diff --git a/src/Standards/Generic/Tests/WhiteSpace/DisallowTabIndentUnitTest.php b/src/Standards/Generic/Tests/WhiteSpace/DisallowTabIndentUnitTest.php
index 94b833d657..7a5f15e9f5 100644
--- a/src/Standards/Generic/Tests/WhiteSpace/DisallowTabIndentUnitTest.php
+++ b/src/Standards/Generic/Tests/WhiteSpace/DisallowTabIndentUnitTest.php
@@ -103,7 +103,7 @@ public function getErrorList($testFile='')
             ];
 
         case 'DisallowTabIndentUnitTest.3.inc':
-            if (\PHP_VERSION_ID >= 70300) {
+            if (PHP_VERSION_ID >= 70300) {
                 return [
                     7  => 1,
                     13 => 1,
diff --git a/src/Standards/PSR12/Sniffs/Classes/AnonClassDeclarationSniff.php b/src/Standards/PSR12/Sniffs/Classes/AnonClassDeclarationSniff.php
index d4792f5e30..552bfea46a 100644
--- a/src/Standards/PSR12/Sniffs/Classes/AnonClassDeclarationSniff.php
+++ b/src/Standards/PSR12/Sniffs/Classes/AnonClassDeclarationSniff.php
@@ -98,7 +98,7 @@ public function process(File $phpcsFile, $stackPtr)
                 $indent = str_repeat(' ', ($tokens[$first]['column'] - 1));
                 $phpcsFile->fixer->beginChangeset();
 
-                if ($tokens[($prev + 1)]['code'] === \T_WHITESPACE) {
+                if ($tokens[($prev + 1)]['code'] === T_WHITESPACE) {
                     $phpcsFile->fixer->replaceToken(($prev + 1), '');
                 }
 
diff --git a/src/Standards/Squiz/Sniffs/PHP/InnerFunctionsSniff.php b/src/Standards/Squiz/Sniffs/PHP/InnerFunctionsSniff.php
index 5ec0d470be..1bc369a2a0 100644
--- a/src/Standards/Squiz/Sniffs/PHP/InnerFunctionsSniff.php
+++ b/src/Standards/Squiz/Sniffs/PHP/InnerFunctionsSniff.php
@@ -56,7 +56,7 @@ public function process(File $phpcsFile, $stackPtr)
                 break;
             }
 
-            if (\array_key_exists($condition, Tokens::$ooScopeTokens) === true) {
+            if (array_key_exists($condition, Tokens::$ooScopeTokens) === true) {
                 // Ignore methods in OOP structures defined within functions.
                 return;
             }
diff --git a/src/Standards/Squiz/Sniffs/PHP/NonExecutableCodeSniff.php b/src/Standards/Squiz/Sniffs/PHP/NonExecutableCodeSniff.php
index a5db965b66..4c0d6bcb7e 100644
--- a/src/Standards/Squiz/Sniffs/PHP/NonExecutableCodeSniff.php
+++ b/src/Standards/Squiz/Sniffs/PHP/NonExecutableCodeSniff.php
@@ -275,7 +275,7 @@ public function process(File $phpcsFile, $stackPtr)
             }
 
             // Skip HTML whitespace.
-            if ($tokens[$i]['code'] === T_INLINE_HTML && \trim($tokens[$i]['content']) === '') {
+            if ($tokens[$i]['code'] === T_INLINE_HTML && trim($tokens[$i]['content']) === '') {
                 continue;
             }
 
diff --git a/src/Tokenizers/PHP.php b/src/Tokenizers/PHP.php
index 31cc0237a2..4be5400a05 100644
--- a/src/Tokenizers/PHP.php
+++ b/src/Tokenizers/PHP.php
@@ -3106,7 +3106,7 @@ protected function processAdditional()
                 }
 
                 if ($suspectedType === 'property or parameter') {
-                    unset($allowed[\T_STATIC]);
+                    unset($allowed[T_STATIC]);
                 }
 
                 $typeTokenCount = 0;
diff --git a/tests/Core/AbstractMethodUnitTest.php b/tests/Core/AbstractMethodUnitTest.php
index 9f7cefec17..b8522bf4bb 100644
--- a/tests/Core/AbstractMethodUnitTest.php
+++ b/tests/Core/AbstractMethodUnitTest.php
@@ -14,7 +14,6 @@
 use PHP_CodeSniffer\Files\File;
 use PHP_CodeSniffer\Tests\ConfigDouble;
 use PHPUnit\Framework\TestCase;
-use ReflectionProperty;
 
 abstract class AbstractMethodUnitTest extends TestCase
 {
diff --git a/tests/Core/File/GetClassPropertiesTest.php b/tests/Core/File/GetClassPropertiesTest.php
index 1bebc5893f..4841b50b6b 100644
--- a/tests/Core/File/GetClassPropertiesTest.php
+++ b/tests/Core/File/GetClassPropertiesTest.php
@@ -52,15 +52,15 @@ public static function dataNotAClassException()
         return [
             'interface'  => [
                 'testMarker' => '/* testNotAClass */',
-                'tokenType'  => \T_INTERFACE,
+                'tokenType'  => T_INTERFACE,
             ],
             'anon-class' => [
                 'testMarker' => '/* testAnonClass */',
-                'tokenType'  => \T_ANON_CLASS,
+                'tokenType'  => T_ANON_CLASS,
             ],
             'enum'       => [
                 'testMarker' => '/* testEnum */',
-                'tokenType'  => \T_ENUM,
+                'tokenType'  => T_ENUM,
             ],
         ];
 
@@ -79,7 +79,7 @@ public static function dataNotAClassException()
      */
     public function testGetClassProperties($testMarker, $expected)
     {
-        $class  = $this->getTargetToken($testMarker, \T_CLASS);
+        $class  = $this->getTargetToken($testMarker, T_CLASS);
         $result = self::$phpcsFile->getClassProperties($class);
         $this->assertSame($expected, $result);
 
diff --git a/tests/Core/Filters/AbstractFilterTestCase.php b/tests/Core/Filters/AbstractFilterTestCase.php
index 9091d1998e..762814e359 100644
--- a/tests/Core/Filters/AbstractFilterTestCase.php
+++ b/tests/Core/Filters/AbstractFilterTestCase.php
@@ -73,7 +73,7 @@ protected function getMockedClass($className, array $constructorArgs=[], $method
     {
         $mockedObj = $this->getMockBuilder($className);
 
-        if (\method_exists($mockedObj, 'onlyMethods') === true) {
+        if (method_exists($mockedObj, 'onlyMethods') === true) {
             // PHPUnit 8+.
             if (is_array($methodsToMock) === true) {
                 return $mockedObj
diff --git a/tests/Core/Filters/Filter/AcceptTest.php b/tests/Core/Filters/Filter/AcceptTest.php
index 64765f3af0..8d622061df 100644
--- a/tests/Core/Filters/Filter/AcceptTest.php
+++ b/tests/Core/Filters/Filter/AcceptTest.php
@@ -10,7 +10,6 @@
 
 namespace PHP_CodeSniffer\Tests\Core\Filters\Filter;
 
-use PHP_CodeSniffer\Config;
 use PHP_CodeSniffer\Filters\Filter;
 use PHP_CodeSniffer\Ruleset;
 use PHP_CodeSniffer\Tests\ConfigDouble;