Introduce `invalidEscapeSequence` semantic token type

23 files changed, 52 insertions, 26 deletions

diff --git a/crates/ide/src/syntax_highlighting/escape.rs b/crates/ide/src/syntax_highlighting/escape.rs
index 2c63a69bdcb..41b27683f6c 100644
--- a/crates/ide/src/syntax_highlighting/escape.rs
+++ b/crates/ide/src/syntax_highlighting/escape.rs
@@ -10,14 +10,14 @@ pub(super) fn highlight_escape_string<T: IsString>(
     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,
             });
         }
diff --git a/crates/ide/src/syntax_highlighting/html.rs b/crates/ide/src/syntax_highlighting/html.rs
index 2c7823069b3..bbc6b55a642 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; }
 </style>
 ";
diff --git a/crates/ide/src/syntax_highlighting/tags.rs b/crates/ide/src/syntax_highlighting/tags.rs
index f983109115f..6d4cdd0efe2 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 9ed65fbc854..4dcbfe4eb62 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; }
 </style>
 <pre><code><span class="keyword">fn</span> <span class="function declaration">not_static</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span><span class="brace">}</span>
 
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 567ab8ccc11..bf5505caf37 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; }
 </style>
 <pre><code><span class="attribute_bracket attribute">#</span><span class="attribute_bracket attribute">[</span><span class="builtin_attr attribute library">allow</span><span class="parenthesis attribute">(</span><span class="none attribute">dead_code</span><span class="parenthesis attribute">)</span><span class="attribute_bracket attribute">]</span>
 <span class="attribute_bracket attribute">#</span><span class="attribute_bracket attribute">[</span><span class="tool_module attribute library">rustfmt</span><span class="operator attribute">::</span><span class="tool_module attribute library">skip</span><span class="attribute_bracket attribute">]</span>
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 1e4c06df7ea..0d1b3c1f183 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; }
 </style>
 <pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root library">foo</span><span class="semicolon">;</span>
 <span class="keyword">use</span> <span class="module crate_root default_library library">core</span><span class="operator">::</span><span class="module default_library library">iter</span><span class="semicolon">;</span>
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 5d66f832daf..dd1528ed03f 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; }
 </style>
 <pre><code><span class="keyword">use</span> <span class="module crate_root default_library library">core</span><span class="operator">::</span><span class="module default_library library">iter</span><span class="semicolon">;</span>
 
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 35f240d4284..d5f92aa5d47 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; }
 </style>
 <pre><code><span class="comment documentation">//! This is a module to test doc injection.</span>
 <span class="comment documentation">//! ```</span>
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 87b9da46e2c..b15f7bca72b 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; }
 </style>
 <pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">std</span><span class="semicolon">;</span>
 <span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">alloc</span> <span class="keyword">as</span> <span class="module crate_root default_library declaration library">abc</span><span class="semicolon">;</span>
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 6b049f379ac..bdeb09d2f83 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; }
 </style>
 <pre><code><span class="keyword">use</span> <span class="module">inner</span><span class="operator">::</span><span class="brace">{</span><span class="self_keyword">self</span> <span class="keyword">as</span> <span class="module declaration">inner_mod</span><span class="brace">}</span><span class="semicolon">;</span>
 <span class="keyword">mod</span> <span class="module declaration">inner</span> <span class="brace">{</span><span class="brace">}</span>
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 d9c3db6fbb5..f9c33b8a601 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; }
 </style>
 <pre><code><span class="keyword">fn</span> <span class="function declaration">fixture</span><span class="parenthesis">(</span><span class="value_param declaration reference">ra_fixture</span><span class="colon">:</span> <span class="punctuation">&</span><span class="builtin_type">str</span><span class="parenthesis">)</span> <span class="brace">{</span><span class="brace">}</span>
 
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 3900959bedf..fd3b39855e2 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; }
 </style>
 <pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="self_keyword crate_root public">self</span><span class="semicolon">;</span>
 
