E0207: Wrong argument count

Explanation

A call-like construct supplied the wrong number of values or bindings. This applies to function and built-in calls, enum tuple-variant construction (including a payload variant used as a bare value), and enum payload patterns with an explicit binding list.

Likely cause

A function or built-in call has a missing or extra argument; an enum value supplies the wrong number of payload values; a payload-carrying variant was used without constructing its payload; or a match pattern's parenthesized bindings do not match the variant's payload arity.

Examples

Missing call argument

fn identity(value: i32) -> i32 { value }
fn main() -> i32 {
    identity()
}

Supply every argument

fn identity(value: i32) -> i32 { value }
fn main() -> i32 {
    identity(42)
}

References

• Call argument arity and modes

• Enum payload-pattern arity

• Enum tuple-variant construction