Fix promotion for by-reference arguments

ChangeLog.md

@@ -3,6 +3,10 @@ XP Compiler ChangeLog
 
 ## ?.?.? / ????-??-??
 
+## 5.1.2 / 2020-04-04
+
+* Fixed promotion for by-reference arguments - @thekid
+
 ## 5.1.1 / 2020-03-29
 
 * Fixed ternary and instanceof operators' precedence - @thekid

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

@@ -406,7 +406,7 @@ protected function emitMethod($result, $method) {
     foreach ($method->signature->parameters as $param) {
       if (isset($param->promote)) {
         $declare.= $param->promote.' $'.$param->name.';';
-        $promote.= '$this->'.$param->name.'= $'.$param->name.';';
+        $promote.= '$this->'.$param->name.'= '.($param->reference ? '&$' : '$').$param->name.';';
         $result->meta[0][self::PROPERTY][$param->name]= [
           DETAIL_RETURNS     => $param->type ? $param->type->name() : 'var',
           DETAIL_ANNOTATIONS => [],

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

@@ -42,6 +42,22 @@ public function run() {
     Assert::equals('tested', $r);
   }
 
+  #[@test]
+  public function parameter_accessible() {
+    $r= $this->run('class <T> {
+      public function __construct(private $id= "test") {
+        if (null === $id) {
+          throw new \\lang\\IllegalArgumentException("ID not set");
+        }
+      }
+
+      public function run() {
+        return $this->id;
+      }
+    }');
+    Assert::equals('test', $r);
+  }
+
   #[@test]
   public function in_method() {
     $r= $this->run('class <T> {
@@ -85,4 +101,20 @@ public function __construct(public string $name, string $initial= null) {
     Assert::equals(['name'], array_map(function($f) { return $f->getName(); }, $t->getFields()));
     Assert::equals('Timm J.', $t->newInstance('Timm', 'J')->name);
   }
+
+  #[@test]
+  public function promoted_by_reference_argument() {
+    $t= $this->type('class <T> {
+      public function __construct(public array &$list) { }
+
+      public static function test() {
+        $list= [1, 2, 3];
+        $self= new self($list);
+        $list[]= 4;
+        return $self->list;
+      }
+    }');
+
+    Assert::equals([1, 2, 3, 4], $t->getMethod('test')->invoke(null, []));
+  }
 }