diff --git a/crates/hir-def/src/body/pretty.rs b/crates/hir-def/src/body/pretty.rs index 0c6cf0b49a..eeaed87164 100644 --- a/crates/hir-def/src/body/pretty.rs +++ b/crates/hir-def/src/body/pretty.rs @@ -634,7 +634,7 @@ impl Printer<'_> { match literal { Literal::String(it) => w!(self, "{:?}", it), Literal::ByteString(it) => w!(self, "\"{}\"", it.escape_ascii()), - Literal::CString(it) => w!(self, "\"{}\\0\"", it), + Literal::CString(it) => w!(self, "\"{}\\0\"", it.escape_ascii()), Literal::Char(it) => w!(self, "'{}'", it.escape_debug()), Literal::Bool(it) => w!(self, "{}", it), Literal::Int(i, suffix) => { diff --git a/crates/hir-def/src/hir.rs b/crates/hir-def/src/hir.rs index 500e880061..8a140a1ec1 100644 --- a/crates/hir-def/src/hir.rs +++ b/crates/hir-def/src/hir.rs @@ -85,7 +85,7 @@ impl fmt::Display for FloatTypeWrapper { pub enum Literal { String(Box), ByteString(Box<[u8]>), - CString(Box), + CString(Box<[u8]>), Char(char), Bool(bool), Int(i128, Option), diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs index e443c58f22..9f25175a3a 100644 --- a/crates/hir-ty/src/mir/lower.rs +++ b/crates/hir-ty/src/mir/lower.rs @@ -1355,7 +1355,6 @@ impl<'ctx> MirLowerCtx<'ctx> { return Ok(Operand::from_concrete_const(data, mm, ty)); } hir_def::hir::Literal::CString(b) => { - let b = b.as_bytes(); let bytes = b.iter().copied().chain(iter::once(0)).collect::>(); let mut data = Vec::with_capacity(mem::size_of::() * 2); diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs index 577bd2bc1f..ae97236409 100644 --- a/crates/ide/src/syntax_highlighting.rs +++ b/crates/ide/src/syntax_highlighting.rs @@ -24,7 +24,7 @@ use syntax::{ use crate::{ syntax_highlighting::{ - escape::{highlight_escape_char, highlight_escape_string}, + escape::{highlight_escape_byte, highlight_escape_char, highlight_escape_string}, format::highlight_format_string, highlights::Highlights, macro_::MacroHighlighter, @@ -471,6 +471,14 @@ fn traverse( }; highlight_escape_char(hl, &char, range.start()) + } else if ast::Byte::can_cast(token.kind()) + && ast::Byte::can_cast(descended_token.kind()) + { + let Some(byte) = ast::Byte::cast(token) else { + continue; + }; + + highlight_escape_byte(hl, &byte, range.start()) } } diff --git a/crates/ide/src/syntax_highlighting/escape.rs b/crates/ide/src/syntax_highlighting/escape.rs index 211e358809..5913ca5e45 100644 --- a/crates/ide/src/syntax_highlighting/escape.rs +++ b/crates/ide/src/syntax_highlighting/escape.rs @@ -1,7 +1,7 @@ //! Syntax highlighting for escape sequences use crate::syntax_highlighting::highlights::Highlights; use crate::{HlRange, HlTag}; -use syntax::ast::{Char, IsString}; +use syntax::ast::{Byte, Char, IsString}; use syntax::{AstToken, TextRange, TextSize}; pub(super) fn highlight_escape_string( @@ -10,14 +10,14 @@ pub(super) fn highlight_escape_string( start: TextSize, ) { string.escaped_char_ranges(&mut |piece_range, char| { - if char.is_err() { - return; - } - if string.text()[piece_range.start().into()..].starts_with('\\') { + let highlight = match char { + Ok(_) => HlTag::EscapeSequence, + Err(_) => HlTag::InvalidEscapeSequence, + }; stack.add(HlRange { range: piece_range + start, - highlight: HlTag::EscapeSequence.into(), + highlight: highlight.into(), binding_hash: None, }); } @@ -26,6 +26,9 @@ pub(super) fn highlight_escape_string( pub(super) fn