Update serde_json to 1.0.79

Test: cd external/rust/crates && atest --host -c
Change-Id: Ic547cf00640b27bac6afe4f77c3c546d472c3d6e

23 files changed, 301 insertions, 174 deletions

diff --git a/src/de.rs b/src/de.rs
index a2f34b9..ffd0d48 100644
--- a/src/de.rs
+++ b/src/de.rs
@@ -3,10 +3,16 @@
 use crate::error::{Error, ErrorCode, Result};
 #[cfg(feature = "float_roundtrip")]
 use crate::lexical;
-use crate::lib::str::FromStr;
-use crate::lib::*;
 use crate::number::Number;
 use crate::read::{self, Fused, Reference};
+use alloc::string::String;
+use alloc::vec::Vec;
+#[cfg(feature = "float_roundtrip")]
+use core::iter;
+use core::iter::FusedIterator;
+use core::marker::PhantomData;
+use core::result;
+use core::str::FromStr;
 use serde::de::{self, Expected, Unexpected};
 use serde::{forward_to_deserialize_any, serde_if_integer128};
 
@@ -87,7 +93,9 @@ impl<'a> Deserializer<read::StrRead<'a>> {
 
 macro_rules! overflow {
     ($a:ident * 10 + $b:ident, $c:expr) => {
-        $a >= $c / 10 && ($a > $c / 10 || $b > $c % 10)
+        match $c {
+            c => $a >= c / 10 && ($a > c / 10 || $b > c % 10),
+        }
     };
 }
 
@@ -856,6 +864,15 @@ impl<'de, R: Read<'de>> Deserializer<R> {
             buf.push('-');
         }
         self.scan_integer(&mut buf)?;
+        if positive {
+            if let Ok(unsigned) = buf.parse() {
+                return Ok(ParserNumber::U64(unsigned));
+            }
+        } else {
+            if let Ok(signed) = buf.parse() {
+                return Ok(ParserNumber::I64(signed));
+            }
+        }
         Ok(ParserNumber::String(buf))
     }
 
@@ -1560,7 +1577,8 @@ impl<'de, 'a, R: Read<'de>> de::Deserializer<'de> for &'a mut Deserializer<R> {
     ///
     /// # Examples
     ///
-    /// You can use this to parse JSON strings containing invalid UTF-8 bytes.
+    /// You can use this to parse JSON strings containing invalid UTF-8 bytes,
+    /// or unpaired surrogates.
     ///
     /// ```
     /// use serde_bytes::ByteBuf;
@@ -1580,20 +1598,18 @@ impl<'de, 'a, R: Read<'de>> de::Deserializer<'de> for &'a mut Deserializer<R> {
     /// ```
     ///
     /// Backslash escape sequences like `\n` are still interpreted and required
-    /// to be valid, and `\u` escape sequences are required to represent valid
-    /// Unicode code points.
+    /// to be valid. `\u` escape sequences are required to represent a valid
+    /// Unicode code point or lone surrogate.
     ///
     /// ```
     /// use serde_bytes::ByteBuf;
     ///
-    /// fn look_at_bytes() {
-    ///     let json_data = b"\"invalid unicode surrogate: \\uD801\"";
-    ///     let parsed: Result<ByteBuf, _> = serde_json::from_slice(json_data);
-    ///
-    ///     assert!(parsed.is_err());
-    ///
-    ///     let expected_msg = "unexpected end of hex escape at line 1 column 35";
-    ///     assert_eq!(expected_msg, parsed.unwrap_err().to_string());
+    /// fn look_at_bytes() -> Result<(), serde_json::Error> {
+    ///     let json_data = b"\"lone surrogate: \\uD801\"";
+    ///     let bytes: ByteBuf = serde_json::from_slice(json_data)?;
+    ///     let expected = b"lone surrogate: \xED\xA0\x81";
+    ///     assert_eq!(expected, bytes.as_slice());
+    ///     Ok(())
     /// }
     /// #
     /// # look_at_bytes();
@@ -2168,10 +2184,18 @@ where
     }
 
     #[inline]
-    fn deserialize_newtype_struct<V>(self, _name: &'static str, visitor: V) -> Result<V::Value>
+    fn deserialize_newtype_struct<V>(self, name: &'static str, visitor: V) -> Result<V::Value>
     where
         V: de::Visitor<'de>,
     {
+        #[cfg(feature = "raw_value")]
+        {
+            if name == crate::raw::TOKEN {
+                return self.de.deserialize_raw_value(visitor);
+            }
+        }
+
+        let _ = name;
         visitor.visit_newtype_struct(self)
     }
 
diff --git a/src/error.rs b/src/error.rs
index 4219d32..6390c43 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -1,9 +1,14 @@
 //! When serializing or deserializing JSON goes wrong.
 
 use crate::io;
-use crate::lib::str::FromStr;
-use crate::lib::*;
+use alloc::boxed::Box;
+use alloc::string::{String, ToString};
+use core::fmt::{self, Debug, Display};
+use core::result;
+use core::str::FromStr;
 use serde::{de, ser};
+#[cfg(feature = "std")]
+use std::error;
 
 /// This type represents all possible errors that can occur when serializing or
 /// deserializing JSON data.
diff --git a/src/io/core.rs b/src/io/core.rs
index 97354eb..465ab8b 100644
--- a/src/io/core.rs
+++ b/src/io/core.rs
@@ -1,7 +1,9 @@
 //! Reimplements core logic and types from `std::io` in an `alloc`-friendly
 //! fashion.
 
