diff --git a/Cargo.lock b/Cargo.lock
index 2ca5899c77..44ef223557 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -609,6 +609,7 @@ dependencies = [
  "hir",
  "ide_db",
  "itertools",
+ "parser",
  "profile",
  "rustc-hash",
  "sourcegen",
@@ -654,6 +655,7 @@ dependencies = [
  "itertools",
  "limit",
  "once_cell",
+ "parser",
  "profile",
  "rayon",
  "rustc-hash",
@@ -695,6 +697,7 @@ dependencies = [
  "hir",
  "ide_db",
  "itertools",
+ "parser",
  "rustc-hash",
  "syntax",
  "test_utils",
diff --git a/crates/ide_assists/Cargo.toml b/crates/ide_assists/Cargo.toml
index 4d97e9150e..3cd186fdf5 100644
--- a/crates/ide_assists/Cargo.toml
+++ b/crates/ide_assists/Cargo.toml
@@ -16,6 +16,7 @@ itertools = "0.10.0"
 either = "1.6.1"
 
 stdx = { path = "../stdx", version = "0.0.0" }
+parser = { path = "../parser", version = "0.0.0" }
 syntax = { path = "../syntax", version = "0.0.0" }
 text_edit = { path = "../text_edit", version = "0.0.0" }
 profile = { path = "../profile", version = "0.0.0" }
diff --git a/crates/ide_assists/src/utils/suggest_name.rs b/crates/ide_assists/src/utils/suggest_name.rs
index 2021db3aba..f91b2fe44e 100644
--- a/crates/ide_assists/src/utils/suggest_name.rs
+++ b/crates/ide_assists/src/utils/suggest_name.rs
@@ -135,7 +135,7 @@ fn normalize(name: &str) -> Option<String> {
 }
 
 fn is_valid_name(name: &str) -> bool {
-    match syntax::lex_single_syntax_kind(name) {
+    match parser::LexedStr::single_token(name) {
         Some((syntax::SyntaxKind::IDENT, _error)) => true,
         _ => false,
     }
diff --git a/crates/ide_db/Cargo.toml b/crates/ide_db/Cargo.toml
index ea20f5372c..cfcf9f56c8 100644
--- a/crates/ide_db/Cargo.toml
+++ b/crates/ide_db/Cargo.toml
@@ -22,6 +22,7 @@ arrayvec = "0.7"
 indexmap = "1.7"
 
 stdx = { path = "../stdx", version = "0.0.0" }
+parser = { path = "../parser", version = "0.0.0" }
 syntax = { path = "../syntax", version = "0.0.0" }
 text_edit = { path = "../text_edit", version = "0.0.0" }
 base_db = { path = "../base_db", version = "0.0.0" }
diff --git a/crates/ide_db/src/rename.rs b/crates/ide_db/src/rename.rs
index 60160f9553..188499db72 100644
--- a/crates/ide_db/src/rename.rs
+++ b/crates/ide_db/src/rename.rs
@@ -28,7 +28,7 @@ use hir::{AsAssocItem, FieldSource, HasSource, InFile, ModuleSource, Semantics};
 use stdx::never;
 use syntax::{
     ast::{self, HasName},
-    lex_single_syntax_kind, AstNode, SyntaxKind, TextRange, T,
+    AstNode, SyntaxKind, TextRange, T,
 };
 use text_edit::{TextEdit, TextEditBuilder};
 
@@ -490,7 +490,7 @@ pub enum IdentifierKind {
 
 impl IdentifierKind {
     pub fn classify(new_name: &str) -> Result<IdentifierKind> {
-        match lex_single_syntax_kind(new_name) {
+        match parser::LexedStr::single_token(new_name) {
             Some(res) => match res {
                 (SyntaxKind::IDENT, _) => Ok(IdentifierKind::Ident),
                 (T![_], _) => Ok(IdentifierKind::Underscore),
diff --git a/crates/ide_ssr/Cargo.toml b/crates/ide_ssr/Cargo.toml
index efa8fd243a..9a8221ac6c 100644
--- a/crates/ide_ssr/Cargo.toml
+++ b/crates/ide_ssr/Cargo.toml
@@ -16,6 +16,7 @@ rustc-hash = "1.1.0"
 itertools = "0.10.0"
 
 text_edit = { path = "../text_edit", version = "0.0.0" }
+parser = { path = "../parser", version = "0.0.0" }
 syntax = { path = "../syntax", version = "0.0.0" }
 ide_db = { path = "../ide_db", version = "0.0.0" }
 hir = { path = "../hir", version = "0.0.0" }
diff --git a/crates/ide_ssr/src/parsing.rs b/crates/ide_ssr/src/parsing.rs
index ed7c033e27..ae7d5b4bf1 100644
--- a/crates/ide_ssr/src/parsing.rs
+++ b/crates/ide_ssr/src/parsing.rs
@@ -256,19 +256,13 @@ fn validate_rule(rule: &SsrRule) -> Result<(), SsrError> {
 }
 
