Struct FormatStringValidationError 

pub struct FormatStringValidationError {
    pub message: String,
    pub input: String,
    pub start: usize,
    pub end: usize,
    pub expression_error: Option<Box<ExpressionError>>,
}

Structured error from FormatString::validate_expressions.

Carries the position of the failing interpolation within the format string so callers can produce caret-style diagnostics or structured error responses.

Fields

message: String

Description of what went wrong (e.g. “Undefined variable ‘Param.X’”).

input: String

The raw format string that was being validated.

start: usize

Byte offset of the {{ that opens the failing interpolation.

end: usize

Byte offset of the }} that closes the failing interpolation.

expression_error: Option<Box<ExpressionError>>

The original expression error, if available. Contains sub_errors for compound failures (e.g., if/else where both branches fail).

Trait Implementations

impl Clone for FormatStringValidationError

fn clone(&self) -> FormatStringValidationError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FormatStringValidationError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for FormatStringValidationError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for FormatStringValidationError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.