-use crate::lib::*;
+use alloc::vec::Vec;
+use core::fmt::{self, Display};
+use core::result;
 
 pub enum ErrorKind {
     Other,
diff --git a/src/lexical/algorithm.rs b/src/lexical/algorithm.rs
index d01e5b9..a2cbf18 100644
--- a/src/lexical/algorithm.rs
+++ b/src/lexical/algorithm.rs
@@ -133,7 +133,7 @@ where
         let shift = fp.normalize();
         errors <<= shift;
 
-        u64::error_is_accurate::<F>(errors, &fp)
+        u64::error_is_accurate::<F>(errors, fp)
     }
 }
 
diff --git a/src/lexical/bhcomp.rs b/src/lexical/bhcomp.rs
index 6d76c59..1f2a7bb 100644
--- a/src/lexical/bhcomp.rs
+++ b/src/lexical/bhcomp.rs
@@ -12,7 +12,7 @@ use super::float::*;
 use super::math::*;
 use super::num::*;
 use super::rounding::*;
-use crate::lib::{cmp, mem};
+use core::{cmp, mem};
 
 // MANTISSA
 
diff --git a/src/lexical/bignum.rs b/src/lexical/bignum.rs
index dee4e68..f9551f5 100644
--- a/src/lexical/bignum.rs
+++ b/src/lexical/bignum.rs
@@ -3,7 +3,7 @@
 //! Big integer type definition.
 
 use super::math::*;
-use crate::lib::Vec;
+use alloc::vec::Vec;
 
 /// Storage for a big integer type.
 #[derive(Clone, PartialEq, Eq)]
diff --git a/src/lexical/float.rs b/src/lexical/float.rs
index e320ead..2d434a2 100644
--- a/src/lexical/float.rs
+++ b/src/lexical/float.rs
@@ -108,7 +108,7 @@ impl ExtendedFloat {
         F: Float,
         Algorithm: FnOnce(&mut ExtendedFloat, i32),
     {
-        round_to_native::<F, _>(self, algorithm)
+        round_to_native::<F, _>(self, algorithm);
     }
 
     // FROM
diff --git a/src/lexical/math.rs b/src/lexical/math.rs
index 4890c0f..37cc1d2 100644
--- a/src/lexical/math.rs
+++ b/src/lexical/math.rs
@@ -9,7 +9,8 @@
 use super::large_powers;
 use super::num::*;
 use super::small_powers::*;
-use crate::lib::{cmp, iter, mem, Vec};
+use alloc::vec::Vec;
+use core::{cmp, iter, mem};
 
 // ALIASES
 // -------
@@ -593,7 +594,7 @@ mod large {
 
         // Iteratively add elements from y to x.
         let mut carry = false;
-        for (xi, yi) in (&mut x[xstart..]).iter_mut().zip(y.iter()) {
+        for (xi, yi) in x[xstart..].iter_mut().zip(y.iter()) {
             // Only one op of the two can overflow, since we added at max
             // Limb::max_value() + Limb::max_value(). Add the previous carry,
             // and store the current carry for the next.
@@ -613,7 +614,7 @@ mod large {
     /// AddAssign bigint to bigint.
     #[inline]
     pub fn iadd(x: &mut Vec<Limb>, y: &[Limb]) {
-        iadd_impl(x, y, 0)
+        iadd_impl(x, y, 0);
     }
 
     /// Add bigint to bigint.
@@ -859,13 +860,13 @@ pub(crate) trait Math: Clone + Sized + Default {
     /// Multiply by a power of 2.
     #[inline]
     fn imul_pow2(&mut self, n: u32) {
-        self.ishl(n as usize)
+        self.ishl(n as usize);
     }
 
     /// Multiply by a power of 5.
     #[inline]
     fn imul_pow5(&mut self, n: u32) {
-        small::imul_pow5(self.data_mut(), n)
+        small::imul_pow5(self.data_mut(), n);
     }
 
     /// MulAssign by a power of 10.
diff --git a/src/lexical/num.rs b/src/lexical/num.rs
index 27c78ed..e47e003 100644
--- a/src/lexical/num.rs
+++ b/src/lexical/num.rs
@@ -2,7 +2,7 @@
 
 //! Utilities for Rust numbers.
 
