Apply async semantic token modifier to async/await keywords

Only async semantic token modifier

crates/hir/src/lib.rs

@@ -873,6 +873,10 @@ impl Function {
         db.function_data(self.id).is_unsafe()
     }
 
+    pub fn is_async(self, db: &dyn HirDatabase) -> bool {
+        db.function_data(self.id).is_async()
+    }
+
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
         let krate = self.module(db).id.krate();
         hir_def::diagnostics::validate_body(db.upcast(), self.id.into(), sink);

crates/ide/src/syntax_highlighting/highlight.rs

@@ -255,6 +255,7 @@ pub(super) fn element(
                     })
                     .map(|modifier| h | modifier)
                     .unwrap_or(h),
+                T![async] | T![await] => h | HlMod::Async,
                 _ => h,
             }
         }
@@ -310,6 +311,9 @@ fn highlight_def(db: &RootDatabase, def: Definition) -> Highlight {
                 if func.is_unsafe(db) {
                     h |= HlMod::Unsafe;
                 }
+                if func.is_async(db) {
+                    h |= HlMod::Async;
+                }
                 return h;
             }
             hir::ModuleDef::Adt(hir::Adt::Struct(_)) => HlTag::Symbol(SymbolKind::Struct),
@@ -409,6 +413,9 @@ fn highlight_method_call(
     if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(&method_call) {
         h |= HlMod::Unsafe;
     }
+    if func.is_async(sema.db) {
+        h |= HlMod::Async;
+    }
     if func.as_assoc_item(sema.db).and_then(|it| it.containing_trait(sema.db)).is_some() {
         h |= HlMod::Trait
     }

crates/ide/src/syntax_highlighting/tags.rs

@@ -65,6 +65,8 @@ pub enum HlMod {
     Static,
     /// Used for items in traits and trait impls.
     Trait,
+    /// Used with keywords like `async` and `await`.
+    Async,
     // Keep this last!
     /// Used for unsafe functions, mutable statics, union accesses and unsafe operations.
     Unsafe,
@@ -186,6 +188,7 @@ impl HlMod {
         HlMod::Mutable,
         HlMod::Static,
         HlMod::Trait,
+        HlMod::Async,
         HlMod::Unsafe,
     ];
 
@@ -203,6 +206,7 @@ impl HlMod {
             HlMod::Mutable => "mutable",
             HlMod::Static => "static",
             HlMod::Trait => "trait",
+            HlMod::Async => "async",
             HlMod::Unsafe => "unsafe",
         }
     }

crates/rust-analyzer/src/semantic_tokens.rs

@@ -91,6 +91,7 @@ define_semantic_token_modifiers![
     (INJECTED, "injected"),
     (MUTABLE, "mutable"),
     (CONSUMING, "consuming"),
+    (ASYNC, "async"),
     (UNSAFE, "unsafe"),
     (ATTRIBUTE_MODIFIER, "attribute"),
     (TRAIT_MODIFIER, "trait"),

crates/rust-analyzer/src/to_proto.rs

@@ -496,6 +496,7 @@ fn semantic_token_type_and_modifiers(
             HlMod::ControlFlow => semantic_tokens::CONTROL_FLOW,
             HlMod::Mutable => semantic_tokens::MUTABLE,
             HlMod::Consuming => semantic_tokens::CONSUMING,
+            HlMod::Async => semantic_tokens::ASYNC,
             HlMod::Unsafe => semantic_tokens::UNSAFE,
             HlMod::Callable => semantic_tokens::CALLABLE,
             HlMod::Static => lsp_types::SemanticTokenModifier::STATIC,