From 805a6adf92ba8da4b6d7ce5ff1def6b53f1f1cb5 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 25 Nov 2023 17:13:54 -0800
Subject: [PATCH] Bypass Ident validation on identifiers created by parser

---
 src/fallback.rs | 38 ++++++++++++++++++++++++--------------
 src/parse.rs    | 19 +++++++++++++------
 src/wrapper.rs  |  8 ++++++++
 3 files changed, 45 insertions(+), 20 deletions(-)

diff --git a/src/fallback.rs b/src/fallback.rs
index b02fd04..408102b 100644
--- a/src/fallback.rs
+++ b/src/fallback.rs
@@ -755,22 +755,30 @@ pub(crate) struct Ident {
 }
 
 impl Ident {
-    fn _new(string: &str, raw: bool, span: Span) -> Self {
-        validate_ident(string, raw);
+    pub fn new(string: &str, span: Span) -> Self {
+        validate_ident(string);
+        Ident::new_unchecked(string, span)
+    }
 
+    pub fn new_unchecked(string: &str, span: Span) -> Self {
         Ident {
             sym: string.to_owned(),
             span,
-            raw,
+            raw: false,
         }
     }
 
-    pub fn new(string: &str, span: Span) -> Self {
-        Ident::_new(string, false, span)
+    pub fn new_raw(string: &str, span: Span) -> Self {
+        validate_ident_raw(string);
+        Ident::new_raw_unchecked(string, span)
     }
 
-    pub fn new_raw(string: &str, span: Span) -> Self {
-        Ident::_new(string, true, span)
+    pub fn new_raw_unchecked(string: &str, span: Span) -> Self {
+        Ident {
+            sym: string.to_owned(),
+            span,
+            raw: true,
+        }
     }
 
     pub fn span(&self) -> Span {
@@ -790,7 +798,7 @@ pub(crate) fn is_ident_continue(c: char) -> bool {
     unicode_ident::is_xid_continue(c)
 }
 
-fn validate_ident(string: &str, raw: bool) {
+fn validate_ident(string: &str) {
     if string.is_empty() {
         panic!("Ident is not allowed to be empty; use Option<Ident>");
     }
@@ -816,14 +824,16 @@ fn validate_ident(string: &str, raw: bool) {
     if !ident_ok(string) {
         panic!("{:?} is not a valid Ident", string);
     }
+}
 
-    if raw {
-        match string {
-            "_" | "super" | "self" | "Self" | "crate" => {
-                panic!("`r#{}` cannot be a raw identifier", string);
-            }
-            _ => {}
+fn validate_ident_raw(string: &str) {
+    validate_ident(string);
+
+    match string {
+        "_" | "super" | "self" | "Self" | "crate" => {
+            panic!("`r#{}` cannot be a raw identifier", string);
         }
+        _ => {}
     }
 }
 
diff --git a/src/parse.rs b/src/parse.rs
index 8c3d9b2..07239bc 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -1,5 +1,5 @@
 use crate::fallback::{
-    is_ident_continue, is_ident_start, Group, LexError, Literal, Span, TokenStream,
+    self, is_ident_continue, is_ident_start, Group, LexError, Literal, Span, TokenStream,
     TokenStreamBuilder,
 };
 use crate::{Delimiter, Punct, Spacing, TokenTree};
@@ -300,7 +300,10 @@ fn ident_any(input: Cursor) -> PResult<crate::Ident> {
     let (rest, sym) = ident_not_raw(rest)?;
 
     if !raw {
-        let ident = crate::Ident::new(sym, crate::Span::call_site());
+        let ident = crate::Ident::_new(crate::imp::Ident::new_unchecked(
+            sym,
+            fallback::Span::call_site(),
+        ));
         return Ok((rest, ident));
     }
 
@@ -309,7 +312,10 @@ fn ident_any(input: Cursor) -> PResult<crate::Ident> {
         _ => {}
     }
 
-    let ident = crate::Ident::new_raw(sym, crate::Span::call_site());
+    let ident = crate::Ident::_new(crate::imp::Ident::new_raw_unchecked(
+        sym,
+        fallback::Span::call_site(),
+    ));
     Ok((rest, ident))
 }
 
@@ -908,12 +914,13 @@ fn doc_comment<'a>(input: Cursor<'a>, trees: &mut TokenStreamBuilder) -> PResult
     #[cfg(span_locations)]
     let lo = input.off;
     let (rest, (comment, inner)) = doc_comment_contents(input)?;
-    let span = crate::Span::_new_fallback(Span {
+    let fallback_span = Span {
         #[cfg(span_locations)]
         lo,
         #[cfg(span_locations)]
         hi: rest.off,
-    });
+    };
+    let span = crate::Span::_new_fallback(fallback_span);
 
     let mut scan_for_bare_cr = comment;
     while let Some(cr) = scan_for_bare_cr.find('\r') {
@@ -934,7 +941,7 @@ fn doc_comment<'a>(input: Cursor<'a>, trees: &mut TokenStreamBuilder) -> PResult
         trees.push_token_from_parser(TokenTree::Punct(bang));
     }
 
-    let doc_ident = crate::Ident::new("doc", span);
+    let doc_ident = crate::Ident::_new(crate::imp::Ident::new_unchecked("doc", fallback_span));
     let mut equal = Punct::new('=', Spacing::Alone);
     equal.set_span(span);
     let mut literal = crate::Literal::string(comment);
diff --git a/src/wrapper.rs b/src/wrapper.rs
index 860b6b7..9bac8d1 100644
--- a/src/wrapper.rs
+++ b/src/wrapper.rs
@@ -646,6 +646,10 @@ impl Ident {
         }
     }
 
+    pub fn new_unchecked(string: &str, span: fallback::Span) -> Self {
+        Ident::Fallback(fallback::Ident::new_unchecked(string, span))
+    }
+
     pub fn new_raw(string: &str, span: Span) -> Self {
         match span {
             Span::Compiler(s) => Ident::Compiler(proc_macro::Ident::new_raw(string, s)),
@@ -653,6 +657,10 @@ impl Ident {
         }
     }
 
+    pub fn new_raw_unchecked(string: &str, span: fallback::Span) -> Self {
+        Ident::Fallback(fallback::Ident::new_raw_unchecked(string, span))
+    }
+
     pub fn span(&self) -> Span {
         match self {
             Ident::Compiler(t) => Span::Compiler(t.span()),