From d868710b2bf890142b8364f648f7272c11dab29a Mon Sep 17 00:00:00 2001
From: Brown <github@muglug.com>
Date: Wed, 8 Apr 2020 16:11:11 -0400
Subject: [PATCH] Fix handling of built arrays

---
 src/Psalm/Config/Creator.php                       |  1 -
 .../Expression/Fetch/ArrayFetchAnalyzer.php        |  2 +-
 src/Psalm/Type/Union.php                           | 13 +++++++++++++
 tests/Loop/ForeachTest.php                         | 14 ++++++++++++++
 4 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/src/Psalm/Config/Creator.php b/src/Psalm/Config/Creator.php
index 2d28c1101..ea7da2e42 100644
--- a/src/Psalm/Config/Creator.php
+++ b/src/Psalm/Config/Creator.php
@@ -121,7 +121,6 @@ class Creator
                 $issues_at_level[$issue_level][$issue_type] = 0;
             }
 
-            /** @psalm-suppress MixedOperand */
             $issues_at_level[$issue_level][$issue_type] += 100/$counted_types;
         }
 
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ArrayFetchAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ArrayFetchAnalyzer.php
index 04142d8a3..46f01d857 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ArrayFetchAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ArrayFetchAnalyzer.php
@@ -118,7 +118,7 @@ class ArrayFetchAnalyzer
         if ($keyed_array_var_id
             && $context->hasVariable($keyed_array_var_id)
             && !$context->vars_in_scope[$keyed_array_var_id]->possibly_undefined
-            && !$context->vars_in_scope[$keyed_array_var_id]->isVanillaMixed()
+            && !$context->vars_in_scope[$keyed_array_var_id]->hasVanillaMixed()
         ) {
             $statements_analyzer->node_data->setType(
                 $stmt,
diff --git a/src/Psalm/Type/Union.php b/src/Psalm/Type/Union.php
index 63c345157..48a977f84 100644
--- a/src/Psalm/Type/Union.php
+++ b/src/Psalm/Type/Union.php
@@ -978,6 +978,19 @@ class Union implements TypeNode
             && count($this->types) === 1;
     }
 
+    /**
+     * @return bool
+     */
+    public function hasVanillaMixed()
+    {
+        /**
+         * @psalm-suppress UndefinedPropertyFetch
+         */
+        return isset($this->types['mixed'])
+            && !$this->types['mixed']->from_loop_isset
+            && get_class($this->types['mixed']) === Type\Atomic\TMixed::class;
+    }
+
     /**
      * @return bool
      */
diff --git a/tests/Loop/ForeachTest.php b/tests/Loop/ForeachTest.php
index d4aca9732..f9a00487d 100644
--- a/tests/Loop/ForeachTest.php
+++ b/tests/Loop/ForeachTest.php
@@ -985,6 +985,20 @@ class ForeachTest extends \Psalm\Tests\TestCase
                         $list = [4, 5, 6];
                     }',
             ],
+            'createNestedArrayInLoop' => [
+                '<?php
+                    function foo() : void {
+                        $arr = [];
+
+                        foreach ([1, 2, 3] as $i) {
+                            if (!isset($arr[$i]["a"])) {
+                                $arr[$i]["a"] = 0;
+                            }
+
+                            $arr[$i]["a"] += 5;
+                        }
+                    }'
+            ],
         ];
     }