Is operator array structure support for ArrayAccess

arrayaccess.diff

diff --git a/src/main/php/lang/ast/syntax/php/IsOperator.class.php b/src/main/php/lang/ast/syntax/php/IsOperator.class.php
index 30832b5..bb1048e 100755
--- a/src/main/php/lang/ast/syntax/php/IsOperator.class.php
+++ b/src/main/php/lang/ast/syntax/php/IsOperator.class.php
@@ -250,24 +250,29 @@ class IsOperator implements Extension {
         }
         return $compound;
       } else if ($pattern instanceof IsArrayStructure) {
-        $compound= new BinaryExpression(
-          new InvokeExpression(new Literal('is_array'), [$init]),
-          '&&',
-          new BinaryExpression(
-            new InvokeExpression(new Literal('sizeof'), [$use]),
-            $pattern->rest ? '>=' : '===',
-            new Literal((string)sizeof($pattern->patterns))
-          )
+        $size= new BinaryExpression(
+          new InvokeExpression(new Literal('sizeof'), [$use]),
+          $pattern->rest ? '>=' : '===',
+          new Literal((string)sizeof($pattern->patterns))
         );
+        $arrays= new BinaryExpression(new InvokeExpression(new Literal('is_array'), [$init]), '&&', $size);
+        $objects= new BinaryExpression(new InstanceOfExpression($init, new IsValue('ArrayAccess')), '&&', $size);
+
         foreach ($pattern->patterns as $key => $p) {
           $offset= new Literal((string)$key);
-          $compound= new BinaryExpression($compound, '&&', new BinaryExpression(
+          $apply= $match($codegen, new OffsetExpression($use, $offset), $p);
+          $arrays= new BinaryExpression($arrays, '&&', new BinaryExpression(
             new InvokeExpression(new Literal('array_key_exists'), [$offset, $use]),
             '&&',
-            $match($codegen, new OffsetExpression($use, $offset), $p),
+            $apply,
+          ));
+          $objects= new BinaryExpression($objects, '&&', new BinaryExpression(
+            new InvokeExpression(new InstanceExpression($use, new Literal('offsetExists')), [$offset]),
+            '&&',
+            $apply,
           ));
         }
-        return $compound;
+        return new Braced(new BinaryExpression($arrays, '||', $objects));
       }
 
       // Should be unreachable
diff --git a/src/test/php/lang/ast/syntax/php/unittest/ArrayStructureTest.class.php b/src/test/php/lang/ast/syntax/php/unittest/ArrayStructureTest.class.php
index 32c1603..2454ebe 100755
--- a/src/test/php/lang/ast/syntax/php/unittest/ArrayStructureTest.class.php
+++ b/src/test/php/lang/ast/syntax/php/unittest/ArrayStructureTest.class.php
@@ -63,4 +63,24 @@ class ArrayStructureTest extends EmittingTest {
       }
     }'));
   }
+
+  #[Test, Values(['$this', 'new ArrayObject([1, 2, 3])'])]
+  public function integrates_with_array_access($expr) {
+    Assert::equals([1, 2, 3], $this->run('class %T implements ArrayAccess, Countable {
+
+      public function count() { return 3; }
+
+      public function offsetExists($i) { return true; }
+
+      public function offsetGet($i) { return $i + 1; }
+
+      public function offsetSet($i, $value) { /* NOOP */ }
+
+      public function offsetUnset($i) { /* NOOP */ }
+
+      public function run() {
+        return '.$expr.' is [$a, $b, $c] ? [$a, $b, $c] : null;
+      }
+    }'));
+  }
 }
\ No newline at end of file