diff --git a/src/Psalm/Internal/PhpVisitor/Reflector/FunctionLikeDocblockParser.php b/src/Psalm/Internal/PhpVisitor/Reflector/FunctionLikeDocblockParser.php
index d230ce8dc..a82c01f6e 100644
--- a/src/Psalm/Internal/PhpVisitor/Reflector/FunctionLikeDocblockParser.php
+++ b/src/Psalm/Internal/PhpVisitor/Reflector/FunctionLikeDocblockParser.php
@@ -190,7 +190,7 @@ class FunctionLikeDocblockParser
 
                     $info->if_this_is = [
                         'type' => str_replace("\n", '', $line_parts[0]),
-                        'line_number' => $comment->getStartLine() + substr_count($comment_text, "\n", 0, $offset),
+                        'line_number' => $comment->getStartLine() + substr_count($comment_text, "\n", 0, $offset - $comment->getStartFilePos()),
                     ];
                 }
             }
diff --git a/tests/IfThisIsTest.php b/tests/IfThisIsTest.php
index 4316021f2..a17e6f806 100644
--- a/tests/IfThisIsTest.php
+++ b/tests/IfThisIsTest.php
@@ -9,7 +9,7 @@ class IfThisIsTest extends TestCase
     /**
      * @return iterable<string,array{string,assertions?:array<string,string>,error_levels?:string[]}>
      */
-    public function providerValidCodeParse()
+    public function providerValidCodeParse(): iterable
     {
         return [
             'worksAfterConvert' => [
@@ -114,7 +114,7 @@ class IfThisIsTest extends TestCase
     /**
      * @return array<string, array{0: string, error_message: string}>
      */
-    public function providerInvalidCodeParse()
+    public function providerInvalidCodeParse(): iterable
     {
         return [
             'blocksWithoutConvert' => [