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 f98e0b1cda6..ec39998de26 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; }
 </style>
 <pre><code>
 <span class="attribute_bracket attribute">#</span><span class="attribute_bracket attribute">[</span><span class="attribute attribute default_library library">derive</span><span class="parenthesis attribute">(</span><span class="parenthesis attribute">)</span><span class="attribute_bracket attribute">]</span>
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 2cbbf696415..c5fcec75680 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; }
 </style>
 <pre><code><span class="module crate_root library">proc_macros</span><span class="operator">::</span><span class="macro library">mirror</span><span class="macro_bang">!</span> <span class="brace macro">{</span>
     <span class="brace macro">{</span>
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 8a1d69816e6..4dcf8e5f01f 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; }
 </style>
 <pre><code><span class="comment documentation">//! </span><span class="struct documentation injected intra_doc_link">[Struct]</span>
 <span class="comment documentation">//! This is an intra doc injection test for modules</span>
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 c4c3e3dc260..084bbf2f742 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; }
 </style>
 <pre><code><span class="comment documentation">/// </span><span class="struct documentation injected intra_doc_link">[crate::foo::Struct]</span>
 <span class="comment documentation">/// This is an intra doc injection test for modules</span>
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 2369071ae2a..1af4bcfbd9d 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; }
 </style>
 <pre><code><span class="keyword">fn</span> <span class="function declaration">main</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span>
     <span class="numeric_literal">1</span> <span class="arithmetic">+</span> <span class="numeric_literal">1</span> <span class="arithmetic">-</span> <span class="numeric_literal">1</span> <span class="arithmetic">*</span> <span class="numeric_literal">1</span> <span class="arithmetic">/</span> <span class="numeric_literal">1</span> <span class="arithmetic">%</span> <span class="numeric_literal">1</span> <span class="bitwise">|</span> <span class="numeric_literal">1</span> <span class="bitwise">&</span> <span class="numeric_literal">1</span> <span class="logical">!</span> <span class="numeric_literal">1</span> <span class="bitwise">^</span> <span class="numeric_literal">1</span> <span class="bitwise">&gt;&gt;</span> <span class="numeric_literal">1</span> <span class="bitwise">&lt;&lt;</span> <span class="numeric_literal">1</span><span class="semicolon">;</span>
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 bff35c897e1..ec18c3ea1f9 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; }
 </style>
 <pre><code><span class="keyword">fn</span> <span class="function declaration">main</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span>
     <span class="keyword">let</span> <span class="variable declaration reference" data-binding-hash="8121853618659664005" style="color: hsl(273,88%,88%);">hello</span> <span class="operator">=</span> <span class="string_literal">"hello"</span><span class="semicolon">;</span>
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 33523e4af7d..dcac8eb7368 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; }
 </style>
 <pre><code><span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration">println</span> <span class="brace">{</span>
     <span class="parenthesis">(</span><span class="punctuation">$</span><span class="parenthesis">(</span><span class="punctuation">$</span>arg<span class="colon">:</span>tt<span class="parenthesis">)</span><span class="punctuation">*</span><span class="parenthesis">)</span> <span class="operator">=</span><span class="angle">&gt;</span> <span class="parenthesis">(</span><span class="brace">{</span>
@@ -161,8 +162,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="macro">println</span><span class="macro_bang">!</span><span class="parenthesis macro">(</span><span class="string_literal macro">"Hello</span><span class="escape_sequence">\n</span><span class="string_literal macro">World"</span><span class="parenthesis macro">)</span><span class="semicolon">;</span>
     <span class="macro">println</span><span class="macro_bang">!</span><span class="parenthesis macro">(</span><span class="string_literal macro">"</span><span class="escape_sequence">\u{48}</span><span class="escape_sequence">\x65</span><span class="escape_sequence">\x6C</span><span class="escape_sequence">\x6C</span><span class="escape_sequence">\x6F</span><span class="string_literal macro"> World"</span><span class="parenthesis macro">)</span><span class="semicolon">;</span>
 
-    <span class="keyword">let</span> <span class="punctuation">_</span> <span class="operator">=</span> <span class="string_literal">"</span><span class="escape_sequence">\x28</span><span class="escape_sequence">\x28</span><span class="escape_sequence">\x00</span><span class="escape_sequence">\x63</span><span class="string_literal">\xFF</span><span class="escape_sequence">\u{FF}</span><span class="escape_sequence">\n</span><span class="string_literal">"</span><span class="semicolon">;</span> <span class="comment">// invalid non-UTF8 escape sequences</span>
-    <span class="keyword">let</span> <span class="punctuation">_</span> <span class="operator">=</span> <span class="string_literal">b"</span><span class="escape_sequence">\x28</span><span class="escape_sequence">\x28</span><span class="escape_sequence">\x00</span><span class="escape_sequence">\x63</span><span class="escape_sequence">\xFF</span><span class="string_literal">\u{FF}</span><span class="escape_sequence">\n</span><span class="string_literal">"</span><span class="semicolon">;</span> <span class="comment">// valid bytes, invalid unicodes</span>
+    <span class="keyword">let</span> <span class="punctuation">_</span> <span class="operator">=</span> <span class="string_literal">"</span><span class="escape_sequence">\x28</span><span class="escape_sequence">\x28</span><span class="escape_sequence">\x00</span><span class="escape_sequence">\x63</span><span class="invalid_escape_sequence">\xFF</span><span class="escape_sequence">\u{FF}</span><span class="escape_sequence">\n</span><span class="string_literal">"</span><span class="semicolon">;</span> <span class="comment">// invalid non-UTF8 escape sequences</span>
+    <span class="keyword">let</span> <span class="punctuation">_</span> <span class="operator">=</span> <span class="string_literal">b"</span><span class="escape_sequence">\x28</span><span class="escape_sequence">\x28</span><span class="escape_sequence">\x00</span><span class="escape_sequence">\x63</span><span class="escape_sequence">\xFF</span><span class="invalid_escape_sequence">\u{FF}</span><span class="escape_sequence">\n</span><span class="string_literal">"</span><span class="semicolon">;</span> <span class="comment">// valid bytes, invalid unicodes</span>
     <span class="keyword">let</span> <span class="punctuation">_</span> <span class="operator">=</span> <span class="string_literal">c"</span><span class="escape_sequence">\u{FF}</span><span class="escape_sequence">\xFF</span><span class="string_literal">"</span><span class="semicolon">;</span> <span class="comment">// valid bytes, valid unicodes</span>
     <span class="keyword">let</span> <span class="variable declaration reference">backslash</span> <span class="operator">=</span> <span class="string_literal">r"\\"</span><span class="semicolon">;</span>
 
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 654d51b8a43..c72ea54e948 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; }
 </style>
 <pre><code><span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration">id</span> <span class="brace">{</span>
     <span class="parenthesis">(</span><span class="punctuation">$</span><span class="parenthesis">(</span><span class="punctuation">$</span>tt<span class="colon">:</span>tt<span class="parenthesis">)</span><span class="punctuation">*</span><span class="parenthesis">)</span> <span class="operator">=</span><span class="angle">&gt;</span> <span class="brace">{</span>
diff --git a/crates/rust-analyzer/src/semantic_tokens.rs b/crates/rust-analyzer/src/semantic_tokens.rs
index d4bb20c8f44..1fe02fc7ead 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 ba3421bf9e7..7a89533a5e9 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/editors/code/package.json b/editors/code/package.json
index ffb5dd9079a..c84fc1cd8ac 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -1801,13 +1801,17 @@
             },
             {
                 "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"
             },