Support extending from generic base classes / parent interfaces

Author: thekid

ChangeLog.md

@@ -3,6 +3,9 @@ XP generics for PHP - ChangeLog
 
 ## ?.?.? / ????-??-??
 
+* Supported extending from generic base classes / parent interfaces
+  Requires https://github.com/xp-framework/core/releases/tag/v11.4.6
+  (@thekid)
 * Added support for declaring and implementing generic interfaces
   (@thekid)
 

src/main/php/lang/ast/syntax/php/Generics.class.php

@@ -214,6 +214,15 @@ public function setup($language, $emitter) {
       if ($node->name instanceof IsGeneric) {
         $values= [];
 
+        // Rewrite if parent class is generic
+        if ($node->parent instanceof IsGeneric) {
+          $values[]= [
+            new Literal("'parent'"),
+            new Literal("'".self::components($node->parent->components)."'")
+          ];
+          $node->parent= $node->parent->base;
+        }
+
         // Rewrite if any of the interfaces is generic
         $implements= [0, []];
         foreach ($node->implements as $i => &$interface) {
@@ -233,7 +242,22 @@ public function setup($language, $emitter) {
     });
     $emitter->transform('interface', function($codegen, $node) {
       if ($node->name instanceof IsGeneric) {
-        return self::type($node, []);
+        $values= [];
+
+        // Rewrite if any of the parent interfaces is generic
+        $implements= [0, []];
+        foreach ($node->parents as $i => &$interface) {
+          if ($interface instanceof IsGeneric) {
+            $implements[1][]= [null, new Literal("'".self::components($interface->components)."'")];
+            $implements[0]= true;
+            $interface= $interface->base;
+          } else {
+            $implements[1][]= [null, new Literal('null')];
+          }
+        }
+        $implements[0] && $values[]= [new Literal("'extends'"), new ArrayLiteral($implements[1])];
+
+        return self::type($node, $values);
       }
       return $node;
     });

src/test/php/lang/ast/syntax/php/unittest/GenericsTest.class.php

@@ -45,6 +45,24 @@ public function implements_generic_interface() {
     Assert::equals([$c], $t->newGenericType([$c])->getInterfaces()[0]->genericArguments());
   }
 
+  #[Test]
+  public function extends_generic_base_class() {
+    $i= $this->type('abstract class <T><E> { }');
+    $t= $this->type('class <T><E> extends '.$i->getName().'<E> { }');
+
+    $c= Primitive::$STRING;
+    Assert::equals([$c], $t->newGenericType([$c])->getParentclass()->genericArguments());
+  }
+
+  #[Test]
+  public function extends_generic_interface() {
+    $i= $this->type('interface <T><E> { }');
+    $t= $this->type('interface <T><E> extends '.$i->getName().'<E> { }');
+
+    $c= Primitive::$STRING;
+    Assert::equals([$c], $t->newGenericType([$c])->getInterfaces()[0]->genericArguments());
+  }
+
   #[Test]
   public function new_creates_generic_types() {
     $r= $this->run('class <T><E> {