Generalize filtered array with maybe falsey values

Author: fmasa

src/Type/Php/ArrayFilterFunctionReturnTypeReturnTypeExtension.php

@@ -84,15 +84,22 @@ public function removeFalsey(Type $type): Type
 $keys = $type->getKeyTypes();
 $values = $type->getValueTypes();
 
+$generalize = false;
+
 foreach ($values as $offset => $value) {
-if (!$falseyTypes->isSuperTypeOf($value)->yes()) {
-continue;
-}
+$isFalsey = $falseyTypes->isSuperTypeOf($value);
 
-unset($keys[$offset], $values[$offset]);
+if ($isFalsey->yes()) {
+unset($keys[$offset], $values[$offset]);
+} elseif ($isFalsey->maybe()) {
+$values[$offset] = TypeCombinator::remove($values[$offset], $falseyTypes);
+$generalize = true;
+}
 }
 
-return new ConstantArrayType(array_values($keys), array_values($values));
+$filteredArray = new ConstantArrayType(array_values($keys), array_values($values));
+
+return $generalize ? $filteredArray->generalize() : $filteredArray;
 }
 
 $keyType = $type->getIterableKeyType();

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -4144,6 +4144,10 @@ public function dataArrayFunctions(): array
 'array(\'a\' => 1)',
 'array_filter($union)',
 ],
+[
+'array<int, int|true>',
+'array_filter($withPossiblyFalsey)',
+],
 ];
 }
 

tests/PHPStan/Analyser/data/array-functions.php

@@ -56,6 +56,13 @@
 $union['b'] = false;
 }
 
+/** @var bool $bool */
+$bool = doFoo();
+/** @var int $integer */
+$integer = doFoo();
+
+$withPossiblyFalsey = [$bool, $integer, '', 'a' => 0];
+
 /** @var array<string, int> $generalStringKeys */
 $generalStringKeys = doFoo();