minor #3888 Remove unused variables and unreachable code (GromNaN)

This PR was merged into the 3.x branch.

Discussion
----------

Remove unused variables and unreachable code

I did some archaeology to find the origin of each useless line of code. Details in comments.

Commits
-------

6d715e2 Remove unused variables and unreachable code

src/Environment.php

@@ -345,7 +345,6 @@ public function loadTemplate(string $cls, string $name, int $index = null): Temp
                 $this->cache->load($key);
             }
 
-            $source = null;
             if (!class_exists($cls, false)) {
                 $source = $this->getLoader()->getSourceContext($name);
                 $content = $this->compileSource($source);

src/ExpressionParser.php

@@ -506,10 +506,6 @@ public function parseSubscriptExpression($node)
             }
 
             if ($node instanceof NameExpression && null !== $this->parser->getImportedSymbol('template', $node->getAttribute('name'))) {
-                if (!$arg instanceof ConstantExpression) {
-                    throw new SyntaxError(sprintf('Dynamic macro names are not supported (called on "%s").', $node->getAttribute('name')), $token->getLine(), $stream->getSourceContext());
-                }
-
                 $name = $arg->getAttribute('value');
 
                 $node = new MethodCallExpression($node, 'macro_'.$name, $arguments, $lineno);

src/Extension/CoreExtension.php

@@ -364,7 +364,6 @@ function twig_random(Environment $env, $values = null, $max = null)
             }
         } else {
             $min = $values;
-            $max = $max;
         }
 
         return mt_rand((int) $min, (int) $max);
@@ -669,7 +668,7 @@ function twig_slice(Environment $env, $item, $start, $length = null, $preserveKe
         return \array_slice($item, $start, $length, $preserveKeys);
     }
 
-    return (string) mb_substr((string) $item, $start, $length, $env->getCharset());
+    return mb_substr((string) $item, $start, $length, $env->getCharset());
 }
 
 /**

src/Node/Node.php

@@ -27,7 +27,6 @@ class Node implements \Countable, \IteratorAggregate
     protected $lineno;
     protected $tag;
 
-    private $name;
     private $sourceContext;
 
     /**

src/NodeVisitor/EscaperNodeVisitor.php

@@ -57,7 +57,7 @@ public function enterNode(Node $node, Environment $env): Node
         } elseif ($node instanceof AutoEscapeNode) {
             $this->statusStack[] = $node->getAttribute('value');
         } elseif ($node instanceof BlockNode) {
-            $this->statusStack[] = isset($this->blocks[$node->getAttribute('name')]) ? $this->blocks[$node->getAttribute('name')] : $this->needEscaping($env);
+            $this->statusStack[] = $this->blocks[$node->getAttribute('name')] ?? $this->needEscaping();
         } elseif ($node instanceof ImportNode) {
             $this->safeVars[] = $node->getNode('var')->getAttribute('name');
         }
@@ -73,7 +73,7 @@ public function leaveNode(Node $node, Environment $env): ?Node
             $this->blocks = [];
         } elseif ($node instanceof FilterExpression) {
             return $this->preEscapeFilterNode($node, $env);
-        } elseif ($node instanceof PrintNode && false !== $type = $this->needEscaping($env)) {
+        } elseif ($node instanceof PrintNode && false !== $type = $this->needEscaping()) {
             $expression = $node->getNode('expr');
             if ($expression instanceof ConditionalExpression && $this->shouldUnwrapConditional($expression, $env, $type)) {
                 return new DoNode($this->unwrapConditional($expression, $env, $type), $expression->getTemplateLine());
@@ -85,7 +85,7 @@ public function leaveNode(Node $node, Environment $env): ?Node
         if ($node instanceof AutoEscapeNode || $node instanceof BlockNode) {
             array_pop($this->statusStack);
         } elseif ($node instanceof BlockReferenceNode) {
-            $this->blocks[$node->getAttribute('name')] = $this->needEscaping($env);
+            $this->blocks[$node->getAttribute('name')] = $this->needEscaping();
         }
 
         return $node;
@@ -183,12 +183,11 @@ private function isSafeFor(string $type, Node $expression, Environment $env): bo
         return \in_array($type, $safe) || \in_array('all', $safe);
     }
 
-    private function needEscaping(Environment $env)
+    private function needEscaping()
     {
         if (\count($this->statusStack)) {
             return $this->statusStack[\count($this->statusStack) - 1];
         }
-
         return $this->defaultStrategy ? $this->defaultStrategy : false;
     }
 

src/NodeVisitor/OptimizerNodeVisitor.php

@@ -63,7 +63,7 @@ public function __construct(int $optimizers = -1)
     public function enterNode(Node $node, Environment $env): Node
     {
         if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
-            $this->enterOptimizeFor($node, $env);
+            $this->enterOptimizeFor($node);
         }
 
         return $node;
@@ -72,14 +72,14 @@ public function enterNode(Node $node, Environment $env): Node
     public function leaveNode(Node $node, Environment $env): ?Node
     {
         if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
-            $this->leaveOptimizeFor($node, $env);
+            $this->leaveOptimizeFor($node);
         }
 
         if (self::OPTIMIZE_RAW_FILTER === (self::OPTIMIZE_RAW_FILTER & $this->optimizers)) {
-            $node = $this->optimizeRawFilter($node, $env);
+            $node = $this->optimizeRawFilter($node);
         }
 
-        $node = $this->optimizePrintNode($node, $env);
+        $node = $this->optimizePrintNode($node);
 
         return $node;
     }
@@ -91,7 +91,7 @@ public function leaveNode(Node $node, Environment $env): ?Node
      *
      *   * "echo $this->render(Parent)Block()" with "$this->display(Parent)Block()"
      */
-    private function optimizePrintNode(Node $node, Environment $env): Node
+    private function optimizePrintNode(Node $node): Node
     {
         if (!$node instanceof PrintNode) {
             return $node;
@@ -113,7 +113,7 @@ private function optimizePrintNode(Node $node, Environment $env): Node
     /**
      * Removes "raw" filters.
      */
-    private function optimizeRawFilter(Node $node, Environment $env): Node
+    private function optimizeRawFilter(Node $node): Node
     {
         if ($node instanceof FilterExpression && 'raw' == $node->getNode('filter')->getAttribute('value')) {
             return $node->getNode('node');
@@ -125,7 +125,7 @@ private function optimizeRawFilter(Node $node, Environment $env): Node
     /**
      * Optimizes "for" tag by removing the "loop" variable creation whenever possible.
      */
-    private function enterOptimizeFor(Node $node, Environment $env): void
+    private function enterOptimizeFor(Node $node): void
     {
         if ($node instanceof ForNode) {
             // disable the loop variable by default
@@ -189,7 +189,7 @@ private function enterOptimizeFor(Node $node, Environment $env): void
     /**
      * Optimizes "for" tag by removing the "loop" variable creation whenever possible.
      */
-    private function leaveOptimizeFor(Node $node, Environment $env): void
+    private function leaveOptimizeFor(Node $node): void
     {
         if ($node instanceof ForNode) {
             array_shift($this->loops);