return [expression]
This instruction must be part of the sequence of instructions making up the body of the function. When a return instruction is encountered, control is returned to the caller and the value of the result variable becomes the result of the function call. If an expression is present, the value of the expression is first assigned to result.
The result variable has the same type as the return type of the function. Thus, if the value of the expression does not belong to the return type of the function, the function call results in Undefined.