diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index 8369ac2430..c04b167b70 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -166,6 +166,7 @@
 use function usort;
 use const PHP_INT_MAX;
 use const PHP_INT_MIN;
+use const PHP_VERSION_ID;
 
 final class MutatingScope implements Scope
 {
@@ -5138,7 +5139,10 @@ private static function generalizeType(Type $a, Type $b, int $depth): Type
 			} else {
 				$constantArraysA = TypeCombinator::union(...$constantArrays['a']);
 				$constantArraysB = TypeCombinator::union(...$constantArrays['b']);
-				if ($constantArraysA->getIterableKeyType()->equals($constantArraysB->getIterableKeyType())) {
+				if (
+					$constantArraysA->getIterableKeyType()->equals($constantArraysB->getIterableKeyType())
+					&& $constantArraysA->getArraySize()->equals($constantArraysB->getArraySize())
+				) {
 					$resultArrayBuilder = ConstantArrayTypeBuilder::createEmpty();
 					foreach (TypeUtils::flattenTypes($constantArraysA->getIterableKeyType()) as $keyType) {
 						$resultArrayBuilder->setOffsetValueType(
@@ -5158,7 +5162,11 @@ private static function generalizeType(Type $a, Type $b, int $depth): Type
 						TypeCombinator::union(self::generalizeType($constantArraysA->getIterableKeyType(), $constantArraysB->getIterableKeyType(), $depth + 1)),
 						TypeCombinator::union(self::generalizeType($constantArraysA->getIterableValueType(), $constantArraysB->getIterableValueType(), $depth + 1)),
 					);
-					if ($constantArraysA->isIterableAtLeastOnce()->yes() && $constantArraysB->isIterableAtLeastOnce()->yes()) {
+					if (
+						$constantArraysA->isIterableAtLeastOnce()->yes()
+						&& $constantArraysB->isIterableAtLeastOnce()->yes()
+						&& $constantArraysA->getArraySize()->getGreaterOrEqualType(new PhpVersion(PHP_VERSION_ID))->isSuperTypeOf($constantArraysB->getArraySize())->yes()
+					) {
 						$resultType = TypeCombinator::intersect($resultType, new NonEmptyArrayType());
 					}
 					if ($constantArraysA->isList()->yes() && $constantArraysB->isList()->yes()) {
diff --git a/tests/PHPStan/Analyser/nsrt/bug-1021.php b/tests/PHPStan/Analyser/nsrt/bug-1021.php
index b085b9a781..37e2f7244f 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-1021.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-1021.php
@@ -13,7 +13,7 @@ function foobar() {
 		}
 	}
 
-	assertType('array{0?: int<1, max>, 1?: 2|3, 2?: 3}', $x);
+	assertType('list<1|2|3>', $x);
 
 	if ($x) {
 	}
diff --git a/tests/PHPStan/Analyser/nsrt/bug7856.php b/tests/PHPStan/Analyser/nsrt/bug7856.php
index fcdca30b44..8da8b7343e 100644
--- a/tests/PHPStan/Analyser/nsrt/bug7856.php
+++ b/tests/PHPStan/Analyser/nsrt/bug7856.php
@@ -10,7 +10,7 @@ function doFoo() {
 	$endDate = new DateTimeImmutable('+1year');
 
 	do {
-		assertType("array{'+1week', '+1months', '+6months', '+17months'}|array{0: literal-string&lowercase-string&non-falsy-string, 1?: literal-string&lowercase-string&non-falsy-string, 2?: '+17months'}", $intervals);
+		assertType("list<literal-string&lowercase-string&non-falsy-string>", $intervals);
 		$periodEnd = $periodEnd->modify(array_shift($intervals));
 	} while (count($intervals) > 0 && $periodEnd->format('U') < $endDate);
 }