8 files changed, 326 insertions, 168 deletions

diff --git a/crates/assists/src/handlers/change_return_type_to_result.rs b/crates/assists/src/handlers/change_return_type_to_result.rs
index be480943c..76f33a5b6 100644
--- a/crates/assists/src/handlers/change_return_type_to_result.rs
+++ b/crates/assists/src/handlers/change_return_type_to_result.rs
@@ -2,7 +2,7 @@ use std::iter;
 
 use syntax::{
     ast::{self, make, BlockExpr, Expr, LoopBodyOwner},
-    AstNode, SyntaxNode,
+    match_ast, AstNode, SyntaxNode,
 };
 use test_utils::mark;
 
@@ -21,8 +21,18 @@ use crate::{AssistContext, AssistId, AssistKind, Assists};
 // ```
 pub(crate) fn change_return_type_to_result(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     let ret_type = ctx.find_node_at_offset::<ast::RetType>()?;
-    // FIXME: extend to lambdas as well
-    let fn_def = ret_type.syntax().parent().and_then(ast::Fn::cast)?;
+    let parent = ret_type.syntax().parent()?;
+    let block_expr = match_ast! {
+        match parent {
+            ast::Fn(func) => func.body()?,
+            ast::ClosureExpr(closure) => match closure.body()? {
+                Expr::BlockExpr(block) => block,
+                // closures require a block when a return type is specified
+                _ => return None,
+            },
+            _ => return None,
+        }
+    };
 
     let type_ref = &ret_type.ty()?;
     let ret_type_str = type_ref.syntax().text().to_string();
@@ -34,16 +44,14 @@ pub(crate) fn change_return_type_to_result(acc: &mut Assists, ctx: &AssistContex
         }
     }
 
-    let block_expr = &fn_def.body()?;
-
     acc.add(
         AssistId("change_return_type_to_result", AssistKind::RefactorRewrite),
         "Wrap return type in Result",
         type_ref.syntax().text_range(),
         |builder| {
             let mut tail_return_expr_collector = TailReturnCollector::new();
-            tail_return_expr_collector.collect_jump_exprs(block_expr, false);
-            tail_return_expr_collector.collect_tail_exprs(block_expr);
+            tail_return_expr_collector.collect_jump_exprs(&block_expr, false);
+            tail_return_expr_collector.collect_tail_exprs(&block_expr);
 
             for ret_expr_arg in tail_return_expr_collector.exprs_to_wrap {
                 let ok_wrapped = make::expr_call(
@@ -285,16 +293,20 @@ mod tests {
     }
 
     #[test]
-    fn change_return_type_to_result_simple_return_type() {
+    fn change_return_type_to_result_simple_closure() {
         check_assist(
             change_return_type_to_result,
-            r#"fn foo() -> i32<|> {
-                let test = "test";
-                return 42i32;
+            r#"fn foo() {
+                || -> i32<|> {
+                    let test = "test";
+                    return 42i32;
+                };
             }"#,
-            r#"fn foo() -> Result<i32, ${0:_}> {
-                let test = "test";
-                return Ok(42i32);
+            r#"fn foo() {
+                || -> Result<i32, ${0:_}> {
+                    let test = "test";
+                    return Ok(42i32);
+                };
             }"#,
         );
     }
@@ -311,6 +323,29 @@ mod tests {
     }
 
     #[test]
+    fn change_return_type_to_result_simple_return_type_bad_cursor_closure() {
+        check_assist_not_applicable(
+            change_return_type_to_result,
+            r#"fn foo() {
+                || -> i32 {
+                    let test = "test";<|>
+                    return 42i32;
+                };
+            }"#,
+        );
+    }
+
+    #[test]
+    fn change_return_type_to_result_closure_non_block() {
+        check_assist_not_applicable(
+            change_return_type_to_result,
+            r#"fn foo() {
+                || -> i<|>32 3;
+            }"#,
+        );
+    }
+
+    #[test]
     fn change_return_type_to_result_simple_return_type_already_result_std() {
         check_assist_not_applicable(
             change_return_type_to_result,
@@ -334,6 +369,19 @@ mod tests {
     }
 
