undefined_getter

The getter '{0}' isn't defined for the '{1}' function type.

The getter '{0}' isn't defined for the type '{1}'.

The analyzer produces this diagnostic when it encounters an identifier that appears to be the name of a getter but either isn't defined or isn't visible in the scope in which it's being referenced.

The following code produces this diagnostic because String has no member named len:

int f(String s) => s.len;

If the identifier isn't defined, then either define it or replace it with the name of a getter that is defined. The example above can be corrected by fixing the spelling of the getter:

int f(String s) => s.length;