infer non-empty-list/array after array_key_exists($i, $arr)

Author: staabm

src/Type/Php/ArrayKeyExistsFunctionTypeSpecifyingExtension.php

@@ -66,13 +66,15 @@ public function specifyTypes(
 			&& !$keyType instanceof ConstantStringType
 		) {
 			if ($context->true()) {
+				$specifiedTypes = $this->typeSpecifier->create(
+					$array,
+					new NonEmptyArrayType(),
+					$context,
+					$scope,
+				);
+
 				if ($arrayType->isIterableAtLeastOnce()->no()) {
-					return $this->typeSpecifier->create(
-						$array,
-						new NonEmptyArrayType(),
-						$context,
-						$scope,
-					);
+					return $specifiedTypes;
 				}
 
 				$arrayKeyType = $arrayType->getIterableKeyType();
@@ -82,12 +84,12 @@ public function specifyTypes(
 					$arrayKeyType = TypeCombinator::union($arrayKeyType, $arrayKeyType->toString());
 				}
 
-				$specifiedTypes = $this->typeSpecifier->create(
+				$specifiedTypes = $specifiedTypes->unionWith($this->typeSpecifier->create(
 					$key,
 					$arrayKeyType,
 					$context,
 					$scope,
-				);
+				));
 
 				$arrayDimFetch = new ArrayDimFetch(
 					$array,

tests/PHPStan/Rules/Arrays/data/slevomat-foreach-array-key-exists-bug.php

@@ -15,7 +15,7 @@ public function doFoo(array $percentageIntervals, array $changes): void
 				if ($percentageInterval->isInInterval((float) $changeInPercents)) {
 					$key = $percentageInterval->getFormatted();
 					if (array_key_exists($key, $intervalResults)) {
-						assertType('array<array{itemsCount: mixed, interval: mixed}>', $intervalResults);
+						assertType('non-empty-array<array{itemsCount: mixed, interval: mixed}>', $intervalResults);
 						assertType('array{itemsCount: mixed, interval: mixed}', $intervalResults[$key]);
 						$intervalResults[$key]['itemsCount'] += $itemsCount;
 						assertType('non-empty-array<array{itemsCount: (array|float|int), interval: mixed}>', $intervalResults);