highlight_escape_char(stack: &mut Highlights, char: &Char, start: TextSize) { if char.value().is_none() { + // We do not emit invalid escapes highlighting here. The lexer would likely be in a bad + // state and this token contains junks, since `'` is not a reliable delimiter (consider + // lifetimes). Nonetheless, parser errors should already be emitted. return; } @@ -43,3 +46,24 @@ pub(super) fn highlight_escape_char(stack: &mut Highlights, char: &Char, start: TextRange::new(start + TextSize::from(1), start + TextSize::from(text.len() as u32 + 1)); stack.add(HlRange { range, highlight: HlTag::EscapeSequence.into(), binding_hash: None }) } + +pub(super) fn highlight_escape_byte(stack: &mut Highlights, byte: &Byte, start: TextSize) { + if byte.value().is_none() { + // See `highlight_escape_char` for why no error highlighting here. + return; + } + + let text = byte.text(); + if !text.starts_with("b'") || !text.ends_with('\'') { + return; + } + + let text = &text[2..text.len() - 1]; + if !text.starts_with('\\') { + return; + } + + let range = + TextRange::new(start + TextSize::from(2), start + TextSize::from(text.len() as u32 + 2)); + stack.add(HlRange { range, highlight: HlTag::EscapeSequence.into(), binding_hash: None }) +} diff --git a/crates/ide/src/syntax_highlighting/html.rs b/crates/ide/src/syntax_highlighting/html.rs index 2c7823069b..bbc6b55a64 100644 --- a/crates/ide/src/syntax_highlighting/html.rs +++ b/crates/ide/src/syntax_highlighting/html.rs @@ -109,6 +109,7 @@ pre { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd .control { font-style: italic; } .reference { font-style: italic; font-weight: bold; } -.unresolved_reference { color: #FC5555; text-decoration: wavy underline; } +.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; } +.unresolved_reference { color: #FC5555; text-decoration: wavy underline; } "; diff --git a/crates/ide/src/syntax_highlighting/tags.rs b/crates/ide/src/syntax_highlighting/tags.rs index f983109115..6d4cdd0efe 100644 --- a/crates/ide/src/syntax_highlighting/tags.rs +++ b/crates/ide/src/syntax_highlighting/tags.rs @@ -29,6 +29,7 @@ pub enum HlTag { Comment, EscapeSequence, FormatSpecifier, + InvalidEscapeSequence, Keyword, NumericLiteral, Operator(HlOperator), @@ -166,6 +167,7 @@ impl HlTag { HlTag::CharLiteral => "char_literal", HlTag::Comment => "comment", HlTag::EscapeSequence => "escape_sequence", + HlTag::InvalidEscapeSequence => "invalid_escape_sequence", HlTag::FormatSpecifier => "format_specifier", HlTag::Keyword => "keyword", HlTag::Punctuation(punct) => match punct { diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_assoc_functions.html b/crates/ide/src/syntax_highlighting/test_data/highlight_assoc_functions.html index 9ed65fbc85..4dcbfe4eb6 100644 --- a/crates/ide/src/syntax_highlighting/test_data/highlight_assoc_functions.html +++ b/crates/ide/src/syntax_highlighting/test_data/highlight_assoc_functions.html @@ -40,7 +40,8 @@ pre { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd .control { font-style: italic; } .reference { font-style: italic; font-weight: bold; } -.unresolved_reference { color: #FC5555; text-decoration: wavy underline; } +.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; } +.unresolved_reference { color: #FC5555; text-decoration: wavy underline; } 
fn not_static() {}
 
