for_in_with_const_variable
A for-in loop variable can't be a 'const'.
Description
#The analyzer produces this diagnostic when the loop variable declared in a for-in loop is declared to be a const
. The variable can't be a const
because the value can't be computed at compile time.
Example
#The following code produces this diagnostic because the loop variable x
is declared to be a const
:
void f() {
for (const x in [0, 1, 2]) {
print(x);
}
}
Common fixes
#If there's a type annotation, then remove the const
modifier from the declaration.
If there's no type, then replace the const
modifier with final
, var
, or a type annotation:
void f() {
for (final x in [0, 1, 2]) {
print(x);
}
}
Unless stated otherwise, the documentation on this site reflects Dart 3.7.3. Page last updated on 2025-05-08. View source or report an issue.