 fn tokenize(source: &str) -> Result<Vec<Token>, SsrError> {
-    let mut start = 0;
-    let (raw_tokens, errors) = syntax::tokenize(source);
-    if let Some(first_error) = errors.first() {
+    let lexed = parser::LexedStr::new(source);
+    if let Some((_, first_error)) = lexed.errors().next() {
         bail!("Failed to parse pattern: {}", first_error);
     }
     let mut tokens: Vec<Token> = Vec::new();
-    for raw_token in raw_tokens {
-        let token_len = usize::from(raw_token.len);
-        tokens.push(Token {
-            kind: raw_token.kind,
-            text: SmolStr::new(&source[start..start + token_len]),
-        });
-        start += token_len;
+    for i in 0..lexed.len() {
+        tokens.push(Token { kind: lexed.kind(i), text: lexed.text(i).into() });
     }
     Ok(tokens)
 }
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index 28a23f6be2..109842b0cd 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -4,10 +4,9 @@ use parser::{ParseError, TreeSink};
 use rustc_hash::{FxHashMap, FxHashSet};
 use syntax::{
     ast::{self, make::tokens::doc_comment},
-    tokenize, AstToken, Parse, PreorderWithTokens, SmolStr, SyntaxElement, SyntaxKind,
+    AstToken, Parse, PreorderWithTokens, SmolStr, SyntaxElement, SyntaxKind,
     SyntaxKind::*,
-    SyntaxNode, SyntaxToken, SyntaxTreeBuilder, TextRange, TextSize, Token as RawToken, WalkEvent,
-    T,
+    SyntaxNode, SyntaxToken, SyntaxTreeBuilder, TextRange, TextSize, WalkEvent, T,
 };
 use tt::buffer::{Cursor, TokenBuffer};
 
@@ -69,15 +68,14 @@ pub fn token_tree_to_syntax_node(
 
 /// Convert a string to a `TokenTree`
 pub fn parse_to_token_tree(text: &str) -> Option<(tt::Subtree, TokenMap)> {
-    let (tokens, errors) = tokenize(text);
-    if !errors.is_empty() {
+    let lexed = parser::LexedStr::new(text);
+    if lexed.errors().next().is_some() {
         return None;
     }
 
     let mut conv = RawConvertor {
-        text,
-        offset: TextSize::default(),
-        inner: tokens.iter(),
+        lexed: lexed,
+        pos: 0,
         id_alloc: TokenIdAlloc {
             map: Default::default(),
             global_offset: TextSize::default(),
@@ -146,7 +144,7 @@ fn convert_tokens<C: TokenConvertor>(conv: &mut C) -> tt::Subtree {
             Some(it) => it,
         };
 
-        let k: SyntaxKind = token.kind();
+        let k: SyntaxKind = token.kind(&conv);
         if k == COMMENT {
             if let Some(tokens) = conv.convert_doc_comment(&token) {
                 // FIXME: There has to be a better way to do this
@@ -199,19 +197,19 @@ fn convert_tokens<C: TokenConvertor>(conv: &mut C) -> tt::Subtree {
             } else {
                 let spacing = match conv.peek() {
                     Some(next)
-                        if next.kind().is_trivia()
-                            || next.kind() == T!['[']
-                            || next.kind() == T!['{']
-                            || next.kind() == T!['('] =>
+                        if next.kind(&conv).is_trivia()
+                            || next.kind(&conv) == T!['[']
+                            || next.kind(&conv) == T!['{']
+                            || next.kind(&conv) == T!['('] =>
                     {
                         tt::Spacing::Alone
                     }
-                    Some(next) if next.kind().is_punct() && next.kind() != UNDERSCORE => {
+                    Some(next) if next.kind(&conv).is_punct() && next.kind(&conv) != UNDERSCORE => {
                         tt::Spacing::Joint
                     }
                     _ => tt::Spacing::Alone,
                 };
-                let char = match token.to_char() {
+                let char = match token.to_char(&conv) {
                     Some(c) => c,
                     None => {
                         panic!("Token from lexer must be single char: token = {:#?}", token);
@@ -222,7 +220,7 @@ fn convert_tokens<C: TokenConvertor>(conv: &mut C) -> tt::Subtree {
         } else {
             macro_rules! make_leaf {
                 ($i:ident) => {
-                    tt::$i { id: conv.id_alloc().alloc(range), text: token.to_text() }.into()
+                    tt::$i { id: conv.id_alloc().alloc(range), text: token.to_text(conv) }.into()
                 };
             }
             let leaf: tt::Leaf = match k {
@@ -243,7 +241,7 @@ fn convert_tokens<C: TokenConvertor>(conv: &mut C) -> tt::Subtree {
 
                     let r = TextRange::at(range.start() + char_unit, range.len() - char_unit);
                     let ident = tt::Leaf::from(tt::Ident {
-                        text: SmolStr::new(&token.to_text()[1..]),
+                        text: SmolStr::new(&token.to_text(conv)[1..]),
                         id: conv.id_alloc().alloc(r),
                     });
                     result.push(ident.into());
@@ -392,22 +390,21 @@ impl TokenIdAlloc {
 
 /// A Raw Token (straightly from lexer) convertor
 struct RawConvertor<'a> {
-    text: &'a str,
-    offset: TextSize,
+    lexed: parser::LexedStr<'a>,
+    pos: usize,
     id_alloc: TokenIdAlloc,
-    inner: std::slice::Iter<'a, RawToken>,
 }
 
-trait SrcToken: std::fmt::Debug {
-    fn kind(&self) -> SyntaxKind;
+trait SrcToken<Ctx>: std::fmt::Debug {
+    fn kind(&self, ctx: &Ctx) -> SyntaxKind;
 
-    fn to_char(&self) -> Option<char>;
+    fn to_char(&self, ctx: &Ctx) -> Option<char>;
 
-    fn to_text(&self) -> SmolStr;
+    fn to_text(&self, ctx: &Ctx) -> SmolStr;
 }
 
-trait TokenConvertor {
-    type Token: SrcToken;
+trait TokenConvertor: Sized {
+    type Token: SrcToken<Self>;
 
     fn convert_doc_comment(&self, token: &Self::Token) -> Option<Vec<tt::TokenTree>>;
 
@@ -418,42 +415,45 @@ trait TokenConvertor {
     fn id_alloc(&mut self) -> &mut TokenIdAlloc;
 }
 
-impl<'a> SrcToken for (&'a RawToken, &'a str) {
-    fn kind(&self) -> SyntaxKind {
-        self.0.kind
+impl<'a> SrcToken<RawConvertor<'a>> for usize {
+    fn kind(&self, ctx: &RawConvertor<'a>) -> SyntaxKind {
+        ctx.lexed.kind(*self)
     }
 
