From fe033f1b6c591eb93721f4643cf1b000af2cf98a Mon Sep 17 00:00:00 2001
From: Matt Brown <github@muglug.com>
Date: Tue, 10 Apr 2018 13:05:31 -0400
Subject: [PATCH] Fix #663 - infer array return types for closures

---
 src/Psalm/Checker/FunctionLikeChecker.php | 40 +++++++++++++----------
 tests/CallableTest.php                    | 36 ++++++++++++++++++++
 2 files changed, 58 insertions(+), 18 deletions(-)

diff --git a/src/Psalm/Checker/FunctionLikeChecker.php b/src/Psalm/Checker/FunctionLikeChecker.php
index e7fe56451..3bbb31cc8 100644
--- a/src/Psalm/Checker/FunctionLikeChecker.php
+++ b/src/Psalm/Checker/FunctionLikeChecker.php
@@ -481,31 +481,35 @@ abstract class FunctionLikeChecker extends SourceChecker implements StatementsSo
                 $storage->return_type_location
             );
 
-            if ($this->function->inferredType
-                && (!$storage->return_type
+            $closure_yield_types = [];
+
+            $closure_return_types = EffectsAnalyser::getReturnTypes(
+                $this->function->stmts,
+                $closure_yield_types,
+                $ignore_nullable_issues,
+                $ignore_falsable_issues,
+                true
+            );
+
+            if ($closure_return_types) {
+                $closure_return_type = new Type\Union($closure_return_types);
+
+                if (!$storage->return_type
                     || $storage->return_type->isMixed()
                     || TypeChecker::isContainedBy(
                         $project_checker->codebase,
-                        $this->function->inferredType,
+                        $closure_return_type,
                         $storage->return_type
                     )
-                )
-            ) {
-                $closure_yield_types = [];
-                $closure_return_types = EffectsAnalyser::getReturnTypes(
-                    $this->function->stmts,
-                    $closure_yield_types,
-                    $ignore_nullable_issues,
-                    $ignore_falsable_issues,
-                    true
-                );
-
-                if ($closure_return_types && $this->function->inferredType) {
-                    /** @var Type\Atomic\Fn */
-                    $closure_atomic = $this->function->inferredType->getTypes()['Closure'];
-                    $closure_atomic->return_type = new Type\Union($closure_return_types);
+                ) {
+                    if ($this->function->inferredType) {
+                        /** @var Type\Atomic\Fn */
+                        $closure_atomic = $this->function->inferredType->getTypes()['Closure'];
+                        $closure_atomic->return_type = $closure_return_type;
+                    }
                 }
             }
+
         }
 
         if ($context->collect_references
diff --git a/tests/CallableTest.php b/tests/CallableTest.php
index 36f081588..8a9675906 100644
--- a/tests/CallableTest.php
+++ b/tests/CallableTest.php
@@ -431,6 +431,42 @@ class CallableTest extends TestCase
                 ],
                 'error_levels' => ['MissingClosureReturnType'],
             ],
+            'inferArrayMapReturnTypeWithoutTypehints' => [
+                '<?php
+                    /**
+                     * @param array{0:string,1:string}[] $ret
+                     * @return array{0:string,1:int}[]
+                     */
+                    function f(array $ret) : array
+                    {
+                        return array_map(
+                          function (array $row) {
+                            return [
+                                strval($row[0]),
+                                intval($row[1]),
+                            ];
+                        }, $ret);
+                    }',
+                'assertions' => [],
+                'error_levels' => ['MissingClosureReturnType'],
+            ],
+            'inferArrayMapReturnTypeWithTypehints' => [
+                '<?php
+                    /**
+                     * @param array{0:string,1:string}[] $ret
+                     * @return array{0:string,1:int}[]
+                     */
+                    function f(array $ret): array
+                    {
+                        return array_map(
+                          function (array $row): array {
+                            return [
+                                strval($row[0]),
+                                intval($row[1]),
+                            ];
+                        }, $ret);
+                    }',
+            ],
         ];
     }