Merge pull request #20012 from lnicola/bump-literal-escaper

Update to literal-escaper 0.0.4

8 files changed, 139 insertions, 169 deletions

diff --git a/src/tools/rust-analyzer/Cargo.lock b/src/tools/rust-analyzer/Cargo.lock
index 2c7b4641641..caa8f28d8e2 100644
--- a/src/tools/rust-analyzer/Cargo.lock
+++ b/src/tools/rust-analyzer/Cargo.lock
@@ -1458,7 +1458,7 @@ dependencies = [
  "edition",
  "expect-test",
  "ra-ap-rustc_lexer",
- "rustc-literal-escaper 0.0.3",
+ "rustc-literal-escaper 0.0.4",
  "stdx",
  "tracing",
 ]
@@ -1927,9 +1927,9 @@ checksum = "0041b6238913c41fe704213a4a9329e2f685a156d1781998128b4149c230ad04"
 
 [[package]]
 name = "rustc-literal-escaper"
-version = "0.0.3"
+version = "0.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "78744cd17f5d01c75b709e49807d1363e02a940ccee2e9e72435843fdb0d076e"
+checksum = "ab03008eb631b703dd16978282ae36c73282e7922fe101a4bd072a40ecea7b8b"
 
 [[package]]
 name = "rustc-stable-hash"
@@ -2207,7 +2207,7 @@ dependencies = [
  "rayon",
  "rowan",
  "rustc-hash 2.1.1",
- "rustc-literal-escaper 0.0.3",
+ "rustc-literal-escaper 0.0.4",
  "rustc_apfloat",
  "smol_str",
  "stdx",
diff --git a/src/tools/rust-analyzer/Cargo.toml b/src/tools/rust-analyzer/Cargo.toml
index 449c75859cf..0a8e6feb46e 100644
--- a/src/tools/rust-analyzer/Cargo.toml
+++ b/src/tools/rust-analyzer/Cargo.toml
@@ -143,7 +143,7 @@ serde = { version = "1.0.219" }
 serde_derive = { version = "1.0.219" }
 serde_json = "1.0.140"
 rustc-hash = "2.1.1"
-rustc-literal-escaper = "0.0.3"
+rustc-literal-escaper = "0.0.4"
 smallvec = { version = "1.15.1", features = [
   "const_new",
   "union",
diff --git a/src/tools/rust-analyzer/crates/hir-expand/src/attrs.rs b/src/tools/rust-analyzer/crates/hir-expand/src/attrs.rs
index 94c97713f06..986f8764f5c 100644
--- a/src/tools/rust-analyzer/crates/hir-expand/src/attrs.rs
+++ b/src/tools/rust-analyzer/crates/hir-expand/src/attrs.rs
@@ -433,20 +433,19 @@ fn unescape(s: &str) -> Option<Cow<'_, str>> {
     let mut buf = String::new();
     let mut prev_end = 0;
     let mut has_error = false;
-    unescape::unescape_unicode(s, unescape::Mode::Str, &mut |char_range, unescaped_char| match (
-        unescaped_char,
-        buf.capacity() == 0,
-    ) {
-        (Ok(c), false) => buf.push(c),
-        (Ok(_), true) if char_range.len() == 1 && char_range.start == prev_end => {
-            prev_end = char_range.end
-        }
-        (Ok(c), true) => {
-            buf.reserve_exact(s.len());
-            buf.push_str(&s[..prev_end]);
-            buf.push(c);
+    unescape::unescape_str(s, |char_range, unescaped_char| {
+        match (unescaped_char, buf.capacity() == 0) {
+            (Ok(c), false) => buf.push(c),
+            (Ok(_), true) if char_range.len() == 1 && char_range.start == prev_end => {
+                prev_end = char_range.end
+            }
+            (Ok(c), true) => {
+                buf.reserve_exact(s.len());
+                buf.push_str(&s[..prev_end]);
+                buf.push(c);
+            }
+            (Err(_), _) => has_error = true,
         }
-        (Err(_), _) => has_error = true,
     });
 
     match (has_error, buf.capacity() == 0) {
diff --git a/src/tools/rust-analyzer/crates/hir-expand/src/builtin/fn_macro.rs b/src/tools/rust-analyzer/crates/hir-expand/src/builtin/fn_macro.rs
index 3180b8dae10..f9abe4f5566 100644
--- a/src/tools/rust-analyzer/crates/hir-expand/src/builtin/fn_macro.rs
+++ b/src/tools/rust-analyzer/crates/hir-expand/src/builtin/fn_macro.rs
@@ -12,7 +12,7 @@ use span::{Edition, FileId, Span};
 use stdx::format_to;
 use syntax::{
     format_smolstr,
-    unescape::{Mode, unescape_byte, unescape_char, unescape_unicode},
+    unescape::{unescape_byte, unescape_char, unescape_str},
 };
 use syntax_bridge::syntax_node_to_token_tree;
 
