pub fn from_str(input: &'de str) -> SpannedResult<Self> {

        Self::from_str_with_options(input, &Options::default())

    }

    pub fn from_bytes(input: &'de [u8]) -> SpannedResult<Self> {

        Self::from_bytes_with_options(input, &Options::default())

    }

    pub fn from_str_with_options(input: &'de str, options: &Options) -> SpannedResult<Self> {

        let mut deserializer = Deserializer {

            parser: Parser::new(input)?,

            last_identifier: None,

            recursion_limit: options.recursion_limit,

        };

        deserializer.parser.exts |= options.default_extensions;

        Ok(deserializer)

    }

    pub fn from_bytes_with_options(input: &'de [u8], options: &Options) -> SpannedResult<Self> {

        let err = match str::from_utf8(input) {

            Ok(input) => return Self::from_str_with_options(input, options),

            Err(err) => err,

        };

        // FIXME: use [`utf8_chunks`](https://github.com/rust-lang/rust/issues/99543) once stabilised

        #[allow(clippy::expect_used)]

        let valid_input =

            str::from_utf8(&input[..err.valid_up_to()]).expect("source is valid up to error");

        Err(SpannedError {

            code: err.into(),

            position: Position::from_src_end(valid_input),

        })

    }

    pub fn remainder(&self) -> &'de str {

        self.parser.src()

    }

    pub fn span_error(&self, code: Error) -> SpannedError {

        self.parser.span_error(code)

    }

    pub fn extensions(&self) -> Extensions {

        self.parser.exts

    }

pub fn from_reader<R, T>(rdr: R) -> SpannedResult<T>

where

    R: io::Read,

    T: de::DeserializeOwned,

{

    Options::default().from_reader(rdr)

}

pub fn from_str<'a, T>(s: &'a str) -> SpannedResult<T>

where

    T: de::Deserialize<'a>,

{

    Options::default().from_str(s)

}

pub fn from_bytes<'a, T>(s: &'a [u8]) -> SpannedResult<T>

where

    T: de::Deserialize<'a>,

{

    Options::default().from_bytes(s)

}

    pub fn end(&mut self) -> Result<()> {

        self.parser.skip_ws()?;

        if self.parser.src().is_empty() {

            Ok(())

            Err(Error::TrailingCharacters)

    }

    fn handle_any_struct<V>(&mut self, visitor: V, ident: Option<&str>) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        let is_serde_content = core::any::type_name::<V::Value>() == SERDE_CONTENT_CANARY

            || core::any::type_name::<V::Value>() == SERDE_TAG_KEY_CANARY;

        let old_serde_content_newtype = self.serde_content_newtype;

        self.serde_content_newtype = false;

        match (

            self.parser.check_struct_type(

                NewtypeMode::NoParensMeanUnit,

                if old_serde_content_newtype {

                    TupleMode::DifferentiateNewtype // separate match on NewtypeOrTuple below

                    TupleMode::ImpreciseTupleOrNewtype // Tuple and NewtypeOrTuple match equally

            )?,

            ident,

            (StructType::Unit, Some(ident)) if is_serde_content => {

                // serde's Content type needs the ident for unit variants

                visitor.visit_str(ident)

            (StructType::Unit, _) => visitor.visit_unit(),

            (_, Some(ident)) if is_serde_content => {

                // serde's Content type uses a singleton map encoding for enums

                visitor.visit_map(SerdeEnumContent {

                    de: self,

                    ident: Some(ident),

                })

                self.handle_struct_after_name("", visitor)

            (StructType::NewtypeTuple, _) if old_serde_content_newtype => {

                // deserialize a newtype struct or variant

                self.parser.consume_char('(');

                self.parser.skip_ws()?;

                let result = self.deserialize_any(visitor);

                self.parser.skip_ws()?;

                self.parser.consume_char(')');

                result

                self.deserialize_tuple(0, visitor)