     #[test]
+    fn change_return_type_to_result_simple_return_type_already_result_closure() {
+        check_assist_not_applicable(
+            change_return_type_to_result,
+            r#"fn foo() {
+                || -> Result<i32<|>, String> {
+                    let test = "test";
+                    return 42i32;
+                };
+            }"#,
+        );
+    }
+
+    #[test]
     fn change_return_type_to_result_simple_with_cursor() {
         check_assist(
             change_return_type_to_result,
@@ -364,6 +412,25 @@ mod tests {
     }
 
     #[test]
+    fn change_return_type_to_result_simple_with_tail_closure() {
+        check_assist(
+            change_return_type_to_result,
+            r#"fn foo() {
+                || -><|> i32 {
+                    let test = "test";
+                    42i32
+                };
+            }"#,
+            r#"fn foo() {
+                || -> Result<i32, ${0:_}> {
+                    let test = "test";
+                    Ok(42i32)
+                };
+            }"#,
+        );
+    }
+
+    #[test]
     fn change_return_type_to_result_simple_with_tail_only() {
         check_assist(
             change_return_type_to_result,
@@ -375,6 +442,7 @@ mod tests {
             }"#,
         );
     }
+
     #[test]
     fn change_return_type_to_result_simple_with_tail_block_like() {
         check_assist(
@@ -397,6 +465,31 @@ mod tests {
     }
 
     #[test]
+    fn change_return_type_to_result_simple_without_block_closure() {
+        check_assist(
+            change_return_type_to_result,
+            r#"fn foo() {
+                || -> i32<|> {
+                    if true {
+                        42i32
+                    } else {
+                        24i32
+                    }
+                };
+            }"#,
+            r#"fn foo() {
+                || -> Result<i32, ${0:_}> {
+                    if true {
+                        Ok(42i32)
+                    } else {
+                        Ok(24i32)
+                    }
+                };
+            }"#,
+        );
+    }
+
+    #[test]
     fn change_return_type_to_result_simple_with_nested_if() {
         check_assist(
             change_return_type_to_result,
diff --git a/crates/assists/src/handlers/convert_integer_literal.rs b/crates/assists/src/handlers/convert_integer_literal.rs
index c8af80701..5957834d3 100644
--- a/crates/assists/src/handlers/convert_integer_literal.rs
+++ b/crates/assists/src/handlers/convert_integer_literal.rs
@@ -1,4 +1,4 @@
-use syntax::{ast, ast::Radix, AstNode};
+use syntax::{ast, ast::Radix, AstToken};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists, GroupLabel};
 
@@ -14,15 +14,13 @@ use crate::{AssistContext, AssistId, AssistKind, Assists, GroupLabel};
 // const _: i32 = 0b1010;
 // ```
 pub(crate) fn convert_integer_literal(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let literal = ctx.find_node_at_offset::<ast::Literal>()?;
-    let (radix, value) = literal.int_value()?;
+    let literal = ctx.find_node_at_offset::<ast::Literal>()?.as_int_number()?;
+    let radix = literal.radix();
+    let value = literal.value()?;
+    let suffix = literal.suffix();
 
     let range = literal.syntax().text_range();
     let group_id = GroupLabel("Convert integer base".into());
-    let suffix = match literal.kind() {
-        ast::LiteralKind::IntNumber { suffix } => suffix,
-        _ => return None,
-    };
 
     for &target_radix in Radix::ALL {
         if target_radix == radix {
@@ -36,16 +34,11 @@ pub(crate) fn convert_integer_literal(acc: &mut Assists, ctx: &AssistContext) ->
             Radix::Hexadecimal => format!("0x{:X}", value),
         };
 