-use crate::lib::ops;
+use core::ops;
 
 /// Precalculated values of radix**i for i in range [0, arr.len()-1].
 /// Each value can be **exactly** represented as that type.
diff --git a/src/lexical/rounding.rs b/src/lexical/rounding.rs
index d2704c9..6ec1292 100644
--- a/src/lexical/rounding.rs
+++ b/src/lexical/rounding.rs
@@ -5,7 +5,7 @@
 use super::float::ExtendedFloat;
 use super::num::*;
 use super::shift::*;
-use crate::lib::mem;
+use core::mem;
 
 // MASKS
 
diff --git a/src/lexical/shift.rs b/src/lexical/shift.rs
index b0bd469..a0bae01 100644
--- a/src/lexical/shift.rs
+++ b/src/lexical/shift.rs
@@ -3,7 +3,7 @@
 //! Bit-shift helpers.
 
 use super::float::ExtendedFloat;
-use crate::lib::mem;
+use core::mem;
 
 // Shift extended-precision float right `shift` bytes.
 #[inline]
diff --git a/src/lib.rs b/src/lib.rs
index 319ce71..63846e7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -300,10 +300,10 @@
 //! [macro]: https://docs.serde.rs/serde_json/macro.json.html
 //! [`serde-json-core`]: https://github.com/rust-embedded-community/serde-json-core
 
-#![doc(html_root_url = "https://docs.rs/serde_json/1.0.68")]
-#![deny(clippy::all, clippy::pedantic)]
+#![doc(html_root_url = "https://docs.rs/serde_json/1.0.79")]
 // Ignored clippy lints
 #![allow(
+    clippy::collapsible_else_if,
     clippy::comparison_chain,
     clippy::deprecated_cfg_attr,
     clippy::doc_markdown,
@@ -313,6 +313,10 @@
     clippy::match_like_matches_macro,
     clippy::match_single_binding,
     clippy::needless_doctest_main,
+    clippy::needless_late_init,
+    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/8366
+    clippy::ptr_arg,
+    clippy::return_self_not_must_use,
     clippy::transmute_ptr_to_ptr,
     clippy::unnecessary_wraps,
     // clippy bug: https://github.com/rust-lang/rust-clippy/issues/5704
@@ -320,6 +324,8 @@
 )]
 // Ignored clippy_pedantic lints
 #![allow(
+    // buggy
+    clippy::iter_not_returning_iterator, // https://github.com/rust-lang/rust-clippy/issues/8285
     // Deserializer::from_str, into_iter
     clippy::should_implement_trait,
     // integer and float ser/de requires these sorts of casts
@@ -359,65 +365,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 #![cfg_attr(docsrs, feature(doc_cfg))]
 
-////////////////////////////////////////////////////////////////////////////////
-
-#[cfg(not(feature = "std"))]
 extern crate alloc;
 
-/// A facade around all the types we need from the `std`, `core`, and `alloc`
-/// crates. This avoids elaborate import wrangling having to happen in every
-/// module.
-mod lib {
-    mod core {
-        #[cfg(not(feature = "std"))]
-        pub use core::*;
-        #[cfg(feature = "std")]
-        pub use std::*;
-    }
-
-    pub use self::core::cell::{Cell, RefCell};
-    pub use self::core::clone::{self, Clone};
-    pub use self::core::convert::{self, From, Into};
-    pub use self::core::default::{self, Default};
-    pub use self::core::fmt::{self, Debug, Display};
-    pub use self::core::hash::{self, Hash};
-    pub use self::core::iter::FusedIterator;
-    pub use self::core::marker::{self, PhantomData};
-    pub use self::core::ops::{Bound, RangeBounds};
-    pub use self::core::result::{self, Result};
-    pub use self::core::{borrow, char, cmp, iter, mem, num, ops, slice, str};
-
-    #[cfg(not(feature = "std"))]
-    pub use alloc::borrow::{Cow, ToOwned};
-    #[cfg(feature = "std")]
-    pub use std::borrow::{Cow, ToOwned};
-
-    #[cfg(not(feature = "std"))]
-    pub use alloc::string::{String, ToString};
-    #[cfg(feature = "std")]
-    pub use std::string::{String, ToString};
-
-    #[cfg(not(feature = "std"))]
-    pub use alloc::vec::{self, Vec};
-    #[cfg(feature = "std")]
-    pub use std::vec::{self, Vec};
-
-    #[cfg(not(feature = "std"))]
-    pub use alloc::boxed::Box;
-    #[cfg(feature = "std")]
-    pub use std::boxed::Box;
-
-    #[cfg(not(feature = "std"))]
-    pub use alloc::collections::{btree_map, BTreeMap};
-    #[cfg(feature = "std")]
-    pub use std::collections::{btree_map, BTreeMap};
-
-    #[cfg(feature = "std")]
-    pub use std::error;
-}
-
-////////////////////////////////////////////////////////////////////////////////
-
 #[cfg(feature = "std")]
 #[doc(inline)]
 pub use crate::de::from_reader;
@@ -436,15 +385,12 @@ pub use crate::value::{from_value, to_value, Map, Number, Value};
 // We only use our own error type; no need for From conversions provided by the
 // standard library's try! macro. This reduces lines of LLVM IR by 4%.
 macro_rules! tri {
-    ($e:expr) => {
+    ($e:expr $(,)?) => {
         match $e {
-            crate::lib::Result::Ok(val) => val,
-            crate::lib::Result::Err(err) => return crate::lib::Result::Err(err),
+            core::result::Result::Ok(val) => val,
+            core::result::Result::Err(err) => return core::result::Result::Err(err),
         }
     };
-    ($e:expr,) => {
-        tri!($e)
-    };
 }
 