    }

    fn handle_struct_after_name<V>(

        &mut self,

        name_for_pretty_errors_only: &'static str,

        visitor: V,

    ) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if self.newtype_variant || self.parser.consume_char('(') {

            let old_newtype_variant = self.newtype_variant;

            self.newtype_variant = false;

            let value = guard_recursion! { self =>

                visitor

                    .visit_map(CommaSeparated::new(Terminator::Struct, self))

                    .map_err(|err| {

                        struct_error_name(

                            err,

                            if !old_newtype_variant && !name_for_pretty_errors_only.is_empty() {

                                Some(name_for_pretty_errors_only)

                                None

                    })?

            self.parser.skip_ws()?;

            if old_newtype_variant || self.parser.consume_char(')') {

                Ok(value)

                Err(Error::ExpectedStructLikeEnd)

        } else if name_for_pretty_errors_only.is_empty() {

            Err(Error::ExpectedStructLike)

            Err(Error::ExpectedNamedStructLike(name_for_pretty_errors_only))

    }

    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if self.newtype_variant {

            if self.parser.check_char(')') {

                return self.deserialize_unit(visitor);

            }

            #[allow(clippy::wildcard_in_or_patterns)]

            match self

                .parser

                .check_struct_type(NewtypeMode::InsideNewtype, TupleMode::DifferentiateNewtype)?

                    return self.handle_struct_after_name("", visitor);

                    return self.deserialize_tuple(0, visitor);

                StructType::NewtypeTuple | _ => {

                    // continue as usual with the inner content of the newtype variant

                    self.newtype_variant = false;

                }

        }

        if self.parser.consume_ident("true") {

            return visitor.visit_bool(true);

        } else if self.parser.consume_ident("false") {

            return visitor.visit_bool(false);

        } else if self.parser.check_ident("Some") {

            return self.deserialize_option(visitor);

        } else if self.parser.consume_ident("None") {

            return visitor.visit_none();

        } else if self.parser.consume_str("()") {

            return visitor.visit_unit();

        } else if self.parser.consume_ident("inf") || self.parser.consume_ident("inff32") {

            return visitor.visit_f32(core::f32::INFINITY);

        } else if self.parser.consume_ident("inff64") {

            return visitor.visit_f64(core::f64::INFINITY);

        } else if self.parser.consume_ident("NaN") || self.parser.consume_ident("NaNf32") {

            return visitor.visit_f32(core::f32::NAN);

        } else if self.parser.consume_ident("NaNf64") {

            return visitor.visit_f64(core::f64::NAN);

        }

        if let Some(ident) = self.parser.skip_identifier() {

            self.parser.skip_ws()?;

            return self.handle_any_struct(visitor, Some(ident));

        }

        match self.parser.peek_char_or_eof()? {

            '(' => self.handle_any_struct(visitor, None),

            '[' => self.deserialize_seq(visitor),

            '{' => self.deserialize_map(visitor),

            '0'..='9' | '+' | '-' | '.' => self.parser.any_number()?.visit(visitor),

            '"' | 'r' => self.deserialize_string(visitor),

            'b' if self.parser.src().starts_with("b'") => self.parser.any_number()?.visit(visitor),

            'b' => self.deserialize_byte_buf(visitor),

            '\'' => self.deserialize_char(visitor),

            other => Err(Error::UnexpectedChar(other)),

    }

    fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_bool(self.parser.bool()?)

    }

    fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_i8(self.parser.integer()?)

    }

    fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_i16(self.parser.integer()?)

    }

    fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_i32(self.parser.integer()?)

    }

    fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_i64(self.parser.integer()?)

    }

    fn deserialize_i128<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_i128(self.parser.integer()?)

    }

    fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_u8(self.parser.integer()?)

    }

    fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_u16(self.parser.integer()?)

    }

    fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_u32(self.parser.integer()?)

    }

    fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_u64(self.parser.integer()?)

    }

    fn deserialize_u128<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_u128(self.parser.integer()?)

    }

    fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_f32(self.parser.float()?)

    }

    fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_f64(self.parser.float()?)

    }

    fn deserialize_char<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        visitor.visit_char(self.parser.char()?)

