Address review: deduplicate test file and fix NeverType to be explicit

- Reuse tests/PHPStan/Analyser/nsrt/bug-2572.php in rule test instead of
  duplicating the file in tests/PHPStan/Rules/Functions/data/
- Use explicit NeverType(true) for empty variadic params so the
  UnresolvableTypeHelper doesn't treat it as unresolvable
- Add staabm's reproducer (value() with Closure|TValue union) as
  additional test coverage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

src/Reflection/GenericParametersAcceptorResolver.php

@@ -63,7 +63,7 @@ public static function resolve(array $argTypes, ParametersAcceptor $parametersAc
 			} elseif ($param->getDefaultValue() !== null) {
 				$argType = $param->getDefaultValue();
 			} elseif ($param->isVariadic()) {
-				$argType = new NeverType();
+				$argType = new NeverType(true);
 			} else {
 				continue;
 			}

tests/PHPStan/Analyser/nsrt/bug-2572.php

@@ -25,3 +25,25 @@ function collect($elt, ...$elts) {
 
 assertType("'a'", collect("a"));
 assertType("'a'|'b'|'c'", collect("a", "b", "c"));
+
+/**
+ * @template TValue
+ * @template TArgs
+ *
+ * @param  TValue|\Closure(TArgs): TValue  $value
+ * @param  TArgs  ...$args
+ * @return TValue
+ */
+function value($value, ...$args)
+{
+	return $value instanceof \Closure ? $value(...$args) : $value;
+}
+
+assertType("'foo'", value('foo'));
+assertType("'foo'", value('foo', 42));
+assertType('42', value(fn () => 42));
+assertType('42', value(function ($foo) {
+	assertType('true', $foo);
+
+	return 42;
+}, true));

tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php

@@ -2693,7 +2693,7 @@ public function testBug8936(): void
 
 	public function testBug2572(): void
 	{
-		$this->analyse([__DIR__ . '/data/bug-2572.php'], []);
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-2572.php'], []);
 	}
 
 	public function testDumpFunctions(): void