 #[macro_use]
diff --git a/src/map.rs b/src/map.rs
index 716f128..146eb6a 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -6,12 +6,19 @@
 //! [`BTreeMap`]: https://doc.rust-lang.org/std/collections/struct.BTreeMap.html
 //! [`IndexMap`]: https://docs.rs/indexmap/*/indexmap/map/struct.IndexMap.html
 
-use crate::lib::borrow::Borrow;
-use crate::lib::iter::FromIterator;
-use crate::lib::*;
 use crate::value::Value;
+use alloc::string::String;
+use core::borrow::Borrow;
+use core::fmt::{self, Debug};
+use core::hash::Hash;
+use core::iter::{FromIterator, FusedIterator};
+#[cfg(feature = "preserve_order")]
+use core::mem;
+use core::ops;
 use serde::de;
 
+#[cfg(not(feature = "preserve_order"))]
+use alloc::collections::{btree_map, BTreeMap};
 #[cfg(feature = "preserve_order")]
 use indexmap::{self, IndexMap};
 
@@ -94,6 +101,20 @@ impl Map<String, Value> {
         self.map.get_mut(key)
     }
 
+    /// Returns the key-value pair matching the given key.
+    ///
+    /// The key may be any borrowed form of the map's key type, but the ordering
+    /// on the borrowed form *must* match the ordering on the key type.
+    #[inline]
+    #[cfg(any(feature = "preserve_order", not(no_btreemap_get_key_value)))]
+    pub fn get_key_value<Q>(&self, key: &Q) -> Option<(&String, &Value)>
+    where
+        String: Borrow<Q>,
+        Q: ?Sized + Ord + Eq + Hash,
+    {
+        self.map.get_key_value(key)
+    }
+
     /// Inserts a key-value pair into the map.
     ///
     /// If the map did not have this key present, `None` is returned.
@@ -151,6 +172,8 @@ impl Map<String, Value> {
             no_btreemap_get_key_value,
         ))]
         {
+            use core::ops::{Bound, RangeBounds};
+
             struct Key<'a, Q: ?Sized>(&'a Q);
 
             impl<'a, Q: ?Sized> RangeBounds<Q> for Key<'a, Q> {
@@ -188,7 +211,7 @@ impl Map<String, Value> {
         S: Into<String>,
     {
         #[cfg(not(feature = "preserve_order"))]
-        use crate::lib::btree_map::Entry as EntryImpl;
+        use alloc::collections::btree_map::Entry as EntryImpl;
         #[cfg(feature = "preserve_order")]
         use indexmap::map::Entry as EntryImpl;
 
@@ -249,6 +272,19 @@ impl Map<String, Value> {
             iter: self.map.values_mut(),
         }
     }
+
+    /// Retains only the elements specified by the predicate.
+    ///
+    /// In other words, remove all pairs `(k, v)` such that `f(&k, &mut v)`
+    /// returns `false`.
+    #[cfg(not(no_btreemap_retain))]
+    #[inline]
+    pub fn retain<F>(&mut self, f: F)
+    where
+        F: FnMut(&String, &mut Value) -> bool,
+    {
+        self.map.retain(f);
+    }
 }
 
 #[allow(clippy::derivable_impls)] // clippy bug: https://github.com/rust-lang/rust-clippy/issues/7655
diff --git a/src/number.rs b/src/number.rs
index c147618..b965271 100644
--- a/src/number.rs
+++ b/src/number.rs
@@ -1,6 +1,8 @@
 use crate::de::ParserNumber;
 use crate::error::Error;
-use crate::lib::*;
+use core::fmt::{self, Debug, Display};
+#[cfg(not(feature = "arbitrary_precision"))]
+use core::hash::{Hash, Hasher};
 use serde::de::{self, Unexpected, Visitor};
 use serde::{
     forward_to_deserialize_any, serde_if_integer128, Deserialize, Deserializer, Serialize,
@@ -16,13 +18,13 @@ use serde::de::{IntoDeserializer, MapAccess};
 pub(crate) const TOKEN: &str = "$serde_json::private::Number";
 
 /// Represents a JSON number, whether integer or floating point.
-#[derive(Clone, Eq, PartialEq)]
+#[derive(Clone, PartialEq, Eq, Hash)]
 pub struct Number {
     n: N,
 }
 