@@ -430,7 +430,7 @@ fn compile_error_expand(
                 kind: tt::LitKind::Str | tt::LitKind::StrRaw(_),
                 suffix: _,
             })),
-        ] => ExpandError::other(span, Box::from(unescape_str(text).as_str())),
+        ] => ExpandError::other(span, Box::from(unescape_symbol(text).as_str())),
         _ => ExpandError::other(span, "`compile_error!` argument must be a string"),
     };
 
@@ -481,7 +481,7 @@ fn concat_expand(
                         format_to!(text, "{}", it.symbol.as_str())
                     }
                     tt::LitKind::Str => {
-                        text.push_str(unescape_str(&it.symbol).as_str());
+                        text.push_str(unescape_symbol(&it.symbol).as_str());
                         record_span(it.span);
                     }
                     tt::LitKind::StrRaw(_) => {
@@ -691,7 +691,7 @@ fn parse_string(tt: &tt::TopSubtree) -> Result<(Symbol, Span), ExpandError> {
                 span,
                 kind: tt::LitKind::Str,
                 suffix: _,
-            })) => Ok((unescape_str(text), *span)),
+            })) => Ok((unescape_symbol(text), *span)),
             TtElement::Leaf(tt::Leaf::Literal(tt::Literal {
                 symbol: text,
                 span,
@@ -712,7 +712,7 @@ fn parse_string(tt: &tt::TopSubtree) -> Result<(Symbol, Span), ExpandError> {
                             span,
                             kind: tt::LitKind::Str,
                             suffix: _,
-                        })) => Some((unescape_str(text), *span)),
+                        })) => Some((unescape_symbol(text), *span)),
                         TtElement::Leaf(tt::Leaf::Literal(tt::Literal {
                             symbol: text,
                             span,
@@ -897,11 +897,11 @@ fn quote_expand(
     )
 }
 
-fn unescape_str(s: &Symbol) -> Symbol {
+fn unescape_symbol(s: &Symbol) -> Symbol {
     if s.as_str().contains('\\') {
         let s = s.as_str();
         let mut buf = String::with_capacity(s.len());
-        unescape_unicode(s, Mode::Str, &mut |_, c| {
+        unescape_str(s, |_, c| {
             if let Ok(c) = c {
                 buf.push(c)
             }
diff --git a/src/tools/rust-analyzer/crates/ide/src/goto_type_definition.rs b/src/tools/rust-analyzer/crates/ide/src/goto_type_definition.rs
index 86d72fefe05..b80e81d39c6 100644
--- a/src/tools/rust-analyzer/crates/ide/src/goto_type_definition.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/goto_type_definition.rs
@@ -70,11 +70,10 @@ pub(crate) fn goto_type_definition(
     }
 
     let range = token.text_range();
-    sema.descend_into_macros_no_opaque(token,false)
+    sema.descend_into_macros_no_opaque(token, false)
         .into_iter()
         .filter_map(|token| {
-            sema
-                .token_ancestors_with_macros(token.value)
+            sema.token_ancestors_with_macros(token.value)
                 // When `token` is within a macro call, we can't determine its type. Don't continue
                 // this traversal because otherwise we'll end up returning the type of *that* macro
                 // call, which is not what we want in general.
@@ -103,7 +102,6 @@ pub(crate) fn goto_type_definition(
                             _ => return None,
                         }
                     };
-
                     Some(ty)
                 })
         })
diff --git a/src/tools/rust-analyzer/crates/parser/src/lexed_str.rs b/src/tools/rust-analyzer/crates/parser/src/lexed_str.rs
index 0fa9a264545..e6c92dec681 100644
--- a/src/tools/rust-analyzer/crates/parser/src/lexed_str.rs
+++ b/src/tools/rust-analyzer/crates/parser/src/lexed_str.rs
@@ -11,7 +11,8 @@
 use std::ops;
 
 use rustc_literal_escaper::{
-    EscapeError, Mode, unescape_byte, unescape_char, unescape_mixed, unescape_unicode,
+    EscapeError, Mode, unescape_byte, unescape_byte_str, unescape_c_str, unescape_char,
+    unescape_str,
 };
 
 use crate::{
@@ -151,14 +152,14 @@ impl<'a> Converter<'a> {
         self.res
     }
 