-    fn to_char(&self) -> Option<char> {
-        self.1.chars().next()
+    fn to_char(&self, ctx: &RawConvertor<'a>) -> Option<char> {
+        ctx.lexed.text(*self).chars().next()
     }
 
-    fn to_text(&self) -> SmolStr {
-        self.1.into()
+    fn to_text(&self, ctx: &RawConvertor<'_>) -> SmolStr {
+        ctx.lexed.text(*self).into()
     }
 }
 
 impl<'a> TokenConvertor for RawConvertor<'a> {
-    type Token = (&'a RawToken, &'a str);
+    type Token = usize;
 
-    fn convert_doc_comment(&self, token: &Self::Token) -> Option<Vec<tt::TokenTree>> {
-        convert_doc_comment(&doc_comment(token.1))
+    fn convert_doc_comment(&self, token: &usize) -> Option<Vec<tt::TokenTree>> {
+        let text = self.lexed.text(*token);
+        convert_doc_comment(&doc_comment(text))
     }
 
     fn bump(&mut self) -> Option<(Self::Token, TextRange)> {
-        let token = self.inner.next()?;
-        let range = TextRange::at(self.offset, token.len);
-        self.offset += token.len;
+        if self.pos == self.lexed.len() {
+            return None;
+        }
+        let token = self.pos;
+        self.pos += 1;
+        let range = self.lexed.text_range(token);
+        let range = TextRange::new(range.start.try_into().unwrap(), range.end.try_into().unwrap());
 
-        Some(((token, &self.text[range]), range))
+        Some((token, range))
     }
 
     fn peek(&self) -> Option<Self::Token> {
-        let token = self.inner.as_slice().get(0);
-
-        token.map(|it| {
-            let range = TextRange::at(self.offset, it.len);
-            (it, &self.text[range])
-        })
+        if self.pos == self.lexed.len() {
+            return None;
+        }
+        Some(self.pos)
     }
 
     fn id_alloc(&mut self) -> &mut TokenIdAlloc {
@@ -523,17 +523,17 @@ impl SynToken {
     }
 }
 
-impl SrcToken for SynToken {
-    fn kind(&self) -> SyntaxKind {
+impl<'a> SrcToken<Convertor<'a>> for SynToken {
+    fn kind(&self, _ctx: &Convertor<'a>) -> SyntaxKind {
         self.token().kind()
     }
-    fn to_char(&self) -> Option<char> {
+    fn to_char(&self, _ctx: &Convertor<'a>) -> Option<char> {
         match self {
             SynToken::Ordinary(_) => None,
             SynToken::Punch(it, i) => it.text().chars().nth((*i).into()),
         }
     }
-    fn to_text(&self) -> SmolStr {
+    fn to_text(&self, _ctx: &Convertor<'a>) -> SmolStr {
         self.token().text().into()
     }
 }
diff --git a/crates/mbe/src/to_parser_tokens.rs b/crates/mbe/src/to_parser_tokens.rs
index 644689f432..f419c78d46 100644
--- a/crates/mbe/src/to_parser_tokens.rs
+++ b/crates/mbe/src/to_parser_tokens.rs
@@ -1,7 +1,7 @@
 //! Convert macro-by-example tokens which are specific to macro expansion into a
 //! format that works for our parser.
 
-use syntax::{lex_single_syntax_kind, SyntaxKind, SyntaxKind::*, T};
+use syntax::{SyntaxKind, SyntaxKind::*, T};
 use tt::buffer::TokenBuffer;
 
 pub(crate) fn to_parser_tokens(buffer: &TokenBuffer) -> parser::Tokens {
@@ -35,7 +35,7 @@ pub(crate) fn to_parser_tokens(buffer: &TokenBuffer) -> parser::Tokens {
                         let is_negated = lit.text.starts_with('-');
                         let inner_text = &lit.text[if is_negated { 1 } else { 0 }..];
 
-                        let kind = lex_single_syntax_kind(inner_text)
+                        let kind = parser::LexedStr::single_token(inner_text)
                             .map(|(kind, _error)| kind)
                             .filter(|kind| {
                                 kind.is_literal()
diff --git a/crates/parser/src/lexed_str.rs b/crates/parser/src/lexed_str.rs
index 9c5d27f51d..1ef29b5210 100644
--- a/crates/parser/src/lexed_str.rs
+++ b/crates/parser/src/lexed_str.rs
@@ -8,6 +8,8 @@
 //! Note that these tokens, unlike the tokens we feed into the parser, do
 //! include info about comments and whitespace.
 
+use std::ops;
+
 use crate::{
     SyntaxKind::{self, *},
     T,
@@ -52,7 +54,7 @@ impl<'a> LexedStr<'a> {
         res
     }
 
-    pub fn single_token(text: &'a str) -> Option<SyntaxKind> {
+    pub fn single_token(text: &'a str) -> Option<(SyntaxKind, Option<String>)> {
         if text.is_empty() {
             return None;
         }
@@ -63,11 +65,7 @@ impl<'a> LexedStr<'a> {
         }
 
         let (kind, err) = from_rustc(&token.kind, text);
-        if err.is_some() {
-            return None;
-        }
-
-        Some(kind)
+        Some((kind, err.map(|it| it.to_owned())))
     }
 
     pub fn as_str(&self) -> &str {
@@ -78,16 +76,40 @@ impl<'a> LexedStr<'a> {
         self.kind.len() - 1
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     pub fn kind(&self, i: usize) -> SyntaxKind {
         assert!(i < self.len());
         self.kind[i]
     }
 
