Resolve psalm deprecations

Author: gharlan

psalm.xml

@@ -4,6 +4,7 @@
     findUnusedCode="true"
     findUnusedPsalmSuppress="true"
     findUnusedVariablesAndParams="true"
+    findUnusedBaselineEntry="true"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"
     xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"

src/Provider/RexTypeReturnProvider.php

@@ -100,7 +100,7 @@ private static function resolveType(Expr $typeExpr, ?Expr $defaultExpr = null):
             return Type::getMixed();
         }
 
-        if ($defaultExpr instanceof ConstFetch && 'null' === $defaultExpr->name->parts[0]) {
+        if ($defaultExpr instanceof ConstFetch && 'null' === $defaultExpr->name->getFirst()) {
             return $type->getBuilder()->addType(new TNull())->freeze();
         }