E4143

Not a valid constant type, only immutable primitive types are allowed.

In MoonBit, you can use const to declare a constant value. Only literal value of immutable primitive types can be assigned to const.

• These are valid constant types: Int32, String, Byte, Char, Float, Bool, etc.

• These are not valid constant types: Array[Int32], (Int32) -> Int32, Ref[Int32], etc.

Erroneous example

pub const A : Array[Int32] = [1, 2, 3] // Error: Not a valid constant type, only immutable primitive types are allowed.

Suggestion

You can bind the value to a variable using let instead.

pub let a : Array[Int32] = [1, 2, 3]