Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 1258 insertions, 0 deletions

diff --git a/rust/proc-macro2/fallback.rs b/rust/proc-macro2/fallback.rs
new file mode 100644
index 000000000..9b43c97df
--- /dev/null
+++ b/rust/proc-macro2/fallback.rs
@@ -0,0 +1,1258 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+#[cfg(wrap_proc_macro)]
+use crate::imp;
+#[cfg(span_locations)]
+use crate::location::LineColumn;
+use crate::parse::{self, Cursor};
+use crate::rcvec::{RcVec, RcVecBuilder, RcVecIntoIter, RcVecMut};
+use crate::{Delimiter, Spacing, TokenTree};
+#[cfg(all(span_locations, not(fuzzing)))]
+use alloc::collections::BTreeMap;
+#[cfg(all(span_locations, not(fuzzing)))]
+use core::cell::RefCell;
+#[cfg(span_locations)]
+use core::cmp;
+#[cfg(all(span_locations, not(fuzzing)))]
+use core::cmp::Ordering;
+use core::fmt::{self, Debug, Display, Write};
+use core::mem::ManuallyDrop;
+#[cfg(span_locations)]
+use core::ops::Range;
+use core::ops::RangeBounds;
+use core::ptr;
+use core::str;
+#[cfg(feature = "proc-macro")]
+use core::str::FromStr;
+use std::ffi::CStr;
+#[cfg(wrap_proc_macro)]
+use std::panic;
+#[cfg(span_locations)]
+use std::path::PathBuf;
+
+/// Force use of proc-macro2's fallback implementation of the API for now, even
+/// if the compiler's implementation is available.
+pub fn force() {
+    #[cfg(wrap_proc_macro)]
+    crate::detection::force_fallback();
+}
+
+/// Resume using the compiler's implementation of the proc macro API if it is
+/// available.
+pub fn unforce() {
+    #[cfg(wrap_proc_macro)]
+    crate::detection::unforce_fallback();
+}
+
+#[derive(Clone)]
+pub(crate) struct TokenStream {
+    inner: RcVec<TokenTree>,
+}
+
+#[derive(Debug)]
+pub(crate) struct LexError {
+    pub(crate) span: Span,
+}
+
+impl LexError {
+    pub(crate) fn span(&self) -> Span {
+        self.span
+    }
+
+    pub(crate) fn call_site() -> Self {
+        LexError {
+            span: Span::call_site(),
+        }
+    }
+}
+
+impl TokenStream {
+    pub(crate) fn new() -> Self {
+        TokenStream {
+            inner: RcVecBuilder::new().build(),
+        }
+    }
+
+    pub(crate) fn from_str_checked(src: &str) -> Result<Self, LexError> {
+        // Create a dummy file & add it to the source map
+        let mut cursor = get_cursor(src);
+
+        // Strip a byte order mark if present
+        const BYTE_ORDER_MARK: &str = "\u{feff}";
+        if cursor.starts_with(BYTE_ORDER_MARK) {
+            cursor = cursor.advance(BYTE_ORDER_MARK.len());
+        }
+
+        parse::token_stream(cursor)
+    }
+
+    #[cfg(feature = "proc-macro")]
+    pub(crate) fn from_str_unchecked(src: &str) -> Self {
+        Self::from_str_checked(src).unwrap()
+    }
+
+    pub(crate) fn is_empty(&self) -> bool {
+        self.inner.len() == 0
+    }
+
+    fn take_inner(self) -> RcVecBuilder<TokenTree> {
+        let nodrop = ManuallyDrop::new(self);
+        unsafe { ptr::read(&nodrop.inner) }.make_owned()
+    }
+}
+
+fn push_token_from_proc_macro(mut vec: RcVecMut<TokenTree>, token: TokenTree) {
+    // https://github.com/dtolnay/proc-macro2/issues/235
+    match token {
+        TokenTree::Literal(crate::Literal {
+            #[cfg(wrap_proc_macro)]
+                inner: crate::imp::Literal::Fallback(literal),
+            #[cfg(not(wrap_proc_macro))]
+                inner: literal,
+            ..
+        }) if literal.repr.starts_with('-') => {
+            push_negative_literal(vec, literal);
+        }
+        _ => vec.push(token),
+    }
+
+    #[cold]
+    fn push_negative_literal(mut vec: RcVecMut<TokenTree>, mut literal: Literal) {
+        literal.repr.remove(0);
+        let mut punct = crate::Punct::new('-', Spacing::Alone);
+        punct.set_span(crate::Span::_new_fallback(literal.span));
+        vec.push(TokenTree::Punct(punct));
+        vec.push(TokenTree::Literal(crate::Literal::_new_fallback(literal)));
+    }
+}
+
+// Nonrecursive to prevent stack overflow.
