obsolete_colon_for_default_value
Using a colon as the separator before a default value is no longer supported.
Description
#The analyzer produces this diagnostic when a colon (:) is used as the
separator before the default value of an optional named parameter.
While this syntax used to be allowed, it was removed in favor of
using an equal sign (=).
Example
#The following code produces this diagnostic because a colon is being used
before the default value of the optional parameter i:
dart
void f({int i : 0}) {}Common fixes
#Replace the colon with an equal sign:
dart
void f({int i = 0}) {}