php8-mod: Optimize compiled string definitions

Author: partikus

src/CompiledContainer.php

@@ -118,7 +118,7 @@ protected function resolveFactory($callable, $entryName, array $extraParameters
      * Resolve a placeholder in string definition
      * - wrap possible NotFound exception to conform to the one from StringDefinition::resolveExpression.
      */
-    protected function resolveStringPlaceholder($placeholder, $entryName)
+    protected function resolveStringPlaceholder(string $placeholder, string $entryName) : mixed
     {
         try {
             return $this->delegateContainer->get($placeholder);

src/Compiler/Compiler.php

@@ -215,9 +215,7 @@ private function compileDefinition(string $entryName, Definition $definition) :
                 break;
             case $definition instanceof StringDefinition:
                 $expression = $definition->getExpression();
-                $callback = function (array $matches) use ($definition) {
-                    return '\'.$this->resolveStringPlaceholder(' . $this->compileValue($matches[1]) . ', ' . $this->compileValue($definition->getName()) . ').\'';
-                };
+                $callback = fn (array $matches) : string => '\'.$this->resolveStringPlaceholder(' . $this->compileValue($matches[1]) . ', ' . $this->compileValue($definition->getName()) . ').\'';
                 $value = preg_replace_callback('#\{([^\{\}]+)\}#', $callback, $expression);
                 $code = 'return \'' . $value . '\';';
                 break;