description bug_report

Keywords

The following table lists the words that the Dart language treats specially.
abstract 2 else import 2 show 1
as 2 enum in static 2
assert export 2 interface 2 super
async 1 extends is switch
await 3 extension 2 late 2 sync 1
base 2 external 2 library 2 this
break factory 2 mixin 2 throw
case false new true
catch final (variable) null try
class final (class) 2 on 1 type 3
const finally operator 2 typedef 2
continue for part 2 var
covariant 2 Function 2 required 2 void
default get 2 rethrow when
deferred 2 hide 1 return while
do if sealed 2 with
dynamic 2 implements 2 set 2 yield 3

Avoid using these words as identifiers. However, if necessary, the keywords marked with superscripts can be identifiers:

  • Words with the superscript 1 are contextual keywords, which have meaning only in specific places. They're valid identifiers everywhere.

  • Words with the superscript 2 are built-in identifiers. These keywords are valid identifiers in most places, but they can't be used as class or type names, or as import prefixes.

  • Words with the superscript 3 are limited reserved words related to asynchrony support. You can't use await or yield as an identifier in any function body marked with async, async*, or sync*.

All other words in the table are reserved words, which can't be identifiers.