3 files changed, 14 insertions, 1 deletions

diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index 750848467..9f864179e 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -579,7 +579,14 @@ fn highlight_element(
                 }
             }
             T![-] if element.parent().and_then(ast::PrefixExpr::cast).is_some() => {
-                HighlightTag::NumericLiteral.into()
+                let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
+
+                let expr = prefix_expr.expr()?;
+                match expr {
+                    ast::Expr::Literal(_) => HighlightTag::NumericLiteral,
+                    _ => HighlightTag::Operator,
+                }
+                .into()
             }
             _ if element.parent().and_then(ast::PrefixExpr::cast).is_some() => {
                 HighlightTag::Operator.into()
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlighting.html b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
index 0cb84866d..c6b4f5a00 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlighting.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
@@ -176,6 +176,9 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 
     <span class="keyword">let</span> <span class="variable declaration callable">a</span> <span class="operator">=</span> <span class="punctuation">|</span><span class="value_param declaration">x</span><span class="punctuation">|</span> <span class="value_param">x</span><span class="punctuation">;</span>
     <span class="keyword">let</span> <span class="variable declaration callable">bar</span> <span class="operator">=</span> <span class="struct">Foo</span><span class="operator">::</span><span class="function">baz</span><span class="punctuation">;</span>
+
+    <span class="keyword">let</span> <span class="variable declaration">baz</span> <span class="operator">=</span> <span class="numeric_literal">-</span><span class="numeric_literal">42</span><span class="punctuation">;</span>
+    <span class="keyword">let</span> <span class="variable declaration">baz</span> <span class="operator">=</span> <span class="operator">-</span><span class="variable">baz</span><span class="punctuation">;</span>
 <span class="punctuation">}</span>
 
 <span class="keyword">enum</span> <span class="enum declaration">Option</span><span class="punctuation">&lt;</span><span class="type_param declaration">T</span><span class="punctuation">&gt;</span> <span class="punctuation">{</span>
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index da20c300e..dd43f9dd9 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -150,6 +150,9 @@ fn main() {
 
     let a = |x| x;
     let bar = Foo::baz;
+
+    let baz = -42;
+    let baz = -baz;
 }
 
 enum Option<T> {