diff --git a/syntax/idris2.vim b/syntax/idris2.vim
index b3e7bfc..d13efba 100644
--- a/syntax/idris2.vim
+++ b/syntax/idris2.vim
@@ -14,6 +14,7 @@ syn match idrisTypeDecl "[a-zA-Z][a-zA-z0-9_']*\s\+:\s\+"
 syn region idrisParens matchgroup=idrisDelimiter start="(" end=")" contains=TOP,idrisTypeDecl
 syn region idrisBrackets matchgroup=idrisDelimiter start="\[" end="]" contains=TOP,idrisTypeDecl
 syn region idrisBlock matchgroup=idrisDelimiter start="{" end="}" contains=TOP,idrisTypeDecl
+syn region idrisIdiom matchgroup=idrisDelimiter start="\[|" end="|]" contains=TOP,idrisTypeDecl
 syn keyword idrisModule module namespace
 syn keyword idrisImport import
 syn keyword idrisStructure data record interface implementation