                        )
                    )) {
                        return false;
                    }

                    continue;
                }
            }

            foreach ($function_signature as &$function_signature_param) {
                if ($function_signature_param->name === $param_name) {
                    $existing_param_type_nullable = $function_signature_param->is_nullable;

                    if ($existing_param_type_nullable && !$new_param_type->isNullable()) {
                        $new_param_type->types['null'] = new Type\Atomic('null');
                    }

                    $function_signature_param->signature_type = $function_signature_param->type;
                    $function_signature_param->type = $new_param_type;
                    break;
                }
            }
        }

        foreach ($function_signature as &$function_signature_param) {
            if (!isset($docblock_param_vars[$function_signature_param->name]) && $function_signature_param->code_location) {
                if (IssueBuffer::accepts(
                    new InvalidDocblock(
                        'Parameter $' . $function_signature_param->name .' does not appear in the docbock for ' .
                            $cased_method_id,
                        $function_signature_param->code_location
                    )
                )) {
                    return false;
                }

                continue;
            }
        }

        return null;
    }

    /**
     * @param  PhpParser\Node\Param $param
     * @param  StatementsSource     $source
     * @return FunctionLikeParameter
     */
    public static function getTranslatedParam(
        PhpParser\Node\Param $param,
        StatementsSource $source
    ) {
        $param_type = null;

        $is_nullable = $param->default !== null &&
            $param->default instanceof \PhpParser\Node\Expr\ConstFetch &&
            $param->default->name instanceof PhpParser\Node\Name &&
            strtolower($param->default->name->parts[0]) === 'null';

        $param_typehint = $param->type;

        if ($param_typehint instanceof PhpParser\Node\NullableType) {
            $is_nullable = true;
            $param_typehint = $param_typehint->type;
        }

        if ($param_typehint) {
            if (is_string($param_typehint)) {
                $param_type_string = $param_typehint;
            } elseif ($param_typehint instanceof PhpParser\Node\Name\FullyQualified) {
                $param_type_string = implode('\\', $param_typehint->parts);
            } elseif ($param_typehint->parts === ['self']) {
                $param_type_string = $source->getFQCLN();
            } else {
                $param_type_string = ClassLikeChecker::getFQCLNFromString(
                    implode('\\', $param_typehint->parts),
                    $source->getNamespace(),
                    $source->getAliasedClasses()
                );

                if (!in_array(strtolower($param_type_string), ClassLikeChecker::$SPECIAL_TYPES)) {
                    ClassLikeChecker::checkFullyQualifiedClassLikeName(
                        $param_type_string,
                        $source->getFileChecker(),
                        new CodeLocation($source, $param_typehint),
                        $source->getSuppressedIssues()
                    );
                }
            }

            if ($param_type_string) {
                if ($is_nullable) {
                    $param_type_string .= '|null';
                }

                $param_type = Type::parseString($param_type_string);

                if ($param->variadic) {
                    $param_type = new Type\Union([
                        new Type\GenericArray(
                            'array',
                            [
                                Type::getInt(),
                                $param_type
                            ]
                        )
                    ]);
                }
            }
        }

        $is_optional = $param->default !== null;

        return new FunctionLikeParameter(
            $param->name,
            $param->byRef,
            $param_type ?: Type::getMixed(),
            new CodeLocation($source, $param, false, self::PARAM_TYPE_REGEX),
            $is_optional,
            $is_nullable,
            $param->variadic
        );
    }

    /**
     * @param  \ReflectionParameter $param
     * @return FunctionLikeParameter
     */
    protected static function getReflectionParamArray(\ReflectionParameter $param)
    {
        $param_type_string = null;

        if ($param->isArray()) {
            $param_type_string = 'array';
        } else {
            $param_class = null;

            try {
                /** @var \ReflectionClass */
                $param_class = $param->getClass();
            } catch (\ReflectionException $e) {
                // do nothing
            }

            if ($param_class) {
                $param_type_string = (string)$param_class->getName();
            }
        }

        $is_nullable = false;

        $is_optional = (bool)$param->isOptional();

        try {
            $is_nullable = $param->getDefaultValue() === null;

            if ($param_type_string && $is_nullable) {
                $param_type_string .= '|null';
            }
        } catch (\ReflectionException $e) {
            // do nothing
        }

        $param_name = (string)$param->getName();
        $param_type = $param_type_string ? Type::parseString($param_type_string) : Type::getMixed();

        return new FunctionLikeParameter(
            $param_name,
            (bool)$param->isPassedByReference(),
            $param_type,
            null,
            $is_optional,
            $is_nullable
        );
    }

    /**
     * @param  string                   $return_type
     * @param  string|null              $fq_class_name
     * @param  string                   $namespace
     * @param  array<string, string>    $aliased_classes
     * @return string
     */
    public static function fixUpLocalType($return_type, $fq_class_name, $namespace, array $aliased_classes)
    {
        if (strpos($return_type, '[') !== false) {
            $return_type = Type::convertSquareBrackets($return_type);
        }

