finished rename optional -> nullable

src/SignatureAssertionUtil.php

@@ -71,32 +71,32 @@ final class SignatureAssertionUtil
 	private static function parseType(string $type): array
 	{
 		$cleanType = $type; // e.g. ?Namespace\Class
-		$optional = FALSE;
+		$nullable = FALSE;
 		if ($type[0] === '?') {
-			$optional = TRUE;
+			$nullable = TRUE;
 			$cleanType = substr($type, 1); // without leading '?'
 		}
-		return [$cleanType, $optional];
+		return [$cleanType, $nullable];
 	}
 
 	private static function checkFunctionParameter(
 		\ReflectionFunction $functionReflection,
 		\ReflectionParameter $parameterReflection,
 		string $expectedParameterType,
-		bool $expectedOptional
+		bool $expectedNullable
 	): void
 	{
 		$reflectionType = $parameterReflection->getType();
 		assert($reflectionType instanceof \ReflectionType);
 
 		// checks:
-		$actuallyOptional = $reflectionType->allowsNull();
-		if ($expectedOptional !== $actuallyOptional) {
+		$actuallyNullable = $reflectionType->allowsNull();
+		if ($expectedNullable !== $actuallyNullable) {
 			throw FunctionSignatureAssertionError::parameterNullability(
 				$functionReflection,
 				$parameterReflection,
-				$expectedOptional,
-				$actuallyOptional
+				$expectedNullable,
+				$actuallyNullable
 			);
 		}
 		if ($expectedParameterType !== (string) $reflectionType) {

src/exceptions.php

@@ -50,12 +50,12 @@ final class FunctionSignatureAssertionError extends \AssertionError {
 	}
 
 
-	public static function parameterNullability(\ReflectionFunction $functionReflection, \ReflectionParameter $param, bool $expectedOptional, bool $actuallyOptional): self
+	public static function parameterNullability(\ReflectionFunction $functionReflection, \ReflectionParameter $param, bool $expectedNullable, bool $actuallyNullable): self
 	{
 		return new self(
 			$functionReflection,
-			$expectedOptional
-				? "Function should have parameter {$param->getName()} optional but it is not."
+			$expectedNullable
+				? "Function should have parameter {$param->getName()} nullable but it is not."
 				: "Function should have parameter {$param->getName()} required but it is not."
 		);
 	}

tests/fn.assertSignature.allOptional.phpt → tests/fn.assertSignature.allNullable.phpt

@@ -8,20 +8,20 @@ use Tester\Assert;
 $fn = function(?T1 $t1, ?T2 $t2): ?T3 {return new T3;};
 assertSignature($fn, params(nullable(T1::class), nullable(T2::class)), nullable(T3::class));
 
-// missing optional check
-Assert::exception(function () use ($fn) {
+// parameter is nullable, non-nullable is expected
+Assert::exception(function () use ($fn) { // 1st param
 	assertSignature($fn, params(T1::class, nullable(T2::class)), nullable(T3::class));
 }, \AssertionError::class /* todo: assert message */);
 
-Assert::exception(function () use ($fn) {
+Assert::exception(function () use ($fn) { // 2nd param
 	assertSignature($fn, params(nullable(T1::class), T2::class), nullable(T3::class));
 }, \AssertionError::class /* todo: assert message */);
 
-Assert::exception(function () use ($fn) {
+Assert::exception(function () use ($fn) { // return type
 	assertSignature($fn, params(nullable(T1::class), nullable(T2::class)), T3::class);
 }, \AssertionError::class /* todo: assert message */);
 
-// Wrong return type type
+// Wrong return type
 Assert::exception(function () use ($fn) {
 	assertSignature($fn, params(nullable(T1::class), nullable(T2::class)), nullable(T2::class));
 }, \AssertionError::class /* todo: assert message */);