+impl Drop for TokenStream {
+    fn drop(&mut self) {
+        let mut stack = Vec::new();
+        let mut current = match self.inner.get_mut() {
+            Some(inner) => inner.take().into_iter(),
+            None => return,
+        };
+        loop {
+            while let Some(token) = current.next() {
+                let group = match token {
+                    TokenTree::Group(group) => group.inner,
+                    _ => continue,
+                };
+                #[cfg(wrap_proc_macro)]
+                let group = match group {
+                    crate::imp::Group::Fallback(group) => group,
+                    crate::imp::Group::Compiler(_) => continue,
+                };
+                let mut group = group;
+                if let Some(inner) = group.stream.inner.get_mut() {
+                    stack.push(current);
+                    current = inner.take().into_iter();
+                }
+            }
+            match stack.pop() {
+                Some(next) => current = next,
+                None => return,
+            }
+        }
+    }
+}
+
+pub(crate) struct TokenStreamBuilder {
+    inner: RcVecBuilder<TokenTree>,
+}
+
+impl TokenStreamBuilder {
+    pub(crate) fn new() -> Self {
+        TokenStreamBuilder {
+            inner: RcVecBuilder::new(),
+        }
+    }
+
+    pub(crate) fn with_capacity(cap: usize) -> Self {
+        TokenStreamBuilder {
+            inner: RcVecBuilder::with_capacity(cap),
+        }
+    }
+
+    pub(crate) fn push_token_from_parser(&mut self, tt: TokenTree) {
+        self.inner.push(tt);
+    }
+
+    pub(crate) fn build(self) -> TokenStream {
+        TokenStream {
+            inner: self.inner.build(),
+        }
+    }
+}
+
+#[cfg(span_locations)]
+fn get_cursor(src: &str) -> Cursor {
+    #[cfg(fuzzing)]
+    return Cursor { rest: src, off: 1 };
+
+    // Create a dummy file & add it to the source map
+    #[cfg(not(fuzzing))]
+    SOURCE_MAP.with(|sm| {
+        let mut sm = sm.borrow_mut();
+        let span = sm.add_file(src);
+        Cursor {
+            rest: src,
+            off: span.lo,
+        }
+    })
+}
+
+#[cfg(not(span_locations))]
+fn get_cursor(src: &str) -> Cursor {
+    Cursor { rest: src }
+}
+
+impl Display for LexError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str("cannot parse string into token stream")
+    }
+}
+
+impl Display for TokenStream {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut joint = false;
+        for (i, tt) in self.inner.iter().enumerate() {
+            if i != 0 && !joint {
+                write!(f, " ")?;
+            }
+            joint = false;
+            match tt {
+                TokenTree::Group(tt) => Display::fmt(tt, f),
+                TokenTree::Ident(tt) => Display::fmt(tt, f),
+                TokenTree::Punct(tt) => {
+                    joint = tt.spacing() == Spacing::Joint;
+                    Display::fmt(tt, f)
+                }
+                TokenTree::Literal(tt) => Display::fmt(tt, f),
+            }?;
+        }
+
+        Ok(())
+    }
+}
+
+impl Debug for TokenStream {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str("TokenStream ")?;
+        f.debug_list().entries(self.clone()).finish()
+    }
+}
+
+#[cfg(feature = "proc-macro")]
+impl From<proc_macro::TokenStream> for TokenStream {
+    fn from(inner: proc_macro::TokenStream) -> Self {
+        TokenStream::from_str_unchecked(&inner.to_string())
+    }
+}
+
+#[cfg(feature = "proc-macro")]
+impl From<TokenStream> for proc_macro::TokenStream {
+    fn from(inner: TokenStream) -> Self {
+        proc_macro::TokenStream::from_str_unchecked(&inner.to_string())
+    }
+}
+
+impl From<TokenTree> for TokenStream {
+    fn from(tree: TokenTree) -> Self {
+        let mut stream = RcVecBuilder::new();
+        push_token_from_proc_macro(stream.as_mut(), tree);
+        TokenStream {
+            inner: stream.build(),
+        }
+    }
+}
+
+impl FromIterator<TokenTree> for TokenStream {
+    fn from_iter<I: IntoIterator<Item = TokenTree>>(tokens: I) -> Self {
+        let mut stream = TokenStream::new();
+        stream.extend(tokens);
+        stream
+    }
+}
+
+impl FromIterator<TokenStream> for TokenStream {
+    fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
+        let mut v = RcVecBuilder::new();
+
+        for stream in streams {
+            v.extend(stream.take_inner());
+        }
+
+        TokenStream { inner: v.build() }
+    }
+}
+
+impl Extend<TokenTree> for TokenStream {
+    fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, tokens: I) {
+        let mut vec = self.inner.make_mut();
+        tokens
+            .into_iter()
+            .for_each(|token| push_token_from_proc_macro(vec.as_mut(), token));
+    }
+}
+
+impl Extend<TokenStream> for TokenStream {
+    fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
+        self.inner.make_mut().extend(streams.into_iter().flatten());
+    }
+}
+
+pub(crate) type TokenTreeIter = RcVecIntoIter<TokenTree>;
+
+impl IntoIterator for TokenStream {
+    type Item = TokenTree;
+    type IntoIter = TokenTreeIter;
+
+    fn into_iter(self) -> TokenTreeIter {
+        self.take_inner().into_iter()
+    }
+}
+
+#[cfg(all(span_locations, not(fuzzing)))]
+thread_local! {
+    static SOURCE_MAP: RefCell<SourceMap> = RefCell::new(SourceMap {
+        // Start with a single dummy file which all call_site() and def_site()
+        // spans reference.
