diff --git a/lib/PhpParser/Comment.php b/lib/PhpParser/Comment.php
index 1a287b6..47d17ec 100644
--- a/lib/PhpParser/Comment.php
+++ b/lib/PhpParser/Comment.php
@@ -138,7 +138,7 @@ class Comment implements \JsonSerializable
      */
     private function getShortestWhitespacePrefixLen(string $str) : int {
         $lines = explode("\n", $str);
-        $shortestPrefixLen = INF;
+        $shortestPrefixLen = \INF;
         foreach ($lines as $line) {
             preg_match('(^\s*)', $line, $matches);
             $prefixLen = strlen($matches[0]);
diff --git a/lib/PhpParser/Lexer.php b/lib/PhpParser/Lexer.php
index aa7ff8a..1dd15d6 100644
--- a/lib/PhpParser/Lexer.php
+++ b/lib/PhpParser/Lexer.php
@@ -34,7 +34,7 @@ class Lexer
         // map of tokens to drop while lexing (the map is only used for isset lookup,
         // that's why the value is simply set to 1; the value is never actually used.)
         $this->dropTokens = array_fill_keys(
-            [T_WHITESPACE, T_OPEN_TAG, T_COMMENT, T_DOC_COMMENT], 1
+            [\T_WHITESPACE, \T_OPEN_TAG, \T_COMMENT, \T_DOC_COMMENT], 1
         );
 
         // the usedAttributes member is a map of the used attribute names to a dummy
@@ -112,7 +112,7 @@ class Lexer
      * @return bool
      */
     private function isUnterminatedComment($token) : bool {
-        return ($token[0] === T_COMMENT || $token[0] === T_DOC_COMMENT)
+        return ($token[0] === \T_COMMENT || $token[0] === \T_DOC_COMMENT)
             && substr($token[1], 0, 2) === '/*'
             && substr($token[1], -2) !== '*/';
     }
@@ -173,7 +173,7 @@ class Lexer
 
                 // Emulate the PHP behavior
                 $isDocComment = isset($comment[3]) && $comment[3] === '*';
-                $this->tokens[] = [$isDocComment ? T_DOC_COMMENT : T_COMMENT, $comment, $line];
+                $this->tokens[] = [$isDocComment ? \T_DOC_COMMENT : \T_COMMENT, $comment, $line];
             } else {
                 // Invalid characters at the end of the input
                 $this->handleInvalidCharacterRange(
@@ -253,18 +253,18 @@ class Lexer
             } elseif (!isset($this->dropTokens[$token[0]])) {
                 $value = $token[1];
                 $id = $this->tokenMap[$token[0]];
-                if (T_CLOSE_TAG === $token[0]) {
+                if (\T_CLOSE_TAG === $token[0]) {
                     $this->prevCloseTagHasNewline = false !== strpos($token[1], "\n");
-                } else if (T_INLINE_HTML === $token[0]) {
+                } else if (\T_INLINE_HTML === $token[0]) {
                     $startAttributes['hasLeadingNewline'] = $this->prevCloseTagHasNewline;
                 }
 
