Resolve type incompatibilities

I don't know whether PHP Parser changed or we always had an interesting
situation, but phpstan pointed out that the TypeFactory contained a type
incompatibility. I have resolved that and made the stringifying code
recursive because an intersection type may contain another intersection
type, etc, etc.

src/phpDocumentor/Reflection/Php/Factory/ClassConstantIterator.php

@@ -22,6 +22,8 @@
 /**
  * This class acts like a combination of a ClassConst and Const_
  * to be able to create constant descriptors using a normal strategy.
+ *
+ * @implements Iterator<int, ClassConstantIterator>
  */
 final class ClassConstantIterator implements Iterator
 {

src/phpDocumentor/Reflection/Php/Factory/GlobalConstantIterator.php

@@ -19,6 +19,9 @@
 use PhpParser\Node\Expr;
 use PhpParser\Node\Stmt\Const_;
 
+/**
+ * @implements Iterator<int, GlobalConstantIterator>
+ */
 final class GlobalConstantIterator implements Iterator
 {
     private Const_ $constant;

src/phpDocumentor/Reflection/Php/Factory/PropertyIterator.php

@@ -25,6 +25,8 @@
 /**
  * This class acts like a combination of a PropertyNode and PropertyProperty to
  * be able to create property descriptors using a normal strategy.
+ *
+ * @implements Iterator<int, PropertyIterator>
  */
 final class PropertyIterator implements Iterator
 {

src/phpDocumentor/Reflection/Php/Factory/Type.php

@@ -23,9 +23,12 @@
 use PhpParser\Node\Name;
 use PhpParser\Node\NullableType;
 use PhpParser\Node\UnionType;
+use PhpParser\NodeAbstract;
 
+use function array_map;
 use function get_class;
 use function implode;
+use function is_string;
 use function sprintf;
 
 final class Type
@@ -39,23 +42,49 @@ public function fromPhpParser($type, ?Context $context = null): ?TypeElement
             return null;
         }
 
-        $typeResolver = new TypeResolver();
+        return (new TypeResolver())
+            ->resolve($this->convertPhpParserTypeToString($type), $context);
+    }
+
+    /**
+     * @param NodeAbstract|string $type
+     */
+    private function convertPhpParserTypeToString($type): string
+    {
+        if (is_string($type)) {
+            return $type;
+        }
+
+        if ($type instanceof Identifier) {
+            return $type->toString();
+        }
+
+        if ($type instanceof Name) {
+            return $type->toString();
+        }
+
         if ($type instanceof NullableType) {
-            return $typeResolver->resolve('?' . $type->type, $context);
+            return '?' . $this->convertPhpParserTypeToString($type->type);
         }
 
         if ($type instanceof UnionType) {
-            return $typeResolver->resolve(implode('|', $type->types), $context);
+            $typesAsStrings = array_map(
+                fn ($typeObject): string => $this->convertPhpParserTypeToString($typeObject),
+                $type->types
+            );
+
+            return implode('|', $typesAsStrings);
         }
 
         if ($type instanceof IntersectionType) {
-            return $typeResolver->resolve(implode('&', $type->types), $context);
-        }
+            $typesAsStrings = array_map(
+                fn ($typeObject): string => $this->convertPhpParserTypeToString($typeObject),
+                $type->types
+            );
 
-        if ($type instanceof ComplexType) {
-            throw new InvalidArgumentException(sprintf('Unsupported complex type %s', get_class($type)));
+            return implode('&', $typesAsStrings);
         }
 
-        return $typeResolver->resolve($type->toString(), $context);
+        throw new InvalidArgumentException(sprintf('Unsupported complex type %s', get_class($type)));
     }
 }

tests/unit/phpDocumentor/Reflection/Php/Factory/TypeTest.php

@@ -78,7 +78,7 @@ public function testReturnsNullableTypeWhenPassedAPhpParserNullable(): void
     public function testReturnsUnion(): void
     {
         $factory = new Type();
-        $given = new UnionType(['integer', 'string']);
+        $given = new UnionType([new Identifier('integer'), new Identifier('string')]);
         $expected = new Compound([new Integer(), new String_()]);
 
         $result = $factory->fromPhpParser($given);