     pub fn text(&self, i: usize) -> &str {
+        self.range_text(i..i + 1)
+    }
+    pub fn range_text(&self, r: ops::Range<usize>) -> &str {
+        assert!(r.start < r.end && r.end <= self.len());
+        let lo = self.start[r.start] as usize;
+        let hi = self.start[r.end] as usize;
+        &self.text[lo..hi]
+    }
+
+    // Naming is hard.
+    pub fn text_range(&self, i: usize) -> ops::Range<usize> {
         assert!(i < self.len());
         let lo = self.start[i] as usize;
         let hi = self.start[i + 1] as usize;
-        &self.text[lo..hi]
+        lo..hi
+    }
+    pub fn text_start(&self, i: usize) -> usize {
+        assert!(i <= self.len());
+        self.start[i] as usize
+    }
+    pub fn text_len(&self, i: usize) -> usize {
+        assert!(i < self.len());
+        let r = self.text_range(i);
+        r.end - r.start
     }
 
     pub fn error(&self, i: usize) -> Option<&str> {
@@ -96,6 +118,10 @@ impl<'a> LexedStr<'a> {
         Some(self.error[err].msg.as_str())
     }
 
+    pub fn errors(&self) -> impl Iterator<Item = (usize, &str)> + '_ {
+        self.error.iter().map(|it| (it.token as usize, it.msg.as_str()))
+    }
+
     pub fn to_tokens(&self) -> crate::Tokens {
         let mut res = crate::Tokens::default();
         let mut was_joint = false;
diff --git a/crates/syntax/src/lib.rs b/crates/syntax/src/lib.rs
index 07817bfc0d..65a6b7ac4e 100644
--- a/crates/syntax/src/lib.rs
+++ b/crates/syntax/src/lib.rs
@@ -48,7 +48,6 @@ use text_edit::Indel;
 
 pub use crate::{
     ast::{AstNode, AstToken},
-    parsing::lexer::{lex_single_syntax_kind, tokenize, Token},
     ptr::{AstPtr, SyntaxNodePtr},
     syntax_error::SyntaxError,
     syntax_node::{
diff --git a/crates/syntax/src/parsing.rs b/crates/syntax/src/parsing.rs
index 865e146482..cba1ddde85 100644
--- a/crates/syntax/src/parsing.rs
+++ b/crates/syntax/src/parsing.rs
@@ -1,7 +1,6 @@
 //! Lexing, bridging to parser (which does the actual parsing) and
 //! incremental reparsing.
 
-pub(crate) mod lexer;
 mod text_tree_sink;
 mod reparsing;
 
@@ -10,18 +9,17 @@ use text_tree_sink::TextTreeSink;
 
 use crate::{syntax_node::GreenNode, AstNode, SyntaxError, SyntaxNode};
 
-pub(crate) use crate::parsing::{lexer::*, reparsing::incremental_reparse};
+pub(crate) use crate::parsing::reparsing::incremental_reparse;
 
 pub(crate) fn parse_text(text: &str) -> (GreenNode, Vec<SyntaxError>) {
-    let (lexer_tokens, lexer_errors) = tokenize(text);
-    let parser_tokens = to_parser_tokens(text, &lexer_tokens);
+    let lexed = parser::LexedStr::new(text);
+    let parser_tokens = lexed.to_tokens();
 
-    let mut tree_sink = TextTreeSink::new(text, &lexer_tokens);
+    let mut tree_sink = TextTreeSink::new(lexed);
 
     parser::parse_source_file(&parser_tokens, &mut tree_sink);
 
-    let (tree, mut parser_errors) = tree_sink.finish();
-    parser_errors.extend(lexer_errors);
+    let (tree, parser_errors) = tree_sink.finish();
 
     (tree, parser_errors)
 }
@@ -31,14 +29,13 @@ pub(crate) fn parse_text_as<T: AstNode>(
     text: &str,
     entry_point: parser::ParserEntryPoint,
 ) -> Result<T, ()> {
-    let (lexer_tokens, lexer_errors) = tokenize(text);
-    if !lexer_errors.is_empty() {
+    let lexed = parser::LexedStr::new(text);
+    if lexed.errors().next().is_some() {
         return Err(());
     }
+    let parser_tokens = lexed.to_tokens();
 
-    let parser_tokens = to_parser_tokens(text, &lexer_tokens);
-
-    let mut tree_sink = TextTreeSink::new(text, &lexer_tokens);
+    let mut tree_sink = TextTreeSink::new(lexed);
 
     // TextTreeSink assumes that there's at least some root node to which it can attach errors and
     // tokens. We arbitrarily give it a SourceFile.
@@ -54,29 +51,3 @@ pub(crate) fn parse_text_as<T: AstNode>(
 