 #[cfg(not(feature = "arbitrary_precision"))]
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone)]
 enum N {
     PosInt(u64),
     /// Always less than zero.
@@ -31,10 +33,42 @@ enum N {
     Float(f64),
 }
 
+#[cfg(not(feature = "arbitrary_precision"))]
+impl PartialEq for N {
+    fn eq(&self, other: &Self) -> bool {
+        match (self, other) {
+            (N::PosInt(a), N::PosInt(b)) => a == b,
+            (N::NegInt(a), N::NegInt(b)) => a == b,
+            (N::Float(a), N::Float(b)) => a == b,
+            _ => false,
+        }
+    }
+}
+
 // Implementing Eq is fine since any float values are always finite.
 #[cfg(not(feature = "arbitrary_precision"))]
 impl Eq for N {}
 
+#[cfg(not(feature = "arbitrary_precision"))]
+impl Hash for N {
+    fn hash<H: Hasher>(&self, h: &mut H) {
+        match *self {
+            N::PosInt(i) => i.hash(h),
+            N::NegInt(i) => i.hash(h),
+            N::Float(f) => {
+                if f == 0.0f64 {
+                    // There are 2 zero representations, +0 and -0, which
+                    // compare equal but have different bits. We use the +0 hash
+                    // for both so that hash(+0) == hash(-0).
+                    0.0f64.to_bits().hash(h);
+                } else {
+                    f.to_bits().hash(h);
+                }
+            }
+        }
+    }
+}
+
 #[cfg(feature = "arbitrary_precision")]
 type N = String;
 
@@ -130,7 +164,7 @@ impl Number {
         {
             for c in self.n.chars() {
                 if c == '.' || c == 'e' || c == 'E' {
-                    return self.n.parse::<f64>().ok().map_or(false, |f| f.is_finite());
+                    return self.n.parse::<f64>().ok().map_or(false, f64::is_finite);
                 }
             }
             false
@@ -254,7 +288,7 @@ impl Number {
     }
 }
 
-impl fmt::Display for Number {
+impl Display for Number {
     #[cfg(not(feature = "arbitrary_precision"))]
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         match self.n {
diff --git a/src/raw.rs b/src/raw.rs
index b8d04ee..c8377ac 100644
--- a/src/raw.rs
+++ b/src/raw.rs
@@ -1,5 +1,9 @@
 use crate::error::Error;
-use crate::lib::*;
+use alloc::borrow::ToOwned;
+use alloc::boxed::Box;
+use alloc::string::String;
+use core::fmt::{self, Debug, Display};
+use core::mem;
 use serde::de::value::BorrowedStrDeserializer;
 use serde::de::{
     self, Deserialize, DeserializeSeed, Deserializer, IntoDeserializer, MapAccess, Unexpected,
@@ -122,6 +126,10 @@ impl RawValue {
     fn from_owned(json: Box<str>) -> Box<Self> {
         unsafe { mem::transmute::<Box<str>, Box<RawValue>>(json) }
     }
+
+    fn into_owned(raw_value: Box<Self>) -> Box<str> {
+        unsafe { mem::transmute::<Box<RawValue>, Box<str>>(raw_value) }
+    }
 }
 
 impl Clone for Box<RawValue> {
@@ -216,6 +224,12 @@ impl RawValue {
     }
 }
 
+impl From<Box<RawValue>> for Box<str> {
+    fn from(raw_value: Box<RawValue>) -> Self {
+        RawValue::into_owned(raw_value)
+    }
+}
+
 /// Convert a `T` into a boxed `RawValue`.
 ///
 /// # Example
@@ -271,7 +285,7 @@ impl RawValue {
 #[cfg_attr(docsrs, doc(cfg(feature = "raw_value")))]
 pub fn to_raw_value<T>(value: &T) -> Result<Box<RawValue>, Error>
 where
-    T: Serialize,
+    T: ?Sized + Serialize,
 {
     let json_string = crate::to_string(value)?;
     Ok(RawValue::from_owned(json_string.into_boxed_str()))
@@ -435,9 +449,10 @@ impl<'de> Visitor<'de> for BoxedFromString {
     where
         E: de::Error,
     {
-        self.visit_string(s.to_owned())
+        Ok(RawValue::from_owned(s.to_owned().into_boxed_str()))
     }
 
+    #[cfg(any(feature = "std", feature = "alloc"))]
     fn visit_string<E>(self, s: String) -> Result<Self::Value, E>
     where
         E: de::Error,
diff --git a/src/read.rs b/src/read.rs
index 8ed3d7d..1319d89 100644
--- a/src/read.rs
+++ b/src/read.rs
@@ -1,6 +1,9 @@
 use crate::error::{Error, ErrorCode, Result};
-use crate::lib::ops::Deref;
-use crate::lib::*;
+use alloc::vec::Vec;
+use core::char;
+use core::cmp;
+use core::ops::Deref;
+use core::str;
 