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_attributes.html b/crates/ide/src/syntax_highlighting/test_data/highlight_attributes.html
index 567ab8ccc1..bf5505caf3 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_attributes.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_attributes.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
#[allow(dead_code)]
 #[rustfmt::skip]
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_crate_root.html b/crates/ide/src/syntax_highlighting/test_data/highlight_crate_root.html
index 1e4c06df7e..0d1b3c1f18 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_crate_root.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_crate_root.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
extern crate foo;
 use core::iter;
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_default_library.html b/crates/ide/src/syntax_highlighting/test_data/highlight_default_library.html
index 5d66f832da..dd1528ed03 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_default_library.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_default_library.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
use core::iter;
 
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html b/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
index 35f240d428..d5f92aa5d4 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
//! This is a module to test doc injection.
 //! ```
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html b/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
index 87b9da46e2..b15f7bca72 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
extern crate std;
 extern crate alloc as abc;
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_general.html b/crates/ide/src/syntax_highlighting/test_data/highlight_general.html
index 6b049f379a..bdeb09d2f8 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_general.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_general.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
use inner::{self as inner_mod};
 mod inner {}
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_injection.html b/crates/ide/src/syntax_highlighting/test_data/highlight_injection.html
index d9c3db6fbb..f9c33b8a60 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_injection.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_injection.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
fn fixture(ra_fixture: &str) {}
 
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_keywords.html b/crates/ide/src/syntax_highlighting/test_data/highlight_keywords.html
index 3900959bed..fd3b39855e 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_keywords.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_keywords.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
extern crate self;
 
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_lifetimes.html b/crates/ide/src/syntax_highlighting/test_data/highlight_lifetimes.html
index f98e0b1cda..ec39998de2 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_lifetimes.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_lifetimes.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 

 #[derive()]
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_macros.html b/crates/ide/src/syntax_highlighting/test_data/highlight_macros.html
index 2cbbf69641..c5fcec7568 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_macros.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_macros.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
proc_macros::mirror! {
     {
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_module_docs_inline.html b/crates/ide/src/syntax_highlighting/test_data/highlight_module_docs_inline.html
index 8a1d69816e..4dcf8e5f01 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_module_docs_inline.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_module_docs_inline.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
//! [Struct]
 //! This is an intra doc injection test for modules
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_module_docs_outline.html b/crates/ide/src/syntax_highlighting/test_data/highlight_module_docs_outline.html
index c4c3e3dc26..084bbf2f74 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_module_docs_outline.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_module_docs_outline.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
/// [crate::foo::Struct]
 /// This is an intra doc injection test for modules
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_operators.html b/crates/ide/src/syntax_highlighting/test_data/highlight_operators.html
index 2369071ae2..1af4bcfbd9 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_operators.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_operators.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
fn main() {
     1 + 1 - 1 * 1 / 1 % 1 | 1 & 1 ! 1 ^ 1 >> 1 << 1;
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_rainbow.html b/crates/ide/src/syntax_highlighting/test_data/highlight_rainbow.html
index bff35c897e..ec18c3ea1f 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_rainbow.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_rainbow.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
fn main() {
     let hello = "hello";
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html b/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
index f4f164aa1d..dcac8eb736 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
macro_rules! println {
     ($($arg:tt)*) => ({
@@ -105,6 +106,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     let a = '\x65';
     let a = '\x00';
 
+    let a = b'\xFF';
+
     println!("Hello {{Hello}}");
     // from https://doc.rust-lang.org/std/fmt/index.html
     println!("Hello");                 // => "Hello"
@@ -159,8 +162,9 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     println!("Hello\nWorld");
     println!("\u{48}\x65\x6C\x6C\x6F World");
 
-    let _ = "\x28\x28\x00\x63\n";
-    let _ = b"\x28\x28\x00\x63\n";
+    let _ = "\x28\x28\x00\x63\xFF\u{FF}\n"; // invalid non-UTF8 escape sequences
+    let _ = b"\x28\x28\x00\x63\xFF\u{FF}\n"; // valid bytes, invalid unicodes
+    let _ = c"\u{FF}\xFF"; // valid bytes, valid unicodes
     let backslash = r"\\";
 
     println!("{\x41}", A = 92);
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html b/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
index 654d51b8a4..c72ea54e94 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
@@ -40,7 +40,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .control            { font-style: italic; }
 .reference          { font-style: italic; font-weight: bold; }
 
