WIP resolve return self better

fixtures/completion/method_return_self.php

@@ -0,0 +1,11 @@
+<?php
+
+class FooClass {
+    public function foo(): self {
+        return $this;
+    }
+}
+
+$fc = new FooClass();
+$foo = $fc->foo();
+$foo->

fixtures/completion/static_method_return_type.php

@@ -1,7 +1,7 @@
 <?php
 
 class FooClass {
-    public static function staticFoo(): FooClass {
+    public static function staticFoo(): self {
         return new FooClass();
     }
 

src/DefinitionResolver.php

@@ -699,7 +699,7 @@ class DefinitionResolver
                     foreach ($classDef->getAncestorDefinitions($this->index, true) as $fqn => $def) {
                         $def = $this->index->getDefinition($fqn . $add);
                         if ($def !== null) {
-                            if ($def->type instanceof Types\This) {
+                            if ($def->type instanceof Types\This || $def->type instanceof Types\Self_) {
                                 return new Types\Object_(new Fqsen('\\' . $classFqn));
                             }
                             return $def->type;
@@ -727,6 +727,9 @@ class DefinitionResolver
             if ($def === null) {
                 return new Types\Mixed_;
             }
+            if ($def->type instanceof Types\Self_) {
+                return new Types\Object_($classType->getFqsen());
+            }
             return $def->type;
         }
 
@@ -1060,6 +1063,8 @@ class DefinitionResolver
                 if ($node->returnType instanceof PhpParser\Token) {
                     // Resolve a string like "bool" to a type object
                     return $this->typeResolver->resolve($node->returnType->getText($node->getFileContents()));
+                } elseif ($node->returnType->getResolvedName() === 'self') {
+                    return new Types\Self_();
                 }
                 return new Types\Object_(new Fqsen('\\' . (string)$node->returnType->getResolvedName()));
             }

tests/Server/TextDocument/CompletionTest.php

@@ -576,6 +576,28 @@ class CompletionTest extends TestCase
         ], true), $items);
     }
 
+    public function testMethodReturnSelf()
+    {
+        $completionUri = pathToUri(__DIR__ . '/../../../fixtures/completion/method_return_self.php');
+        $this->loader->open($completionUri, file_get_contents($completionUri));
+        $items = $this->textDocument->completion(
+            new TextDocumentIdentifier($completionUri),
+            new Position(10, 6)
+        )->wait();
+        $this->assertCompletionsListSubset(new CompletionList([
+            new CompletionItem(
+                'foo',
+                CompletionItemKind::METHOD,
+                'self',
+                null,
+                null,
+                null,
+                null,
+                null
+            )
+        ], true), $items);
+    }
+
     public function testStaticMethodReturnType()
     {
         $completionUri = pathToUri(__DIR__ . '/../../../fixtures/completion/static_method_return_type.php');