From e6cf9e96dfada0065ae71f7e092c9a7e79f8a62f Mon Sep 17 00:00:00 2001
From: Brown <github@muglug.com>
Date: Wed, 17 Oct 2018 13:22:57 -0400
Subject: [PATCH] Add support for class concats when checking for callables

---
 .../Statements/Expression/CallChecker.php     | 20 ++++++++-
 tests/CallableTest.php                        | 42 ++++++++++++++++++-
 2 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/src/Psalm/Checker/Statements/Expression/CallChecker.php b/src/Psalm/Checker/Statements/Expression/CallChecker.php
index 34f87e7fa..0eba84246 100644
--- a/src/Psalm/Checker/Statements/Expression/CallChecker.php
+++ b/src/Psalm/Checker/Statements/Expression/CallChecker.php
@@ -1238,6 +1238,7 @@ class CallChecker
         if (!$closure_type instanceof Type\Atomic\Fn) {
             if (!$closure_arg->value instanceof PhpParser\Node\Scalar\String_
                 && !$closure_arg->value instanceof PhpParser\Node\Expr\Array_
+                && !$closure_arg->value instanceof PhpParser\Node\Expr\BinaryOp\Concat
             ) {
                 return;
             }
@@ -1720,6 +1721,7 @@ class CallChecker
             }
         } elseif ($input_expr instanceof PhpParser\Node\Scalar\String_
             || $input_expr instanceof PhpParser\Node\Expr\Array_
+            || $input_expr instanceof PhpParser\Node\Expr\BinaryOp\Concat
         ) {
             foreach ($param_type->getTypes() as $param_type_part) {
                 if ($param_type_part instanceof TClassString
@@ -1921,7 +1923,8 @@ class CallChecker
     }
 
     /**
-     * @param  PhpParser\Node\Scalar\String_|PhpParser\Node\Expr\Array_ $callable_arg
+     * @param  PhpParser\Node\Scalar\String_|PhpParser\Node\Expr\Array_|PhpParser\Node\Expr\BinaryOp\Concat
+     *         $callable_arg
      *
      * @return string[]
      */
@@ -1929,6 +1932,21 @@ class CallChecker
         \Psalm\FileSource $file_source,
         $callable_arg
     ) {
+        if ($callable_arg instanceof PhpParser\Node\Expr\BinaryOp\Concat) {
+            if ($callable_arg->left instanceof PhpParser\Node\Expr\ClassConstFetch
+                && $callable_arg->left->class instanceof PhpParser\Node\Name
+                && $callable_arg->left->name instanceof PhpParser\Node\Identifier
+                && strtolower($callable_arg->left->name->name) === 'class'
+                && !in_array(strtolower($callable_arg->left->class->parts[0]), ['self', 'static', 'parent'])
+                && $callable_arg->right instanceof PhpParser\Node\Scalar\String_
+                && preg_match('/^::[A-Za-z0-9]+$/', $callable_arg->right->value)
+            ) {
+                return [(string) $callable_arg->left->class->getAttribute('resolvedName') . $callable_arg->right->value];
+            }
+
+            return [];
+        }
+
         if ($callable_arg instanceof PhpParser\Node\Scalar\String_) {
             return [preg_replace('/^\\\/', '', $callable_arg->value)];
         }
diff --git a/tests/CallableTest.php b/tests/CallableTest.php
index 14135f948..11bde3bb2 100644
--- a/tests/CallableTest.php
+++ b/tests/CallableTest.php
@@ -129,6 +129,7 @@ class CallableTest extends TestCase
                     function foo(callable $c): void {}
 
                     foo("A::bar");
+                    foo(A::class . "::bar");
                     foo(["A", "bar"]);
                     foo([A::class, "bar"]);
                     $a = new A();
@@ -625,7 +626,7 @@ class CallableTest extends TestCase
                 'error_message' => 'InvalidFunctionCall',
                 'error_levels' => ['UndefinedClass'],
             ],
-            'undefinedCallableMethod' => [
+            'undefinedCallableMethodFullString' => [
                 '<?php
                     class A {
                         public static function bar(string $a): string {
@@ -638,6 +639,45 @@ class CallableTest extends TestCase
                     foo("A::barr");',
                 'error_message' => 'UndefinedMethod',
             ],
+            'undefinedCallableMethodClassConcat' => [
+                '<?php
+                    class A {
+                        public static function bar(string $a): string {
+                            return $a . "b";
+                        }
+                    }
+
+                    function foo(callable $c): void {}
+
+                    foo(A::class . "::barr");',
+                'error_message' => 'UndefinedMethod',
+            ],
+            'undefinedCallableMethodArray' => [
+                '<?php
+                    class A {
+                        public static function bar(string $a): string {
+                            return $a . "b";
+                        }
+                    }
+
+                    function foo(callable $c): void {}
+
+                    foo([A::class, "::barr"]);',
+                'error_message' => 'UndefinedMethod',
+            ],
+            'undefinedCallableMethodArrayWithoutClass' => [
+                '<?php
+                    class A {
+                        public static function bar(string $a): string {
+                            return $a . "b";
+                        }
+                    }
+
+                    function foo(callable $c): void {}
+
+                    foo(["A", "::barr"]);',
+                'error_message' => 'UndefinedMethod',
+            ],
             'undefinedCallableMethodClass' => [
                 '<?php
                     class A {