-        let label = format!(
-            "Convert {} to {}{}",
-            literal,
-            converted,
-            suffix.as_deref().unwrap_or_default()
-        );
+        let label = format!("Convert {} to {}{}", literal, converted, suffix.unwrap_or_default());
 
         // Appends the type suffix back into the new literal if it exists.
-        if let Some(suffix) = &suffix {
-            converted.push_str(&suffix);
+        if let Some(suffix) = suffix {
+            converted.push_str(suffix);
         }
 
         acc.add_group(
diff --git a/crates/project_model/src/sysroot.rs b/crates/project_model/src/sysroot.rs
index 3fe494729..b0e8863f6 100644
--- a/crates/project_model/src/sysroot.rs
+++ b/crates/project_model/src/sysroot.rs
@@ -114,8 +114,12 @@ fn discover_sysroot_src_dir(current_dir: &AbsPath) -> Result<AbsPathBuf> {
     if let Ok(path) = env::var("RUST_SRC_PATH") {
         let path = AbsPathBuf::try_from(path.as_str())
             .map_err(|path| format_err!("RUST_SRC_PATH must be absolute: {}", path.display()))?;
-        log::debug!("Discovered sysroot by RUST_SRC_PATH: {}", path.display());
-        return Ok(path);
+        let core = path.join("core");
+        if core.exists() {
+            log::debug!("Discovered sysroot by RUST_SRC_PATH: {}", path.display());
+            return Ok(path);
+        }
+        log::debug!("RUST_SRC_PATH is set, but is invalid (no core: {:?}), ignoring", core);
     }
 
     let sysroot_path = {
diff --git a/crates/syntax/src/ast.rs b/crates/syntax/src/ast.rs
index a16ac6a7c..8a0e3d27b 100644
--- a/crates/syntax/src/ast.rs
+++ b/crates/syntax/src/ast.rs
@@ -16,7 +16,7 @@ use crate::{
 };
 
 pub use self::{
-    expr_ext::{ArrayExprKind, BinOp, Effect, ElseBranch, LiteralKind, PrefixOp, Radix, RangeOp},
+    expr_ext::{ArrayExprKind, BinOp, Effect, ElseBranch, LiteralKind, PrefixOp, RangeOp},
     generated::{nodes::*, tokens::*},
     node_ext::{
         AttrKind, FieldKind, NameOrNameRef, PathSegmentKind, SelfParamKind, SlicePatComponents,
diff --git a/crates/syntax/src/ast/expr_ext.rs b/crates/syntax/src/ast/expr_ext.rs
index 3aff01e83..3d33cd1cf 100644
--- a/crates/syntax/src/ast/expr_ext.rs
+++ b/crates/syntax/src/ast/expr_ext.rs
@@ -2,7 +2,7 @@
 
 use crate::{
     ast::{self, support, AstChildren, AstNode},
-    SmolStr,
+    AstToken, SmolStr,
     SyntaxKind::*,
     SyntaxToken, T,
 };
@@ -316,6 +316,10 @@ impl ast::Literal {
             .unwrap()
     }
 
+    pub fn as_int_number(&self) -> Option<ast::IntNumber> {
+        ast::IntNumber::cast(self.token())
+    }
+
     fn find_suffix(text: &str, possible_suffixes: &[&str]) -> Option<SmolStr> {
         possible_suffixes
             .iter()
@@ -324,11 +328,6 @@ impl ast::Literal {
     }
 
     pub fn kind(&self) -> LiteralKind {
-        const INT_SUFFIXES: [&str; 12] = [
-            "u64", "u32", "u16", "u8", "usize", "isize", "i64", "i32", "i16", "i8", "u128", "i128",
-        ];
-        const FLOAT_SUFFIXES: [&str; 2] = ["f32", "f64"];
-
         let token = self.token();
 
