Fix #566 - check for abstract methods inheriting from non-abstract ones

src/Psalm/Checker/ClassChecker.php

@@ -782,7 +782,10 @@ class ClassChecker extends ClassLikeChecker
             $global_context ? clone $global_context : null
         );
 
-        if ($stmt->name !== '__construct' && $config->reportIssueInFile('InvalidReturnType', $source->getFilePath())) {
+        if ($stmt->name !== '__construct'
+            && $config->reportIssueInFile('InvalidReturnType', $source->getFilePath())
+            && $stmt->stmts !== null
+        ) {
             $return_type_location = null;
             $secondary_return_type_location = null;
 

src/Psalm/Checker/MethodChecker.php

@@ -392,6 +392,23 @@ class MethodChecker extends FunctionLikeChecker
             return null;
         }
 
+        if (!$guide_method_storage->abstract
+            && $implementer_method_storage->abstract
+            && !$implementer_classlike_storage->abstract
+        ) {
+            if (IssueBuffer::accepts(
+                new MethodSignatureMismatch(
+                    'Method ' . $cased_implementer_method_id . ' cannot be abstract when inherited method '
+                        . $cased_guide_method_id . ' is non-abstract',
+                    $code_location
+                )
+            )) {
+                return false;
+            }
+
+            return null;
+        }
+
         if ($guide_method_storage->signature_return_type) {
             $guide_signature_return_type = ExpressionChecker::fleshOutType(
                 $project_checker,

src/Psalm/Provider/FileStorageCacheProvider.php

@@ -27,6 +27,8 @@ class FileStorageCacheProvider
         $dependent_files = [
             $storage_dir . 'FileStorage.php',
             $storage_dir . 'FunctionLikeStorage.php',
+            $storage_dir . 'ClassLikeStorage.php',
+            $storage_dir . 'MethodStorage.php',
         ];
 
         foreach ($dependent_files as $dependent_file_path) {

src/Psalm/Storage/FunctionLikeStorage.php

@@ -67,11 +67,6 @@ class FunctionLikeStorage
      */
     public $returns_by_ref = false;
 
-    /**
-     * @var bool
-     */
-    public $abstract = false;
-
     /**
      * @var int
      */

src/Psalm/Storage/MethodStorage.php

@@ -20,6 +20,11 @@ class MethodStorage extends FunctionLikeStorage
      */
     public $final;
 
+    /**
+     * @var bool
+     */
+    public $abstract;
+
     /**
      * @var array<int, CodeLocation>
      */

src/psalter.php

@@ -102,6 +102,9 @@ $vendor_dir = getVendorDir($current_dir);
 
 $first_autoloader = requireAutoloaders($current_dir, isset($options['r']), $vendor_dir);
 
+// If XDebug is enabled, restart without it
+(new \Composer\XdebugHandler\XdebugHandler('PSALTER'))->check();
+
 $paths_to_check = getPathsToCheck(isset($options['f']) ? $options['f'] : null);
 
 if ($paths_to_check && count($paths_to_check) > 1) {

tests/MethodSignatureTest.php

@@ -430,6 +430,17 @@ class MethodSignatureTest extends TestCase
                     }',
                 'error_message' => 'MethodSignatureMismatch',
             ],
+            'abstractExtendsNonAbstractWithMethod' => [
+                '<?php
+                    class A {
+                        public function foo() : void {}
+                    }
+
+                    abstract class B extends A {
+                        abstract public function foo() : void;
+                    }',
+                'error_message' => 'MethodSignatureMismatch',
+            ],
         ];
     }
 }