-.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
+.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 
 
macro_rules! id {
     ($($tt:tt)*) => {
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index 1ee451a06d..696aa59002 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -451,6 +451,8 @@ fn main() {
     let a = '\x65';
     let a = '\x00';
 
+    let a = b'\xFF';
+
     println!("Hello {{Hello}}");
     // from https://doc.rust-lang.org/std/fmt/index.html
     println!("Hello");                 // => "Hello"
@@ -505,8 +507,9 @@ fn main() {
     println!("Hello\nWorld");
     println!("\u{48}\x65\x6C\x6C\x6F World");
 
-    let _ = "\x28\x28\x00\x63\n";
-    let _ = b"\x28\x28\x00\x63\n";
+    let _ = "\x28\x28\x00\x63\xFF\u{FF}\n"; // invalid non-UTF8 escape sequences
+    let _ = b"\x28\x28\x00\x63\xFF\u{FF}\n"; // valid bytes, invalid unicodes
+    let _ = c"\u{FF}\xFF"; // valid bytes, valid unicodes
     let backslash = r"\\";
 
     println!("{\x41}", A = 92);
diff --git a/crates/rust-analyzer/src/semantic_tokens.rs b/crates/rust-analyzer/src/semantic_tokens.rs
index d4bb20c8f4..1fe02fc7ea 100644
--- a/crates/rust-analyzer/src/semantic_tokens.rs
+++ b/crates/rust-analyzer/src/semantic_tokens.rs
@@ -78,6 +78,7 @@ define_semantic_token_types![
         (DERIVE_HELPER, "deriveHelper") => DECORATOR,
         (DOT, "dot"),
         (ESCAPE_SEQUENCE, "escapeSequence") => STRING,
+        (INVALID_ESCAPE_SEQUENCE, "invalidEscapeSequence") => STRING,
         (FORMAT_SPECIFIER, "formatSpecifier") => STRING,
         (GENERIC, "generic") => TYPE_PARAMETER,
         (LABEL, "label"),
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index ba3421bf9e..7a89533a5e 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -640,6 +640,7 @@ fn semantic_token_type_and_modifiers(
         HlTag::CharLiteral => semantic_tokens::CHAR,
         HlTag::Comment => semantic_tokens::COMMENT,
         HlTag::EscapeSequence => semantic_tokens::ESCAPE_SEQUENCE,
+        HlTag::InvalidEscapeSequence => semantic_tokens::INVALID_ESCAPE_SEQUENCE,
         HlTag::FormatSpecifier => semantic_tokens::FORMAT_SPECIFIER,
         HlTag::Keyword => semantic_tokens::KEYWORD,
         HlTag::None => semantic_tokens::GENERIC,
diff --git a/crates/syntax/src/ast/token_ext.rs b/crates/syntax/src/ast/token_ext.rs
index 090eb89f47..87fd51d703 100644
--- a/crates/syntax/src/ast/token_ext.rs
+++ b/crates/syntax/src/ast/token_ext.rs
@@ -2,7 +2,9 @@
 
 use std::borrow::Cow;
 
-use rustc_lexer::unescape::{unescape_byte, unescape_char, unescape_literal, Mode};
+use rustc_lexer::unescape::{
+    unescape_byte, unescape_c_string, unescape_char, unescape_literal, CStrUnit, Mode,
+};
 
 use crate::{
     ast::{self, AstToken},
@@ -146,6 +148,7 @@ impl QuoteOffsets {
 
 pub trait IsString: AstToken {
     const RAW_PREFIX: &'static str;
+    const MODE: Mode;
     fn is_raw(&self) -> bool {
         self.text().starts_with(Self::RAW_PREFIX)
     }
@@ -181,7 +184,7 @@ pub trait IsString: AstToken {
         let text = &self.text()[text_range_no_quotes - start];
         let offset = text_range_no_quotes.start() - start;
 