         match token.kind() {
@@ -337,17 +336,20 @@ impl ast::Literal {
                 // The lexer treats e.g. `1f64` as an integer literal. See
                 // https://github.com/rust-analyzer/rust-analyzer/issues/1592
                 // and the comments on the linked PR.
-
                 let text = token.text();
-                if let suffix @ Some(_) = Self::find_suffix(&text, &FLOAT_SUFFIXES) {
+                if let suffix @ Some(_) = Self::find_suffix(&text, &ast::FloatNumber::SUFFIXES) {
                     LiteralKind::FloatNumber { suffix }
                 } else {
-                    LiteralKind::IntNumber { suffix: Self::find_suffix(&text, &INT_SUFFIXES) }
+                    LiteralKind::IntNumber {
+                        suffix: Self::find_suffix(&text, &ast::IntNumber::SUFFIXES),
+                    }
                 }
             }
             FLOAT_NUMBER => {
                 let text = token.text();
-                LiteralKind::FloatNumber { suffix: Self::find_suffix(&text, &FLOAT_SUFFIXES) }
+                LiteralKind::FloatNumber {
+                    suffix: Self::find_suffix(&text, &ast::FloatNumber::SUFFIXES),
+                }
             }
             STRING | RAW_STRING => LiteralKind::String,
             T![true] => LiteralKind::Bool(true),
@@ -358,71 +360,6 @@ impl ast::Literal {
             _ => unreachable!(),
         }
     }
-
-    // FIXME: should probably introduce string token type?
-    // https://github.com/rust-analyzer/rust-analyzer/issues/6308
-    pub fn int_value(&self) -> Option<(Radix, u128)> {
-        let suffix = match self.kind() {
-            LiteralKind::IntNumber { suffix } => suffix,
-            _ => return None,
-        };
-
-        let token = self.token();
-        let mut text = token.text().as_str();
-        text = &text[..text.len() - suffix.map_or(0, |it| it.len())];
-
-        let buf;
-        if text.contains("_") {
-            buf = text.replace('_', "");
-            text = buf.as_str();
-        };
-
-        let radix = Radix::identify(text)?;
-        let digits = &text[radix.prefix_len()..];
-        let value = u128::from_str_radix(digits, radix as u32).ok()?;
-        Some((radix, value))
-    }
-}
-
-#[derive(Debug, PartialEq, Eq, Copy, Clone)]
-pub enum Radix {
-    Binary = 2,
-    Octal = 8,
-    Decimal = 10,
-    Hexadecimal = 16,
-}
-
-impl Radix {
-    pub const ALL: &'static [Radix] =
-        &[Radix::Binary, Radix::Octal, Radix::Decimal, Radix::Hexadecimal];
-
-    fn identify(literal_text: &str) -> Option<Self> {
-        // We cannot express a literal in anything other than decimal in under 3 characters, so we return here if possible.
-        if literal_text.len() < 3 && literal_text.chars().all(|c| c.is_digit(10)) {
-            return Some(Self::Decimal);
-        }
-
-        let res = match &literal_text[..2] {
-            "0b" => Radix::Binary,
-            "0o" => Radix::Octal,
-            "0x" => Radix::Hexadecimal,
-            _ => Radix::Decimal,
-        };
-
-        // Checks that all characters after the base prefix are all valid digits for that base.
-        if literal_text[res.prefix_len()..].chars().all(|c| c.is_digit(res as u32)) {
-            Some(res)
-        } else {
-            None
-        }
-    }
-
-    const fn prefix_len(&self) -> usize {
-        match self {
-            Self::Decimal => 0,
-            _ => 2,
-        }
-    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
diff --git a/crates/syntax/src/ast/generated/tokens.rs b/crates/syntax/src/ast/generated/tokens.rs
index abadd0b61..1b8449221 100644
--- a/crates/syntax/src/ast/generated/tokens.rs
+++ b/crates/syntax/src/ast/generated/tokens.rs
@@ -89,3 +89,45 @@ impl AstToken for RawString {
     }
     fn syntax(&self) -> &SyntaxToken { &self.syntax }
 }
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct IntNumber {
+    pub(crate) syntax: SyntaxToken,
+}
+impl std::fmt::Display for IntNumber {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(&self.syntax, f)
+    }
+}
+impl AstToken for IntNumber {
+    fn can_cast(kind: SyntaxKind) -> bool { kind == INT_NUMBER }
+    fn cast(syntax: SyntaxToken) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    fn syntax(&self) -> &SyntaxToken { &self.syntax }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct FloatNumber {
+    pub(crate) syntax: SyntaxToken,
+}
+impl std::fmt::Display for FloatNumber {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(&self.syntax, f)
+    }
+}
+impl AstToken for FloatNumber {
+    fn can_cast(kind: SyntaxKind) -> bool { kind == FLOAT_NUMBER }
+    fn cast(syntax: SyntaxToken) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    fn syntax(&self) -> &SyntaxToken { &self.syntax }
+}
diff --git a/crates/syntax/src/ast/token_ext.rs b/crates/syntax/src/ast/token_ext.rs
index c5ef92733..8d3fad5a6 100644
--- a/crates/syntax/src/ast/token_ext.rs
+++ b/crates/syntax/src/ast/token_ext.rs
@@ -8,11 +8,11 @@ use std::{
 use rustc_lexer::unescape::{unescape_literal, Mode};
 
