Function build_call 

pub fn build_call(
    ctor: Constructor,
    args: Vec<CallArg>,
    span: Span,
) -> Result<ParserAst, Vec<ValidationError>>

Build the ParserAst for ctor(args…), or report every reason it cannot be built.

Nothing is built before the shape is checked (IP-07): the argument list goes through check_call first, so by the time an arm below runs it has exactly the arguments §7.5 gives that constructor and there is nothing left for it to drop.

Errors

A non-empty ValidationError list. Each carries the DiagCode the caller reports it under.