                 $this->line += substr_count($value, "\n");
                 $this->filePos += \strlen($value);
             } else {
-                if (T_COMMENT === $token[0] || T_DOC_COMMENT === $token[0]) {
+                if (\T_COMMENT === $token[0] || \T_DOC_COMMENT === $token[0]) {
                     if (isset($this->usedAttributes['comments'])) {
-                        $comment = T_DOC_COMMENT === $token[0]
+                        $comment = \T_DOC_COMMENT === $token[0]
                             ? new Comment\Doc($token[1], $this->line, $this->filePos, $this->pos)
                             : new Comment($token[1], $this->line, $this->filePos, $this->pos);
                         $startAttributes['comments'][] = $comment;
@@ -344,13 +344,13 @@ class Lexer
         // 256 is the minimum possible token number, as everything below
         // it is an ASCII value
         for ($i = 256; $i < 1000; ++$i) {
-            if (T_DOUBLE_COLON === $i) {
+            if (\T_DOUBLE_COLON === $i) {
                 // T_DOUBLE_COLON is equivalent to T_PAAMAYIM_NEKUDOTAYIM
                 $tokenMap[$i] = Tokens::T_PAAMAYIM_NEKUDOTAYIM;
-            } elseif(T_OPEN_TAG_WITH_ECHO === $i) {
+            } elseif(\T_OPEN_TAG_WITH_ECHO === $i) {
                 // T_OPEN_TAG_WITH_ECHO with dropped T_OPEN_TAG results in T_ECHO
                 $tokenMap[$i] = Tokens::T_ECHO;
-            } elseif(T_CLOSE_TAG === $i) {
+            } elseif(\T_CLOSE_TAG === $i) {
                 // T_CLOSE_TAG is equivalent to ';'
                 $tokenMap[$i] = ord(';');
             } elseif ('UNKNOWN' !== $name = token_name($i)) {
@@ -366,11 +366,11 @@ class Lexer
 
         // HHVM uses a special token for numbers that overflow to double
         if (defined('T_ONUMBER')) {
-            $tokenMap[T_ONUMBER] = Tokens::T_DNUMBER;
+            $tokenMap[\T_ONUMBER] = Tokens::T_DNUMBER;
         }
         // HHVM also has a separate token for the __COMPILER_HALT_OFFSET__ constant
         if (defined('T_COMPILER_HALT_OFFSET')) {
-            $tokenMap[T_COMPILER_HALT_OFFSET] = Tokens::T_STRING;
+            $tokenMap[\T_COMPILER_HALT_OFFSET] = Tokens::T_STRING;
         }
 
         return $tokenMap;
diff --git a/lib/PhpParser/NameContext.php b/lib/PhpParser/NameContext.php
index ec6d91a..68d283a 100644
--- a/lib/PhpParser/NameContext.php
+++ b/lib/PhpParser/NameContext.php
@@ -214,7 +214,7 @@ class NameContext {
 
         // Find shortest name
         $shortestName = null;
-        $shortestLength = INF;
+        $shortestLength = \INF;
         foreach ($possibleNames as $possibleName) {
             $length = strlen($possibleName->toCodeString());
             if ($length < $shortestLength) {
diff --git a/lib/PhpParser/PrettyPrinter/Standard.php b/lib/PhpParser/PrettyPrinter/Standard.php
index 6d75689..342e386 100644
--- a/lib/PhpParser/PrettyPrinter/Standard.php
+++ b/lib/PhpParser/PrettyPrinter/Standard.php
@@ -888,7 +888,7 @@ class Standard extends PrettyPrinterAbstract
             $oct = decoct(ord($matches[1]));
             if ($matches[2] !== '') {
                 // If there is a trailing digit, use the full three character form
-                return '\\' . str_pad($oct, 3, '0', STR_PAD_LEFT);
+                return '\\' . str_pad($oct, 3, '0', \STR_PAD_LEFT);
             }
             return '\\' . $oct;
         }, $escaped);
diff --git a/lib/PhpParser/PrettyPrinterAbstract.php b/lib/PhpParser/PrettyPrinterAbstract.php
index 5807d50..b537700 100644
--- a/lib/PhpParser/PrettyPrinterAbstract.php
+++ b/lib/PhpParser/PrettyPrinterAbstract.php
@@ -1068,10 +1068,10 @@ abstract class PrettyPrinterAbstract
     protected function initializeRemovalMap() {
         if ($this->removalMap) return;
 