 #[cfg(feature = "std")]
 use crate::io;
@@ -225,7 +228,7 @@ where
                     return result(self, scratch);
                 }
                 b'\\' => {
-                    tri!(parse_escape(self, scratch));
+                    tri!(parse_escape(self, validate, scratch));
                 }
                 _ => {
                     if validate {
@@ -465,7 +468,7 @@ impl<'a> SliceRead<'a> {
                 b'\\' => {
                     scratch.extend_from_slice(&self.slice[start..self.index]);
                     self.index += 1;
-                    tri!(parse_escape(self, scratch));
+                    tri!(parse_escape(self, validate, scratch));
                     start = self.index;
                 }
                 _ => {
@@ -654,8 +657,9 @@ impl<'a> Read<'a> for StrRead<'a> {
 
     fn parse_str<'s>(&'s mut self, scratch: &'s mut Vec<u8>) -> Result<Reference<'a, 's, str>> {
         self.delegate.parse_str_bytes(scratch, true, |_, bytes| {
-            // The input is assumed to be valid UTF-8 and the \u-escapes are
-            // checked along the way, so don't need to check here.
+            // The deserialization input came in as &str with a UTF-8 guarantee,
+            // and the \u-escapes are checked along the way, so don't need to
+            // check here.
             Ok(unsafe { str::from_utf8_unchecked(bytes) })
         })
     }
@@ -677,7 +681,7 @@ impl<'a> Read<'a> for StrRead<'a> {
 
     #[cfg(feature = "raw_value")]
     fn begin_raw_buffering(&mut self) {
-        self.delegate.begin_raw_buffering()
+        self.delegate.begin_raw_buffering();
     }
 
     #[cfg(feature = "raw_value")]
@@ -753,7 +757,7 @@ where
 
     #[cfg(feature = "raw_value")]
     fn begin_raw_buffering(&mut self) {
-        R::begin_raw_buffering(self)
+        R::begin_raw_buffering(self);
     }
 
     #[cfg(feature = "raw_value")]
@@ -816,6 +820,16 @@ where
     }
 }
 
+fn peek_or_eof<'de, R>(read: &mut R) -> Result<u8>
+where
+    R: ?Sized + Read<'de>,
+{
+    match tri!(read.peek()) {
+        Some(b) => Ok(b),
+        None => error(read, ErrorCode::EofWhileParsingString),
+    }
+}
+
 fn error<'de, R, T>(read: &R, reason: ErrorCode) -> Result<T>
 where
     R: ?Sized + Read<'de>,
@@ -830,7 +844,11 @@ fn as_str<'de, 's, R: Read<'de>>(read: &R, slice: &'s [u8]) -> Result<&'s str> {
 
 /// Parses a JSON escape sequence and appends it into the scratch space. Assumes
 /// the previous byte read was a backslash.
-fn parse_escape<'de, R: Read<'de>>(read: &mut R, scratch: &mut Vec<u8>) -> Result<()> {
+fn parse_escape<'de, R: Read<'de>>(
+    read: &mut R,
+    validate: bool,
+    scratch: &mut Vec<u8>,
+) -> Result<()> {
     let ch = tri!(next_or_eof(read));
 
     match ch {
@@ -843,19 +861,56 @@ fn parse_escape<'de, R: Read<'de>>(read: &mut R, scratch: &mut Vec<u8>) -> Resul
         b'r' => scratch.push(b'\r'),
         b't' => scratch.push(b'\t'),
         b'u' => {
+            fn encode_surrogate(scratch: &mut Vec<u8>, n: u16) {
+                scratch.extend_from_slice(&[
+                    (n >> 12 & 0b0000_1111) as u8 | 0b1110_0000,
+                    (n >> 6 & 0b0011_1111) as u8 | 0b1000_0000,
+                    (n & 0b0011_1111) as u8 | 0b1000_0000,
+                ]);
+            }
+
             let c = match tri!(read.decode_hex_escape()) {
-                0xDC00..=0xDFFF => {
-                    return error(read, ErrorCode::LoneLeadingSurrogateInHexEscape);
+                n @ 0xDC00..=0xDFFF => {
+                    return if validate {
+                        error(read, ErrorCode::LoneLeadingSurrogateInHexEscape)
+                    } else {
+                        encode_surrogate(scratch, n);
+                        Ok(())
+                    };
                 }
 
