From 5eb0bb8126886b0d7c8322462add8ed00a475ff1 Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Sun, 20 Jan 2019 11:49:13 -0500
Subject: [PATCH] Make foreach var annotation use more cautious

---
 .../Statements/Block/ForeachAnalyzer.php      | 31 ++++++++++++++
 tests/AnnotationTest.php                      | 42 +++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/src/Psalm/Internal/Analyzer/Statements/Block/ForeachAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Block/ForeachAnalyzer.php
index 637d4fb1a..c2f2b6ce3 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Block/ForeachAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Block/ForeachAnalyzer.php
@@ -66,11 +66,42 @@ class ForeachAnalyzer
             }
         }
 
+        $safe_var_ids = [];
+
+        if ($stmt->keyVar instanceof PhpParser\Node\Expr\Variable && is_string($stmt->keyVar->name)) {
+            $safe_var_ids['$' . $stmt->keyVar->name] = true;
+        }
+
+        if ($stmt->valueVar instanceof PhpParser\Node\Expr\Variable && is_string($stmt->valueVar->name)) {
+            $safe_var_ids['$' . $stmt->valueVar->name] = true;
+        } elseif ($stmt->valueVar instanceof PhpParser\Node\Expr\List_) {
+            foreach ($stmt->valueVar->items as $list_item) {
+                if (!$list_item) {
+                    continue;
+                }
+
+                $list_item_key = $list_item->key;
+                $list_item_value = $list_item->value;
+
+                if ($list_item_value instanceof PhpParser\Node\Expr\Variable && is_string($list_item_value->name)) {
+                    $safe_var_ids['$' . $list_item_value->name] = true;
+                }
+
+                if ($list_item_key instanceof PhpParser\Node\Expr\Variable && is_string($list_item_key->name)) {
+                    $safe_var_ids['$' . $list_item_key->name] = true;
+                }
+            }
+        }
+
         foreach ($var_comments as $var_comment) {
             if (!$var_comment->var_id) {
                 continue;
             }
 
+            if (isset($safe_var_ids[$var_comment->var_id])) {
+                continue;
+            }
+
             $comment_type = ExpressionAnalyzer::fleshOutType(
                 $codebase,
                 $var_comment->type,
diff --git a/tests/AnnotationTest.php b/tests/AnnotationTest.php
index 092fa9631..5e0eeec46 100644
--- a/tests/AnnotationTest.php
+++ b/tests/AnnotationTest.php
@@ -797,6 +797,48 @@ class AnnotationTest extends TestCase
 
                     echo strlen($a);',
             ],
+            'annotationOnForeachItems' => [
+                '<?php
+                    function foo(array $arr) : void {
+                        $item = null;
+
+                        /** @var string $item */
+                        foreach ($arr as $item) {}
+
+                        if (is_null($item)) {}
+                    }
+
+                    function bar(array $arr) : void {
+                        $item = null;
+
+                        /** @var string $item */
+                        foreach ($arr as $item => $_) {}
+
+                        if (is_null($item)) {}
+                    }
+
+                    function bat(array $arr) : void {
+                        $item = null;
+
+                        /** @var string $item */
+                        foreach ($arr as list($item)) {}
+
+                        if (is_null($item)) {}
+                    }
+
+                    function baz(array $arr) : void {
+                        $item = null;
+
+                        /** @var string $item */
+                        foreach ($arr as list($item => $_)) {}
+
+                        if (is_null($item)) {}
+                    }',
+                [],
+                [
+                    'MixedAssignment'
+                ]
+            ],
         ];
     }