diff --git a/.travis.yml b/.travis.yml
index 12a247654..5399c90ac 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -55,6 +55,10 @@ jobs:
       env: DB=sqlite DEPENDENCIES=low
       install: travis_retry composer update --prefer-dist --prefer-lowest
 
+    - stage: Test
+      env: DB=sqlite DEPENDENCIES=stable
+      install: travis_retry composer update --prefer-dist --prefer-stable
+
     - stage: Test
       env: DB=sqlite COVERAGE
       before_script:
@@ -68,9 +72,10 @@ jobs:
 
     - stage: Code Quality
       env: DB=none STATIC_ANALYSIS
+      install: travis_retry composer update --prefer-dist --prefer-stable
       before_script:
         - echo "extension=redis.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
-        - travis_retry composer require --dev --prefer-dist --prefer-stable phpstan/phpstan:^0.8 symfony/console:^3.0
+        - travis_retry composer require --dev --prefer-dist --prefer-stable phpstan/phpstan:^0.9
       script: vendor/bin/phpstan analyse -l 1 -c phpstan.neon lib
 
     - stage: Code Quality
diff --git a/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php b/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
index 067a8c577..34703c6d2 100644
--- a/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
+++ b/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
@@ -52,7 +52,7 @@ class CommitOrderCalculator
      * - <b>dependencyList</b> (array<string>)
      * Map of node dependencies defined as hashes.
      *
-     * @var array<stdClass>
+     * @var array<\stdClass>
      */
     private $nodeList = [];
 
diff --git a/lib/Doctrine/ORM/Query/Parser.php b/lib/Doctrine/ORM/Query/Parser.php
index c21b2de96..e726aa062 100644
--- a/lib/Doctrine/ORM/Query/Parser.php
+++ b/lib/Doctrine/ORM/Query/Parser.php
@@ -834,6 +834,8 @@ class Parser
      */
     public function QueryLanguage()
     {
+        $statement = null;
+
         $this->lexer->moveNext();
 
         switch ($this->lexer->lookahead['type']) {
@@ -3357,7 +3359,7 @@ class Parser
         switch (true) {
             case $customFunctionDeclaration !== null:
                 return $customFunctionDeclaration;
-            
+
             case (isset(self::$_STRING_FUNCTIONS[$funcName])):
                 return $this->FunctionsReturningStrings();
 
diff --git a/lib/Doctrine/ORM/Tools/Export/Driver/YamlExporter.php b/lib/Doctrine/ORM/Tools/Export/Driver/YamlExporter.php
index 8fa1a7ffc..c685cd41d 100644
--- a/lib/Doctrine/ORM/Tools/Export/Driver/YamlExporter.php
+++ b/lib/Doctrine/ORM/Tools/Export/Driver/YamlExporter.php
@@ -158,7 +158,7 @@ class YamlExporter extends AbstractExporter
                 $associationMappingArray['fetch'] = $this->_getFetchModeString($associationMapping['fetch']);
             }
 
-            if (isset($mapping['id']) && $mapping['id'] === true) {
+            if (isset($associationMapping['id']) && $associationMapping['id'] === true) {
                 $array['id'][$name]['associationKey'] = true;
             }