 use crate::{
-    ast::{AstToken, Comment, RawString, String, Whitespace},
+    ast::{self, AstToken},
     TextRange, TextSize,
 };
 
-impl Comment {
+impl ast::Comment {
     pub fn kind(&self) -> CommentKind {
         kind_by_prefix(self.text())
     }
@@ -80,7 +80,7 @@ fn kind_by_prefix(text: &str) -> CommentKind {
     panic!("bad comment text: {:?}", text)
 }
 
-impl Whitespace {
+impl ast::Whitespace {
     pub fn spans_multiple_lines(&self) -> bool {
         let text = self.text();
         text.find('\n').map_or(false, |idx| text[idx + 1..].contains('\n'))
@@ -138,19 +138,19 @@ pub trait HasQuotes: AstToken {
     }
 }
 
-impl HasQuotes for String {}
-impl HasQuotes for RawString {}
+impl HasQuotes for ast::String {}
+impl HasQuotes for ast::RawString {}
 
 pub trait HasStringValue: HasQuotes {
     fn value(&self) -> Option<Cow<'_, str>>;
 }
 
-impl HasStringValue for String {
+impl HasStringValue for ast::String {
     fn value(&self) -> Option<Cow<'_, str>> {
         let text = self.text().as_str();
         let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
 
-        let mut buf = std::string::String::with_capacity(text.len());
+        let mut buf = String::with_capacity(text.len());
         let mut has_error = false;
         unescape_literal(text, Mode::Str, &mut |_, unescaped_char| match unescaped_char {
             Ok(c) => buf.push(c),
@@ -166,7 +166,8 @@ impl HasStringValue for String {
     }
 }
 
-impl HasStringValue for RawString {
+// FIXME: merge `ast::RawString` and `ast::String`.
+impl HasStringValue for ast::RawString {
     fn value(&self) -> Option<Cow<'_, str>> {
         let text = self.text().as_str();
         let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
@@ -174,7 +175,7 @@ impl HasStringValue for RawString {
     }
 }
 
-impl RawString {
+impl ast::RawString {
     pub fn map_range_up(&self, range: TextRange) -> Option<TextRange> {
         let contents_range = self.text_range_between_quotes()?;
         assert!(TextRange::up_to(contents_range.len()).contains_range(range));
@@ -500,7 +501,7 @@ pub trait HasFormatSpecifier: AstToken {
     }
 }
 
