diff --git a/ftplugin/markdown.vim b/ftplugin/markdown.vim
index 80b082e..6c403a7 100644
--- a/ftplugin/markdown.vim
+++ b/ftplugin/markdown.vim
@@ -28,7 +28,7 @@ if !exists("g:no_plugin_maps") && !exists("g:no_markdown_maps")
 endif
 
 function! s:NotCodeBlock(lnum) abort
-  return synIDattr(synID(v:lnum, 1, 1), 'name') !=# 'markdownCode'
+  return synIDattr(synID(a:lnum, 1, 1), 'name') !=# 'markdownCode'
 endfunction
 
 function! MarkdownFold() abort