    }

    fn deserialize_str<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        match self.parser.string()? {

            ParsedStr::Allocated(s) => visitor.visit_string(s),

            ParsedStr::Slice(s) => visitor.visit_borrowed_str(s),

    }

    fn deserialize_string<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        self.deserialize_str(visitor)

    }

    fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        self.deserialize_byte_buf(visitor)

    }

    fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if self.parser.check_char('[') {

            let bytes = Vec::<u8>::deserialize(self)?;

            return visitor.visit_byte_buf(bytes);

        }

        match self.parser.byte_string()? {

            ParsedByteStr::Allocated(byte_buf) => visitor.visit_byte_buf(byte_buf),

            ParsedByteStr::Slice(bytes) => visitor.visit_borrowed_bytes(bytes),

    }

    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if self.parser.consume_ident("None") {

            visitor.visit_none()

        } else if self.parser.consume_ident("Some") && {

            self.parser.skip_ws()?;

            self.parser.consume_char('(')

            self.parser.skip_ws()?;

            self.newtype_variant = self

                .parser

                .exts

                .contains(Extensions::UNWRAP_VARIANT_NEWTYPES);

            let v = guard_recursion! { self => visitor.visit_some(&mut *self)? };

            self.newtype_variant = false;

            self.parser.comma()?;

            if self.parser.consume_char(')') {

                Ok(v)

                Err(Error::ExpectedOptionEnd)

        } else if self.parser.exts.contains(Extensions::IMPLICIT_SOME) {

            guard_recursion! { self => visitor.visit_some(&mut *self) }

            Err(Error::ExpectedOption)

    }

    fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if self.newtype_variant || self.parser.consume_str("()") {

            self.newtype_variant = false;

            visitor.visit_unit()

            Err(Error::ExpectedUnit)

    }

    fn deserialize_unit_struct<V>(self, name: &'static str, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if self.newtype_variant || self.parser.consume_struct_name(name)? {

            self.newtype_variant = false;

            visitor.visit_unit()

            self.deserialize_unit(visitor)

    }

    fn deserialize_newtype_struct<V>(self, name: &'static str, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if name == crate::value::raw::RAW_VALUE_TOKEN {

            let src_before = self.parser.pre_ws_src();

            self.parser.skip_ws()?;

            let _ignored = self.deserialize_ignored_any(serde::de::IgnoredAny)?;

            self.parser.skip_ws()?;

            let src_after = self.parser.src();

            if self.parser.has_unclosed_line_comment() {

                return Err(Error::UnclosedLineComment);

            }

            let ron_str = &src_before[..src_before.len() - src_after.len()];

            return visitor

                .visit_borrowed_str::<Error>(ron_str)

                .map_err(|_| Error::ExpectedRawValue);

        }

        if self.parser.exts.contains(Extensions::UNWRAP_NEWTYPES) || self.newtype_variant {

            self.newtype_variant = false;

            return guard_recursion! { self => visitor.visit_newtype_struct(&mut *self) };

        }

        self.parser.consume_struct_name(name)?;

        self.parser.skip_ws()?;

        if self.parser.consume_char('(') {

            self.parser.skip_ws()?;

            let value = guard_recursion! { self => visitor.visit_newtype_struct(&mut *self)? };

            self.parser.comma()?;

            if self.parser.consume_char(')') {

                Ok(value)

                Err(Error::ExpectedStructLikeEnd)

        } else if name.is_empty() {

            Err(Error::ExpectedStructLike)

            Err(Error::ExpectedNamedStructLike(name))

    }

    fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        self.newtype_variant = false;

        if self.parser.consume_char('[') {

            let value = guard_recursion! { self =>

                visitor.visit_seq(CommaSeparated::new(Terminator::Seq, self))?

            self.parser.skip_ws()?;

            if self.parser.consume_char(']') {

                Ok(value)

                Err(Error::ExpectedArrayEnd)

            Err(Error::ExpectedArray)

    }

    fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if self.newtype_variant || self.parser.consume_char('(') {

            let old_newtype_variant = self.newtype_variant;

            self.newtype_variant = false;

            let value = guard_recursion! { self =>

                visitor.visit_seq(CommaSeparated::new(Terminator::Tuple, self))?

