E0056

Missing field in struct pattern.

The warning is emitted when pattern matching on a struct pattern and having missing fields.

错误示例

///|
struct Point {
  x : Int
  y : Int
}

///|
pub fn quadrant(p : Point) -> String {
  match p {
    { x: _..<0 } => "Third or Fourth Quadrant"
    { x: 0..<_ } => "First or Second Quadrant"
  }
}

建议

Add .. if you want to omit the other fields, or use them.

///|
struct Point {
  x : Int
  y : Int
}

///|
pub fn quadrant(p : Point) -> String {
  match p {
    { x: _..<0, .. } => "Third or Fourth Quadrant"
    { x: 0..<_, y: 0..<_ } => "First Quadrant"
    { x: 0..<_, y: _..<0 } => "Second Quadrant"
  }
}