-    fn push(&mut self, kind: SyntaxKind, len: usize, err: Option<&str>) {
+    fn push(&mut self, kind: SyntaxKind, len: usize, errors: Vec<String>) {
         self.res.push(kind, self.offset);
         self.offset += len;
 
-        if let Some(err) = err {
-            let token = self.res.len() as u32;
-            let msg = err.to_owned();
-            self.res.error.push(LexError { msg, token });
+        for msg in errors {
+            if !msg.is_empty() {
+                self.res.error.push(LexError { msg, token: self.res.len() as u32 });
+            }
         }
     }
 
@@ -167,14 +168,16 @@ impl<'a> Converter<'a> {
         // We drop some useful information here (see patterns with double dots `..`)
         // Storing that info in `SyntaxKind` is not possible due to its layout requirements of
         // being `u16` that come from `rowan::SyntaxKind`.
-        let mut err = "";
+        let mut errors: Vec<String> = vec![];
 
         let syntax_kind = {
             match kind {
                 rustc_lexer::TokenKind::LineComment { doc_style: _ } => COMMENT,
                 rustc_lexer::TokenKind::BlockComment { doc_style: _, terminated } => {
                     if !terminated {
-                        err = "Missing trailing `*/` symbols to terminate the block comment";
+                        errors.push(
+                            "Missing trailing `*/` symbols to terminate the block comment".into(),
+                        );
                     }
                     COMMENT
                 }
@@ -184,9 +187,9 @@ impl<'a> Converter<'a> {
                     invalid_infostring,
                 } => {
                     if *has_invalid_preceding_whitespace {
-                        err = "invalid preceding whitespace for frontmatter opening"
+                        errors.push("invalid preceding whitespace for frontmatter opening".into());
                     } else if *invalid_infostring {
-                        err = "invalid infostring for frontmatter"
+                        errors.push("invalid infostring for frontmatter".into());
                     }
                     FRONTMATTER
                 }
@@ -198,7 +201,7 @@ impl<'a> Converter<'a> {
                     SyntaxKind::from_keyword(token_text, self.edition).unwrap_or(IDENT)
                 }
                 rustc_lexer::TokenKind::InvalidIdent => {
-                    err = "Ident contains invalid characters";
+                    errors.push("Ident contains invalid characters".into());
                     IDENT
                 }
 
@@ -206,7 +209,7 @@ impl<'a> Converter<'a> {
 
                 rustc_lexer::TokenKind::GuardedStrPrefix if self.edition.at_least_2024() => {
                     // FIXME: rustc does something better for recovery.
-                    err = "Invalid string literal (reserved syntax)";
+                    errors.push("Invalid string literal (reserved syntax)".into());
                     ERROR
                 }
                 rustc_lexer::TokenKind::GuardedStrPrefix => {
@@ -222,12 +225,12 @@ impl<'a> Converter<'a> {
 
                 rustc_lexer::TokenKind::Lifetime { starts_with_number } => {
                     if *starts_with_number {
-                        err = "Lifetime name cannot start with a number";
+                        errors.push("Lifetime name cannot start with a number".into());
                     }
                     LIFETIME_IDENT
                 }
                 rustc_lexer::TokenKind::UnknownPrefixLifetime => {
-                    err = "Unknown lifetime prefix";
+                    errors.push("Unknown lifetime prefix".into());
                     LIFETIME_IDENT
                 }
                 rustc_lexer::TokenKind::RawLifetime => LIFETIME_IDENT,
@@ -262,119 +265,128 @@ impl<'a> Converter<'a> {
                 rustc_lexer::TokenKind::Unknown => ERROR,
                 rustc_lexer::TokenKind::UnknownPrefix if token_text == "builtin" => IDENT,
                 rustc_lexer::TokenKind::UnknownPrefix => {
-                    err = "unknown literal prefix";
+                    errors.push("unknown literal prefix".into());
                     IDENT
                 }
                 rustc_lexer::TokenKind::Eof => EOF,
             }
         };
 