            self.parser.skip_ws()?;

            if old_newtype_variant || self.parser.consume_char(')') {

                Ok(value)

                Err(Error::ExpectedStructLikeEnd)

            Err(Error::ExpectedStructLike)

    }

    fn deserialize_tuple_struct<V>(

        self,

        name: &'static str,

        len: usize,

        visitor: V,

    ) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if !self.newtype_variant {

            self.parser.consume_struct_name(name)?;

        }

        self.deserialize_tuple(len, visitor).map_err(|e| match e {

            Error::ExpectedStructLike if !name.is_empty() => Error::ExpectedNamedStructLike(name),

            e => e,

        })

    }

    fn deserialize_map<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

            fn fmt(&self, fmt: &mut core::fmt::Formatter) -> core::fmt::Result {

                self.0.expecting(fmt)

            }

        self.newtype_variant = false;

        // TODO: Avoid allocating to perform this check.

        let serde_flatten_canary = VisitorExpecting(&visitor)

            .to_string()

            .starts_with("struct ");

        let terminator = if serde_flatten_canary {

            Terminator::MapAsStruct

            Terminator::Map

        if self.parser.consume_char('{') {

            let value = guard_recursion! { self =>

                visitor.visit_map(CommaSeparated::new(terminator, self))?

            self.parser.skip_ws()?;

            if self.parser.consume_char('}') {

                Ok(value)

                Err(Error::ExpectedMapEnd)

            Err(Error::ExpectedMap)

    }

    fn deserialize_struct<V>(

        self,

        name: &'static str,

        _fields: &'static [&'static str],

        visitor: V,

    ) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        if !self.newtype_variant {

            self.parser.consume_struct_name(name)?;

        }

        self.parser.skip_ws()?;

        self.handle_struct_after_name(name, visitor)

    }

    fn deserialize_enum<V>(

        self,

        name: &'static str,

        _variants: &'static [&'static str],

        visitor: V,

    ) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        self.newtype_variant = false;

        match guard_recursion! { self => visitor.visit_enum(Enum::new(self)) } {

            Ok(value) => Ok(value),

                expected,

                found,

            }) if !name.is_empty() => Err(Error::NoSuchEnumVariant {

                expected,

                found,

                outer: Some(String::from(name)),

            }),

            Err(e) => Err(e),

    }

    fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        let identifier = self.parser.identifier()?;

        self.last_identifier = Some(identifier);

        visitor.visit_borrowed_str(identifier)

    }

    fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        self.deserialize_any(visitor)

    }

    fn as_char(&self) -> char {

        match self {

            Terminator::Map | Terminator::MapAsStruct => '}',

            Terminator::Tuple | Terminator::Struct => ')',

            Terminator::Seq => ']',

    }

    fn new(terminator: Terminator, de: &'a mut Deserializer<'de>) -> Self {

        CommaSeparated {

            de,

            terminator,

            had_comma: true,

            inside_internally_tagged_enum: false,

        }

    }

    fn has_element(&mut self) -> Result<bool> {

        self.de.parser.skip_ws()?;

        match (

            self.had_comma,

            !self.de.parser.check_char(self.terminator.as_char()),

        ) {

            (true, has_element) => Ok(has_element),

            (false, false) => Ok(false),

            (false, true) => Err(Error::ExpectedComma),

    }

    fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>>

    where

        T: DeserializeSeed<'de>,

    {

        if self.has_element()? {

            let res = guard_recursion! { self.de => seed.deserialize(&mut *self.de)? };

            self.had_comma = self.de.parser.comma()?;

            Ok(Some(res))

            Ok(None)

    }

    fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>>

    where

        K: DeserializeSeed<'de>,

    {

        if self.has_element()? {

            self.inside_internally_tagged_enum =

                core::any::type_name::<K::Value>() == SERDE_TAG_KEY_CANARY;

            match self.terminator {

                Terminator::Struct => guard_recursion! { self.de =>

                    seed.deserialize(&mut id::Deserializer::new(&mut *self.de, false)).map(Some)

