Report unknown parameter for implicit variadic methods (#4481)

Author: VincentLanglet

src/Rules/FunctionCallParametersCheck.php

@@ -562,11 +562,13 @@ private function processArguments(
 		$originalParametersByName = [];
 		$unusedParametersByName = [];
 		$errors = [];
+		$isNativelyVariadic = false;
 		foreach ($parameters as $i => $parameter) {
 			$parametersByName[$parameter->getName()] = $parameter;
 			$originalParametersByName[$parameter->getName()] = $originalParameters[$i];
 
 			if ($parameter->isVariadic()) {
+				$isNativelyVariadic = true;
 				continue;
 			}
 
@@ -603,7 +605,7 @@ private function processArguments(
 
 				$parametersCount = count($parameters);
 				if (
-					!$parametersAcceptor->isVariadic()
+					!$isNativelyVariadic
 					|| $parametersCount <= 0
 					|| $isBuiltin
 				) {

tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php

@@ -534,6 +534,21 @@ public function testBug4514(): void
 		$this->analyse([__DIR__ . '/data/bug-4514.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug13719(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-13719.php'], [
+			[
+				'Unknown parameter $greetings in call to function Bug13719\non_variadic.',
+				20,
+			],
+			[
+				'Unknown parameter $greetings in call to function Bug13719\implicit_variadic.',
+				27,
+			],
+		]);
+	}
+
 	public function testBug4530(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-4530.php'], []);

tests/PHPStan/Rules/Functions/data/bug-13719.php

@@ -0,0 +1,27 @@
+<?php declare(strict_types = 1);
+
+namespace Bug13719;
+
+function non_variadic(string $name, ?string $greeting = null): void {
+	var_dump($name);
+}
+
+// Explicitly defined with variadic arguments.
+function explicit_variadic(string $name, ?string $greeting = null, string ...$args): void {
+	var_dump($name);
+}
+
+// Treated as variadic due to usage of `func_get_args()`.
+function implicit_variadic(string $name, ?string $greeting = null): void {
+	var_dump(func_get_args());
+}
+
+// PHPStan correctly detects the error ('greetings' vs 'greeting').
+non_variadic('my name', greetings: 'my greeting');
+
+// PHPStan correctly doesn't report anything since the function
+// accepts variadic arguments and this is not an error.
+explicit_variadic('my name', greetings: 'my greeting');
+
+// ISSUE: PHPStan should detect argument.unknown error here, but it doesn't.
+implicit_variadic('my name', greetings: 'my greeting');