Detect unused properties that are written to inside arrays

vimeo · Dec 11, 2021 · b558748 · b558748
1 parent 19ae9e8
commit b558748
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Showing 2 changed files with 37 additions and 2 deletions.
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php
@@ -228,7 +228,7 @@ public static function analyze(
 
         $naive_property_exists = $codebase->properties->propertyExists(
             $property_id,
-            true,
+            !$in_assignment,
             $statements_analyzer,
             $context,
             $codebase->collect_locations ? new CodeLocation($statements_analyzer->getSource(), $stmt) : null
@@ -252,7 +252,7 @@ public static function analyze(
                 if ($new_class_storage
                     && ($codebase->properties->propertyExists(
                         $new_property_id,
-                        true,
+                        !$in_assignment,
                         $statements_analyzer,
                         $context,
                         $codebase->collect_locations

diff --git a/tests/UnusedCodeTest.php b/tests/UnusedCodeTest.php
@@ -1195,6 +1195,17 @@ public function validate(): void
                     foobar
                 ',
             ],
+            'usedPropertyAsAssignmentKey' => [
+                '<?php
+                    class A {
+                        public string $foo = "bar";
+                        public array $bar = [];
+                    }
+
+                    $a = new A();
+                    $a->bar[$a->foo] = "bar";
+                    print_r($a->bar);',
+            ],
         ];
     }
 
@@ -1248,6 +1259,30 @@ class A {
                 'error_message' => 'PossiblyUnusedProperty',
                 'error_levels' => ['UnusedVariable'],
             ],
+            'possiblyUnusedPropertyWrittenNeverRead' => [
+                '<?php
+                    class A {
+                        /** @var string */
+                        public $foo = "hello";
+                    }
+
+                    $a = new A();
+                    $a->foo = "bar";',
+                'error_message' => 'PossiblyUnusedProperty',
+                'error_levels' => ['UnusedVariable'],
+            ],
+            'possiblyUnusedPropertyWithArrayWrittenNeverRead' => [
+                '<?php
+                    class A {
+                        /** @var list<string> */
+                        public array $foo = [];
+                    }
+
+                    $a = new A();
+                    $a->foo[] = "bar";',
+                'error_message' => 'PossiblyUnusedProperty',
+                'error_levels' => ['UnusedVariable'],
+            ],
             'unusedProperty' => [
                 '<?php
                     class A {