+        files: vec![FileInfo {
+            source_text: String::new(),
+            span: Span { lo: 0, hi: 0 },
+            lines: vec![0],
+            char_index_to_byte_offset: BTreeMap::new(),
+        }],
+    });
+}
+
+#[cfg(span_locations)]
+pub(crate) fn invalidate_current_thread_spans() {
+    #[cfg(not(fuzzing))]
+    SOURCE_MAP.with(|sm| sm.borrow_mut().files.truncate(1));
+}
+
+#[cfg(all(span_locations, not(fuzzing)))]
+struct FileInfo {
+    source_text: String,
+    span: Span,
+    lines: Vec<usize>,
+    char_index_to_byte_offset: BTreeMap<usize, usize>,
+}
+
+#[cfg(all(span_locations, not(fuzzing)))]
+impl FileInfo {
+    fn offset_line_column(&self, offset: usize) -> LineColumn {
+        assert!(self.span_within(Span {
+            lo: offset as u32,
+            hi: offset as u32,
+        }));
+        let offset = offset - self.span.lo as usize;
+        match self.lines.binary_search(&offset) {
+            Ok(found) => LineColumn {
+                line: found + 1,
+                column: 0,
+            },
+            Err(idx) => LineColumn {
+                line: idx,
+                column: offset - self.lines[idx - 1],
+            },
+        }
+    }
+
+    fn span_within(&self, span: Span) -> bool {
+        span.lo >= self.span.lo && span.hi <= self.span.hi
+    }
+
+    fn byte_range(&mut self, span: Span) -> Range<usize> {
+        let lo_char = (span.lo - self.span.lo) as usize;
+
+        // Look up offset of the largest already-computed char index that is
+        // less than or equal to the current requested one. We resume counting
+        // chars from that point.
+        let (&last_char_index, &last_byte_offset) = self
+            .char_index_to_byte_offset
+            .range(..=lo_char)
+            .next_back()
+            .unwrap_or((&0, &0));
+
+        let lo_byte = if last_char_index == lo_char {
+            last_byte_offset
+        } else {
+            let total_byte_offset = match self.source_text[last_byte_offset..]
+                .char_indices()
+                .nth(lo_char - last_char_index)
+            {
+                Some((additional_offset, _ch)) => last_byte_offset + additional_offset,
+                None => self.source_text.len(),
+            };
+            self.char_index_to_byte_offset
+                .insert(lo_char, total_byte_offset);
+            total_byte_offset
+        };
+
+        let trunc_lo = &self.source_text[lo_byte..];
+        let char_len = (span.hi - span.lo) as usize;
+        lo_byte..match trunc_lo.char_indices().nth(char_len) {
+            Some((offset, _ch)) => lo_byte + offset,
+            None => self.source_text.len(),
+        }
+    }
+
+    fn source_text(&mut self, span: Span) -> String {
+        let byte_range = self.byte_range(span);
+        self.source_text[byte_range].to_owned()
+    }
+}
+
+/// Computes the offsets of each line in the given source string
+/// and the total number of characters
+#[cfg(all(span_locations, not(fuzzing)))]
+fn lines_offsets(s: &str) -> (usize, Vec<usize>) {
+    let mut lines = vec![0];
+    let mut total = 0;
+
+    for ch in s.chars() {
+        total += 1;
+        if ch == '\n' {
+            lines.push(total);
+        }
+    }
+
+    (total, lines)
+}
+
+#[cfg(all(span_locations, not(fuzzing)))]
+struct SourceMap {
+    files: Vec<FileInfo>,
+}
+
+#[cfg(all(span_locations, not(fuzzing)))]
+impl SourceMap {
+    fn next_start_pos(&self) -> u32 {
+        // Add 1 so there's always space between files.
+        //
+        // We'll always have at least 1 file, as we initialize our files list
+        // with a dummy file.