-        $stripBoth = ['left' => T_WHITESPACE, 'right' => T_WHITESPACE];
-        $stripLeft = ['left' => T_WHITESPACE];
-        $stripRight = ['right' => T_WHITESPACE];
-        $stripDoubleArrow = ['right' => T_DOUBLE_ARROW];
+        $stripBoth = ['left' => \T_WHITESPACE, 'right' => \T_WHITESPACE];
+        $stripLeft = ['left' => \T_WHITESPACE];
+        $stripRight = ['right' => \T_WHITESPACE];
+        $stripDoubleArrow = ['right' => \T_DOUBLE_ARROW];
         $stripColon = ['left' => ':'];
         $stripEquals = ['left' => '='];
         $this->removalMap = [
@@ -1086,8 +1086,8 @@ abstract class PrettyPrinterAbstract
             'Param->default' => $stripEquals,
             'Stmt_Break->num' => $stripBoth,
             'Stmt_ClassMethod->returnType' => $stripColon,
-            'Stmt_Class->extends' => ['left' => T_EXTENDS],
-            'Expr_PrintableNewAnonClass->extends' => ['left' => T_EXTENDS],
+            'Stmt_Class->extends' => ['left' => \T_EXTENDS],
+            'Expr_PrintableNewAnonClass->extends' => ['left' => \T_EXTENDS],
             'Stmt_Continue->num' => $stripBoth,
             'Stmt_Foreach->keyVar' => $stripDoubleArrow,
             'Stmt_Function->returnType' => $stripColon,
@@ -1114,21 +1114,21 @@ abstract class PrettyPrinterAbstract
             'Expr_ArrayItem->key' => [null, null, ' => '],
             'Expr_Closure->returnType' => [')', ' : ', null],
             'Expr_Ternary->if' => ['?', ' ', ' '],
-            'Expr_Yield->key' => [T_YIELD, null, ' => '],
-            'Expr_Yield->value' => [T_YIELD, ' ', null],
+            'Expr_Yield->key' => [\T_YIELD, null, ' => '],
+            'Expr_Yield->value' => [\T_YIELD, ' ', null],
             'Param->type' => [null, null, ' '],
             'Param->default' => [null, ' = ', null],
-            'Stmt_Break->num' => [T_BREAK, ' ', null],
+            'Stmt_Break->num' => [\T_BREAK, ' ', null],
             'Stmt_ClassMethod->returnType' => [')', ' : ', null],
             'Stmt_Class->extends' => [null, ' extends ', null],
             'Expr_PrintableNewAnonClass->extends' => [null, ' extends ', null],
-            'Stmt_Continue->num' => [T_CONTINUE, ' ', null],
-            'Stmt_Foreach->keyVar' => [T_AS, null, ' => '],
+            'Stmt_Continue->num' => [\T_CONTINUE, ' ', null],
+            'Stmt_Foreach->keyVar' => [\T_AS, null, ' => '],
             'Stmt_Function->returnType' => [')', ' : ', null],
             'Stmt_If->else' => [null, ' ', null],
-            'Stmt_Namespace->name' => [T_NAMESPACE, ' ', null],
+            'Stmt_Namespace->name' => [\T_NAMESPACE, ' ', null],
             'Stmt_PropertyProperty->default' => [null, ' = ', null],
-            'Stmt_Return->expr' => [T_RETURN, ' ', null],
+            'Stmt_Return->expr' => [\T_RETURN, ' ', null],
             'Stmt_StaticVar->default' => [null, ' = ', null],
             //'Stmt_TraitUseAdaptation_Alias->newName' => [T_AS, ' ', null], // TODO
             'Stmt_TryCatch->finally' => [null, ' ', null],
@@ -1214,10 +1214,10 @@ abstract class PrettyPrinterAbstract
         if ($this->modifierChangeMap) return;
 