-                // Non-BMP characters are encoded as a sequence of
-                // two hex escapes, representing UTF-16 surrogates.
+                // Non-BMP characters are encoded as a sequence of two hex
+                // escapes, representing UTF-16 surrogates. If deserializing a
+                // utf-8 string the surrogates are required to be paired,
+                // whereas deserializing a byte string accepts lone surrogates.
                 n1 @ 0xD800..=0xDBFF => {
-                    if tri!(next_or_eof(read)) != b'\\' {
-                        return error(read, ErrorCode::UnexpectedEndOfHexEscape);
+                    if tri!(peek_or_eof(read)) == b'\\' {
+                        read.discard();
+                    } else {
+                        return if validate {
+                            read.discard();
+                            error(read, ErrorCode::UnexpectedEndOfHexEscape)
+                        } else {
+                            encode_surrogate(scratch, n1);
+                            Ok(())
+                        };
                     }
-                    if tri!(next_or_eof(read)) != b'u' {
-                        return error(read, ErrorCode::UnexpectedEndOfHexEscape);
+
+                    if tri!(peek_or_eof(read)) == b'u' {
+                        read.discard();
+                    } else {
+                        return if validate {
+                            read.discard();
+                            error(read, ErrorCode::UnexpectedEndOfHexEscape)
+                        } else {
+                            encode_surrogate(scratch, n1);
+                            // The \ prior to this byte started an escape sequence,
+                            // so we need to parse that now. This recursive call
+                            // does not blow the stack on malicious input because
+                            // the escape is not \u, so it will be handled by one
+                            // of the easy nonrecursive cases.
+                            parse_escape(read, validate, scratch)
+                        };
                     }
 
                     let n2 = tri!(read.decode_hex_escape());
@@ -874,12 +929,9 @@ fn parse_escape<'de, R: Read<'de>>(read: &mut R, scratch: &mut Vec<u8>) -> Resul
                     }
                 }
 
-                n => match char::from_u32(n as u32) {
-                    Some(c) => c,
-                    None => {
-                        return error(read, ErrorCode::InvalidUnicodeCodePoint);
-                    }
-                },
+                // Every u16 outside of the surrogate ranges above is guaranteed
+                // to be a legal char.
+                n => char::from_u32(n as u32).unwrap(),
             };
 
             scratch.extend_from_slice(c.encode_utf8(&mut [0_u8; 4]).as_bytes());
@@ -903,36 +955,13 @@ where
     match ch {
         b'"' | b'\\' | b'/' | b'b' | b'f' | b'n' | b'r' | b't' => {}
         b'u' => {
-            let n = match tri!(read.decode_hex_escape()) {
-                0xDC00..=0xDFFF => {
-                    return error(read, ErrorCode::LoneLeadingSurrogateInHexEscape);
-                }
+            // At this point we don't care if the codepoint is valid. We just
+            // want to consume it. We don't actually know what is valid or not
+            // at this point, because that depends on if this string will
+            // ultimately be parsed into a string or a byte buffer in the "real"
+            // parse.
 
-                // Non-BMP characters are encoded as a sequence of
-                // two hex escapes, representing UTF-16 surrogates.
-                n1 @ 0xD800..=0xDBFF => {
-                    if tri!(next_or_eof(read)) != b'\\' {
-                        return error(read, ErrorCode::UnexpectedEndOfHexEscape);
-                    }
-                    if tri!(next_or_eof(read)) != b'u' {
-                        return error(read, ErrorCode::UnexpectedEndOfHexEscape);
-                    }
-
-                    let n2 = tri!(read.decode_hex_escape());
-
-                    if n2 < 0xDC00 || n2 > 0xDFFF {
-                        return error(read, ErrorCode::LoneLeadingSurrogateInHexEscape);
-                    }
-
-                    (((n1 - 0xD800) as u32) << 10 | (n2 - 0xDC00) as u32) + 0x1_0000
-                }
-
-                n => n as u32,
-            };
-
-            if char::from_u32(n).is_none() {
-                return error(read, ErrorCode::InvalidUnicodeCodePoint);
-            }
+            tri!(read.decode_hex_escape());
         }
         _ => {
             return error(read, ErrorCode::InvalidEscape);
diff --git a/src/ser.rs b/src/ser.rs
index 54b0bf2..db77cd8 100644
--- a/src/ser.rs
+++ b/src/ser.rs
@@ -2,8 +2,10 @@
 
 use crate::error::{Error, ErrorCode, Result};
 use crate::io;
-use crate::lib::num::FpCategory;
-use crate::lib::*;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use core::fmt::{self, Display};
+use core::num::FpCategory;
 use serde::ser::{self, Impossible, Serialize};
 use serde::serde_if_integer128;
 
@@ -756,7 +758,7 @@ where
             #[cfg(feature = "arbitrary_precision")]
             Compound::Number { ref mut ser, .. } => {
                 if key == crate::number::TOKEN {
-                    tri!(value.serialize(NumberStrEmitter(&mut *ser)));
+                    tri!(value.serialize(NumberStrEmitter(ser)));
                     Ok(())
                 } else {
                     Err(invalid_number())
@@ -765,7 +767,7 @@ where
             #[cfg(feature = "raw_value")]
             Compound::RawValue { ref mut ser, .. } => {
                 if key == crate::raw::TOKEN {
-                    tri!(value.serialize(RawValueStrEmitter(&mut *ser)));
+                    tri!(value.serialize(RawValueStrEmitter(ser)));
                     Ok(())
                 } else {
                     Err(invalid_raw_value())
@@ -1546,6 +1548,13 @@ impl<'a, W: io::Write, F: Formatter> ser::Serializer for RawValueStrEmitter<'a,
     ) -> Result<Self::SerializeStructVariant> {
         Err(ser::Error::custom("expected RawValue"))
     }
+
+    fn collect_str<T>(self, value: &T) -> Result<Self::Ok>
+    where
+        T: ?Sized + Display,
+    {
+        self.serialize_str(&value.to_string())
+    }
 }
 