     SyntaxNode::new_root(tree).first_child().and_then(T::cast).ok_or(())
 }
-
-pub(crate) fn to_parser_tokens(text: &str, lexer_tokens: &[lexer::Token]) -> ::parser::Tokens {
-    let mut off = 0;
-    let mut res = parser::Tokens::default();
-    let mut was_joint = false;
-    for t in lexer_tokens {
-        if t.kind.is_trivia() {
-            was_joint = false;
-        } else {
-            if t.kind == SyntaxKind::IDENT {
-                let token_text = &text[off..][..usize::from(t.len)];
-                let contextual_kw =
-                    SyntaxKind::from_contextual_keyword(token_text).unwrap_or(SyntaxKind::IDENT);
-                res.push_ident(contextual_kw);
-            } else {
-                if was_joint {
-                    res.was_joint();
-                }
-                res.push(t.kind);
-            }
-            was_joint = true;
-        }
-        off += usize::from(t.len);
-    }
-    res
-}
diff --git a/crates/syntax/src/parsing/lexer.rs b/crates/syntax/src/parsing/lexer.rs
deleted file mode 100644
index d94f5f067d..0000000000
--- a/crates/syntax/src/parsing/lexer.rs
+++ /dev/null
@@ -1,249 +0,0 @@
-//! Lexer analyzes raw input string and produces lexemes (tokens).
-//! It is just a bridge to `rustc_lexer`.
-
-use std::convert::TryInto;
-
-use rustc_lexer::RawStrError;
-
-use crate::{
-    SyntaxError,
-    SyntaxKind::{self, *},
-    TextRange, TextSize, T,
-};
-
-/// A token of Rust source.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Token {
-    /// The kind of token.
-    pub kind: SyntaxKind,
-    /// The length of the token.
-    pub len: TextSize,
-}
-
-/// Break a string up into its component tokens.
-/// Beware that it checks for shebang first and its length contributes to resulting
-/// tokens offsets.
-pub fn tokenize(text: &str) -> (Vec<Token>, Vec<SyntaxError>) {
-    // non-empty string is a precondition of `rustc_lexer::strip_shebang()`.
-    if text.is_empty() {
-        return Default::default();
-    }
-
-    let mut tokens = Vec::new();
-    let mut errors = Vec::new();
-
-    let mut offset = match rustc_lexer::strip_shebang(text) {
-        Some(shebang_len) => {
-            tokens.push(Token { kind: SHEBANG, len: shebang_len.try_into().unwrap() });
-            shebang_len
-        }
-        None => 0,
-    };
-
-    let text_without_shebang = &text[offset..];
-
-    for rustc_token in rustc_lexer::tokenize(text_without_shebang) {
-        let token_len: TextSize = rustc_token.len.try_into().unwrap();
-        let token_range = TextRange::at(offset.try_into().unwrap(), token_len);
-
-        let (syntax_kind, err_message) =
-            rustc_token_kind_to_syntax_kind(&rustc_token.kind, &text[token_range]);
-
-        tokens.push(Token { kind: syntax_kind, len: token_len });
-
-        if let Some(err_message) = err_message {
-            errors.push(SyntaxError::new(err_message, token_range));
-        }
-
-        offset += rustc_token.len;
-    }
-
-    (tokens, errors)
-}
-
-/// Returns `SyntaxKind` and `Option<SyntaxError>` if `text` parses as a single token.
-///
-/// Returns `None` if the string contains zero *or two or more* tokens.
-/// The token is malformed if the returned error is not `None`.
-///
-/// Beware that unescape errors are not checked at tokenization time.
-pub fn lex_single_syntax_kind(text: &str) -> Option<(SyntaxKind, Option<SyntaxError>)> {
-    let (first_token, err) = lex_first_token(text)?;
-    if first_token.len != TextSize::of(text) {
-        return None;
-    }
-    Some((first_token.kind, err))
-}
-
-/// Returns `SyntaxKind` and `Option<SyntaxError>` of the first token
-/// encountered at the beginning of the string.
-///
-/// Returns `None` if the string contains zero tokens or if the token was parsed
-/// with an error.
-/// The token is malformed if the returned error is not `None`.
-///
-/// Beware that unescape errors are not checked at tokenization time.
-fn lex_first_token(text: &str) -> Option<(Token, Option<SyntaxError>)> {
-    // non-empty string is a precondition of `rustc_lexer::first_token()`.
-    if text.is_empty() {
-        return None;
-    }
-
-    let rustc_token = rustc_lexer::first_token(text);
-    let (syntax_kind, err_message) = rustc_token_kind_to_syntax_kind(&rustc_token.kind, text);
-
-    let token = Token { kind: syntax_kind, len: rustc_token.len.try_into().unwrap() };
-    let optional_error = err_message
-        .map(|err_message| SyntaxError::new(err_message, TextRange::up_to(TextSize::of(text))));
-
-    Some((token, optional_error))
-}
-
-/// Returns `SyntaxKind` and an optional tokenize error message.
-fn rustc_token_kind_to_syntax_kind(
-    rustc_token_kind: &rustc_lexer::TokenKind,
-    token_text: &str,
-) -> (SyntaxKind, Option<&'static str>) {
-    // A note on an intended tradeoff:
-    // 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 syntax_kind = {
-        match rustc_token_kind {
-            rustc_lexer::TokenKind::LineComment { doc_style: _ } => COMMENT,
-
-            rustc_lexer::TokenKind::BlockComment { doc_style: _, terminated: true } => COMMENT,
-            rustc_lexer::TokenKind::BlockComment { doc_style: _, terminated: false } => {
-                return (
-                    COMMENT,
-                    Some("Missing trailing `*/` symbols to terminate the block comment"),
-                );
-            }
-
-            rustc_lexer::TokenKind::Whitespace => WHITESPACE,
-
-            rustc_lexer::TokenKind::Ident => {
-                if token_text == "_" {
-                    UNDERSCORE
-                } else {
-                    SyntaxKind::from_keyword(token_text).unwrap_or(IDENT)
-                }
-            }
-
-            rustc_lexer::TokenKind::RawIdent => IDENT,
-            rustc_lexer::TokenKind::Literal { kind, .. } => return match_literal_kind(kind),
-
-            rustc_lexer::TokenKind::Lifetime { starts_with_number: false } => LIFETIME_IDENT,
-            rustc_lexer::TokenKind::Lifetime { starts_with_number: true } => {
-                return (LIFETIME_IDENT, Some("Lifetime name cannot start with a number"))
-            }
-
-            rustc_lexer::TokenKind::Semi => T![;],
-            rustc_lexer::TokenKind::Comma => T![,],
-            rustc_lexer::TokenKind::Dot => T![.],
-            rustc_lexer::TokenKind::OpenParen => T!['('],
-            rustc_lexer::TokenKind::CloseParen => T![')'],
-            rustc_lexer::TokenKind::OpenBrace => T!['{'],
-            rustc_lexer::TokenKind::CloseBrace => T!['}'],
-            rustc_lexer::TokenKind::OpenBracket => T!['['],
-            rustc_lexer::TokenKind::CloseBracket => T![']'],
-            rustc_lexer::TokenKind::At => T![@],
-            rustc_lexer::TokenKind::Pound => T![#],
-            rustc_lexer::TokenKind::Tilde => T![~],
-            rustc_lexer::TokenKind::Question => T![?],
-            rustc_lexer::TokenKind::Colon => T![:],
-            rustc_lexer::TokenKind::Dollar => T![$],
-            rustc_lexer::TokenKind::Eq => T![=],
-            rustc_lexer::TokenKind::Bang => T![!],
-            rustc_lexer::TokenKind::Lt => T![<],
-            rustc_lexer::TokenKind::Gt => T![>],
-            rustc_lexer::TokenKind::Minus => T![-],
-            rustc_lexer::TokenKind::And => T![&],
-            rustc_lexer::TokenKind::Or => T![|],
-            rustc_lexer::TokenKind::Plus => T![+],
-            rustc_lexer::TokenKind::Star => T![*],
-            rustc_lexer::TokenKind::Slash => T![/],
-            rustc_lexer::TokenKind::Caret => T![^],
-            rustc_lexer::TokenKind::Percent => T![%],
-            rustc_lexer::TokenKind::Unknown => ERROR,
-        }
-    };
-
-    return (syntax_kind, None);
-
-    fn match_literal_kind(kind: &rustc_lexer::LiteralKind) -> (SyntaxKind, Option<&'static str>) {
-        let mut err = "";
-        let syntax_kind = match *kind {
-            rustc_lexer::LiteralKind::Int { empty_int, base: _ } => {
-                if empty_int {
-                    err = "Missing digits after the integer base prefix";
-                }
-                INT_NUMBER
-            }
-            rustc_lexer::LiteralKind::Float { empty_exponent, base: _ } => {
-                if empty_exponent {
-                    err = "Missing digits after the exponent symbol";
-                }
-                FLOAT_NUMBER
-            }
-            rustc_lexer::LiteralKind::Char { terminated } => {
-                if !terminated {
-                    err = "Missing trailing `'` symbol to terminate the character literal";
-                }
-                CHAR
-            }
-            rustc_lexer::LiteralKind::Byte { terminated } => {
-                if !terminated {
-                    err = "Missing trailing `'` symbol to terminate the byte literal";
-                }
-                BYTE
-            }
-            rustc_lexer::LiteralKind::Str { terminated } => {
-                if !terminated {
-                    err = "Missing trailing `\"` symbol to terminate the string literal";
-                }
-                STRING
-            }
-            rustc_lexer::LiteralKind::ByteStr { terminated } => {
-                if !terminated {
-                    err = "Missing trailing `\"` symbol to terminate the byte string literal";
-                }
-                BYTE_STRING
-            }
-            rustc_lexer::LiteralKind::RawStr { err: raw_str_err, .. } => {
-                if let Some(raw_str_err) = raw_str_err {
-                    err = match raw_str_err {
-                        RawStrError::InvalidStarter { .. } => "Missing `\"` symbol after `#` symbols to begin the raw string literal",
-                        RawStrError::NoTerminator { expected, found, .. } => if expected == found {
-                            "Missing trailing `\"` to terminate the raw string literal"
-                        } else {
-                            "Missing trailing `\"` with `#` symbols to terminate the raw string literal"
-                        },
-                        RawStrError::TooManyDelimiters { .. } => "Too many `#` symbols: raw strings may be delimited by up to 65535 `#` symbols",
-                    };
-                };
-                STRING
-            }
-            rustc_lexer::LiteralKind::RawByteStr { err: raw_str_err, .. } => {
-                if let Some(raw_str_err) = raw_str_err {
-                    err = match raw_str_err {
-                        RawStrError::InvalidStarter { .. } => "Missing `\"` symbol after `#` symbols to begin the raw byte string literal",
-                        RawStrError::NoTerminator { expected, found, .. } => if expected == found {
-                            "Missing trailing `\"` to terminate the raw byte string literal"
-                        } else {
-                            "Missing trailing `\"` with `#` symbols to terminate the raw byte string literal"
-                        },
-                        RawStrError::TooManyDelimiters { .. } => "Too many `#` symbols: raw byte strings may be delimited by up to 65535 `#` symbols",
-                    };
-                };
-
-                BYTE_STRING
-            }
-        };
-
-        let err = if err.is_empty() { None } else { Some(err) };
-
-        (syntax_kind, err)
-    }
-}
diff --git a/crates/syntax/src/parsing/reparsing.rs b/crates/syntax/src/parsing/reparsing.rs
index 62f39a9347..e9567a838c 100644
--- a/crates/syntax/src/parsing/reparsing.rs
+++ b/crates/syntax/src/parsing/reparsing.rs
@@ -10,11 +10,7 @@ use parser::Reparser;
 use text_edit::Indel;
 
