diff --git a/src/HookDocsRule.php b/src/HookDocsRule.php
index 4d386aa..5579448 100644
--- a/src/HookDocsRule.php
+++ b/src/HookDocsRule.php
@@ -11,7 +11,10 @@
 use PhpParser\Node;
 use PhpParser\Node\Arg;
 use PhpParser\Node\Expr\FuncCall;
+use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Name;
 use PHPStan\Analyser\Scope;
+use PHPStan\PhpDoc\ResolvedPhpDocBlock;
 use PHPStan\PhpDoc\Tag\ParamTag;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
@@ -67,7 +70,7 @@ public function processNode(Node $node, Scope $scope): array
         $this->currentNode = $node;
         $this->currentScope = $scope;
 
-        if (!($name instanceof \PhpParser\Node\Name)) {
+        if (!($name instanceof Name)) {
             return [];
         }
 
@@ -91,7 +94,7 @@ public function processNode(Node $node, Scope $scope): array
      * @param \PHPStan\PhpDoc\ResolvedPhpDocBlock $resolvedPhpDoc
      * @return array<int,\PHPStan\Rules\RuleError>
      */
-    public function validateDocBlock(\PHPStan\PhpDoc\ResolvedPhpDocBlock $resolvedPhpDoc): array
+    public function validateDocBlock(ResolvedPhpDocBlock $resolvedPhpDoc): array
     {
         // Count all documented `@param` tag strings in the docblock.
         $numberOfParamTagStrings = substr_count($resolvedPhpDoc->getPhpDocString(), '* @param ');
@@ -169,7 +172,7 @@ public function validateParamCount(int $numberOfParamTagStrings): void
      */
     public function validateParamDocumentation(
         int $numberOfParamTags,
-        \PHPStan\PhpDoc\ResolvedPhpDocBlock $resolvedPhpDoc
+        ResolvedPhpDocBlock $resolvedPhpDoc
     ): void {
         $nodeArgs = $this->currentNode->getArgs();
         $numberOfParams = count($nodeArgs) - 1;
@@ -182,7 +185,7 @@ public function validateParamDocumentation(
         // We might have an invalid `@param` tag because it's named `$this`.
         if (strpos($resolvedPhpDoc->getPhpDocString(), ' $this') !== false) {
             foreach ($nodeArgs as $param) {
-                if (($param->value instanceof \PhpParser\Node\Expr\Variable) && $param->value->name === 'this') {
+                if (($param->value instanceof Variable) && $param->value->name === 'this') {
                     // PHPStan does not detect param tags named `$this`, it skips the tag.
                     // We can indirectly detect this by checking the actual parameter name,
                     // and if one of them is `$this` assume that's the problem.
diff --git a/src/IsWpErrorRule.php b/src/IsWpErrorRule.php
index 4c27be9..fcb14ea 100644
--- a/src/IsWpErrorRule.php
+++ b/src/IsWpErrorRule.php
@@ -10,6 +10,7 @@
 
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node;
+use PhpParser\Node\Name;
 use PHPStan\Analyser\Scope;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
@@ -46,7 +47,7 @@ public function processNode(Node $node, Scope $scope): array
     {
         $name = $node->name;
 
-        if (! ($name instanceof \PhpParser\Node\Name)) {
+        if (! ($name instanceof Name)) {
             return [];
         }
 
diff --git a/src/WpThemeGetDynamicMethodReturnTypeExtension.php b/src/WpThemeGetDynamicMethodReturnTypeExtension.php
index b463be7..e173fd5 100644
--- a/src/WpThemeGetDynamicMethodReturnTypeExtension.php
+++ b/src/WpThemeGetDynamicMethodReturnTypeExtension.php
@@ -20,6 +20,7 @@
 use PHPStan\Type\StringType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
+use WP_Theme;
 
 class WpThemeGetDynamicMethodReturnTypeExtension implements \PHPStan\Type\DynamicMethodReturnTypeExtension
 {
@@ -46,7 +47,7 @@ class WpThemeGetDynamicMethodReturnTypeExtension implements \PHPStan\Type\Dynami
 
     public function getClass(): string
     {
-        return 'WP_Theme';
+        return WP_Theme::class;
     }
 
     public function isMethodSupported(MethodReflection $methodReflection): bool
diff --git a/tests/HookDocsRuleTest.php b/tests/HookDocsRuleTest.php
index bb1ca46..73e1184 100644
--- a/tests/HookDocsRuleTest.php
+++ b/tests/HookDocsRuleTest.php
@@ -4,6 +4,7 @@
 
 namespace SzepeViktor\PHPStan\WordPress\Tests;
 
+use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\Type\FileTypeMapper;
 use SzepeViktor\PHPStan\WordPress\HookDocsRule;
@@ -13,7 +14,7 @@
  */
 class HookDocsRuleTest extends \PHPStan\Testing\RuleTestCase
 {
-    protected function getRule(): \PHPStan\Rules\Rule
+    protected function getRule(): Rule
     {
         /** @var \PHPStan\Type\FileTypeMapper */
         $fileTypeMapper = self::getContainer()->getByType(FileTypeMapper::class);
diff --git a/tests/IsWpErrorRuleTest.php b/tests/IsWpErrorRuleTest.php
index a744fee..afce04c 100644
--- a/tests/IsWpErrorRuleTest.php
+++ b/tests/IsWpErrorRuleTest.php
@@ -4,6 +4,7 @@
 
 namespace SzepeViktor\PHPStan\WordPress\Tests;
 
+use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleLevelHelper;
 use SzepeViktor\PHPStan\WordPress\IsWpErrorRule;
 
@@ -12,7 +13,7 @@
  */
 class IsWpErrorRuleTest extends \PHPStan\Testing\RuleTestCase
 {
-    protected function getRule(): \PHPStan\Rules\Rule
+    protected function getRule(): Rule
     {
         /** @var \PHPStan\Rules\RuleLevelHelper */
         $ruleLevelHelper = self::getContainer()->getByType(RuleLevelHelper::class);
diff --git a/tests/data/esc_sql.php b/tests/data/esc_sql.php
index 0bdc14a..c75ed13 100644
--- a/tests/data/esc_sql.php
+++ b/tests/data/esc_sql.php
@@ -18,4 +18,4 @@
 assertType('string', esc_sql('someValueToEscape'));
 
 // Wrong type provided (esc_sql() returns an empty string in that case)
-assertType('string', esc_sql(new \stdClass()));
+assertType('string', esc_sql(new stdClass()));
diff --git a/tests/data/get_post.php b/tests/data/get_post.php
index 4f8fa82..6e03324 100644
--- a/tests/data/get_post.php
+++ b/tests/data/get_post.php
@@ -4,10 +4,11 @@
 
 namespace SzepeViktor\PHPStan\WordPress\Tests;
 
+use stdClass;
 use function PHPStan\Testing\assertType;
 
 /** @var \WP_Post $wpPostType */
-$wpPostType = new \stdClass();
+$wpPostType = new stdClass();
 
 // Default output
 assertType('WP_Post|null', get_post());