Method as_const_err

src/expr/src/relation.rs:1121–1127

If self is a constant error, return the error, otherwise `None`. Looks behind `ArrangeBy`s.

(&self)

    /// If self is a constant error, return the error, otherwise `None`.
    /// Looks behind `ArrangeBy`s.
    pub fn as_const_err(&self) -> Option<&EvalError> {
        match self {
            MirRelationExpr::Constant { rows: Err(e), .. } => Some(e),
            MirRelationExpr::ArrangeBy { input, .. } => input.as_const_err(),
            _ => None,
        }
    }

    /// Checks if `self` is the single element collection with no columns.
    pub fn is_constant_singleton(&self) -> bool {