Fix

Author: ondrejmirtes

src/Type/ClassStringType.php

@@ -46,7 +46,7 @@ public function isString(): TrinaryLogic
 
 	public function isNumericString(): TrinaryLogic
 	{
-		return TrinaryLogic::createMaybe();
+		return TrinaryLogic::createNo();
 	}
 
 	public function isDecimalIntegerString(): TrinaryLogic

src/Type/StringType.php

@@ -184,6 +184,13 @@ public function toArrayKey(): Type
 			return $this;
 		}
 
+		$isDecimalIntString = $this->isDecimalIntegerString();
+		if ($isDecimalIntString->no()) {
+			return $this;
+		} elseif ($isDecimalIntString->yes()) {
+			return new IntegerType();
+		}
+
 		return new UnionType([
 			new IntegerType(),
 			TypeCombinator::intersect($this, new AccessoryDecimalIntegerStringType(inverse: true)),