-        let err = if err.is_empty() { None } else { Some(err) };
-        self.push(syntax_kind, token_text.len(), err);
+        self.push(syntax_kind, token_text.len(), errors);
     }
 
     fn extend_literal(&mut self, len: usize, kind: &rustc_lexer::LiteralKind) {
-        let mut err = "";
+        let invalid_raw_msg = String::from("Invalid raw string literal");
+
+        let mut errors = vec![];
+        let mut no_end_quote = |c: char, kind: &str| {
+            errors.push(format!("Missing trailing `{c}` symbol to terminate the {kind} literal"));
+        };
 
         let syntax_kind = match *kind {
             rustc_lexer::LiteralKind::Int { empty_int, base: _ } => {
                 if empty_int {
-                    err = "Missing digits after the integer base prefix";
+                    errors.push("Missing digits after the integer base prefix".into());
                 }
                 INT_NUMBER
             }
             rustc_lexer::LiteralKind::Float { empty_exponent, base: _ } => {
                 if empty_exponent {
-                    err = "Missing digits after the exponent symbol";
+                    errors.push("Missing digits after the exponent symbol".into());
                 }
                 FLOAT_NUMBER
             }
             rustc_lexer::LiteralKind::Char { terminated } => {
                 if !terminated {
-                    err = "Missing trailing `'` symbol to terminate the character literal";
+                    no_end_quote('\'', "character");
                 } else {
                     let text = &self.res.text[self.offset + 1..][..len - 1];
-                    let i = text.rfind('\'').unwrap();
-                    let text = &text[..i];
+                    let text = &text[..text.rfind('\'').unwrap()];
                     if let Err(e) = unescape_char(text) {
-                        err = error_to_diagnostic_message(e, Mode::Char);
+                        errors.push(err_to_msg(e, Mode::Char));
                     }
                 }
                 CHAR
             }
             rustc_lexer::LiteralKind::Byte { terminated } => {
                 if !terminated {
-                    err = "Missing trailing `'` symbol to terminate the byte literal";
+                    no_end_quote('\'', "byte");
                 } else {
                     let text = &self.res.text[self.offset + 2..][..len - 2];
-                    let i = text.rfind('\'').unwrap();
-                    let text = &text[..i];
+                    let text = &text[..text.rfind('\'').unwrap()];
                     if let Err(e) = unescape_byte(text) {
-                        err = error_to_diagnostic_message(e, Mode::Byte);
+                        errors.push(err_to_msg(e, Mode::Byte));
                     }
                 }
-
                 BYTE
             }
             rustc_lexer::LiteralKind::Str { terminated } => {
                 if !terminated {
-                    err = "Missing trailing `\"` symbol to terminate the string literal";
+                    no_end_quote('"', "string");
                 } else {
                     let text = &self.res.text[self.offset + 1..][..len - 1];
-                    let i = text.rfind('"').unwrap();
-                    let text = &text[..i];
-                    err = unescape_string_error_message(text, Mode::Str);
+                    let text = &text[..text.rfind('"').unwrap()];
+                    unescape_str(text, |_, res| {
+                        if let Err(e) = res {
+                            errors.push(err_to_msg(e, Mode::Str));
+                        }
+                    });
                 }
                 STRING
             }
             rustc_lexer::LiteralKind::ByteStr { terminated } => {
                 if !terminated {
-                    err = "Missing trailing `\"` symbol to terminate the byte string literal";
+                    no_end_quote('"', "byte string");
                 } else {
                     let text = &self.res.text[self.offset + 2..][..len - 2];
-                    let i = text.rfind('"').unwrap();
-                    let text = &text[..i];
-                    err = unescape_string_error_message(text, Mode::ByteStr);
+                    let text = &text[..text.rfind('"').unwrap()];
+                    unescape_byte_str(text, |_, res| {
+                        if let Err(e) = res {
+                            errors.push(err_to_msg(e, Mode::ByteStr));
+                        }
+                    });
                 }
                 BYTE_STRING
             }
             rustc_lexer::LiteralKind::CStr { terminated } => {
                 if !terminated {
-                    err = "Missing trailing `\"` symbol to terminate the string literal";
+                    no_end_quote('"', "C string")
                 } else {
                     let text = &self.res.text[self.offset + 2..][..len - 2];
-                    let i = text.rfind('"').unwrap();
-                    let text = &text[..i];
-                    err = unescape_string_error_message(text, Mode::CStr);
+                    let text = &text[..text.rfind('"').unwrap()];
+                    unescape_c_str(text, |_, res| {
+                        if let Err(e) = res {
+                            errors.push(err_to_msg(e, Mode::CStr));
+                        }
+                    });
                 }
                 C_STRING
             }
             rustc_lexer::LiteralKind::RawStr { n_hashes } => {
                 if n_hashes.is_none() {
-                    err = "Invalid raw string literal";
+                    errors.push(invalid_raw_msg);
                 }
                 STRING
             }
             rustc_lexer::LiteralKind::RawByteStr { n_hashes } => {
                 if n_hashes.is_none() {
-                    err = "Invalid raw string literal";
+                    errors.push(invalid_raw_msg);
                 }
                 BYTE_STRING
             }
             rustc_lexer::LiteralKind::RawCStr { n_hashes } => {
                 if n_hashes.is_none() {
-                    err = "Invalid raw string literal";
+                    errors.push(invalid_raw_msg);
                 }
                 C_STRING
             }
         };
 
