Emit issues for null/mixed array access

src/Psalm/Checker/CommentChecker.php

@@ -20,6 +20,7 @@ class CommentChecker
      * @param  string           $var_id
      * @return Type\Union|null
      * @throws DocblockParseException If there was a problem parsing the docblock.
+     * @psalm-suppress MixedArrayAccess
      */
     public static function getTypeFromComment(
         $comment,
@@ -80,6 +81,7 @@ public static function getTypeFromComment(
      * @param  string $comment
      * @return FunctionDocblockComment
      * @throws DocblockParseException If there was a problem parsing the docblock.
+     * @psalm-suppress MixedArrayAccess
      */
     public static function extractDocblockInfo($comment)
     {

src/Psalm/Checker/FileChecker.php

@@ -698,6 +698,7 @@ public static function goodRun($start_time)
             $cache_directory .= '/' . self::PARSER_CACHE_DIRECTORY;
 
             if (is_dir($cache_directory)) {
+                /** @var array<string> */
                 $directory_files = scandir($cache_directory);
 
                 foreach ($directory_files as $directory_file) {
@@ -743,6 +744,7 @@ public static function deleteOldParserCaches($time_before)
             $cache_directory .= '/' . self::PARSER_CACHE_DIRECTORY;
 
             if (is_dir($cache_directory)) {
+                /** @var array<string> */
                 $directory_files = scandir($cache_directory);
 
                 foreach ($directory_files as $directory_file) {

src/Psalm/Checker/Statements/Expression/FetchChecker.php

@@ -15,6 +15,7 @@
 use Psalm\Issue\InvalidPropertyFetch;
 use Psalm\Issue\InvisibleProperty;
 use Psalm\Issue\MissingPropertyType;
+use Psalm\Issue\MixedArrayAccess;
 use Psalm\Issue\MixedArrayOffset;
 use Psalm\Issue\MixedPropertyFetch;
 use Psalm\Issue\NoInterfaceProperties;
@@ -904,19 +905,42 @@ public static function checkArrayAccess(
 
                     $stmt->inferredType = Type::getString();
                 } elseif ($type->isNull()) {
-                    // @todo emit NullArrayAccess issue
+                    if (IssueBuffer::accepts(
+                        new NullReference(
+                            'Cannot access array value on possibly null variable ' . $array_var_id . ' of type ' . $var_type,
+                            $statements_checker->getCheckedFileName(),
+                            $stmt->getLine()
+                        ),
+                        $statements_checker->getSuppressedIssues()
+                    )) {
+                        $stmt->inferredType = Type::getMixed();
+                        break;
+                    }
                 } elseif ($type->isMixed() || $type->isEmpty()) {
-                    // @todo emit MixedArrayAccess issue
-                } elseif ($type->value && !ClassChecker::classImplements($type->value, 'ArrayAccess')) {
+                    if (IssueBuffer::accepts(
+                        new MixedArrayAccess(
+                            'Cannot access array value on mixed variable ' . $array_var_id,
+                            $statements_checker->getCheckedFileName(),
+                            $stmt->getLine()
+                        ),
+                        $statements_checker->getSuppressedIssues()
+                    )) {
+                        $stmt->inferredType = Type::getMixed();
+                        break;
+                    }
+                } elseif (strtolower($type->value) !== 'simplexmlelement' &&
+                    !ClassChecker::classImplements($type->value, 'ArrayAccess')
+                ) {
                     if (IssueBuffer::accepts(
                         new InvalidArrayAccess(
-                            'Cannot access value on non-array variable ' . $var_id . ' of type ' . $var_type,
+                            'Cannot access array value on non-array variable ' . $array_var_id . ' of type ' . $var_type,
                             $statements_checker->getCheckedFileName(),
                             $stmt->getLine()
                         ),
                         $statements_checker->getSuppressedIssues()
                     )) {
                         $stmt->inferredType = Type::getMixed();
+                        break;
                     }
                 }
             }

src/Psalm/Checker/Statements/ExpressionChecker.php

@@ -964,6 +964,13 @@ protected static function fleshOutAtomicType(Type\Atomic $return_type, array $ar
         } elseif ($return_type->value[0] === '$' && $method_id) {
             $method_params = MethodChecker::getMethodParams($method_id);
 
