diff --git a/src/Psalm/CallMap.php b/src/Psalm/CallMap.php
index da548f44e..e074a2595 100644
--- a/src/Psalm/CallMap.php
+++ b/src/Psalm/CallMap.php
@@ -5456,7 +5456,7 @@ return [
 'is_uploaded_file' => ['bool', 'path'=>'string'],
 'is_writable' => ['bool', 'filename'=>'string'],
 'is_writeable' => ['bool', 'filename'=>'string'],
-'isset' => ['bool', 'var'=>'mixed', 'rest='=>'...mixed='],
+'isset' => ['bool', 'var'=>'mixed', '...rest='=>'mixed'],
 'Iterator::current' => ['mixed'],
 'Iterator::key' => ['int|string'],
 'Iterator::next' => ['void'],
@@ -6375,7 +6375,7 @@ return [
 'MongoCollection::getWriteConcern' => ['array'],
 'MongoCollection::group' => ['array', 'keys'=>'mixed', 'initial'=>'array', 'reduce'=>'mongocode', 'options='=>'array'],
 'MongoCollection::insert' => ['bool|array', 'a'=>'array', 'options='=>'array'],
-'MongoCollection::parallelCollectionScan' => ['array[MongoCommandCursor]', 'num_cursors'=>'int'],
+'MongoCollection::parallelCollectionScan' => ['MongoCommandCursor[]', 'num_cursors'=>'int'],
 'MongoCollection::remove' => ['bool|array', 'criteria='=>'array', 'options='=>'array'],
 'MongoCollection::save' => ['mixed', 'a'=>'array', 'options='=>'array'],
 'MongoCollection::setReadPreference' => ['bool', 'read_preference'=>'string', 'tags='=>'array'],
@@ -8074,7 +8074,7 @@ return [
 'pcntl_get_last_error' => ['int'],
 'pcntl_getpriority' => ['int', 'pid='=>'int', 'process_identifier='=>'int'],
 'pcntl_setpriority' => ['bool', 'priority'=>'int', 'pid='=>'int', 'process_identifier='=>'int'],
-'pcntl_signal' => ['bool', 'signo'=>'int', 'handle'=>'(callable(mixed...):void)|int', 'restart_syscalls='=>'bool'],
+'pcntl_signal' => ['bool', 'signo'=>'int', 'handle'=>'callable(mixed...):void|int', 'restart_syscalls='=>'bool'],
 'pcntl_signal_dispatch' => ['bool'],
 'pcntl_signal_get_handler' => ['int|string', 'signo'=>'int'],
 'pcntl_sigprocmask' => ['bool', 'how'=>'int', 'set'=>'array', '&w_oldset='=>'array'],
diff --git a/src/Psalm/Type/ParseTree.php b/src/Psalm/Type/ParseTree.php
index c5a5c78b0..66bd33c78 100644
--- a/src/Psalm/Type/ParseTree.php
+++ b/src/Psalm/Type/ParseTree.php
@@ -252,6 +252,11 @@ class ParseTree
                 case '|':
                     $current_parent = $current_leaf->parent;
 
+                    if ($current_parent instanceof ParseTree\CallableWithReturnTypeTree) {
+                        $current_leaf = $current_parent;
+                        $current_parent = $current_parent->parent;
+                    }
+
                     if ($current_leaf instanceof ParseTree\UnionTree) {
                         throw new TypeParseTreeException('Unexpected token ' . $type_token);
                     }
diff --git a/tests/TypeParseTest.php b/tests/TypeParseTest.php
index 22dc92c9a..369d5d658 100644
--- a/tests/TypeParseTest.php
+++ b/tests/TypeParseTest.php
@@ -356,6 +356,14 @@ class TypeParseTest extends TestCase
         );
     }
 
+    public function testCallableOrInt()
+    {
+        $this->assertSame(
+            'callable(string):void|int',
+            (string)Type::parseString('callable(string):void|int')
+        );
+    }
+
     /**
      * @expectedException \Psalm\Exception\TypeParseTreeException
      *
@@ -457,4 +465,52 @@ class TypeParseTest extends TestCase
             (string)Type::parseString('callable(int, string)')
         );
     }
+
+    /**
+     * @dataProvider providerTestValidCallMapType
+     *
+     * @param string $expected
+     * @param array<int|string, string> $arr
+     *
+     * @return void
+     */
+    public function testValidCallMapType(
+        $return_type,
+        $param_type_1 = '',
+        $param_type_2 = '',
+        $param_type_3 = '',
+        $param_type_4 = ''
+    ) {
+        if ($return_type && $return_type !== 'void') {
+            \Psalm\Type::parseString($return_type);
+        }
+
+        if ($param_type_1 && $param_type_1 !== 'mixed') {
+            if (strpos($param_type_1, 'oci-') !== false) {
+                return;
+            }
+
+            \Psalm\Type::parseString($param_type_1);
+        }
+
+        if ($param_type_2 && $param_type_2 !== 'mixed') {
+            \Psalm\Type::parseString($param_type_2);
+        }
+
+        if ($param_type_3 && $param_type_3 !== 'mixed') {
+            \Psalm\Type::parseString($param_type_3);
+        }
+
+        if ($param_type_4 && $param_type_4 !== 'mixed') {
+            \Psalm\Type::parseString($param_type_4);
+        }
+    }
+
+    /**
+     * @return void
+     */
+    public function providerTestValidCallMapType()
+    {
+        return \Psalm\Codebase\CallMap::getCallMap();
+    }
 }