Function validate_path_constructor

graphlite/src/ast/validator.rs:1299–1340

Validate PATH constructor expressions

(
    path_constructor: &crate::ast::PathConstructor,
    ctx: &mut ValidationContext,
    errors: &mut Vec<ValidationError>,
)

/// Validate PATH constructor expressions
fn validate_path_constructor(
    path_constructor: &crate::ast::PathConstructor,
    ctx: &mut ValidationContext,
    errors: &mut Vec<ValidationError>,
) {
    // Validate each element in the PATH constructor
    for element in &path_constructor.elements {
        validate_expression(element, ctx, errors);

        // Check that element types are suitable for PATH constructor
        if let Ok(element_type) = infer_expression_type(element, ctx) {
            match element_type {
                GqlType::String { .. }
                | GqlType::Integer
                | GqlType::BigInt
                | GqlType::SmallInt
                | GqlType::Double
                | GqlType::Float { .. }
                | GqlType::Real => {
                    // These types are valid for PATH elements (can be converted to string IDs)
                }
                _ => {
                    errors.push(ValidationError {
                        message: format!(
                            "PATH constructor element must be a string or number type, got: {:?}",
                            element_type
                        ),
                        location: Some(crate::ast::Location::default()),
                        error_type: ValidationErrorType::Type,
                    });
                }
            }
        }
    }

    // PATH elements should follow node-edge-node pattern (optional validation)
    if path_constructor.elements.len().is_multiple_of(2) && path_constructor.elements.len() > 2 {
        // Even number of elements > 2 might indicate incomplete path
        // This is a warning rather than an error since PATH[node, edge] might be valid
        // in some contexts
    }
}

/// Validate CAST expressions
fn validate_cast_expression(