1 An unknown field was specified into a structure.
3 Erroneous code example:
10 let s = Simba { mother: 1, father: 0 };
11 // error: structure `Simba` has no field named `father`
14 Verify you didn't misspell the field's name or that the field exists. Example:
22 let s = Simba { mother: 1, father: 0 }; // ok!