+            if (!$method_params) {
+                throw new \InvalidArgumentException(
+                    'Cannot get method params of ' . $method_id,
+                    null
+                );
+            }
+
             foreach ($args as $i => $arg) {
                 $method_param = $method_params[$i];
 

src/Psalm/Checker/TypeChecker.php

@@ -115,8 +115,8 @@ public static function getNegatableTypeAssertions(
     }
 
     /**
-     * @param   array   $left_assertions
-     * @param   array   $right_assertions
+     * @param   array<string, string>   $left_assertions
+     * @param   array<string, string>   $right_assertions
      * @return  array
      */
     private static function combineTypeAssertions(array $left_assertions, array $right_assertions)

src/Psalm/Config.php

@@ -177,13 +177,15 @@ public static function loadFromXML($file_name)
         }
 
         if (isset($config_xml->mockClasses) && isset($config_xml->mockClasses->class)) {
+            /** @var \SimpleXMLElement $mock_class */
             foreach ($config_xml->mockClasses->class as $mock_class) {
                 $config->mock_classes[] = $mock_class['name'];
             }
         }
 
         // this plugin loading system borrows heavily from etsy/phan
         if (isset($config_xml->plugins) && isset($config_xml->plugins->plugin)) {
+            /** @var \SimpleXMLElement $plugin */
             foreach ($config_xml->plugins->plugin as $plugin) {
                 $plugin_file_name = $plugin['filename'];
 
@@ -213,6 +215,7 @@ public static function loadFromXML($file_name)
         }
 
         if (isset($config_xml->issueHandler)) {
+            /** @var \SimpleXMLElement $issue_handler */
             foreach ($config_xml->issueHandler->children() as $key => $issue_handler) {
                 if (isset($issue_handler['errorLevel'])) {
                     $error_level = (string) $issue_handler['errorLevel'];
@@ -249,6 +252,7 @@ public static function getInstance()
      * @param  array<\SimpleXMLElement> $extensions
      * @return void
      * @throws ConfigException If a Config file could not be found.
+     * @psalm-suppress MixedArrayAccess
      */
     protected function loadFileExtensions($extensions)
     {

src/Psalm/Config/FileFilter.php

@@ -63,25 +63,29 @@ public static function loadFromXML(SimpleXMLElement $e, $inclusive)
             $filter->inclusive = true;
 
             if ($e->directory) {
+                /** @var \SimpleXMLElement $directory */
                 foreach ($e->directory as $directory) {
                     $filter->include_dirs[] = self::slashify((string)$directory['name']);
                 }
             }
 
             if ($e->file) {
+                /** @var \SimpleXMLElement $file */
                 foreach ($e->file as $file) {
                     $filter->include_files[] = $file['name'];
                     $filter->include_files_lowercase[] = strtolower((string)$file['name']);
                 }
             }
         } else {
             if ($e->directory) {
+                /** @var \SimpleXMLElement $directory */
                 foreach ($e->directory as $directory) {
                     $filter->exclude_dirs[] = self::slashify((string)$directory['name']);
                 }
             }
 
             if ($e->file) {
+                /** @var \SimpleXMLElement $file */
                 foreach ($e->file as $file) {
                     $filter->exclude_files[] = (string)$file['name'];
                     $filter->exclude_files_lowercase[] = strtolower((string)$file['name']);

src/Psalm/Issue/MixedArrayAccess.php

@@ -0,0 +1,6 @@
+<?php
+namespace Psalm\Issue;
+
+class MixedArrayAccess extends CodeError
+{
+}

src/Psalm/Type.php

@@ -223,7 +223,7 @@ public static function convertSquareBrackets($type)
         $class_chars = '[a-zA-Z\<\>\\\\_]+';
         return preg_replace_callback(
             '/(' . $class_chars . '|' . '\((' . $class_chars . '(\|' . $class_chars . ')*' . ')\))((\[\])+)/',
-            function ($matches) {
+            function (array $matches) {
                 $inner_type = str_replace(['(', ')'], '', (string)$matches[1]);
 
                 $dimensionality = strlen((string)$matches[4]) / 2;