diff --git a/src/Rules/MissingTypehintCheck.php b/src/Rules/MissingTypehintCheck.php
index 80b5e3e6ba8..704aca05db5 100644
--- a/src/Rules/MissingTypehintCheck.php
+++ b/src/Rules/MissingTypehintCheck.php
@@ -24,15 +24,16 @@
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeTraverser;
-use PHPStan\Type\UnionType;
 use PHPStan\Type\VerbosityLevel;
 use Traversable;
 use function array_filter;
 use function array_keys;
 use function array_merge;
+use function array_slice;
 use function count;
 use function implode;
 use function in_array;
+use function spl_object_id;
 use function sprintf;
 use function strtolower;
 
@@ -73,7 +74,8 @@ public function __construct(
 	public function getIterableTypesWithMissingValueTypehint(Type $type): array
 	{
 		$descriptions = [];
-		TypeTraverser::map($type, function (Type $type, callable $traverse) use (&$descriptions): Type {
+		$sealed = [];
+		TypeTraverser::map($type, self::oncePerType($descriptions, function (Type $type, callable $traverse) use (&$descriptions, &$sealed): Type {
 			if ($type instanceof TemplateType) {
 				return $type;
 			}
@@ -108,19 +110,16 @@ public function getIterableTypesWithMissingValueTypehint(Type $type): array
 			}
 			if ($type->isIterable()->yes()) {
 				if ($type->isConstantArray()->yes()) {
-					$type = TypeTraverser::map($type, static function (Type $type, callable $traverse) {
-						if ($type instanceof UnionType || $type instanceof IntersectionType) {
-							return $traverse($type);
+					$type = TypeTraverser::map($type, static function (Type $type, callable $traverse) use (&$sealed) {
+						$id = spl_object_id($type);
+						if (!isset($sealed[$id])) {
+							$sealedType = $type instanceof ConstantArrayType && $type->getUnsealedTypes() !== null
+								? $type->dropUnsealedTypes()
+								: $type;
+							$sealed[$id] = [$type, $traverse($sealedType)];
 						}
 
-						if ($type instanceof ConstantArrayType) {
-							$unsealed = $type->getUnsealedTypes();
-							if ($unsealed !== null) {
-								return $traverse($type->dropUnsealedTypes());
-							}
-						}
-
-						return $traverse($type);
+						return $sealed[$id][1];
 					});
 				}
 				$iterableValue = $type->getIterableValueType();
@@ -136,11 +135,41 @@ public function getIterableTypesWithMissingValueTypehint(Type $type): array
 				}
 			}
 			return $traverse($type);
-		});
+		}));
 
