Stub semantic tokens handler

crates/lsp/src/lib.rs

@@ -68,6 +68,23 @@ impl LanguageServer for LspBackend {
                         ..Default::default()
                     },
                 )),
+                semantic_tokens_provider: Some(
+                    SemanticTokensServerCapabilities::SemanticTokensOptions(
+                        SemanticTokensOptions {
+                            work_done_progress_options: WorkDoneProgressOptions {
+                                work_done_progress: None,
+                            },
+                            legend: SemanticTokensLegend {
+                                token_types: vec![SemanticTokenType::COMMENT],
+                                token_modifiers: vec![],
+                            },
+                            // TODO: range support
+                            range: None,
+                            // TODO: delta support
+                            full: Some(SemanticTokensFullOptions::Bool(true)),
+                        },
+                    ),
+                ),
                 ..Default::default()
             },
             server_info: Default::default(),
@@ -131,6 +148,22 @@ impl LanguageServer for LspBackend {
         // update diagnostics
         self.update_diagnostics().await;
     }
+
+    async fn semantic_tokens_full(
+        &self,
+        _params: SemanticTokensParams,
+    ) -> Result<Option<SemanticTokensResult>> {
+        Ok(Some(SemanticTokensResult::Tokens(SemanticTokens {
+            result_id: None,
+            data: vec![SemanticToken {
+                delta_line: 0,
+                delta_start: 0,
+                length: 30,
+                token_type: 0,
+                token_modifiers_bitset: 0,
+            }],
+        })))
+    }
 }
 
 impl LspBackend {