Fix #588 - allow anonymous classes to call $this functions

src/Psalm/Checker/Statements/Expression/Call/MethodCallChecker.php

@@ -59,7 +59,7 @@ class MethodCallChecker extends \Psalm\Checker\Statements\Expression\CallChecker
         $method_id = null;
 
         if ($stmt->var instanceof PhpParser\Node\Expr\Variable) {
-            if (is_string($stmt->var->name) && $stmt->var->name === 'this' && !$statements_checker->getClassName()) {
+            if (is_string($stmt->var->name) && $stmt->var->name === 'this' && !$statements_checker->getFQCLN()) {
                 if (IssueBuffer::accepts(
                     new InvalidScope(
                         'Use of $this in non-class context',

src/Psalm/Checker/StatementsChecker.php

@@ -438,7 +438,7 @@ class StatementsChecker extends SourceChecker implements StatementsSource
                 }
             } elseif ($stmt instanceof PhpParser\Node\Stmt\Class_) {
                 try {
-                    $class_checker = (new ClassChecker($stmt, $this->source, $stmt->name));
+                    $class_checker = new ClassChecker($stmt, $this->source, $stmt->name);
                     $class_checker->analyze(null, $global_context);
                 } catch (\InvalidArgumentException $e) {
                     // disregard this exception, we'll likely see it elsewhere in the form

tests/Php70Test.php

@@ -157,6 +157,18 @@ class Php70Test extends TestCase
                         public function foo2(): void {} // commenting this line out fixes
                     }',
             ],
+            'anonymousClassExtendsWithThis' => [
+                '<?php
+                    class A {
+                        public function foo() : void {}
+                    }
+                    $class = new class extends A {
+                        public function f(): int {
+                            $this->foo();
+                            return 42;
+                        }
+                    };',
+            ],
             'returnAnonymousClass' => [
                 '<?php
                     /** @return object */