expression_ in_ map
Expressions can't be used in a map literal.
Description
#The analyzer produces this diagnostic when the analyzer finds an expression, rather than a map entry, in what appears to be a map literal.
Example
#The following code produces this diagnostic:
var map = <String, int>{'a': 0, 'b': 1, 'c'};
Common fixes
#If the expression is intended to compute either a key or a value in an entry, fix the issue by replacing the expression with the key or the value. For example:
var map = <String, int>{'a': 0, 'b': 1, 'c': 2};
Unless stated otherwise, the documentation on this site reflects Dart 3.9.2. Page last updated on 2025-9-1. View source or report an issue.