diff --git a/Command/GenerateCommand.php b/Command/GenerateCommand.php
index d8ed6ae..00a5132 100644
--- a/Command/GenerateCommand.php
+++ b/Command/GenerateCommand.php
@@ -38,7 +38,7 @@ public function execute(InputInterface $input, OutputInterface $output)
 
         $options = require $configFile;
 
-        if (!is_array($options)) {
+        if (!\is_array($options)) {
             throw new \RuntimeException(sprintf('Invalid config file specified or invalid return type in file %s', $configFile));
         }
 
diff --git a/Generator/EndpointGenerator.php b/Generator/EndpointGenerator.php
index e527db2..8cf00d1 100644
--- a/Generator/EndpointGenerator.php
+++ b/Generator/EndpointGenerator.php
@@ -340,7 +340,7 @@ private function getGetBody(Operation $operation, Context $context): Stmt\ClassM
         $isSerializableBody = false;
         $isFormBody = false;
         $hasFileInForm = false;
-        $consumes = is_array($operation->getOperation()->getConsumes()) ? $operation->getOperation()->getConsumes() : [$operation->getOperation()->getConsumes()];
+        $consumes = \is_array($operation->getOperation()->getConsumes()) ? $operation->getOperation()->getConsumes() : [$operation->getOperation()->getConsumes()];
 
         foreach ($operation->getParameters() as $key => $parameter) {
             if ($parameter instanceof BodyParameter && $parameter->getSchema() !== null) {
diff --git a/Generator/Psr7HttplugClientGenerator.php b/Generator/Psr7HttplugClientGenerator.php
index 4fa4fa1..ed52344 100644
--- a/Generator/Psr7HttplugClientGenerator.php
+++ b/Generator/Psr7HttplugClientGenerator.php
@@ -113,7 +113,7 @@ private function getHttpClientCreateExpr(Context $context)
         if (null !== $openApi->getHost()) {
             $scheme = 'https';
 
-            if (null !== $openApi->getSchemes() && count($openApi->getSchemes()) > 0 && !in_array('https', $openApi->getSchemes())) {
+            if (null !== $openApi->getSchemes() && \count($openApi->getSchemes()) > 0 && !\in_array('https', $openApi->getSchemes())) {
                 $scheme = $openApi->getSchemes()[0];
             }
 
diff --git a/Guesser/OpenApiSchema/AdditionalPropertiesGuesser.php b/Guesser/OpenApiSchema/AdditionalPropertiesGuesser.php
index b17443a..aabe2b2 100644
--- a/Guesser/OpenApiSchema/AdditionalPropertiesGuesser.php
+++ b/Guesser/OpenApiSchema/AdditionalPropertiesGuesser.php
@@ -20,7 +20,7 @@ public function supportObject($object)
             return false;
         }
 
-        if (true !== $object->getAdditionalProperties() && !is_object($object->getAdditionalProperties())) {
+        if (true !== $object->getAdditionalProperties() && !\is_object($object->getAdditionalProperties())) {
             return false;
         }
 
diff --git a/Guesser/OpenApiSchema/AllOfGuesser.php b/Guesser/OpenApiSchema/AllOfGuesser.php
index fdf3006..57ea425 100644
--- a/Guesser/OpenApiSchema/AllOfGuesser.php
+++ b/Guesser/OpenApiSchema/AllOfGuesser.php
@@ -12,7 +12,7 @@ class AllOfGuesser extends BaseAllOfGuesser
      */
     public function supportObject($object)
     {
-        return ($object instanceof Schema) && is_array($object->getAllOf()) && count($object->getAllOf()) > 0;
+        return ($object instanceof Schema) && \is_array($object->getAllOf()) && \count($object->getAllOf()) > 0;
     }
 
     /**
diff --git a/Guesser/OpenApiSchema/ItemsGuesser.php b/Guesser/OpenApiSchema/ItemsGuesser.php
index 06f7609..a39e1b7 100644
--- a/Guesser/OpenApiSchema/ItemsGuesser.php
+++ b/Guesser/OpenApiSchema/ItemsGuesser.php
@@ -18,9 +18,9 @@ public function supportObject($object)
                 $object->getItems() instanceof Schema
                 ||
                 (
-                    is_array($object->getItems())
+                    \is_array($object->getItems())
                     &&
-                    count($object->getItems()) > 0
+                    \count($object->getItems()) > 0
                 )
             )
         ;
diff --git a/Guesser/OpenApiSchema/MultipleGuesser.php b/Guesser/OpenApiSchema/MultipleGuesser.php
index 79d8b6b..a068f86 100644
--- a/Guesser/OpenApiSchema/MultipleGuesser.php
+++ b/Guesser/OpenApiSchema/MultipleGuesser.php
@@ -12,6 +12,6 @@ class MultipleGuesser extends BaseMultipleGuesser
      */
     public function supportObject($object)
     {
-        return ($object instanceof Schema) && is_array($object->getType());
+        return ($object instanceof Schema) && \is_array($object->getType());
     }
 }
diff --git a/Guesser/OpenApiSchema/SimpleTypeGuesser.php b/Guesser/OpenApiSchema/SimpleTypeGuesser.php
index b9341eb..180fbe4 100644
--- a/Guesser/OpenApiSchema/SimpleTypeGuesser.php
+++ b/Guesser/OpenApiSchema/SimpleTypeGuesser.php
@@ -14,9 +14,9 @@ public function supportObject($object)
     {
         return ($object instanceof Schema)
             &&
-            in_array($object->getType(), $this->typesSupported)
+            \in_array($object->getType(), $this->typesSupported)
             &&
-            !in_array($object->getFormat(), $this->excludeFormat)
+            !\in_array($object->getFormat(), $this->excludeFormat)
         ;
     }
 }
diff --git a/Naming/OperationUrlNaming.php b/Naming/OperationUrlNaming.php
index 6bda1ea..ffaed03 100644
--- a/Naming/OperationUrlNaming.php
+++ b/Naming/OperationUrlNaming.php
@@ -59,11 +59,11 @@ function ($match) {
                 }
             } else {
                 $methodNameParts[] = ucfirst($part);
-                $lastNonParameterPartIndex = count($methodNameParts) - 1;
+                $lastNonParameterPartIndex = \count($methodNameParts) - 1;
             }
         }
 
-        if ($shouldSingularize && count($methodNameParts) > 0) {
+        if ($shouldSingularize && \count($methodNameParts) > 0) {
             $methodNameParts[$lastNonParameterPartIndex] = Inflector::singularize($methodNameParts[$lastNonParameterPartIndex]);
         }
 
diff --git a/Tests/JaneOpenApiResourceTest.php b/Tests/JaneOpenApiResourceTest.php
index d63ebe0..6b4578f 100644
--- a/Tests/JaneOpenApiResourceTest.php
+++ b/Tests/JaneOpenApiResourceTest.php
@@ -40,7 +40,7 @@ public function testRessources($name, SplFileInfo $testDirectory)
 
         $generatedData = [];
 
-        $this->assertEquals(count($expectedFinder), count($generatedFinder), 'Assert same files for ' . $testDirectory->getRealPath());
+        $this->assertEquals(\count($expectedFinder), \count($generatedFinder), 'Assert same files for ' . $testDirectory->getRealPath());
 
         foreach ($generatedFinder as $generatedFile) {
             $generatedData[$generatedFile->getRelativePathname()] = $generatedFile->getRealPath();