Compile the generator guard as an unreachable yield instead of a yield from

CHANGELOG

@@ -2,6 +2,7 @@
 
  * Fix the escaping safe analysis retaining every compiled template node for the lifetime of the environment
  * Speed up loading a template that the environment has already loaded
+ * Speed up rendering by compiling a cheaper generator guard into templates
  * Fix `IntlExtension` letting the pattern derived from a date formatter prototype override an explicit locale
  * Fix `IntlExtension` not honoring the locale of a date formatter prototype configured with no date and time styles
  * Speed up macro calls

src/Node/BlockNode.php

@@ -42,7 +42,7 @@ class BlockNode extends Node
 
         $compiler
             ->subcompile($this->getNode('body'))
-            ->write("yield from [];\n")
+            ->write("return; yield;\n")
             ->outdent()
             ->write("}\n\n")
         ;

src/Node/CaptureNode.php

@@ -39,7 +39,7 @@ class CaptureNode extends Node
             ->raw("(function () use (&\$context, \$macros, \$blocks) {\n")
             ->indent()
             ->subcompile($this->getNode('body'))
-            ->write("yield from [];\n")
+            ->write("return; yield;\n")
             ->outdent()
             ->write('})()')
         ;

src/Node/ModuleNode.php

@@ -379,7 +379,7 @@ final class ModuleNode extends Node implements CoercesChildrenToStringInterface
         $compiler->subcompile($this->getNode('display_end'));
 
         if (!$this->hasNode('parent')) {
-            $compiler->write("yield from [];\n");
+            $compiler->write("return; yield;\n");
         }
 
         $compiler

tests/Node/BlockTest.php

@@ -49,7 +49,7 @@ public function block_foo(array \$context, array \$blocks = []): iterable
 {
     \$macros = \$this->macros;
     yield "foo";
-    yield from [];
+    return; yield;
 }
 EOF, new Environment(new ArrayLoader()),
         ];

tests/Node/MacroTest.php

@@ -77,7 +77,7 @@ new \\Twig\\TwigMacro("foo", function (\$foo = null, \$bar = "Foo", \$_underscor
 
     return ('' === \$tmp = implode('', iterator_to_array((function () use (&\$context, \$macros, \$blocks) {
         yield "foo";
-        yield from [];
+        return; yield;
     })(), false))) ? '' : new Markup(\$tmp, \$this->env->getCharset());
 }, ["foo" => true, "bar" => true, "_underscore" => true], false)
 EOF, new Environment(new ArrayLoader(), ['use_yield' => true]),
@@ -98,7 +98,7 @@ new \\Twig\\TwigMacro("foo", function (\$foo = null, \$bar = "Foo", \$_underscor
 
     return ('' === \$tmp = \\Twig\\Extension\\CoreExtension::captureOutput((function () use (&\$context, \$macros, \$blocks) {
         yield "foo";
-        yield from [];
+        return; yield;
     })())) ? '' : new Markup(\$tmp, \$this->env->getCharset());
 }, ["foo" => true, "bar" => true, "_underscore" => true], false)
 EOF, new Environment(new ArrayLoader(), ['use_yield' => false]),

tests/Node/MacrosTest.php

@@ -74,7 +74,7 @@ protected function loadDeclaredMacros(): array
 
             return ('' === \$tmp = implode('', iterator_to_array((function () use (&\$context, \$macros, \$blocks) {
                 yield "foo";
-                yield from [];
+                return; yield;
             })(), false))) ? '' : new Markup(\$tmp, \$this->env->getCharset());
         }, ["foo" => true], false),
     ];

tests/Node/ModuleTest.php

@@ -159,7 +159,7 @@ class __TwigTemplate_%x extends Template
         \$macros = \$this->macros;
         // line 1
         yield "foo";
-        yield from [];
+        return; yield;
     }
 
     /**

tests/Node/SetTest.php

@@ -65,7 +65,7 @@ EOF
 // line 1
 \$context["foo"] = ('' === \$tmp = implode('', iterator_to_array((function () use (&\$context, \$macros, \$blocks) {
     yield "foo";
-    yield from [];
+    return; yield;
 })(), false))) ? '' : new Markup(\$tmp, \$this->env->getCharset());
 EOF, new Environment(new ArrayLoader(), ['use_yield' => true]),
         ];
@@ -74,7 +74,7 @@ EOF, new Environment(new ArrayLoader(), ['use_yield' => true]),
 // line 1
 $context["foo"] = ('' === $tmp = \Twig\Extension\CoreExtension::captureOutput((function () use (&$context, $macros, $blocks) {
     yield "foo";
-    yield from [];
+    return; yield;
 })())) ? '' : new Markup($tmp, $this->env->getCharset());
 EOF, new Environment(new ArrayLoader(), ['use_yield' => false]),
         ];