E4115

Cannot auto-fill parameter of this type.

MoonBit supports and auto-filling SourceLoc and ArgsLoc parameters in functions. Leaving the default value of parameter of other types will result in this error.

Erroneous example

///|
#callsite(autofill(parameter))
fn f(parameter~ : Int) -> Unit {
  // ^~~~~~~~~ Error: Cannot auto-fill parameter of type Int
}

Suggestion

Use a default value for the parameter:

///|
pub fn f(parameter? : Int = 0) -> Int {
  parameter
}

///|
test {
  inspect(f(), content="0")
  inspect(f(parameter=1), content="1")
}