From 8f192801c1f380641db5053d433f6037b37c86ce Mon Sep 17 00:00:00 2001
From: Matt Brown <github@muglug.com>
Date: Wed, 16 Dec 2020 08:18:18 -0500
Subject: [PATCH] Prevent mixed array offset in array creation

Fixes #4846
---
 .../Statements/Expression/ArrayAnalyzer.php   | 48 ++++++++++++++-----
 tests/ArrayAssignmentTest.php                 | 18 ++++---
 2 files changed, 46 insertions(+), 20 deletions(-)

diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/ArrayAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/ArrayAnalyzer.php
index d8a11d59c..69f5d2729 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/ArrayAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/ArrayAnalyzer.php
@@ -8,6 +8,7 @@ use Psalm\CodeLocation;
 use Psalm\Context;
 use Psalm\Issue\DuplicateArrayKey;
 use Psalm\Issue\InvalidArrayOffset;
+use Psalm\Issue\MixedArrayOffset;
 use Psalm\IssueBuffer;
 use Psalm\Type;
 use Psalm\Internal\Type\TypeCombiner;
@@ -130,6 +131,25 @@ class ArrayAnalyzer
             $good_types = [];
 
             foreach ($item_key_type->getAtomicTypes() as $atomic_key_type) {
+                if ($atomic_key_type instanceof Type\Atomic\TMixed) {
+                    if (IssueBuffer::accepts(
+                        new MixedArrayOffset(
+                            'Cannot create mixed offset – expecting array-key',
+                            new CodeLocation($statements_analyzer->getSource(), $stmt)
+                        ),
+                        $statements_analyzer->getSuppressedIssues()
+                    )) {
+                        // do nothing
+                    }
+
+                    $bad_types[] = $atomic_key_type;
+
+                    $good_types[] = new Type\Atomic\TArrayKey;
+
+
+                    continue;
+                }
+
                 if (!$atomic_key_type instanceof Type\Atomic\TString
                     && !$atomic_key_type instanceof Type\Atomic\TInt
                     && !$atomic_key_type instanceof Type\Atomic\TArrayKey
@@ -146,20 +166,22 @@ class ArrayAnalyzer
                         ),
                         $statements_analyzer->getSuppressedIssues()
                     )) {
-                        $bad_types[] = $atomic_key_type;
+                        // do nothing
+                    }
 
-                        if ($atomic_key_type instanceof Type\Atomic\TFalse) {
-                            $good_types[] = new Type\Atomic\TLiteralInt(0);
-                        } elseif ($atomic_key_type instanceof Type\Atomic\TTrue) {
-                            $good_types[] = new Type\Atomic\TLiteralInt(1);
-                        } elseif ($atomic_key_type instanceof Type\Atomic\TBool) {
-                            $good_types[] = new Type\Atomic\TLiteralInt(0);
-                            $good_types[] = new Type\Atomic\TLiteralInt(1);
-                        } elseif ($atomic_key_type instanceof Type\Atomic\TFloat) {
-                            $good_types[] = new Type\Atomic\TInt;
-                        } else {
-                            $good_types[] = new Type\Atomic\TArrayKey;
-                        }
+                    $bad_types[] = $atomic_key_type;
+
+                    if ($atomic_key_type instanceof Type\Atomic\TFalse) {
+                        $good_types[] = new Type\Atomic\TLiteralInt(0);
+                    } elseif ($atomic_key_type instanceof Type\Atomic\TTrue) {
+                        $good_types[] = new Type\Atomic\TLiteralInt(1);
+                    } elseif ($atomic_key_type instanceof Type\Atomic\TBool) {
+                        $good_types[] = new Type\Atomic\TLiteralInt(0);
+                        $good_types[] = new Type\Atomic\TLiteralInt(1);
+                    } elseif ($atomic_key_type instanceof Type\Atomic\TFloat) {
+                        $good_types[] = new Type\Atomic\TInt;
+                    } else {
+                        $good_types[] = new Type\Atomic\TArrayKey;
                     }
                 }
             }
diff --git a/tests/ArrayAssignmentTest.php b/tests/ArrayAssignmentTest.php
index 9b0e5125b..0d348f28c 100644
--- a/tests/ArrayAssignmentTest.php
+++ b/tests/ArrayAssignmentTest.php
@@ -1494,13 +1494,6 @@ class ArrayAssignmentTest extends TestCase
                     return [...$data];
                 }'
             ],
-            'ArrayCreateOffsetMixed' => [
-                '<?php
-                    /** @var mixed $b */
-                    $b = "";
-                    $_a = [$b => "a"];
-                ',
-            ],
             'ArrayOffsetNumericSupPHPINTMAX' => [
                 '<?php
                     $_a = [
@@ -1873,6 +1866,17 @@ class ArrayAssignmentTest extends TestCase
                     }',
                 'error_message' => 'LessSpecificReturnStatement',
             ],
+            'createArrayWithMixedOffset' => [
+                '<?php
+                    /**
+                     * @param mixed $index
+                     */
+                    function test($index): array {
+                        $arr = [$index => 5];
+                        return $arr;
+                    }',
+                'error_message' => 'MixedArrayOffset'
+            ]
         ];
     }
 }