 /// Represents a character escape code in a type-safe manner.
diff --git a/src/value/de.rs b/src/value/de.rs
index 24ca826..75e49df 100644
--- a/src/value/de.rs
+++ b/src/value/de.rs
@@ -1,9 +1,15 @@
 use crate::error::Error;
-use crate::lib::str::FromStr;
-use crate::lib::*;
 use crate::map::Map;
 use crate::number::Number;
 use crate::value::Value;
+use alloc::borrow::{Cow, ToOwned};
+use alloc::string::String;
+#[cfg(feature = "raw_value")]
+use alloc::string::ToString;
+use alloc::vec::{self, Vec};
+use core::fmt;
+use core::slice;
+use core::str::FromStr;
 use serde::de::{
     self, Deserialize, DeserializeSeed, EnumAccess, Expected, IntoDeserializer, MapAccess,
     SeqAccess, Unexpected, VariantAccess, Visitor,
diff --git a/src/value/from.rs b/src/value/from.rs
index 59e09fd..7b37ef6 100644
--- a/src/value/from.rs
+++ b/src/value/from.rs
@@ -1,8 +1,10 @@
 use super::Value;
-use crate::lib::iter::FromIterator;
-use crate::lib::*;
 use crate::map::Map;
 use crate::number::Number;
+use alloc::borrow::Cow;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use core::iter::FromIterator;
 
 #[cfg(feature = "arbitrary_precision")]
 use serde::serde_if_integer128;
diff --git a/src/value/index.rs b/src/value/index.rs
index d759a1d..0d90a5d 100644
--- a/src/value/index.rs
+++ b/src/value/index.rs
@@ -1,6 +1,9 @@
 use super::Value;
-use crate::lib::*;
 use crate::map::Map;
+use alloc::borrow::ToOwned;
+use alloc::string::String;
+use core::fmt::{self, Display};
+use core::ops;
 
 /// A type that can be used to index into a `serde_json::Value`.
 ///
@@ -133,14 +136,14 @@ mod private {
     pub trait Sealed {}
     impl Sealed for usize {}
     impl Sealed for str {}
-    impl Sealed for super::String {}
+    impl Sealed for alloc::string::String {}
     impl<'a, T> Sealed for &'a T where T: ?Sized + Sealed {}
 }
 
 /// Used in panic messages.
 struct Type<'a>(&'a Value);
 
-impl<'a> fmt::Display for Type<'a> {
+impl<'a> Display for Type<'a> {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         match *self.0 {
             Value::Null => formatter.write_str("null"),
diff --git a/src/value/mod.rs b/src/value/mod.rs
index a28da66..3f00c95 100644
--- a/src/value/mod.rs
+++ b/src/value/mod.rs
@@ -92,7 +92,11 @@
 
 use crate::error::Error;
 use crate::io;
-use crate::lib::*;
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::fmt::{self, Debug, Display};
+use core::mem;
+use core::str;
 use serde::de::DeserializeOwned;
 use serde::ser::Serialize;
 
@@ -191,7 +195,7 @@ impl Debug for Value {
     }
 }
 
-impl fmt::Display for Value {
+impl Display for Value {
     /// Display a JSON value as a string.
     ///
     /// ```
diff --git a/src/value/partial_eq.rs b/src/value/partial_eq.rs
index 354ea5a..b4ef84c 100644
--- a/src/value/partial_eq.rs
+++ b/src/value/partial_eq.rs
@@ -1,5 +1,5 @@
 use super::Value;
-use crate::lib::*;
+use alloc::string::String;
 
 fn eq_i64(value: &Value, other: i64) -> bool {
     value.as_i64().map_or(false, |i| i == other)
diff --git a/src/value/ser.rs b/src/value/ser.rs
index 03cb12b..179380a 100644
--- a/src/value/ser.rs
+++ b/src/value/ser.rs
@@ -1,8 +1,12 @@
 use crate::error::{Error, ErrorCode, Result};
-use crate::lib::*;
 use crate::map::Map;
 use crate::number::Number;
 use crate::value::{to_value, Value};
+use alloc::borrow::ToOwned;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use core::fmt::Display;
+use core::result;
 use serde::ser::{Impossible, Serialize};
 
 #[cfg(feature = "arbitrary_precision")]
@@ -1016,4 +1020,11 @@ impl serde::ser::Serializer for RawValueEmitter {
     ) -> Result<Self::SerializeStructVariant> {
         Err(invalid_raw_value())
     }
+
+    fn collect_str<T>(self, value: &T) -> Result<Self::Ok>
+    where
+        T: ?Sized + Display,
+    {
+        self.serialize_str(&value.to_string())
+    }
 }