Support (void)-casts

src/main/php/lang/ast/emit/PHP.class.php

@@ -259,7 +259,7 @@ protected function emitExpression($result, $expression) {
   }
 
   protected function emitCast($result, $cast) {
-    static $native= ['string' => true, 'int' => true, 'float' => true, 'bool' => true, 'array' => true, 'object' => true];
+    static $native= ['string' => true, 'int' => true, 'float' => true, 'bool' => true, 'array' => true, 'object' => true, 'void' => true];
 
     // Inline nullable checks using ternaries
     if ($cast->type instanceof IsNullable) {

src/main/php/lang/ast/emit/PHP74.class.php

@@ -21,6 +21,7 @@ class PHP74 extends PHP {
     OmitArgumentNames,
     OmitConstantTypes,
     ReadonlyClasses,
+    RemoveVoidCasts,
     RewriteBlockLambdaExpressions,
     RewriteCloneWith,
     RewriteEnums,

src/main/php/lang/ast/emit/PHP80.class.php

@@ -24,6 +24,7 @@ class PHP80 extends PHP {
     EmulatePipelines,
     OmitConstantTypes,
     ReadonlyClasses,
+    RemoveVoidCasts,
     RewriteBlockLambdaExpressions,
     RewriteCloneWith,
     RewriteDynamicClassConstants,

src/main/php/lang/ast/emit/PHP81.class.php

@@ -21,6 +21,7 @@
 class PHP81 extends PHP {
   use
     EmulatePipelines,
+    RemoveVoidCasts,
     RewriteBlockLambdaExpressions,
     RewriteCallableClone,
     RewriteCloneWith,

src/main/php/lang/ast/emit/PHP82.class.php

@@ -21,6 +21,7 @@
 class PHP82 extends PHP {
   use
     EmulatePipelines,
+    RemoveVoidCasts,
     RewriteBlockLambdaExpressions,
     RewriteCallableClone,
     RewriteCloneWith,

src/main/php/lang/ast/emit/PHP83.class.php

@@ -19,7 +19,14 @@
  * @see  https://wiki.php.net/rfc#php_83
  */
 class PHP83 extends PHP {
-  use EmulatePipelines, RewriteCallableClone, RewriteCloneWith, RewriteBlockLambdaExpressions, RewriteProperties;
+  use
+    EmulatePipelines,
+    RemoveVoidCasts,
+    RewriteCallableClone,
+    RewriteCloneWith,
+    RewriteBlockLambdaExpressions,
+    RewriteProperties
+  ;
 
   public $targetVersion= 80300;
 

src/main/php/lang/ast/emit/PHP84.class.php

@@ -19,7 +19,7 @@
  * @see  https://wiki.php.net/rfc#php_84
  */
 class PHP84 extends PHP {
-  use EmulatePipelines, RewriteCallableClone, RewriteCloneWith, RewriteBlockLambdaExpressions;
+  use EmulatePipelines, RemoveVoidCasts, RewriteCallableClone, RewriteCloneWith, RewriteBlockLambdaExpressions;
 
   public $targetVersion= 80400;
 

src/main/php/lang/ast/emit/RemoveVoidCasts.class.php

@@ -0,0 +1,17 @@
+<?php namespace lang\ast\emit;
+
+/**
+ * Removes (void) casts for any PHP version < 8.5
+ *
+ * @see  https://wiki.php.net/rfc/marking_return_value_as_important
+ */
+trait RemoveVoidCasts {
+
+  protected function emitCast($result, $cast) {
+    if ('void' === $cast->type->name()) {
+      $this->emitOne($result, $cast->expression);
+    } else {
+      parent::emitCast($result, $cast);
+    }
+  }
+}

src/test/php/lang/ast/unittest/emit/CastingTest.class.php

@@ -161,4 +161,16 @@ public function run($value) {
       $value
     ));
   }
+
+  #[Test, Values(['null', '$this', 'strlen("Test")'])]
+  public function void_cast($expr) {
+    Assert::true($this->run(
+      'class %T {
+        public function run() {
+          (void)'.$expr.';
+          return true;
+        }
+      }'
+    ));
+  }
 }