-        let err = if err.is_empty() { None } else { Some(err) };
-        self.push(syntax_kind, len, err);
+        self.push(syntax_kind, len, errors);
     }
 }
 
-fn error_to_diagnostic_message(error: EscapeError, mode: Mode) -> &'static str {
+fn err_to_msg(error: EscapeError, mode: Mode) -> String {
     match error {
         EscapeError::ZeroChars => "empty character literal",
         EscapeError::MoreThanOneChar => "character literal may only contain one codepoint",
@@ -410,28 +422,5 @@ fn error_to_diagnostic_message(error: EscapeError, mode: Mode) -> &'static str {
         EscapeError::UnskippedWhitespaceWarning => "",
         EscapeError::MultipleSkippedLinesWarning => "",
     }
-}
-
-fn unescape_string_error_message(text: &str, mode: Mode) -> &'static str {
-    let mut error_message = "";
-    match mode {
-        Mode::CStr => {
-            unescape_mixed(text, mode, &mut |_, res| {
-                if let Err(e) = res {
-                    error_message = error_to_diagnostic_message(e, mode);
-                }
-            });
-        }
-        Mode::ByteStr | Mode::Str => {
-            unescape_unicode(text, mode, &mut |_, res| {
-                if let Err(e) = res {
-                    error_message = error_to_diagnostic_message(e, mode);
-                }
-            });
-        }
-        _ => {
-            // Other Modes are not supported yet or do not apply
-        }
-    }
-    error_message
+    .into()
 }
diff --git a/src/tools/rust-analyzer/crates/syntax/src/ast/token_ext.rs b/src/tools/rust-analyzer/crates/syntax/src/ast/token_ext.rs
index ced3b713d8d..4afdda78a0e 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/ast/token_ext.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/ast/token_ext.rs
@@ -1,9 +1,11 @@
 //! There are many AstNodes, but only a few tokens, so we hand-write them here.
 
+use std::ops::Range;
 use std::{borrow::Cow, num::ParseIntError};
 
 use rustc_literal_escaper::{
-    EscapeError, MixedUnit, Mode, unescape_byte, unescape_char, unescape_mixed, unescape_unicode,
+    EscapeError, MixedUnit, unescape_byte, unescape_byte_str, unescape_c_str, unescape_char,
+    unescape_str,
 };
 use stdx::always;
 
@@ -150,7 +152,7 @@ impl QuoteOffsets {
 
 pub trait IsString: AstToken {
     const RAW_PREFIX: &'static str;
-    const MODE: Mode;
+    fn unescape(s: &str, callback: impl FnMut(Range<usize>, Result<char, EscapeError>));
     fn is_raw(&self) -> bool {
         self.text().starts_with(Self::RAW_PREFIX)
     }
@@ -185,7 +187,7 @@ pub trait IsString: AstToken {
         let text = &self.text()[text_range_no_quotes - start];
         let offset = text_range_no_quotes.start() - start;
 
