diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php
index 7e59c0527..c4520f937 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php
@@ -290,8 +290,12 @@ class NonDivArithmeticOpAnalyzer
     ): ?Type\Union {
         if ($left_type_part instanceof TLiteralInt
             && $right_type_part instanceof TLiteralInt
-            && ($left instanceof PhpParser\Node\Scalar || $left instanceof PhpParser\Node\Expr\ConstFetch)
-            && ($right instanceof PhpParser\Node\Scalar || $right instanceof PhpParser\Node\Expr\ConstFetch)
+            && ($left instanceof PhpParser\Node\Scalar
+                || $left instanceof PhpParser\Node\Expr\ConstFetch
+                || $left instanceof PhpParser\Node\Expr\ClassConstFetch)
+            && ($right instanceof PhpParser\Node\Scalar
+                || $right instanceof PhpParser\Node\Expr\ConstFetch
+                || $right instanceof PhpParser\Node\Expr\ClassConstFetch)
         ) {
             // time for some arithmetic!
 
diff --git a/src/Psalm/Internal/Type/Comparator/ScalarTypeComparator.php b/src/Psalm/Internal/Type/Comparator/ScalarTypeComparator.php
index 19d1efef6..27da36a43 100644
--- a/src/Psalm/Internal/Type/Comparator/ScalarTypeComparator.php
+++ b/src/Psalm/Internal/Type/Comparator/ScalarTypeComparator.php
@@ -272,6 +272,12 @@ class ScalarTypeComparator
             return true;
         }
 
+        if (get_class($container_type_part) === TInt::class
+            && $input_type_part instanceof TInt
+        ) {
+            return true;
+        }
+
         if ((get_class($input_type_part) === TInt::class && $container_type_part instanceof TLiteralInt)
             || (get_class($input_type_part) === TPositiveInt::class
                 && $container_type_part instanceof TLiteralInt
diff --git a/src/Psalm/Internal/Type/TypeExpander.php b/src/Psalm/Internal/Type/TypeExpander.php
index df5c11f72..4d4c18cd6 100644
--- a/src/Psalm/Internal/Type/TypeExpander.php
+++ b/src/Psalm/Internal/Type/TypeExpander.php
@@ -379,7 +379,46 @@ class TypeExpander
                     $final
                 );
 
-                if (\is_array($new_value_type) || !$new_value_type instanceof Type\Atomic\TLiteralInt) {
+                if (\is_array($new_value_type)) {
+                    $new_value_type = reset($new_value_type);
+                }
+
+                if (!$new_value_type instanceof Type\Atomic\TLiteralInt) {
+                    return new Type\Atomic\TInt();
+                }
+
+                $potential_ints[] = $new_value_type->value;
+            }
+
+            return \Psalm\Internal\Type\TypeParser::getComputedIntsFromMask($potential_ints);
+        }
+
+        if ($return_type instanceof Type\Atomic\TIntMaskOf) {
+            if (!$evaluate_class_constants) {
+                return new Type\Atomic\TInt();
+            }
+
+            $value_type = $return_type->value;
+
+            $new_value_types = self::expandAtomic(
+                $codebase,
+                $value_type,
+                $self_class,
+                $static_class_type,
+                $parent_class,
+                $evaluate_class_constants,
+                $evaluate_conditional_types,
+                $final
+            );
+
+            if (!is_array($new_value_types)) {
+                return new Type\Atomic\TInt();
+            }
+
+            $potential_ints = [];
+
+            foreach ($new_value_types as $new_value_type) {
+                if (!$new_value_type instanceof Type\Atomic\TLiteralInt) {
                     return new Type\Atomic\TInt();
                 }
 
diff --git a/tests/AnnotationTest.php b/tests/AnnotationTest.php
index 3da9826a3..3a3c4ece8 100644
--- a/tests/AnnotationTest.php
+++ b/tests/AnnotationTest.php
@@ -1143,6 +1143,40 @@ class AnnotationTest extends TestCase
                     /** @var DateTime $obj */
                     echo $obj->format("Y");'
             ],
+            'intMaskWithClassConstants' => [
+                '<?php
+                    class FileFlag {
+                        public const OPEN = 1;
+                        public const MODIFIED = 2;
+                        public const NEW = 4;
+                    }
+
+                    /**
+                     * @param int-mask<FileFlag::OPEN, FileFlag::MODIFIED, FileFlag::NEW> $flags
+                     */
+                    function takesFlags(int $flags) : void {
+                        echo $flags;
+                    }
+
+                    takesFlags(FileFlag::MODIFIED | FileFlag::NEW);'
+            ],
+            'intMaskOfWithClassWildcard' => [
+                '<?php
+                    class FileFlag {
+                        public const OPEN = 1;
+                        public const MODIFIED = 2;
+                        public const NEW = 4;
+                    }
+
+                    /**
+                     * @param int-mask-of<FileFlag::*> $flags
+                     */
+                    function takesFlags(int $flags) : void {
+                        echo $flags;
+                    }
+
+                    takesFlags(FileFlag::MODIFIED | FileFlag::NEW);'
+            ],
         ];
     }
 
diff --git a/tests/Php56Test.php b/tests/Php56Test.php
index cdc1f786d..352021387 100644
--- a/tests/Php56Test.php
+++ b/tests/Php56Test.php
@@ -49,8 +49,8 @@ class Php56Test extends TestCase
                     $c4 = (new C)->four;',
                 'assertions' => [
                     '$c1' => 'int',
-                    '$c2' => 'positive-int',
-                    '$c3' => 'positive-int',
+                    '$c2===' => 'int(2)',
+                    '$c3===' => 'int(3)',
                     '$c1_3rd' => 'float|int',
                     '$c_sentence' => 'string',
                     '$cf' => 'int',