Merge pull request #6746 from orklah/instanceof-classstring

throwable Instanceof throwable negated
vimeo · Oct 27, 2021 · 7807a85 · 7807a85
2 parents 6fba5eb + dc2ac42
commit 7807a85
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diff --git a/src/Psalm/Internal/Type/NegatedAssertionReconciler.php b/src/Psalm/Internal/Type/NegatedAssertionReconciler.php
@@ -285,6 +285,12 @@ public static function reconcile(
             $existing_var_type->addType(new TString);
         } elseif (strpos($assertion, 'getclass-') === 0) {
             $assertion = substr($assertion, 9);
+        } elseif ($existing_var_type->isSingle()
+            && $existing_var_type->hasNamedObjectType()
+            && isset($existing_var_type->getAtomicTypes()[$assertion])
+        ) {
+            // checking if two types share a common parent is not enough to guarantee childs are instanceof each other
+            // fall through
         } elseif (!$is_equality) {
             $codebase = $statements_analyzer->getCodebase();
 

diff --git a/tests/TypeReconciliation/TypeAlgebraTest.php b/tests/TypeReconciliation/TypeAlgebraTest.php
@@ -1138,6 +1138,22 @@ public function shouldReport(Throwable $t): bool
                     $h->shouldReport(new Exception());
                     $h->shouldReport(new RuntimeException());'
             ],
+            'ThrowableInstanceOfThrowableMayBeTrue' => [
+                '<?php
+
+                    class Mapper
+                    {
+                        /** @param class-string<Throwable> $class */
+                        final public function map(Throwable $throwable, string $class): ?Throwable
+                        {
+                            if (! $throwable instanceof $class) {
+                                return null;
+                            }
+
+                            return $throwable;
+                        }
+                    }'
+            ],
         ];
     }