E3016

Unexpected ~ in argument. Did you mean label=pattern or label~?

Erroneous example

enum A {
  A(b~ : Int)
}

fn main {
  match A(b=1) {
    A(b~=c) => {
      println("Hello, world! \{c}") // Error: unexpected `~` in argument. Did you mean `label=pattern` or `label~`?
    }
  }
}

Suggestion

Replace b~ with b= or b~ as appropriate.

enum A {
  A(b~ : Int)
}

fn main {
  match A(b=1) {
    A(b~) => {
      println("Hello, world! \{b}")
    }
  }
}

Or,

enum A {
  A(b~ : Int)
}

fn main {
  match A(b=1) {
    A(b=c) => {
      println("Hello, world! \{c}")
    }
  }
}