An unknown field was specified into a structure.
Erroneous code example:
struct Simba { mother: u32, } let s = Simba { mother: 1, father: 0 }; // error: structure `Simba` has no field named `father`
Verify you didn‘t misspell the field’s name or that the field exists. Example:
struct Simba { mother: u32, father: u32, } let s = Simba { mother: 1, father: 0 }; // ok!