use proper return types in ErrorHandler and ArgumentResolver

src/Symfony/Component/Debug/ErrorHandler.php

@@ -369,18 +369,13 @@ class ErrorHandler
     /**
      * Handles errors by filtering then logging them according to the configured bit fields.
      *
-     * @param int    $type    One of the E_* constants
-     * @param string $message
-     * @param string $file
-     * @param int    $line
-     *
      * @return bool Returns false when no handling happens so that the PHP engine can handle the error itself
      *
      * @throws \ErrorException When $this->thrownErrors requests so
      *
      * @internal
      */
-    public function handleError($type, $message, $file, $line)
+    public function handleError(int $type, string $message, string $file, int $line): bool
     {
         // @deprecated to be removed in Symfony 5.0
         if (\PHP_VERSION_ID >= 70300 && $message && '"' === $message[0] && 0 === strpos($message, '"continue') && preg_match('/^"continue(?: \d++)?" targeting switch is equivalent to "break(?: \d++)?"\. Did you mean to use "continue(?: \d++)?"\?$/', $message)) {
@@ -443,7 +438,7 @@ class ErrorHandler
                 self::$silencedErrorCache[$id][$message] = $errorAsException;
             }
             if (null === $lightTrace) {
-                return;
+                return true;
             }
         } else {
             $errorAsException = new \ErrorException($logMessage, 0, $type, $file, $line);

src/Symfony/Component/HttpKernel/Controller/ArgumentResolver.php

@@ -55,12 +55,14 @@ final class ArgumentResolver implements ArgumentResolverInterface
 
                 $resolved = $resolver->resolve($request, $metadata);
 
-                if (!$resolved instanceof \Generator) {
-                    throw new \InvalidArgumentException(sprintf('%s::resolve() must yield at least one value.', \get_class($resolver)));
+                $atLeastOne = false;
+                foreach ($resolved as $append) {
+                    $atLeastOne = true;
+                    $arguments[] = $append;
                 }
 
-                foreach ($resolved as $append) {
-                    $arguments[] = $append;
+                if (!$atLeastOne) {
+                    throw new \InvalidArgumentException(sprintf('%s::resolve() must yield at least one value.', \get_class($resolver)));
                 }
 
                 // continue to the next controller argument

src/Symfony/Component/HttpKernel/Controller/ArgumentResolver/VariadicValueResolver.php

@@ -41,8 +41,6 @@ final class VariadicValueResolver implements ArgumentValueResolverInterface
             throw new \InvalidArgumentException(sprintf('The action argument "...$%1$s" is required to be an array, the request attribute "%1$s" contains a type of "%2$s" instead.', $argument->getName(), \gettype($values)));
         }
 
-        foreach ($values as $value) {
-            yield $value;
-        }
+        yield from $values;
     }
 }

src/Symfony/Component/HttpKernel/Controller/ArgumentValueResolverInterface.php

@@ -37,7 +37,7 @@ interface ArgumentValueResolverInterface
      * @param Request          $request
      * @param ArgumentMetadata $argument
      *
-     * @return \Generator
+     * @return iterable
      */
     public function resolve(Request $request, ArgumentMetadata $argument);
 }

src/Symfony/Component/HttpKernel/ControllerMetadata/ArgumentMetadataFactory.php

@@ -42,30 +42,24 @@ final class ArgumentMetadataFactory implements ArgumentMetadataFactoryInterface
 
     /**
      * Returns an associated type to the given parameter if available.
-     *
-     * @param \ReflectionParameter $parameter
-     *
-     * @return string|null
      */
-    private function getType(\ReflectionParameter $parameter, \ReflectionFunctionAbstract $function)
+    private function getType(\ReflectionParameter $parameter, \ReflectionFunctionAbstract $function): ?string
     {
         if (!$type = $parameter->getType()) {
-            return;
+            return null;
         }
         $name = $type->getName();
-        $lcName = strtolower($name);
 
-        if ('self' !== $lcName && 'parent' !== $lcName) {
-            return $name;
-        }
-        if (!$function instanceof \ReflectionMethod) {
-            return;
-        }
-        if ('self' === $lcName) {
-            return $function->getDeclaringClass()->name;
-        }
-        if ($parent = $function->getDeclaringClass()->getParentClass()) {
-            return $parent->name;
+        if ($function instanceof \ReflectionMethod) {
+            $lcName = strtolower($name);
+            switch ($lcName) {
+                case 'self':
+                    return $function->getDeclaringClass()->name;
+                case 'parent':
+                    return ($parent = $function->getDeclaringClass()->getParentClass()) ? $parent->name : null;
+            }
         }
+
+        return $name;
     }
 }

src/Symfony/Component/HttpKernel/Tests/Controller/ArgumentResolverTest.php

@@ -185,7 +185,7 @@ class ArgumentResolverTest extends TestCase
         $resolver = new ArgumentResolver($factory, [$valueResolver]);
 
         $valueResolver->expects($this->any())->method('supports')->willReturn(true);
-        $valueResolver->expects($this->any())->method('resolve')->willReturn('foo');
+        $valueResolver->expects($this->any())->method('resolve')->willReturn([]);
 
         $request = Request::create('/');
         $request->attributes->set('foo', 'foo');