Index: mlir/utils/vim/syntax/mlir.vim
===================================================================
--- mlir/utils/vim/syntax/mlir.vim
+++ mlir/utils/vim/syntax/mlir.vim
@@ -84,12 +84,13 @@
 syn match   mlirFloat  /-\?\<\d\+\.\d*\(e[+-]\d\+\)\?\>/
 syn match   mlirFloat  /\<0x\x\+\>/
 syn keyword mlirBoolean true false
-syn match   mlirComment /\/\/.*$/
+" Spell checking is enabled only in comments by default.
+syn match   mlirComment /\/\/.*$/ contains=@Spell
 syn region  mlirString start=/"/ skip=/\\"/ end=/"/
 syn match   mlirLabel /[-a-zA-Z$._][-a-zA-Z$._0-9]*:/
-syn match   mlirIdentifier /[%@][a-zA-Z$._-][a-zA-Z0-9$._-]*/
-syn match   mlirIdentifier /[%@!]\d\+\>/
-syn match mlirMapSetOutline "#.*$"
+" Prefixed identifiers, including attribute aliases (starting with '#').
+syn match   mlirIdentifier /[%@#][a-zA-Z$._-][a-zA-Z0-9$._-]*/
+syn match   mlirIdentifier /[%@#!]\d\+\>/
 
 " Syntax-highlight lit test commands and bug numbers.
 syn match  mlirSpecialComment /\/\/\s*RUN:.*$/
@@ -111,7 +112,6 @@
 
   HiLink mlirType Type
   HiLink mlirOps Statement
-  HiLink mlirMapSetOutline PreProc
   HiLink mlirNumber Number
   HiLink mlirComment Comment
   HiLink mlirString String