+        self.files.last().unwrap().span.hi + 1
+    }
+
+    fn add_file(&mut self, src: &str) -> Span {
+        let (len, lines) = lines_offsets(src);
+        let lo = self.next_start_pos();
+        let span = Span {
+            lo,
+            hi: lo + (len as u32),
+        };
+
+        self.files.push(FileInfo {
+            source_text: src.to_owned(),
+            span,
+            lines,
+            // Populated lazily by source_text().
+            char_index_to_byte_offset: BTreeMap::new(),
+        });
+
+        span
+    }
+
+    fn find(&self, span: Span) -> usize {
+        match self.files.binary_search_by(|file| {
+            if file.span.hi < span.lo {
+                Ordering::Less
+            } else if file.span.lo > span.hi {
+                Ordering::Greater
+            } else {
+                assert!(file.span_within(span));
+                Ordering::Equal
+            }
+        }) {
+            Ok(i) => i,
+            Err(_) => unreachable!("Invalid span with no related FileInfo!"),
+        }
+    }
+
+    fn filepath(&self, span: Span) -> String {
+        let i = self.find(span);
+        if i == 0 {
+            "<unspecified>".to_owned()
+        } else {
+            format!("<parsed string {}>", i)
+        }
+    }
+
+    fn fileinfo(&self, span: Span) -> &FileInfo {
+        let i = self.find(span);
+        &self.files[i]
+    }
+
+    fn fileinfo_mut(&mut self, span: Span) -> &mut FileInfo {
+        let i = self.find(span);
+        &mut self.files[i]
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub(crate) struct Span {
+    #[cfg(span_locations)]
+    pub(crate) lo: u32,
+    #[cfg(span_locations)]
+    pub(crate) hi: u32,
+}
+
+impl Span {
+    #[cfg(not(span_locations))]
+    pub(crate) fn call_site() -> Self {
+        Span {}
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn call_site() -> Self {
+        Span { lo: 0, hi: 0 }
+    }
+
+    pub(crate) fn mixed_site() -> Self {
+        Span::call_site()
+    }
+
+    #[cfg(procmacro2_semver_exempt)]
+    pub(crate) fn def_site() -> Self {
+        Span::call_site()
+    }
+
+    pub(crate) fn resolved_at(&self, _other: Span) -> Span {
+        // Stable spans consist only of line/column information, so
+        // `resolved_at` and `located_at` only select which span the
+        // caller wants line/column information from.
+        *self
+    }
+
+    pub(crate) fn located_at(&self, other: Span) -> Span {
+        other
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn byte_range(&self) -> Range<usize> {
+        #[cfg(fuzzing)]
+        return 0..0;
+
+        #[cfg(not(fuzzing))]
+        {
+            if self.is_call_site() {
+                0..0
+            } else {
+                SOURCE_MAP.with(|sm| sm.borrow_mut().fileinfo_mut(*self).byte_range(*self))
+            }
+        }
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn start(&self) -> LineColumn {
+        #[cfg(fuzzing)]
+        return LineColumn { line: 0, column: 0 };
+
+        #[cfg(not(fuzzing))]
+        SOURCE_MAP.with(|sm| {
+            let sm = sm.borrow();
+            let fi = sm.fileinfo(*self);
+            fi.offset_line_column(self.lo as usize)
+        })
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn end(&self) -> LineColumn {
+        #[cfg(fuzzing)]
+        return LineColumn { line: 0, column: 0 };
+
+        #[cfg(not(fuzzing))]
+        SOURCE_MAP.with(|sm| {
+            let sm = sm.borrow();
+            let fi = sm.fileinfo(*self);
+            fi.offset_line_column(self.hi as usize)
+        })
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn file(&self) -> String {
+        #[cfg(fuzzing)]
+        return "<unspecified>".to_owned();
+
+        #[cfg(not(fuzzing))]
+        SOURCE_MAP.with(|sm| {
+            let sm = sm.borrow();
+            sm.filepath(*self)
+        })
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn local_file(&self) -> Option<PathBuf> {
+        None
+    }
+
+    #[cfg(not(span_locations))]
+    pub(crate) fn join(&self, _other: Span) -> Option<Span> {
+        Some(Span {})
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn join(&self, other: Span) -> Option<Span> {
+        #[cfg(fuzzing)]
+        return {
+            let _ = other;
+            None
+        };
+
+        #[cfg(not(fuzzing))]
+        SOURCE_MAP.with(|sm| {
+            let sm = sm.borrow();
+            // If `other` is not within the same FileInfo as us, return None.