        $return_type_tokens = Type::tokenize($return_type);

        foreach ($return_type_tokens as $i => &$return_type_token) {
            if ($return_type_token[0] === '\\') {
                $return_type_token = substr($return_type_token, 1);
                continue;
            }

            if (in_array($return_type_token, ['<', '>', '|', '?', ',', '{', '}', ':'])) {
                continue;
            }

            if (isset($return_type_tokens[$i + 1]) && $return_type_tokens[$i + 1] === ':') {
                continue;
            }

            $return_type_token = Type::fixScalarTerms($return_type_token);

            if ($return_type_token[0] === strtoupper($return_type_token[0])) {
                if ($return_type_token[0] === '$') {
                    if ($return_type === '$this') {
                        $return_type_token = 'static';
                    }

                    continue;
                }

                $return_type_token = ClassLikeChecker::getFQCLNFromString(
                    $return_type_token,
                    $namespace,
                    $aliased_classes
                );
            }
        }

        return implode('', $return_type_tokens);
    }

    /**
     * @param  string                           $method_id
     * @param  array<int, PhpParser\Node\Arg>   $args
     * @param  FileChecker                      $file_checker
     * @return array<int, FunctionLikeParameter>
     */
    public static function getMethodParamsById($method_id, array $args, FileChecker $file_checker)
    {
        $fq_class_name = strpos($method_id, '::') !== false ? explode('::', $method_id)[0] : null;

        if ($fq_class_name && ClassLikeChecker::isUserDefined($fq_class_name)) {
            $method_params = MethodChecker::getMethodParams($method_id);

            if ($method_params === null) {
                throw new \UnexpectedValueException('Not expecting $method_params to be null');
            }

            return $method_params;
        }

        $declaring_method_id = MethodChecker::getDeclaringMethodId($method_id);

        if (FunctionChecker::inCallMap($declaring_method_id ?: $method_id)) {
            $function_param_options = FunctionChecker::getParamsFromCallMap($declaring_method_id ?: $method_id);

            if ($function_param_options === null) {
                throw new \UnexpectedValueException('Not expecting $function_param_options to be null');
            }

            return self::getMatchingParamsFromCallMapOptions($function_param_options, $args, $file_checker);
        }

        if ($method_params = MethodChecker::getMethodParams($method_id)) {
            // fall back to using reflected params anyway
            return $method_params;
        }

        throw new \InvalidArgumentException('Cannot get params for ' . $method_id);
    }

    /**
     * @param  string                           $method_id
     * @param  array<int, PhpParser\Node\Arg>   $args
     * @param  string                           $file_path
     * @param  FileChecker                      $file_checker
     * @return array<int, FunctionLikeParameter>
     */
    public static function getFunctionParamsById($method_id, array $args, $file_path, FileChecker $file_checker)
    {
        if (FunctionChecker::inCallMap($method_id)) {
            $function_param_options = FunctionChecker::getParamsFromCallMap($method_id);

            if ($function_param_options === null) {
                throw new \UnexpectedValueException('Not expecting $function_param_options to be null');
            }

            return self::getMatchingParamsFromCallMapOptions($function_param_options, $args, $file_checker);
        }

        return FunctionChecker::getParams(strtolower($method_id), $file_path);
    }

     /**
     * @param  array<int, array<int, FunctionLikeParameter>>  $function_param_options
     * @param  array<int, PhpParser\Node\Arg>                 $args
     * @param  FileChecker                                    $file_checker
     * @return array<int, FunctionLikeParameter>
     */
    protected static function getMatchingParamsFromCallMapOptions(
        array $function_param_options,
        array $args,
        FileChecker $file_checker
    ) {
        $function_params = null;

        if (count($function_param_options) === 1) {
            return $function_param_options[0];
        }

        foreach ($function_param_options as $possible_function_params) {
            $all_args_match = true;

            $last_param = count($possible_function_params)
                ? $possible_function_params[count($possible_function_params) - 1]
                : null;

            $mandatory_param_count = count($possible_function_params);

            foreach ($possible_function_params as $i => $possible_function_param) {
                if ($possible_function_param->is_optional) {
                    $mandatory_param_count = $i;
                    break;
                }
            }

            if ($mandatory_param_count > count($args)) {
                continue;
            }

            foreach ($args as $argument_offset => $arg) {
                if (count($possible_function_params) <= $argument_offset &&
                    (!$last_param || substr($last_param->name, 0, 3) !== '...')
                ) {
                    $all_args_match = false;
                    break;
                }

                $param_type = $possible_function_params[$argument_offset]->type;

                if (!isset($arg->value->inferredType)) {
                    continue;
                }

                if ($arg->value->inferredType->isMixed()) {
                    continue;
                }

                if (TypeChecker::isContainedBy($arg->value->inferredType, $param_type, $file_checker)) {
                    continue;
                }

                $all_args_match = false;
                break;
            }

            if ($all_args_match) {
                return $possible_function_params;
            }
        }

        // if we don't succeed in finding a match, set to the first possible and wait for issues below
        return $function_param_options[0];
    }
}