 use crate::{
-    parsing::{
-        lexer::{lex_single_syntax_kind, tokenize, Token},
-        text_tree_sink::TextTreeSink,
-        to_parser_tokens,
-    },
+    parsing::text_tree_sink::TextTreeSink,
     syntax_node::{GreenNode, GreenToken, NodeOrToken, SyntaxElement, SyntaxNode},
     SyntaxError,
     SyntaxKind::*,
@@ -53,7 +49,7 @@ fn reparse_token(
             }
 
             let mut new_text = get_text_after_edit(prev_token.clone().into(), edit);
-            let (new_token_kind, new_err) = lex_single_syntax_kind(&new_text)?;
+            let (new_token_kind, new_err) = parser::LexedStr::single_token(&new_text)?;
 
             if new_token_kind != prev_token_kind
                 || (new_token_kind == IDENT && is_contextual_kw(&new_text))
@@ -66,7 +62,7 @@ fn reparse_token(
             // `b` no longer remains an identifier, but becomes a part of byte string literal
             if let Some(next_char) = root.text().char_at(prev_token.text_range().end()) {
                 new_text.push(next_char);
-                let token_with_next_char = lex_single_syntax_kind(&new_text);
+                let token_with_next_char = parser::LexedStr::single_token(&new_text);
                 if let Some((_kind, _error)) = token_with_next_char {
                     return None;
                 }
@@ -74,9 +70,10 @@ fn reparse_token(
             }
 