 		return $descriptions;
 	}
 
+	/**
+	 * A type alias used in several places is one shared object: check it once, then replay the descriptions it added.
+	 *
+	 * @param string[] $descriptions
+	 * @param callable(Type, callable(Type): Type): Type $check
+	 * @return callable(Type, callable(Type): Type): Type
+	 */
+	private static function oncePerType(array &$descriptions, callable $check): callable
+	{
+		$checked = [];
+
+		return static function (Type $type, callable $traverse) use ($check, &$checked, &$descriptions): Type {
+			$id = spl_object_id($type);
+			if (isset($checked[$id])) {
+				[, $result, $added] = $checked[$id];
+				foreach ($added as $description) {
+					$descriptions[] = $description;
+				}
+
+				return $result;
+			}
+
+			$count = count($descriptions);
+			$result = $check($type, $traverse);
+			$checked[$id] = [$type, $result, array_slice($descriptions, $count)];
+
+			return $result;
+		};
+	}
+
 	/**
 	 * @return array<int, array{string, string}>
 	 */
diff --git a/tests/bench/data/nested-array-shape-alias.php b/tests/bench/data/nested-array-shape-alias.php
new file mode 100644
index 00000000000..29138bc0cf9
--- /dev/null
+++ b/tests/bench/data/nested-array-shape-alias.php
@@ -0,0 +1,28 @@
+<?php declare(strict_types = 1);
+
+namespace BenchNestedArrayShapeAlias;
+
+/**
+ * A type alias that many keys of an array shape refer to is one shared object. Checking the
+ * parameter below for a missing iterable value type used to walk that object again from every
+ * key that refers to it.
+ *
+ * @phpstan-type Value = 'a'|'b'|'c'|'d'|string
+ * @phpstan-type Inner = array{p0?: Value, p1?: Value, p2?: Value, p3?: Value, p4?: Value, p5?: Value, p6?: Value, p7?: Value, p8?: Value, p9?: Value, p10?: Value, p11?: Value, p12?: Value, p13?: Value, p14?: Value, p15?: Value, p16?: Value, p17?: Value, p18?: Value, p19?: Value, p20?: Value, p21?: Value, p22?: Value, p23?: Value, p24?: Value, p25?: Value, p26?: Value, p27?: Value, p28?: Value, p29?: Value, p30?: Value, p31?: Value, p32?: Value, p33?: Value, p34?: Value, p35?: Value, p36?: Value, p37?: Value, p38?: Value, p39?: Value, p40?: Value, p41?: Value, p42?: Value, p43?: Value, p44?: Value, p45?: Value, p46?: Value, p47?: Value, p48?: Value, p49?: Value, p50?: Value, p51?: Value, p52?: Value, p53?: Value, p54?: Value, p55?: Value, p56?: Value, p57?: Value, p58?: Value, p59?: Value, p60?: Value, p61?: Value, p62?: Value, p63?: Value, p64?: Value, p65?: Value, p66?: Value, p67?: Value, p68?: Value, p69?: Value, p70?: Value, p71?: Value, p72?: Value, p73?: Value, p74?: Value, p75?: Value, p76?: Value, p77?: Value, p78?: Value, p79?: Value, p80?: Value, p81?: Value, p82?: Value, p83?: Value, p84?: Value, p85?: Value, p86?: Value, p87?: Value, p88?: Value, p89?: Value, p90?: Value, p91?: Value, p92?: Value, p93?: Value, p94?: Value, p95?: Value, p96?: Value, p97?: Value, p98?: Value, p99?: Value, p100?: Value, p101?: Value, p102?: Value, p103?: Value, p104?: Value, p105?: Value, p106?: Value, p107?: Value, p108?: Value, p109?: Value, p110?: Value, p111?: Value, p112?: Value, p113?: Value, p114?: Value, p115?: Value, p116?: Value, p117?: Value, p118?: Value, p119?: Value, p120?: Value, p121?: Value, p122?: Value, p123?: Value, p124?: Value, p125?: Value, p126?: Value, p127?: Value, p128?: Value, p129?: Value, p130?: Value, p131?: Value, p132?: Value, p133?: Value, p134?: Value, p135?: Value, p136?: Value, p137?: Value, p138?: Value, p139?: Value, p140?: Value, p141?: Value, p142?: Value, p143?: Value, p144?: Value, p145?: Value, p146?: Value, p147?: Value, p148?: Value, p149?: Value}
+ * @phpstan-type Outer = array{p0?: Value, p1?: Value, p2?: Value, p3?: Value, p4?: Value, p5?: Value, p6?: Value, p7?: Value, p8?: Value, p9?: Value, p10?: Value, p11?: Value, p12?: Value, p13?: Value, p14?: Value, p15?: Value, p16?: Value, p17?: Value, p18?: Value, p19?: Value, p20?: Value, p21?: Value, p22?: Value, p23?: Value, p24?: Value, p25?: Value, p26?: Value, p27?: Value, p28?: Value, p29?: Value, p30?: Value, p31?: Value, p32?: Value, p33?: Value, p34?: Value, p35?: Value, p36?: Value, p37?: Value, p38?: Value, p39?: Value, p40?: Value, p41?: Value, p42?: Value, p43?: Value, p44?: Value, p45?: Value, p46?: Value, p47?: Value, p48?: Value, p49?: Value, p50?: Value, p51?: Value, p52?: Value, p53?: Value, p54?: Value, p55?: Value, p56?: Value, p57?: Value, p58?: Value, p59?: Value, p60?: Value, p61?: Value, p62?: Value, p63?: Value, p64?: Value, p65?: Value, p66?: Value, p67?: Value, p68?: Value, p69?: Value, p70?: Value, p71?: Value, p72?: Value, p73?: Value, p74?: Value, p75?: Value, p76?: Value, p77?: Value, p78?: Value, p79?: Value, p80?: Value, p81?: Value, p82?: Value, p83?: Value, p84?: Value, p85?: Value, p86?: Value, p87?: Value, p88?: Value, p89?: Value, p90?: Value, p91?: Value, p92?: Value, p93?: Value, p94?: Value, p95?: Value, p96?: Value, p97?: Value, p98?: Value, p99?: Value, p100?: Value, p101?: Value, p102?: Value, p103?: Value, p104?: Value, p105?: Value, p106?: Value, p107?: Value, p108?: Value, p109?: Value, p110?: Value, p111?: Value, p112?: Value, p113?: Value, p114?: Value, p115?: Value, p116?: Value, p117?: Value, p118?: Value, p119?: Value, p120?: Value, p121?: Value, p122?: Value, p123?: Value, p124?: Value, p125?: Value, p126?: Value, p127?: Value, p128?: Value, p129?: Value, p130?: Value, p131?: Value, p132?: Value, p133?: Value, p134?: Value, p135?: Value, p136?: Value, p137?: Value, p138?: Value, p139?: Value, p140?: Value, p141?: Value, p142?: Value, p143?: Value, p144?: Value, p145?: Value, p146?: Value, p147?: Value, p148?: Value, p149?: Value, c0?: Inner, c1?: Inner, c2?: Inner, c3?: Inner, c4?: Inner, c5?: Inner, c6?: Inner, c7?: Inner, c8?: Inner, c9?: Inner, c10?: Inner, c11?: Inner, c12?: Inner, c13?: Inner, c14?: Inner, c15?: Inner, c16?: Inner, c17?: Inner, c18?: Inner, c19?: Inner, c20?: Inner, c21?: Inner, c22?: Inner, c23?: Inner, c24?: Inner, c25?: Inner, c26?: Inner, c27?: Inner, c28?: Inner, c29?: Inner, c30?: Inner, c31?: Inner, c32?: Inner, c33?: Inner, c34?: Inner, c35?: Inner, c36?: Inner, c37?: Inner, c38?: Inner, c39?: Inner}
+ */
+final class Styles
+{
+
+	/** @param Outer|null $styles */
+	public function css(?array $styles): string
+	{
+		return '';
+	}
+
+}
+
+function render(Styles $styles): void
+{
+	echo $styles->css(['p0' => 'a', 'p1' => 'b', 'c0' => ['p2' => 'c']]);
+}