-impl HasFormatSpecifier for String {
+impl HasFormatSpecifier for ast::String {
     fn char_ranges(
         &self,
     ) -> Option<Vec<(TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>> {
@@ -521,7 +522,7 @@ impl HasFormatSpecifier for String {
     }
 }
 
-impl HasFormatSpecifier for RawString {
+impl HasFormatSpecifier for ast::RawString {
     fn char_ranges(
         &self,
     ) -> Option<Vec<(TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>> {
@@ -536,3 +537,77 @@ impl HasFormatSpecifier for RawString {
         Some(res)
     }
 }
+
+impl ast::IntNumber {
+    #[rustfmt::skip]
+    pub(crate) const SUFFIXES: &'static [&'static str] = &[
+        "u8", "u16", "u32", "u64", "u128", "usize",
+        "i8", "i16", "i32", "i64", "i128", "isize",
+    ];
+
+    pub fn radix(&self) -> Radix {
+        match self.text().get(..2).unwrap_or_default() {
+            "0b" => Radix::Binary,
+            "0o" => Radix::Octal,
+            "0x" => Radix::Hexadecimal,
+            _ => Radix::Decimal,
+        }
+    }
+
+    pub fn value(&self) -> Option<u128> {
+        let token = self.syntax();
+
+        let mut text = token.text().as_str();
+        if let Some(suffix) = self.suffix() {
+            text = &text[..text.len() - suffix.len()]
+        }
+
+        let radix = self.radix();
+        text = &text[radix.prefix_len()..];
+
+        let buf;
+        if text.contains("_") {
+            buf = text.replace('_', "");
+            text = buf.as_str();
+        };
+
+        let value = u128::from_str_radix(text, radix as u32).ok()?;
+        Some(value)
+    }
+
+    pub fn suffix(&self) -> Option<&str> {
+        let text = self.text();
+        // FIXME: don't check a fixed set of suffixes, `1_0_1___lol` is valid
+        // syntax, suffix is `lol`.
+        ast::IntNumber::SUFFIXES.iter().find_map(|suffix| {
+            if text.ends_with(suffix) {
+                return Some(&text[text.len() - suffix.len()..]);
+            }
+            None
+        })
+    }
+}
+
+impl ast::FloatNumber {
+    pub(crate) const SUFFIXES: &'static [&'static str] = &["f32", "f64"];
+}
+
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub enum Radix {
+    Binary = 2,
+    Octal = 8,
+    Decimal = 10,
+    Hexadecimal = 16,
+}
+
+impl Radix {
+    pub const ALL: &'static [Radix] =
+        &[Radix::Binary, Radix::Octal, Radix::Decimal, Radix::Hexadecimal];
+
+    const fn prefix_len(&self) -> usize {
+        match self {
+            Self::Decimal => 0,
+            _ => 2,
+        }
+    }
+}
diff --git a/crates/syntax/src/parsing/lexer.rs b/crates/syntax/src/parsing/lexer.rs
index 7e38c32cc..5674ecb84 100644
--- a/crates/syntax/src/parsing/lexer.rs
+++ b/crates/syntax/src/parsing/lexer.rs
@@ -3,7 +3,7 @@
 
 use std::convert::TryInto;
 
-use rustc_lexer::{LiteralKind as LK, RawStrError};
+use rustc_lexer::RawStrError;
 
 use crate::{
     SyntaxError,
@@ -185,63 +185,77 @@ fn rustc_token_kind_to_syntax_kind(
     return (syntax_kind, None);
 