+            if !sm.fileinfo(*self).span_within(other) {
+                return None;
+            }
+            Some(Span {
+                lo: cmp::min(self.lo, other.lo),
+                hi: cmp::max(self.hi, other.hi),
+            })
+        })
+    }
+
+    #[cfg(not(span_locations))]
+    pub(crate) fn source_text(&self) -> Option<String> {
+        None
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn source_text(&self) -> Option<String> {
+        #[cfg(fuzzing)]
+        return None;
+
+        #[cfg(not(fuzzing))]
+        {
+            if self.is_call_site() {
+                None
+            } else {
+                Some(SOURCE_MAP.with(|sm| sm.borrow_mut().fileinfo_mut(*self).source_text(*self)))
+            }
+        }
+    }
+
+    #[cfg(not(span_locations))]
+    pub(crate) fn first_byte(self) -> Self {
+        self
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn first_byte(self) -> Self {
+        Span {
+            lo: self.lo,
+            hi: cmp::min(self.lo.saturating_add(1), self.hi),
+        }
+    }
+
+    #[cfg(not(span_locations))]
+    pub(crate) fn last_byte(self) -> Self {
+        self
+    }
+
+    #[cfg(span_locations)]
+    pub(crate) fn last_byte(self) -> Self {
+        Span {
+            lo: cmp::max(self.hi.saturating_sub(1), self.lo),
+            hi: self.hi,
+        }
+    }
+
+    #[cfg(span_locations)]
+    fn is_call_site(&self) -> bool {
+        self.lo == 0 && self.hi == 0
+    }
+}
+
+impl Debug for Span {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        #[cfg(span_locations)]
+        return write!(f, "bytes({}..{})", self.lo, self.hi);
+
+        #[cfg(not(span_locations))]
+        write!(f, "Span")
+    }
+}
+
+pub(crate) fn debug_span_field_if_nontrivial(debug: &mut fmt::DebugStruct, span: Span) {
+    #[cfg(span_locations)]
+    {
+        if span.is_call_site() {
+            return;
+        }
+    }
+
+    if cfg!(span_locations) {
+        debug.field("span", &span);
+    }
+}
+
+#[derive(Clone)]
+pub(crate) struct Group {
+    delimiter: Delimiter,
+    stream: TokenStream,
+    span: Span,
+}
+
+impl Group {
+    pub(crate) fn new(delimiter: Delimiter, stream: TokenStream) -> Self {
+        Group {
+            delimiter,
+            stream,
+            span: Span::call_site(),
+        }
+    }
+
+    pub(crate) fn delimiter(&self) -> Delimiter {
+        self.delimiter
+    }
+
+    pub(crate) fn stream(&self) -> TokenStream {
+        self.stream.clone()
+    }
+
+    pub(crate) fn span(&self) -> Span {
+        self.span
+    }
+
+    pub(crate) fn span_open(&self) -> Span {
+        self.span.first_byte()
+    }
+
+    pub(crate) fn span_close(&self) -> Span {
+        self.span.last_byte()
+    }
+
+    pub(crate) fn set_span(&mut self, span: Span) {
+        self.span = span;
+    }
+}
+
+impl Display for Group {
+    // We attempt to match libproc_macro's formatting.
+    // Empty parens: ()
+    // Nonempty parens: (...)
+    // Empty brackets: []
+    // Nonempty brackets: [...]
+    // Empty braces: { }
+    // Nonempty braces: { ... }
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let (open, close) = match self.delimiter {
+            Delimiter::Parenthesis => ("(", ")"),
+            Delimiter::Brace => ("{ ", "}"),
+            Delimiter::Bracket => ("[", "]"),
+            Delimiter::None => ("", ""),
+        };
+
+        f.write_str(open)?;
+        Display::fmt(&self.stream, f)?;
+        if self.delimiter == Delimiter::Brace && !self.stream.inner.is_empty() {
+            f.write_str(" ")?;
+        }
+        f.write_str(close)?;
+
+        Ok(())
+    }
+}
+
+impl Debug for Group {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        let mut debug = fmt.debug_struct("Group");
+        debug.field("delimiter", &self.delimiter);
+        debug.field("stream", &self.stream);
+        debug_span_field_if_nontrivial(&mut debug, self.span);
+        debug.finish()
+    }
+}
+
+#[derive(Clone)]
+pub(crate) struct Ident {
+    sym: Box<str>,
+    span: Span,
+    raw: bool,
+}
+
+impl Ident {
+    #[track_caller]
+    pub(crate) fn new_checked(string: &str, span: Span) -> Self {
+        validate_ident(string);
+        Ident::new_unchecked(string, span)
+    }
+
+    pub(crate) fn new_unchecked(string: &str, span: Span) -> Self {
+        Ident {
+            sym: Box::from(string),
+            span,
+            raw: false,
+        }
+    }
+
+    #[track_caller]
+    pub(crate) fn new_raw_checked(string: &str, span: Span) -> Self {
+        validate_ident_raw(string);
+        Ident::new_raw_unchecked(string, span)
+    }
+
+    pub(crate) fn new_raw_unchecked(string: &str, span: Span) -> Self {
+        Ident {
+            sym: Box::from(string),
+            span,
+            raw: true,
+        }
+    }
+