             let new_token = GreenToken::new(rowan::SyntaxKind(prev_token_kind.into()), &new_text);
+            let range = TextRange::up_to(TextSize::of(&new_text));
             Some((
                 prev_token.replace_with(new_token),
-                new_err.into_iter().collect(),
+                new_err.into_iter().map(|msg| SyntaxError::new(msg, range)).collect(),
                 prev_token.text_range(),
             ))
         }
@@ -91,17 +88,17 @@ fn reparse_block(
     let (node, reparser) = find_reparsable_node(root, edit.delete)?;
     let text = get_text_after_edit(node.clone().into(), edit);
 
-    let (lexer_tokens, new_lexer_errors) = tokenize(&text);
-    if !is_balanced(&lexer_tokens) {
+    let lexed = parser::LexedStr::new(text.as_str());
+    let parser_tokens = lexed.to_tokens();
+    if !is_balanced(&lexed) {
         return None;
     }
-    let parser_tokens = to_parser_tokens(&text, &lexer_tokens);
 
-    let mut tree_sink = TextTreeSink::new(&text, &lexer_tokens);
+    let mut tree_sink = TextTreeSink::new(lexed);
+
     reparser.parse(&parser_tokens, &mut tree_sink);
 
-    let (green, mut new_parser_errors) = tree_sink.finish();
-    new_parser_errors.extend(new_lexer_errors);
+    let (green, new_parser_errors) = tree_sink.finish();
 
     Some((node.replace_with(green), new_parser_errors, node.text_range()))
 }
@@ -131,16 +128,13 @@ fn find_reparsable_node(node: &SyntaxNode, range: TextRange) -> Option<(SyntaxNo
     })
 }
 
-fn is_balanced(tokens: &[Token]) -> bool {
-    if tokens.is_empty()
-        || tokens.first().unwrap().kind != T!['{']
-        || tokens.last().unwrap().kind != T!['}']
-    {
+fn is_balanced(lexed: &parser::LexedStr<'_>) -> bool {
+    if lexed.is_empty() || lexed.kind(0) != T!['{'] || lexed.kind(lexed.len() - 1) != T!['}'] {
         return false;
     }
     let mut balance = 0usize;
-    for t in &tokens[1..tokens.len() - 1] {
-        match t.kind {
+    for i in 1..lexed.len() - 1 {
+        match lexed.kind(i) {
             T!['{'] => balance += 1,
             T!['}'] => {
                 balance = match balance.checked_sub(1) {
diff --git a/crates/syntax/src/parsing/text_tree_sink.rs b/crates/syntax/src/parsing/text_tree_sink.rs
index c1792199fd..c9e7feb965 100644
--- a/crates/syntax/src/parsing/text_tree_sink.rs
+++ b/crates/syntax/src/parsing/text_tree_sink.rs
@@ -2,25 +2,22 @@
 
 use std::mem;
 
-use parser::{ParseError, TreeSink};
+use parser::{LexedStr, ParseError, TreeSink};
 
 use crate::{
     ast,
-    parsing::Token,
     syntax_node::GreenNode,
     SyntaxError,
     SyntaxKind::{self, *},
-    SyntaxTreeBuilder, TextRange, TextSize,
+    SyntaxTreeBuilder, TextRange,
 };
 
 /// Bridges the parser with our specific syntax tree representation.
 ///
 /// `TextTreeSink` also handles attachment of trivia (whitespace) to nodes.
 pub(crate) struct TextTreeSink<'a> {
-    text: &'a str,
-    tokens: &'a [Token],
-    text_pos: TextSize,
-    token_pos: usize,
+    lexed: LexedStr<'a>,
+    pos: usize,
     state: State,
     inner: SyntaxTreeBuilder,
 }
@@ -39,12 +36,7 @@ impl<'a> TreeSink for TextTreeSink<'a> {
             State::Normal => (),
         }
         self.eat_trivias();
-        let n_tokens = n_tokens as usize;
-        let len = self.tokens[self.token_pos..self.token_pos + n_tokens]
-            .iter()
-            .map(|it| it.len)
-            .sum::<TextSize>();
-        self.do_token(kind, len, n_tokens);
+        self.do_token(kind, n_tokens as usize);
     }
 
     fn start_node(&mut self, kind: SyntaxKind) {
@@ -60,20 +52,12 @@ impl<'a> TreeSink for TextTreeSink<'a> {
         }
 
         let n_trivias =
-            self.tokens[self.token_pos..].iter().take_while(|it| it.kind.is_trivia()).count();
-        let leading_trivias = &self.tokens[self.token_pos..self.token_pos + n_trivias];
-        let mut trivia_end =
-            self.text_pos + leading_trivias.iter().map(|it| it.len).sum::<TextSize>();
-
-        let n_attached_trivias = {
-            let leading_trivias = leading_trivias.iter().rev().map(|it| {
-                let next_end = trivia_end - it.len;
-                let range = TextRange::new(next_end, trivia_end);
-                trivia_end = next_end;
-                (it.kind, &self.text[range])
-            });
-            n_attached_trivias(kind, leading_trivias)
-        };
+            (self.pos..self.lexed.len()).take_while(|&it| self.lexed.kind(it).is_trivia()).count();
+        let leading_trivias = self.pos..self.pos + n_trivias;
+        let n_attached_trivias = n_attached_trivias(
+            kind,
+            leading_trivias.rev().map(|it| (self.lexed.kind(it), self.lexed.text(it))),
+        );
         self.eat_n_trivias(n_trivias - n_attached_trivias);
         self.inner.start_node(kind);
         self.eat_n_trivias(n_attached_trivias);
@@ -88,20 +72,14 @@ impl<'a> TreeSink for TextTreeSink<'a> {
     }
 