-        unescape_unicode(text, Self::MODE, &mut |range, unescaped_char| {
+        Self::unescape(text, &mut |range: Range<usize>, unescaped_char| {
             if let Some((s, e)) = range.start.try_into().ok().zip(range.end.try_into().ok()) {
                 cb(TextRange::new(s, e) + offset, unescaped_char);
             }
@@ -203,7 +205,9 @@ pub trait IsString: AstToken {
 
 impl IsString for ast::String {
     const RAW_PREFIX: &'static str = "r";
-    const MODE: Mode = Mode::Str;
+    fn unescape(s: &str, cb: impl FnMut(Range<usize>, Result<char, EscapeError>)) {
+        unescape_str(s, cb)
+    }
 }
 
 impl ast::String {
@@ -218,20 +222,19 @@ impl ast::String {
         let mut buf = String::new();
         let mut prev_end = 0;
         let mut has_error = None;
-        unescape_unicode(text, Self::MODE, &mut |char_range, unescaped_char| match (
-            unescaped_char,
-            buf.capacity() == 0,
-        ) {
-            (Ok(c), false) => buf.push(c),
-            (Ok(_), true) if char_range.len() == 1 && char_range.start == prev_end => {
-                prev_end = char_range.end
-            }
-            (Ok(c), true) => {
-                buf.reserve_exact(text.len());
-                buf.push_str(&text[..prev_end]);
-                buf.push(c);
+        unescape_str(text, |char_range, unescaped_char| {
+            match (unescaped_char, buf.capacity() == 0) {
+                (Ok(c), false) => buf.push(c),
+                (Ok(_), true) if char_range.len() == 1 && char_range.start == prev_end => {
+                    prev_end = char_range.end
+                }
+                (Ok(c), true) => {
+                    buf.reserve_exact(text.len());
+                    buf.push_str(&text[..prev_end]);
+                    buf.push(c);
+                }
+                (Err(e), _) => has_error = Some(e),
             }
-            (Err(e), _) => has_error = Some(e),
         });
 
         match (has_error, buf.capacity() == 0) {
@@ -244,7 +247,9 @@ impl ast::String {
 
 impl IsString for ast::ByteString {
     const RAW_PREFIX: &'static str = "br";
-    const MODE: Mode = Mode::ByteStr;
+    fn unescape(s: &str, mut callback: impl FnMut(Range<usize>, Result<char, EscapeError>)) {
+        unescape_byte_str(s, |range, res| callback(range, res.map(char::from)))
+    }
 }
 
 impl ast::ByteString {
@@ -259,20 +264,19 @@ impl ast::ByteString {
         let mut buf: Vec<u8> = Vec::new();
         let mut prev_end = 0;
         let mut has_error = None;
-        unescape_unicode(text, Self::MODE, &mut |char_range, unescaped_char| match (
-            unescaped_char,
-            buf.capacity() == 0,
-        ) {
-            (Ok(c), false) => buf.push(c as u8),
-            (Ok(_), true) if char_range.len() == 1 && char_range.start == prev_end => {
-                prev_end = char_range.end
-            }
-            (Ok(c), true) => {
-                buf.reserve_exact(text.len());
-                buf.extend_from_slice(&text.as_bytes()[..prev_end]);
-                buf.push(c as u8);
+        unescape_byte_str(text, |char_range, unescaped_byte| {
+            match (unescaped_byte, buf.capacity() == 0) {
+                (Ok(b), false) => buf.push(b),
+                (Ok(_), true) if char_range.len() == 1 && char_range.start == prev_end => {
+                    prev_end = char_range.end
+                }
+                (Ok(b), true) => {
+                    buf.reserve_exact(text.len());
+                    buf.extend_from_slice(&text.as_bytes()[..prev_end]);
+                    buf.push(b);
+                }
+                (Err(e), _) => has_error = Some(e),
             }
-            (Err(e), _) => has_error = Some(e),
         });
 
         match (has_error, buf.capacity() == 0) {
@@ -285,25 +289,10 @@ impl ast::ByteString {
 
 impl IsString for ast::CString {
     const RAW_PREFIX: &'static str = "cr";
-    const MODE: Mode = Mode::CStr;
-
-    fn escaped_char_ranges(&self, cb: &mut dyn FnMut(TextRange, Result<char, EscapeError>)) {
-        let text_range_no_quotes = match self.text_range_between_quotes() {
-            Some(it) => it,
-            None => return,
-        };
-
-        let start = self.syntax().text_range().start();
-        let text = &self.text()[text_range_no_quotes - start];
-        let offset = text_range_no_quotes.start() - start;
-
-        unescape_mixed(text, Self::MODE, &mut |range, unescaped_char| {
-            let text_range =
-                TextRange::new(range.start.try_into().unwrap(), range.end.try_into().unwrap());
-            // XXX: This method should only be used for highlighting ranges. The unescaped
-            // char/byte is not used. For simplicity, we return an arbitrary placeholder char.
-            cb(text_range + offset, unescaped_char.map(|_| ' '));
-        });
+    // NOTE: This method should only be used for highlighting ranges. The unescaped
+    // char/byte is not used. For simplicity, we return an arbitrary placeholder char.
+    fn unescape(s: &str, mut callback: impl FnMut(Range<usize>, Result<char, EscapeError>)) {
+        unescape_c_str(s, |range, _res| callback(range, Ok('_')))
     }
 }
 
