From 2e2f2f4ffbfa6703174a5c153ba8841949471174 Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Mon, 16 Jan 2017 01:22:36 -0500
Subject: [PATCH] Add new suppressable error for missing closure return types

---
 config.xsd                                   |  1 +
 src/Psalm/Checker/FunctionLikeChecker.php    | 15 +++++++++++++++
 src/Psalm/Issue/MissingClosureReturnType.php |  6 ++++++
 tests/ClosureTest.php                        |  2 +-
 4 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 src/Psalm/Issue/MissingClosureReturnType.php

diff --git a/config.xsd b/config.xsd
index 6e2dce3b8..8a77b1224 100644
--- a/config.xsd
+++ b/config.xsd
@@ -102,6 +102,7 @@
             <xs:element name="InvalidToString" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MethodSignatureMismatch" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MisplacedRequiredParam" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="MissingClosureReturnType" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MissingPropertyDeclaration" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MissingPropertyType" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MissingReturnType" type="IssueHandlerType" minOccurs="0" />
diff --git a/src/Psalm/Checker/FunctionLikeChecker.php b/src/Psalm/Checker/FunctionLikeChecker.php
index 4b367903b..173453886 100644
--- a/src/Psalm/Checker/FunctionLikeChecker.php
+++ b/src/Psalm/Checker/FunctionLikeChecker.php
@@ -20,6 +20,7 @@ use Psalm\Issue\InvalidReturnType;
 use Psalm\Issue\InvalidToString;
 use Psalm\Issue\MethodSignatureMismatch;
 use Psalm\Issue\MisplacedRequiredParam;
+use Psalm\Issue\MissingClosureReturnType;
 use Psalm\Issue\MissingReturnType;
 use Psalm\Issue\MixedInferredReturnType;
 use Psalm\Issue\OverriddenMethodAccess;
@@ -785,6 +786,20 @@ abstract class FunctionLikeChecker extends SourceChecker implements StatementsSo
         }
 
         if (!$return_type && !$update_docblock && !$is_to_string) {
+            if ($this->function instanceof Closure) {
+                if (IssueBuffer::accepts(
+                    new MissingClosureReturnType(
+                        'Closure does not have a return type',
+                        new CodeLocation($this, $this->function, true)
+                    ),
+                    $this->suppressed_issues
+                )) {
+                    // fall through
+                }
+
+                return null;
+            }
+
             if (IssueBuffer::accepts(
                 new MissingReturnType(
                     'Method ' . $cased_method_id . ' does not have a return type',
diff --git a/src/Psalm/Issue/MissingClosureReturnType.php b/src/Psalm/Issue/MissingClosureReturnType.php
new file mode 100644
index 000000000..019a059bf
--- /dev/null
+++ b/src/Psalm/Issue/MissingClosureReturnType.php
@@ -0,0 +1,6 @@
+<?php
+namespace Psalm\Issue;
+
+class MissingClosureReturnType extends CodeError
+{
+}
diff --git a/tests/ClosureTest.php b/tests/ClosureTest.php
index b0fae2728..f2c410845 100644
--- a/tests/ClosureTest.php
+++ b/tests/ClosureTest.php
@@ -126,7 +126,7 @@ class ClosureTest extends PHPUnit_Framework_TestCase
 
         $bam = array_map(
             /**
-             * @psalm-suppress MissingReturnType
+             * @psalm-suppress MissingClosureReturnType
              */
             function(string $a) {
                 return $a . "blah";