     fn error(&mut self, error: ParseError) {
-        self.inner.error(error, self.text_pos);
+        let text_pos = self.lexed.text_start(self.pos).try_into().unwrap();
+        self.inner.error(error, text_pos);
     }
 }
 
 impl<'a> TextTreeSink<'a> {
-    pub(super) fn new(text: &'a str, tokens: &'a [Token]) -> Self {
-        Self {
-            text,
-            tokens,
-            text_pos: 0.into(),
-            token_pos: 0,
-            state: State::PendingStart,
-            inner: SyntaxTreeBuilder::default(),
-        }
+    pub(super) fn new(lexed: parser::LexedStr<'a>) -> Self {
+        Self { lexed, pos: 0, state: State::PendingStart, inner: SyntaxTreeBuilder::default() }
     }
 
     pub(super) fn finish_eof(mut self) -> (GreenNode, Vec<SyntaxError>, bool) {
@@ -113,8 +91,17 @@ impl<'a> TextTreeSink<'a> {
             State::PendingStart | State::Normal => unreachable!(),
         }
 
-        let (node, errors) = self.inner.finish_raw();
-        let is_eof = self.token_pos == self.tokens.len();
+        let (node, mut errors) = self.inner.finish_raw();
+        for (i, err) in self.lexed.errors() {
+            let text_range = self.lexed.text_range(i);
+            let text_range = TextRange::new(
+                text_range.start.try_into().unwrap(),
+                text_range.end.try_into().unwrap(),
+            );
+            errors.push(SyntaxError::new(err, text_range))
+        }
+
+        let is_eof = self.pos == self.lexed.len();
 
         (node, errors, is_eof)
     }
@@ -125,27 +112,26 @@ impl<'a> TextTreeSink<'a> {
     }
 
     fn eat_trivias(&mut self) {
-        while let Some(&token) = self.tokens.get(self.token_pos) {
-            if !token.kind.is_trivia() {
+        while self.pos < self.lexed.len() {
+            let kind = self.lexed.kind(self.pos);
+            if !kind.is_trivia() {
                 break;
             }
-            self.do_token(token.kind, token.len, 1);
+            self.do_token(kind, 1);
         }
     }
 
     fn eat_n_trivias(&mut self, n: usize) {
         for _ in 0..n {
-            let token = self.tokens[self.token_pos];
-            assert!(token.kind.is_trivia());
-            self.do_token(token.kind, token.len, 1);
+            let kind = self.lexed.kind(self.pos);
+            assert!(kind.is_trivia());
+            self.do_token(kind, 1);
         }
     }
 
-    fn do_token(&mut self, kind: SyntaxKind, len: TextSize, n_tokens: usize) {
-        let range = TextRange::at(self.text_pos, len);
-        let text = &self.text[range];
-        self.text_pos += len;
-        self.token_pos += n_tokens;
+    fn do_token(&mut self, kind: SyntaxKind, n_tokens: usize) {
+        let text = &self.lexed.range_text(self.pos..self.pos + n_tokens);
+        self.pos += n_tokens;
         self.inner.token(kind, text);
     }
 }
diff --git a/crates/syntax/src/tests.rs b/crates/syntax/src/tests.rs
index 022db39f33..69c5b1cd35 100644
--- a/crates/syntax/src/tests.rs
+++ b/crates/syntax/src/tests.rs
@@ -3,7 +3,6 @@ mod sourcegen_ast;
 mod ast_src;
 
 use std::{
-    fmt::Write,
     fs,
     path::{Path, PathBuf},
 };
@@ -13,25 +12,7 @@ use expect_test::expect_file;
 use rayon::prelude::*;
 use test_utils::{bench, bench_fixture, project_root};
 
-use crate::{ast, fuzz, tokenize, AstNode, SourceFile, SyntaxError, TextRange, TextSize, Token};
-
-#[test]
-fn lexer_tests() {
-    // FIXME:
-    // * Add tests for unicode escapes in byte-character and [raw]-byte-string literals
-    // * Add tests for unescape errors
-
-    dir_tests(&test_data_dir(), &["lexer/ok"], "txt", |text, path| {
-        let (tokens, errors) = tokenize(text);
-        assert_errors_are_absent(&errors, path);
-        dump_tokens_and_errors(&tokens, &errors, text)
-    });
-    dir_tests(&test_data_dir(), &["lexer/err"], "txt", |text, path| {
-        let (tokens, errors) = tokenize(text);
-        assert_errors_are_present(&errors, path);
-        dump_tokens_and_errors(&tokens, &errors, text)
-    });
-}
+use crate::{ast, fuzz, AstNode, SourceFile, SyntaxError};
 
 #[test]
 fn parse_smoke_test() {
@@ -206,22 +187,6 @@ fn assert_errors_are_absent(errors: &[SyntaxError], path: &Path) {
     );
 }
 
-fn dump_tokens_and_errors(tokens: &[Token], errors: &[SyntaxError], text: &str) -> String {
-    let mut acc = String::new();
-    let mut offset: TextSize = 0.into();
-    for token in tokens {
-        let token_len = token.len;
-        let token_text = &text[TextRange::at(offset, token.len)];
-        offset += token.len;
-        writeln!(acc, "{:?} {:?} {:?}", token.kind, token_len, token_text).unwrap();
-    }
-    for err in errors {
-        writeln!(acc, "> error{:?} token({:?}) msg({})", err.range(), &text[err.range()], err)
-            .unwrap();
-    }
-    acc
-}
-
 fn fragment_parser_dir_test<T, F>(ok_paths: &[&str], err_paths: &[&str], f: F)
 where
     T: crate::AstNode,