+    pub(crate) fn span(&self) -> Span {
+        self.span
+    }
+
+    pub(crate) fn set_span(&mut self, span: Span) {
+        self.span = span;
+    }
+}
+
+pub(crate) fn is_ident_start(c: char) -> bool {
+    c == '_' || c.is_ascii_alphabetic()
+}
+
+pub(crate) fn is_ident_continue(c: char) -> bool {
+    c == '_' || c.is_ascii_alphanumeric()
+}
+
+#[track_caller]
+fn validate_ident(string: &str) {
+    if string.is_empty() {
+        panic!("Ident is not allowed to be empty; use Option<Ident>");
+    }
+
+    if string.bytes().all(|digit| b'0' <= digit && digit <= b'9') {
+        panic!("Ident cannot be a number; use Literal instead");
+    }
+
+    fn ident_ok(string: &str) -> bool {
+        let mut chars = string.chars();
+        let first = chars.next().unwrap();
+        if !is_ident_start(first) {
+            return false;
+        }
+        for ch in chars {
+            if !is_ident_continue(ch) {
+                return false;
+            }
+        }
+        true
+    }
+
+    if !ident_ok(string) {
+        panic!("{:?} is not a valid Ident", string);
+    }
+}
+
+#[track_caller]
+fn validate_ident_raw(string: &str) {
+    validate_ident(string);
+
+    match string {
+        "_" | "super" | "self" | "Self" | "crate" => {
+            panic!("`r#{}` cannot be a raw identifier", string);
+        }
+        _ => {}
+    }
+}
+
+impl PartialEq for Ident {
+    fn eq(&self, other: &Ident) -> bool {
+        self.sym == other.sym && self.raw == other.raw
+    }
+}
+
+impl<T> PartialEq<T> for Ident
+where
+    T: ?Sized + AsRef<str>,
+{
+    fn eq(&self, other: &T) -> bool {
+        let other = other.as_ref();
+        if self.raw {
+            other.starts_with("r#") && *self.sym == other[2..]
+        } else {
+            *self.sym == *other
+        }
+    }
+}
+
+impl Display for Ident {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if self.raw {
+            f.write_str("r#")?;
+        }
+        Display::fmt(&self.sym, f)
+    }
+}
+
+#[allow(clippy::missing_fields_in_debug)]
+impl Debug for Ident {
+    // Ident(proc_macro), Ident(r#union)
+    #[cfg(not(span_locations))]
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut debug = f.debug_tuple("Ident");
+        debug.field(&format_args!("{}", self));
+        debug.finish()
+    }
+
+    // Ident {
+    //     sym: proc_macro,
+    //     span: bytes(128..138)
+    // }
+    #[cfg(span_locations)]
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut debug = f.debug_struct("Ident");
+        debug.field("sym", &format_args!("{}", self));
+        debug_span_field_if_nontrivial(&mut debug, self.span);
+        debug.finish()
+    }
+}
+
+#[derive(Clone)]
+pub(crate) struct Literal {
+    pub(crate) repr: String,
+    span: Span,
+}
+
+macro_rules! suffixed_numbers {
+    ($($name:ident => $kind:ident,)*) => ($(
+        pub(crate) fn $name(n: $kind) -> Literal {
+            Literal::_new(format!(concat!("{}", stringify!($kind)), n))
+        }
+    )*)
+}
+
+macro_rules! unsuffixed_numbers {
+    ($($name:ident => $kind:ident,)*) => ($(
+        pub(crate) fn $name(n: $kind) -> Literal {
+            Literal::_new(n.to_string())
+        }
+    )*)
+}
+
+impl Literal {
+    pub(crate) fn _new(repr: String) -> Self {
+        Literal {
+            repr,
+            span: Span::call_site(),
+        }
+    }
+
+    pub(crate) fn from_str_checked(repr: &str) -> Result<Self, LexError> {
+        let mut cursor = get_cursor(repr);
+        #[cfg(span_locations)]
+        let lo = cursor.off;
+
+        let negative = cursor.starts_with_char('-');
+        if negative {
+            cursor = cursor.advance(1);
+            if !cursor.starts_with_fn(|ch| ch.is_ascii_digit()) {
+                return Err(LexError::call_site());
+            }
+        }
+
+        if let Ok((rest, mut literal)) = parse::literal(cursor) {
+            if rest.is_empty() {
+                if negative {
+                    literal.repr.insert(0, '-');
+                }
+                literal.span = Span {
+                    #[cfg(span_locations)]
+                    lo,
+                    #[cfg(span_locations)]
+                    hi: rest.off,
+                };
+                return Ok(literal);
+            }
+        }
+        Err(LexError::call_site())
+    }
+
+    pub(crate) unsafe fn from_str_unchecked(repr: &str) -> Self {
+        Literal::_new(repr.to_owned())
+    }
+
+    suffixed_numbers! {
+        u8_suffixed => u8,
+        u16_suffixed => u16,
+        u32_suffixed => u32,
+        u64_suffixed => u64,
+        u128_suffixed => u128,
+        usize_suffixed => usize,
+        i8_suffixed => i8,
+        i16_suffixed => i16,
+        i32_suffixed => i32,
+        i64_suffixed => i64,
+        i128_suffixed => i128,
+        isize_suffixed => isize,
+
+        f32_suffixed => f32,
