Support clone with unpack on PHP 7.4

Author: thekid

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

@@ -1,33 +1,35 @@
 <?php namespace lang\ast\emit;
 
-use lang\ast\nodes\{Signature, Parameter, UnpackExpression};
+use lang\ast\nodes\{ArrayLiteral, UnpackExpression};
 
 /** @see https://wiki.php.net/rfc/clone_with_v2 */
 trait RewriteCloneWith {
 
   protected function emitClone($result, $clone) {
+    static $wrapper= '(function($c, array $w) { foreach ($w as $p=>$v) { $c->$p=$v; } return $c;})';
+
     $expr= $clone->arguments['object'] ?? $clone->arguments[0] ?? null;
     $with= $clone->arguments['withProperties'] ?? $clone->arguments[1] ?? null;
 
-    // Wrap clone with, e.g. clone($x, ['id' => 6100]), inside an IIFE which
-    /// iterates over the property-value pairs, assigning them to the clone.
-    if ($with) {
-      $result->out->write('(function($object, array $withProperties) {');
-      $result->out->write('foreach ($withProperties as $p=>$v) { $object->$p=$v; } return $object;})(clone ');
+    // Built ontop of a wrapper function which iterates over the property-value pairs,
+    // assigning them to the clone. Unwind unpack statements, e.g. `clone(...$args)`,
+    // into an array, manually unpacking it for invocation.
+    if ($expr instanceof UnpackExpression || $with instanceof UnpackExpression) {
+      $t= $result->temp();
+      $result->out->write('('.$t.'=');
+      $this->emitOne($result, new ArrayLiteral($with ? [[null, $expr], [null, $with]] : [[null, $expr]], $clone->line));
+      $result->out->write(')?');
+      $result->out->write($wrapper.'(clone ('.$t.'["object"] ?? '.$t.'[0]), '.$t.'["withProperties"] ?? '.$t.'[1] ?? [])');
+      $result->out->write(':null');
+    } else if ($with) {
+      $result->out->write($wrapper.'(clone ');
       $this->emitOne($result, $expr);
       $result->out->write(',');
       $this->emitOne($result, $with);
       $result->out->write(')');
-    } else if (isset($clone->arguments['object'])) {
+    } else {
       $result->out->write('clone ');
       $this->emitOne($result, $expr);
-    } else if ($expr instanceof UnpackExpression) {
-      $result->out->write('(function($u) { $c= clone $u["object"] ?? $u[0];');
-      $result->out->write('foreach ($u["withProperties"] ?? $u[1] ?? [] as $p=>$v) { $c->$p=$v; } return $c;})(');
-      $this->emitOne($result, $expr->expression);
-      $result->out->write(')');
-    } else {
-      return parent::emitClone($result, $clone);
     }
   }
 }

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

@@ -108,6 +108,17 @@ public function run($in) {
     Assert::equals('<id: 2, name: Changed>', $clone->toString());
   }
 
+  #[Test]
+  public function clone_unpack_object_and_properties() {
+    $clone= $this->run('class %T {
+      public function run($in) {
+        return clone(...["object" => $in], ...["withProperties" => ["name" => "Changed"]]);
+      }
+    }', $this->fixture);
+
+    Assert::equals('<id: 2, name: Changed>', $clone->toString());
+  }
+
   #[Test]
   public function clone_unpack_only_properties() {
     $clone= $this->run('class %T {