         $this->modifierChangeMap = [
-            'Stmt_ClassConst->flags' => T_CONST,
-            'Stmt_ClassMethod->flags' => T_FUNCTION,
-            'Stmt_Class->flags' => T_CLASS,
-            'Stmt_Property->flags' => T_VARIABLE,
+            'Stmt_ClassConst->flags' => \T_CONST,
+            'Stmt_ClassMethod->flags' => \T_FUNCTION,
+            'Stmt_Class->flags' => \T_CLASS,
+            'Stmt_Property->flags' => \T_VARIABLE,
             //'Stmt_TraitUseAdaptation_Alias->newModifier' => 0, // TODO
         ];
 
diff --git a/lib/PhpParser/TokenStream.php b/lib/PhpParser/TokenStream.php
index 2822a97..e507375 100644
--- a/lib/PhpParser/TokenStream.php
+++ b/lib/PhpParser/TokenStream.php
@@ -67,8 +67,8 @@ class TokenStream {
             if ($tokenType === $expectedTokenType) {
                 return true;
             }
-            if ($tokenType !== T_WHITESPACE
-                && $tokenType !== T_COMMENT && $tokenType !== T_DOC_COMMENT) {
+            if ($tokenType !== \T_WHITESPACE
+                && $tokenType !== \T_COMMENT && $tokenType !== \T_DOC_COMMENT) {
                 break;
             }
         }
@@ -93,8 +93,8 @@ class TokenStream {
             if ($tokenType === $expectedTokenType) {
                 return true;
             }
-            if ($tokenType !== T_WHITESPACE
-                && $tokenType !== T_COMMENT && $tokenType !== T_DOC_COMMENT) {
+            if ($tokenType !== \T_WHITESPACE
+                && $tokenType !== \T_COMMENT && $tokenType !== \T_DOC_COMMENT) {
                 break;
             }
         }
@@ -105,7 +105,7 @@ class TokenStream {
         $tokens = $this->tokens;
 
         $pos = $this->skipLeftWhitespace($pos);
-        if ($skipTokenType === T_WHITESPACE) {
+        if ($skipTokenType === \T_WHITESPACE) {
             return $pos;
         }
 
@@ -122,7 +122,7 @@ class TokenStream {
         $tokens = $this->tokens;
 
         $pos = $this->skipRightWhitespace($pos);
-        if ($skipTokenType === T_WHITESPACE) {
+        if ($skipTokenType === \T_WHITESPACE) {
             return $pos;
         }
 
@@ -145,7 +145,7 @@ class TokenStream {
         $tokens = $this->tokens;
         for (; $pos >= 0; $pos--) {
             $type = $tokens[$pos][0];
-            if ($type !== T_WHITESPACE && $type !== T_COMMENT && $type !== T_DOC_COMMENT) {
+            if ($type !== \T_WHITESPACE && $type !== \T_COMMENT && $type !== \T_DOC_COMMENT) {
                 break;
             }
         }
@@ -162,7 +162,7 @@ class TokenStream {
         $tokens = $this->tokens;
         for ($count = \count($tokens); $pos < $count; $pos++) {
             $type = $tokens[$pos][0];
-            if ($type !== T_WHITESPACE && $type !== T_COMMENT && $type !== T_DOC_COMMENT) {
+            if ($type !== \T_WHITESPACE && $type !== \T_COMMENT && $type !== \T_DOC_COMMENT) {
                 break;
             }
         }
@@ -208,7 +208,7 @@ class TokenStream {
             if (\is_array($token)) {
                 $type = $token[0];
                 $content = $token[1];
-                if ($type === T_CONSTANT_ENCAPSED_STRING || $type === T_ENCAPSED_AND_WHITESPACE) {
+                if ($type === \T_CONSTANT_ENCAPSED_STRING || $type === \T_ENCAPSED_AND_WHITESPACE) {
                     $result .= $content;
                 } else {
                     // TODO Handle non-space indentation
@@ -238,7 +238,7 @@ class TokenStream {
         foreach ($this->tokens as $token) {
             $indentMap[] = $indent;
 
-            if ($token[0] === T_WHITESPACE) {
+            if ($token[0] === \T_WHITESPACE) {
                 $content = $token[1];
                 $newlinePos = \strrpos($content, "\n");
                 if (false !== $newlinePos) {