Added asPositiveInt() method

src/Type.php

@@ -70,6 +70,26 @@ public function asInt(): int
         return $this->variable;
     }
 
+    /**
+     * Asserts and narrow down the type to positive integer.
+     *
+     * @phpstan-assert positive-int $this->variable
+     *
+     * @return (TVariable is positive-int ? TVariable : never)
+     */
+    public function asPositiveInt(): int
+    {
+        if (! is_int($this->variable)) {
+            throw new TypeError('Variable is not an [integer].');
+        }
+
+        if ($this->variable <= 0) {
+            throw new TypeError('Variable is not a [positive integer].');
+        }
+
+        return $this->variable;
+    }
+
     /**
      * Asserts and narrow down the type to float.
      *

tests/AsPositiveIntTest.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+test('positive int', function (): void {
+    $variable = 1;
+
+    $value = type($variable)->asPositiveInt();
+
+    expect($value)->toBeInt();
+});
+
+test('not integer type', function (): void {
+    $variable = 'string';
+
+    type($variable)->asPositiveInt();
+})->throws(TypeError::class, 'Variable is not an [integer].');
+
+test('not a positive int', function (int $variable): void {
+    type($variable)->asPositiveInt();
+})
+    ->with([-1, 0])
+    ->throws(TypeError::class, 'Variable is not a [positive integer].');

types/AsPositiveIntTest.php

@@ -0,0 +1,8 @@
+<?php
+
+declare(strict_types=1);
+
+use function PHPStan\Testing\assertType;
+
+$variable = random_int(0, 1) !== 0 ? 'string' : 1;
+assertType('int<1, max>', $x = type($variable)->asPositiveInt());