phpstan-1142.diff

diff --git a/src/Reflection/Php/PhpParameterReflection.php b/src/Reflection/Php/PhpParameterReflection.php
index 02ce9255..03b8a5f2 100644
--- a/src/Reflection/Php/PhpParameterReflection.php
+++ b/src/Reflection/Php/PhpParameterReflection.php
@@ -7,6 +7,7 @@ use PHPStan\Reflection\PassedByReference;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypehintHelper;
+use ReflectionClass;

 class PhpParameterReflection implements ParameterReflection
 {
@@ -52,6 +53,24 @@ class PhpParameterReflection implements ParameterReflection
                                $this->reflection->getDeclaringClass() !== null ? $this->reflection->getDeclaringClass()->getName() : null,
                                $this->isVariadic()
                        );
+
+                       if (($this->type instanceof MixedType) && ! $this->type->isExplicitMixed()) {
+                               $traits = class_uses($this->reflection->getDeclaringClass()->getName());
+
+                               $method = $this->reflection->getDeclaringFunction()->getName();
+
+                               foreach ($traits as $trait) {
+                                       $traitRef = new ReflectionClass($trait);
+
+                                       if ($traitRef->hasMethod($method)) {
+                                               /**
+                                               * @var \ReflectionMethod
+                                               */
+                                               $traitMethod = $traitRef->getMethod($method);
+                                               $traitMethodParam = $traitMethod->getParameters()[$this->reflection->getPosition()] ?? null;
+                                       }
+                               }
+                       }
                }

                return $this->type;