                Terminator::MapAsStruct => guard_recursion! { self.de =>

                    seed.deserialize(&mut id::Deserializer::new(&mut *self.de, true)).map(Some)

                _ => guard_recursion! { self.de => seed.deserialize(&mut *self.de).map(Some) },

            Ok(None)

    }

    fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value>

    where

        V: DeserializeSeed<'de>,

    {

        self.de.parser.skip_ws()?;

        if self.de.parser.consume_char(':') {

            self.de.parser.skip_ws()?;

            let res = if self.inside_internally_tagged_enum

                && core::any::type_name::<V::Value>() != SERDE_CONTENT_CANARY

                guard_recursion! { self.de =>

                    seed.deserialize(&mut tag::Deserializer::new(&mut *self.de))?

                guard_recursion! { self.de =>

                    seed.deserialize(&mut *self.de)?

            self.had_comma = self.de.parser.comma()?;

            Ok(res)

            Err(Error::ExpectedMapColon)

    }

    fn new(de: &'a mut Deserializer<'de>) -> Self {

        Enum { de }

    }

    fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self::Variant)>

    where

        V: DeserializeSeed<'de>,

    {

        self.de.parser.skip_ws()?;

        let value = guard_recursion! { self.de => seed.deserialize(&mut *self.de)? };

        Ok((value, self))

    }

    fn unit_variant(self) -> Result<()> {

        Ok(())

    }

    fn newtype_variant_seed<T>(self, seed: T) -> Result<T::Value>

    where

        T: DeserializeSeed<'de>,

    {

        let newtype_variant = self.de.last_identifier;

        self.de.parser.skip_ws()?;

        if self.de.parser.consume_char('(') {

            self.de.parser.skip_ws()?;

            self.de.newtype_variant = self

                .de

                .parser

                .exts

                .contains(Extensions::UNWRAP_VARIANT_NEWTYPES);

            let val = guard_recursion! { self.de =>

                seed

                    .deserialize(&mut *self.de)

                    .map_err(|err| struct_error_name(err, newtype_variant))?

            self.de.newtype_variant = false;

            self.de.parser.comma()?;

            if self.de.parser.consume_char(')') {

                Ok(val)

                Err(Error::ExpectedStructLikeEnd)

            Err(Error::ExpectedStructLike)

    }

    fn tuple_variant<V>(self, len: usize, visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        self.de.parser.skip_ws()?;

        self.de.deserialize_tuple(len, visitor)

    }

    fn struct_variant<V>(self, _fields: &'static [&'static str], visitor: V) -> Result<V::Value>

    where

        V: Visitor<'de>,

    {

        let struct_variant = self.de.last_identifier;

        self.de.parser.skip_ws()?;

        self.de

            .handle_struct_after_name("", visitor)

            .map_err(|err| struct_error_name(err, struct_variant))

    }

fn struct_error_name(error: Error, name: Option<&str>) -> Error {

    match error {

            expected,

            found,

            outer: None,

        } => Error::NoSuchStructField {

            expected,

            found,

            outer: name.map(ToOwned::to_owned),

        },

        Error::MissingStructField { field, outer: None } => Error::MissingStructField {

            field,

            outer: name.map(ToOwned::to_owned),

        },

        Error::DuplicateStructField { field, outer: None } => Error::DuplicateStructField {

            field,

            outer: name.map(ToOwned::to_owned),

        },

        e => e,

}

    fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>>

    where

        K: DeserializeSeed<'de>,

    {

        self.ident

            .take()

            .map(|ident| seed.deserialize(serde::de::value::StrDeserializer::new(ident)))

            .transpose()

    }

    fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value>

    where

        V: DeserializeSeed<'de>,

    {

        self.de.parser.skip_ws()?;

        let old_serde_content_newtype = self.de.serde_content_newtype;

        self.de.serde_content_newtype = true;

        let result = seed.deserialize(&mut *self.de);

        self.de.serde_content_newtype = old_serde_content_newtype;

        result

    }