-        unescape_literal(text, Mode::Str, &mut |range, unescaped_char| {
+        unescape_literal(text, Self::MODE, &mut |range, unescaped_char| {
             let text_range =
                 TextRange::new(range.start.try_into().unwrap(), range.end.try_into().unwrap());
             cb(text_range + offset, unescaped_char);
@@ -196,6 +199,7 @@ pub trait IsString: AstToken {
 
 impl IsString for ast::String {
     const RAW_PREFIX: &'static str = "r";
+    const MODE: Mode = Mode::Str;
 }
 
 impl ast::String {
@@ -213,7 +217,7 @@ impl ast::String {
         let mut buf = String::new();
         let mut prev_end = 0;
         let mut has_error = false;
-        unescape_literal(text, Mode::Str, &mut |char_range, unescaped_char| match (
+        unescape_literal(text, Self::MODE, &mut |char_range, unescaped_char| match (
             unescaped_char,
             buf.capacity() == 0,
         ) {
@@ -239,6 +243,7 @@ impl ast::String {
 
 impl IsString for ast::ByteString {
     const RAW_PREFIX: &'static str = "br";
+    const MODE: Mode = Mode::ByteStr;
 }
 
 impl ast::ByteString {
@@ -256,7 +261,7 @@ impl ast::ByteString {
         let mut buf: Vec = Vec::new();
         let mut prev_end = 0;
         let mut has_error = false;
-        unescape_literal(text, Mode::ByteStr, &mut |char_range, unescaped_char| match (
+        unescape_literal(text, Self::MODE, &mut |char_range, unescaped_char| match (
             unescaped_char,
             buf.capacity() == 0,
         ) {
@@ -282,42 +287,70 @@ 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),
+    ) {
+        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_c_string(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(|_| ' '));
+        });
+    }
 }
 
 impl ast::CString {
-    pub fn value(&self) -> Option> {
+    pub fn value(&self) -> Option> {
         if self.is_raw() {
             let text = self.text();
             let text =
                 &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
-            return Some(Cow::Borrowed(text));
+            return Some(Cow::Borrowed(text.as_bytes()));
         }
 
         let text = self.text();
         let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
 
-        let mut buf = String::new();
+        let mut buf = Vec::new();
         let mut prev_end = 0;
         let mut has_error = false;
-        unescape_literal(text, Mode::Str, &mut |char_range, unescaped_char| match (
-            unescaped_char,
+        let mut char_buf = [0u8; 4];
+        let mut extend_unit = |buf: &mut Vec, unit: CStrUnit| match unit {
+            CStrUnit::Byte(b) => buf.push(b),
+            CStrUnit::Char(c) => buf.extend(c.encode_utf8(&mut char_buf).as_bytes()),
+        };
+        unescape_c_string(text, Self::MODE, &mut |char_range, unescaped| match (
+            unescaped,
             buf.capacity() == 0,
         ) {
-            (Ok(c), false) => buf.push(c),
+            (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
             }
-            (Ok(c), true) => {
+            (Ok(u), true) => {
                 buf.reserve_exact(text.len());
-                buf.push_str(&text[..prev_end]);
-                buf.push(c);
+                buf.extend(text[..prev_end].as_bytes());
+                extend_unit(&mut buf, u);
             }
             (Err(_), _) => has_error = true,
         });
 
         match (has_error, buf.capacity() == 0) {
             (true, _) => None,
-            (false, true) => Some(Cow::Borrowed(text)),
+            (false, true) => Some(Cow::Borrowed(text.as_bytes())),
             (false, false) => Some(Cow::Owned(buf)),
         }
     }
diff --git a/editors/code/package.json b/editors/code/package.json
index 31c483beb6..a4897899ca 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -1804,12 +1804,16 @@
             },
             {
                 "id": "escapeSequence",
-                "description": "Style for char escapes in strings"
+                "description": "Style for char or byte escapes in strings"
             },
             {
                 "id": "formatSpecifier",
                 "description": "Style for {} placeholders in format strings"
             },
+            {
+                "id": "invalidEscapeSequence",
+                "description": "Style for invalid char or byte escapes in strings"
+            },
             {
                 "id": "label",
                 "description": "Style for labels"