feat(type): add nonnull type (#392)

docs/component/type.md

@@ -32,6 +32,7 @@
 - [non_empty_dict](./../../src/Psl/Type/non_empty_dict.php#L16)
 - [non_empty_string](./../../src/Psl/Type/non_empty_string.php#L10)
 - [non_empty_vec](./../../src/Psl/Type/non_empty_vec.php#L14)
+- [nonnull](./../../src/Psl/Type/nonnull.php#L12)
 - [null](./../../src/Psl/Type/null.php#L10)
 - [nullable](./../../src/Psl/Type/nullable.php#L14)
 - [num](./../../src/Psl/Type/num.php#L10)

src/Psl/Internal/Loader.php

@@ -315,6 +315,7 @@ final class Loader
         'Psl\\Type\\mixed' => 'Psl/Type/mixed.php',
         'Psl\\Type\\mixed_dict' => 'Psl/Type/mixed_dict.php',
         'Psl\\Type\\mixed_vec' => 'Psl/Type/mixed_vec.php',
+        'Psl\\Type\\nonnull' => 'Psl/Type/nonnull.php',
         'Psl\\Type\\null' => 'Psl/Type/null.php',
         'Psl\\Type\\nullable' => 'Psl/Type/nullable.php',
         'Psl\\Type\\optional' => 'Psl/Type/optional.php',
@@ -622,6 +623,7 @@ final class Loader
         'Psl\\Type\\Internal\\IterableType' => 'Psl/Type/Internal/IterableType.php',
         'Psl\\Type\\Internal\\MixedType' => 'Psl/Type/Internal/MixedType.php',
         'Psl\\Type\\Internal\\NullType' => 'Psl/Type/Internal/NullType.php',
+        'Psl\\Type\\Internal\\NonNullType' => 'Psl/Type/Internal/NonNullType.php',
         'Psl\\Type\\Internal\\NullableType' => 'Psl/Type/Internal/NullableType.php',
         'Psl\\Type\\Internal\\OptionalType' => 'Psl/Type/Internal/OptionalType.php',
         'Psl\\Type\\Internal\\PositiveIntType' => 'Psl/Type/Internal/PositiveIntType.php',

src/Psl/Type/Internal/NonNullType.php

@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Type\Internal;
+
+use Psl\Type;
+use Psl\Type\Exception\AssertException;
+use Psl\Type\Exception\CoercionException;
+
+/**
+ * @ara-extends Type\Type<nonnull>
+ *
+ * @extends Type\Type<mixed>
+ *
+ * @internal
+ */
+final class NonNullType extends Type\Type
+{
+    /**
+     * @psalm-assert-if-true mixed $value
+     *
+     * @ara-assert-if-true nonnull $value
+     */
+    public function matches(mixed $value): bool
+    {
+        return null !== $value;
+    }
+
+    /**
+     * @ara-return nonnull
+     *
+     * @return mixed
+     */
+    public function coerce(mixed $value): mixed
+    {
+        if (null !== $value) {
+            return $value;
+        }
+
+        throw CoercionException::withValue($value, $this->toString(), $this->getTrace());
+    }
+
+    /**
+     * @ara-assert nonnull $value
+     *
+     * @psalm-assert mixed $value
+     *
+     * @ara-return nonnull
+     *
+     * @return mixed
+     */
+    public function assert(mixed $value): mixed
+    {
+        if (null !== $value) {
+            return $value;
+        }
+
+        throw AssertException::withValue($value, $this->toString(), $this->getTrace());
+    }
+
+    public function toString(): string
+    {
+        return 'nonnull';
+    }
+}

src/Psl/Type/nonnull.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Type;
+
+/**
+ * @ara-return TypeInterface<nonnull>
+ *
+ * @return TypeInterface<mixed>
+ */
+function nonnull(): TypeInterface
+{
+    return new Internal\NonNullType();
+}

tests/unit/Type/NonNullTypeTest.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Unit\Type;
+
+use Psl\Type;
+
+final class NonNullTypeTest extends TypeTest
+{
+    public function getType(): Type\TypeInterface
+    {
+        return Type\nonnull();
+    }
+
+    public function getValidCoercions(): iterable
+    {
+        yield [$_ = Type\bool(), $_];
+        yield [$_ = 1, $_];
+        yield [$_ = 0, $_];
+        yield [$_ = false, $_];
+        yield [$_ = true, $_];
+        yield [$_ = '', $_];
+        yield [$_ = 'null', $_];
+        yield [$_ = 'foo', $_];
+        yield [$_ = [null], $_];
+        yield [$_ = [], $_];
+        yield [$_ = [1, 2, 3], $_];
+        yield [$_ = $this->stringable(''), $_];
+    }
+
+    public function getInvalidCoercions(): iterable
+    {
+        yield [null];
+    }
+
+    public function getToStringExamples(): iterable
+    {
+        yield [$this->getType(), 'nonnull'];
+    }
+}