+        f64_suffixed => f64,
+    }
+
+    unsuffixed_numbers! {
+        u8_unsuffixed => u8,
+        u16_unsuffixed => u16,
+        u32_unsuffixed => u32,
+        u64_unsuffixed => u64,
+        u128_unsuffixed => u128,
+        usize_unsuffixed => usize,
+        i8_unsuffixed => i8,
+        i16_unsuffixed => i16,
+        i32_unsuffixed => i32,
+        i64_unsuffixed => i64,
+        i128_unsuffixed => i128,
+        isize_unsuffixed => isize,
+    }
+
+    pub(crate) fn f32_unsuffixed(f: f32) -> Literal {
+        let mut s = f.to_string();
+        if !s.contains('.') {
+            s.push_str(".0");
+        }
+        Literal::_new(s)
+    }
+
+    pub(crate) fn f64_unsuffixed(f: f64) -> Literal {
+        let mut s = f.to_string();
+        if !s.contains('.') {
+            s.push_str(".0");
+        }
+        Literal::_new(s)
+    }
+
+    pub(crate) fn string(string: &str) -> Literal {
+        let mut repr = String::with_capacity(string.len() + 2);
+        repr.push('"');
+        escape_utf8(string, &mut repr);
+        repr.push('"');
+        Literal::_new(repr)
+    }
+
+    pub(crate) fn character(ch: char) -> Literal {
+        let mut repr = String::new();
+        repr.push('\'');
+        if ch == '"' {
+            // escape_debug turns this into '\"' which is unnecessary.
+            repr.push(ch);
+        } else {
+            repr.extend(ch.escape_debug());
+        }
+        repr.push('\'');
+        Literal::_new(repr)
+    }
+
+    pub(crate) fn byte_character(byte: u8) -> Literal {
+        let mut repr = "b'".to_string();
+        #[allow(clippy::match_overlapping_arm)]
+        match byte {
+            b'\0' => repr.push_str(r"\0"),
+            b'\t' => repr.push_str(r"\t"),
+            b'\n' => repr.push_str(r"\n"),
+            b'\r' => repr.push_str(r"\r"),
+            b'\'' => repr.push_str(r"\'"),
+            b'\\' => repr.push_str(r"\\"),
+            b'\x20'..=b'\x7E' => repr.push(byte as char),
+            _ => {
+                let _ = write!(repr, r"\x{:02X}", byte);
+            }
+        }
+        repr.push('\'');
+        Literal::_new(repr)
+    }
+
+    pub(crate) fn byte_string(bytes: &[u8]) -> Literal {
+        let mut repr = "b\"".to_string();
+        let mut bytes = bytes.iter();
+        while let Some(&b) = bytes.next() {
+            #[allow(clippy::match_overlapping_arm)]
+            match b {
+                b'\0' => repr.push_str(match bytes.as_slice().first() {
+                    // circumvent clippy::octal_escapes lint
+                    Some(b'0'..=b'7') => r"\x00",
+                    _ => r"\0",
+                }),
+                b'\t' => repr.push_str(r"\t"),
+                b'\n' => repr.push_str(r"\n"),
+                b'\r' => repr.push_str(r"\r"),
+                b'"' => repr.push_str("\\\""),
+                b'\\' => repr.push_str(r"\\"),
+                b'\x20'..=b'\x7E' => repr.push(b as char),
+                _ => {
+                    let _ = write!(repr, r"\x{:02X}", b);
+                }
+            }
+        }
+        repr.push('"');
+        Literal::_new(repr)
+    }
+
+    pub(crate) fn c_string(string: &CStr) -> Literal {
+        let mut repr = "c\"".to_string();
+        let mut bytes = string.to_bytes();
+        while !bytes.is_empty() {
+            let (valid, invalid) = match str::from_utf8(bytes) {
+                Ok(all_valid) => {
+                    bytes = b"";
+                    (all_valid, bytes)
+                }
+                Err(utf8_error) => {
+                    let (valid, rest) = bytes.split_at(utf8_error.valid_up_to());
+                    let valid = str::from_utf8(valid).unwrap();
+                    let invalid = utf8_error
+                        .error_len()
+                        .map_or(rest, |error_len| &rest[..error_len]);
+                    bytes = &bytes[valid.len() + invalid.len()..];
+                    (valid, invalid)
+                }
+            };
+            escape_utf8(valid, &mut repr);
+            for &byte in invalid {
+                let _ = write!(repr, r"\x{:02X}", byte);
+            }
+        }
+        repr.push('"');
+        Literal::_new(repr)
+    }
+
+    pub(crate) fn span(&self) -> Span {
+        self.span
+    }
+
+    pub(crate) fn set_span(&mut self, span: Span) {
+        self.span = span;
+    }
+
+    pub(crate) fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
+        #[cfg(not(span_locations))]
+        {
+            let _ = range;
+            None
+        }
+
+        #[cfg(span_locations)]
+        {
+            use core::ops::Bound;
+
+            let lo = match range.start_bound() {
+                Bound::Included(start) => {
+                    let start = u32::try_from(*start).ok()?;
+                    self.span.lo.checked_add(start)?