     fn match_literal_kind(kind: &rustc_lexer::LiteralKind) -> (SyntaxKind, Option<&'static str>) {
-        #[rustfmt::skip]
+        let mut err = "";
         let syntax_kind = match *kind {
-            LK::Int { empty_int: false, .. } => INT_NUMBER,
-            LK::Int { empty_int: true, .. } => {
-                return (INT_NUMBER, Some("Missing digits after the integer base prefix"))
+            rustc_lexer::LiteralKind::Int { empty_int, base: _ } => {
+                if empty_int {
+                    err = "Missing digits after the integer base prefix";
+                }
+                INT_NUMBER
             }
-
-            LK::Float { empty_exponent: false, .. } => FLOAT_NUMBER,
-            LK::Float { empty_exponent: true, .. } => {
-                return (FLOAT_NUMBER, Some("Missing digits after the exponent symbol"))
+            rustc_lexer::LiteralKind::Float { empty_exponent, base: _ } => {
+                if empty_exponent {
+                    err = "Missing digits after the exponent symbol";
+                }
+                FLOAT_NUMBER
             }
-
-            LK::Char { terminated: true } => CHAR,
-            LK::Char { terminated: false } => {
-                return (CHAR, Some("Missing trailing `'` symbol to terminate the character literal"))
+            rustc_lexer::LiteralKind::Char { terminated } => {
+                if !terminated {
+                    err = "Missing trailing `'` symbol to terminate the character literal";
+                }
+                CHAR
             }
-
-            LK::Byte { terminated: true } => BYTE,
-            LK::Byte { terminated: false } => {
-                return (BYTE, Some("Missing trailing `'` symbol to terminate the byte literal"))
+            rustc_lexer::LiteralKind::Byte { terminated } => {
+                if !terminated {
+                    err = "Missing trailing `'` symbol to terminate the byte literal";
+                }
+                BYTE
             }
-
-            LK::Str { terminated: true } => STRING,
-            LK::Str { terminated: false } => {
-                return (STRING, Some("Missing trailing `\"` symbol to terminate the string literal"))
+            rustc_lexer::LiteralKind::Str { terminated } => {
+                if !terminated {
+                    err = "Missing trailing `\"` symbol to terminate the string literal";
+                }
+                STRING
             }
-
-
-            LK::ByteStr { terminated: true } => BYTE_STRING,
-            LK::ByteStr { terminated: false } => {
-                return (BYTE_STRING, Some("Missing trailing `\"` symbol to terminate the byte string literal"))
+            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",
+                    };
+                };
+                RAW_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",
+                    };
+                };
+
+                RAW_BYTE_STRING
             }
-
-            LK::RawStr { err, .. } => match err {
-                None => RAW_STRING,
-                Some(RawStrError::InvalidStarter { .. }) => return (RAW_STRING, Some("Missing `\"` symbol after `#` symbols to begin the raw string literal")),
-                Some(RawStrError::NoTerminator { expected, found, .. }) => if expected == found {
-                    return (RAW_STRING, Some("Missing trailing `\"` to terminate the raw string literal"))
-                } else {
-                    return (RAW_STRING, Some("Missing trailing `\"` with `#` symbols to terminate the raw string literal"))
-
-                },
-                Some(RawStrError::TooManyDelimiters { .. }) => return (RAW_STRING, Some("Too many `#` symbols: raw strings may be delimited by up to 65535 `#` symbols")),
-            },
-            LK::RawByteStr { err, .. } => match err {
-                None => RAW_BYTE_STRING,
-                Some(RawStrError::InvalidStarter { .. }) => return (RAW_BYTE_STRING, Some("Missing `\"` symbol after `#` symbols to begin the raw byte string literal")),
-                Some(RawStrError::NoTerminator { expected, found, .. }) => if expected == found {
-                    return (RAW_BYTE_STRING, Some("Missing trailing `\"` to terminate the raw byte string literal"))
-                } else {
-                    return (RAW_BYTE_STRING, Some("Missing trailing `\"` with `#` symbols to terminate the raw byte string literal"))
-
-                },
-                Some(RawStrError::TooManyDelimiters { .. }) => return (RAW_BYTE_STRING, Some("Too many `#` symbols: raw byte strings may be delimited by up to 65535 `#` symbols")),
-            },
         };
 
-        (syntax_kind, None)
+        let err = if err.is_empty() { None } else { Some(err) };
+
+        (syntax_kind, err)
     }
 }