@@ -323,10 +312,7 @@ impl ast::CString {
             MixedUnit::Char(c) => buf.extend(c.encode_utf8(&mut [0; 4]).as_bytes()),
             MixedUnit::HighByte(b) => buf.push(b),
         };
-        unescape_mixed(text, Self::MODE, &mut |char_range, unescaped| match (
-            unescaped,
-            buf.capacity() == 0,
-        ) {
+        unescape_c_str(text, |char_range, unescaped| match (unescaped, buf.capacity() == 0) {
             (Ok(u), false) => extend_unit(&mut buf, u),
             (Ok(_), true) if char_range.len() == 1 && char_range.start == prev_end => {
                 prev_end = char_range.end
diff --git a/src/tools/rust-analyzer/crates/syntax/src/validation.rs b/src/tools/rust-analyzer/crates/syntax/src/validation.rs
index 5bfeb3bff87..4180f9cd185 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/validation.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/validation.rs
@@ -6,7 +6,9 @@ mod block;
 
 use itertools::Itertools;
 use rowan::Direction;
-use rustc_literal_escaper::{self, EscapeError, Mode, unescape_mixed, unescape_unicode};
+use rustc_literal_escaper::{
+    EscapeError, unescape_byte, unescape_byte_str, unescape_c_str, unescape_char, unescape_str,
+};
 
 use crate::{
     AstNode, SyntaxError,
@@ -47,7 +49,7 @@ pub(crate) fn validate(root: &SyntaxNode, errors: &mut Vec<SyntaxError>) {
 }
 
 fn rustc_unescape_error_to_string(err: EscapeError) -> (&'static str, bool) {
-    use rustc_literal_escaper::EscapeError as EE;
+    use EscapeError as EE;
 
     #[rustfmt::skip]
     let err_message = match err {
@@ -142,7 +144,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
         ast::LiteralKind::String(s) => {
             if !s.is_raw() {
                 if let Some(without_quotes) = unquote(text, 1, '"') {
-                    unescape_unicode(without_quotes, Mode::Str, &mut |range, char| {
+                    unescape_str(without_quotes, |range, char| {
                         if let Err(err) = char {
                             push_err(1, range.start, err);
                         }
@@ -153,7 +155,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
         ast::LiteralKind::ByteString(s) => {
             if !s.is_raw() {
                 if let Some(without_quotes) = unquote(text, 2, '"') {
-                    unescape_unicode(without_quotes, Mode::ByteStr, &mut |range, char| {
+                    unescape_byte_str(without_quotes, |range, char| {
                         if let Err(err) = char {
                             push_err(1, range.start, err);
                         }
@@ -164,7 +166,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
         ast::LiteralKind::CString(s) => {
             if !s.is_raw() {
                 if let Some(without_quotes) = unquote(text, 2, '"') {
-                    unescape_mixed(without_quotes, Mode::CStr, &mut |range, char| {
+                    unescape_c_str(without_quotes, |range, char| {
                         if let Err(err) = char {
                             push_err(1, range.start, err);
                         }
@@ -174,20 +176,16 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
         }
         ast::LiteralKind::Char(_) => {
             if let Some(without_quotes) = unquote(text, 1, '\'') {
-                unescape_unicode(without_quotes, Mode::Char, &mut |range, char| {
-                    if let Err(err) = char {
-                        push_err(1, range.start, err);
-                    }
-                });
+                if let Err(err) = unescape_char(without_quotes) {
+                    push_err(1, 0, err);
+                }
             }
         }
         ast::LiteralKind::Byte(_) => {
             if let Some(without_quotes) = unquote(text, 2, '\'') {
-                unescape_unicode(without_quotes, Mode::Byte, &mut |range, char| {
-                    if let Err(err) = char {
-                        push_err(2, range.start, err);
-                    }
-                });
+                if let Err(err) = unescape_byte(without_quotes) {
+                    push_err(2, 0, err);
+                }
             }
         }
         ast::LiteralKind::IntNumber(_)