+                }
+                Bound::Excluded(start) => {
+                    let start = u32::try_from(*start).ok()?;
+                    self.span.lo.checked_add(start)?.checked_add(1)?
+                }
+                Bound::Unbounded => self.span.lo,
+            };
+            let hi = match range.end_bound() {
+                Bound::Included(end) => {
+                    let end = u32::try_from(*end).ok()?;
+                    self.span.lo.checked_add(end)?.checked_add(1)?
+                }
+                Bound::Excluded(end) => {
+                    let end = u32::try_from(*end).ok()?;
+                    self.span.lo.checked_add(end)?
+                }
+                Bound::Unbounded => self.span.hi,
+            };
+            if lo <= hi && hi <= self.span.hi {
+                Some(Span { lo, hi })
+            } else {
+                None
+            }
+        }
+    }
+}
+
+impl Display for Literal {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        Display::fmt(&self.repr, f)
+    }
+}
+
+impl Debug for Literal {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        let mut debug = fmt.debug_struct("Literal");
+        debug.field("lit", &format_args!("{}", self.repr));
+        debug_span_field_if_nontrivial(&mut debug, self.span);
+        debug.finish()
+    }
+}
+
+fn escape_utf8(string: &str, repr: &mut String) {
+    let mut chars = string.chars();
+    while let Some(ch) = chars.next() {
+        if ch == '\0' {
+            repr.push_str(
+                if chars
+                    .as_str()
+                    .starts_with(|next| '0' <= next && next <= '7')
+                {
+                    // circumvent clippy::octal_escapes lint
+                    r"\x00"
+                } else {
+                    r"\0"
+                },
+            );
+        } else if ch == '\'' {
+            // escape_debug turns this into "\'" which is unnecessary.
+            repr.push(ch);
+        } else {
+            repr.extend(ch.escape_debug());
+        }
+    }
+}
+
+#[cfg(feature = "proc-macro")]
+pub(crate) trait FromStr2: FromStr<Err = proc_macro::LexError> {
+    #[cfg(wrap_proc_macro)]
+    fn valid(src: &str) -> bool;
+
+    #[cfg(wrap_proc_macro)]
+    fn from_str_checked(src: &str) -> Result<Self, imp::LexError> {
+        // Validate using fallback parser, because rustc is incapable of
+        // returning a recoverable Err for certain invalid token streams, and
+        // will instead permanently poison the compilation.
+        if !Self::valid(src) {
+            return Err(imp::LexError::CompilerPanic);
+        }
+
+        // Catch panic to work around https://github.com/rust-lang/rust/issues/58736.
+        match panic::catch_unwind(|| Self::from_str(src)) {
+            Ok(Ok(ok)) => Ok(ok),
+            Ok(Err(lex)) => Err(imp::LexError::Compiler(lex)),
+            Err(_panic) => Err(imp::LexError::CompilerPanic),
+        }
+    }
+
+    fn from_str_unchecked(src: &str) -> Self {
+        Self::from_str(src).unwrap()
+    }
+}
+
+#[cfg(feature = "proc-macro")]
+impl FromStr2 for proc_macro::TokenStream {
+    #[cfg(wrap_proc_macro)]
+    fn valid(src: &str) -> bool {
+        TokenStream::from_str_checked(src).is_ok()
+    }
+}
+
+#[cfg(feature = "proc-macro")]
+impl FromStr2 for proc_macro::Literal {
+    #[cfg(wrap_proc_macro)]
+    fn valid(src: &str) -> bool {
+        Literal::from_str_checked(src).is_ok()
+    }
+}