# Struct serde_json::error::Error

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    pub struct Error { /* private fields */ }

Expand description

This type represents all possible errors that can occur when serializing or deserializing JSON data.

## Implementations

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### impl Error

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#### pub fn line(&self) -> usize

One-based line number at which the error was detected.

Characters in the first line of the input (before the first newline character) are in line 1.

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#### pub fn column(&self) -> usize

One-based column number at which the error was detected.

The first character in the input and any characters immediately following a newline character are in column 1.

Note that errors may occur in column 0, for example if a read from an IO stream fails immediately following a previously read newline character.

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#### pub fn classify(&self) -> Category

Categorizes the cause of this error.

- `Category::Io` - failure to read or write bytes on an IO stream
- `Category::Syntax` - input that is not syntactically valid JSON
- `Category::Data` - input data that is semantically incorrect
- `Category::Eof` - unexpected end of the input data

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#### pub fn is_io(&self) -> bool

Returns true if this error was caused by a failure to read or write bytes on an IO stream.

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#### pub fn is_syntax(&self) -> bool

Returns true if this error was caused by input that was not syntactically valid JSON.

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#### pub fn is_data(&self) -> bool

Returns true if this error was caused by input data that was semantically incorrect.

For example, JSON containing a number is semantically incorrect when the type being deserialized into holds a String.

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#### pub fn is_eof(&self) -> bool

Returns true if this error was caused by prematurely reaching the end of the input data.

Callers that process streaming input may be interested in retrying the deserialization once more data is available.

## Trait Implementations

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### impl Debug for Error

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

Formats the value using the given formatter. Read more

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### impl Display for Error

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

Formats the value using the given formatter. Read more

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### impl Error for Error

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

The lower-level source of this error, if any. Read more

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#### fn description(&self) -> &str

👎 Deprecated since 1.42.0:

use the Display impl or to_string()

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

👎 Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

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#### fn provide(&'a self, req: &mut Demand<'a>)

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

Provides type based access to context intended for error reports. Read more

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### impl Error for Error

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#### fn custom<T: Display>(msg: T) -> Error

Raised when there is general error when deserializing a type. Read more

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#### fn invalid_type(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self

Raised when a `Deserialize` receives a type different from what it was expecting. Read more

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#### fn invalid_value(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self

Raised when a `Deserialize` receives a value of the right type but that is wrong for some other reason. Read more

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#### fn invalid_length(len: usize, exp: &dyn Expected) -> Self

Raised when deserializing a sequence or map and the input data contains too many or too few elements. Read more

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#### fn unknown_variant(variant: &str, expected: &'static [&'static str]) -> Self

Raised when a `Deserialize` enum type received a variant with an unrecognized name. Read more

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#### fn unknown_field(field: &str, expected: &'static [&'static str]) -> Self

Raised when a `Deserialize` struct type received a field with an unrecognized name. Read more

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#### fn missing_field(field: &'static str) -> Self

Raised when a `Deserialize` struct type expected to receive a required field with a particular name but that field was not present in the input. Read more

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#### fn duplicate_field(field: &'static str) -> Self

Raised when a `Deserialize` struct type received more than one of the same field. Read more

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### impl Error for Error

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#### fn custom<T: Display>(msg: T) -> Error

Used when a `Serialize` implementation encounters any error while serializing a type. Read more

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### impl From<Error> for Error

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#### fn from(j: Error) -> Self

Convert a `serde_json::Error` into an `io::Error`.

JSON syntax and data errors are turned into `InvalidData` IO errors. EOF errors are turned into `UnexpectedEof` IO errors.

    use std::io;

    enum MyError {
        Io(io::Error),
        Json(serde_json::Error),
    }

    impl From<serde_json::Error> for MyError {
        fn from(err: serde_json::Error) -> MyError {
            use serde_json::error::Category;
            match err.classify() {
                Category::Io => {
                    MyError::Io(err.into())
                }
                Category::Syntax | Category::Data | Category::Eof => {
                    MyError::Json(err)
                }
            }
        }
    }

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### impl<'de> IntoDeserializer<'de, Error> for Value

#### type Deserializer = Value

The type of the deserializer being converted into.

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#### fn into_deserializer(self) -> Self::Deserializer

Convert this value into a deserializer.

## Auto Trait Implementations

### impl !RefUnwindSafe for Error

### impl Send for Error

### impl Sync for Error

### impl Unpin for Error

### impl !UnwindSafe for Error

## Blanket Implementations

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### impl<T> Any for T where
T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more

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### impl<T> Borrow<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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### impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

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### impl<T> From<T> for T

const: unstable · source

#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T where
U: From<T>,

const: unstable · source

#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> ToString for T where
T: Display + ?Sized,

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#### default fn to_string(&self) -> String

Converts the given value to a `String`. Read more

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### impl<T, U> TryFrom<U> for T where
U: Into<T>,

#### type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

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### impl<T, U> TryInto<U> for T where
U: TryFrom<T>,

#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.