fix(server): reject invalid params consistently across handlers

Document symbols, code lens, and code action swallowed a params parse
failure and answered success with an empty result, while formatting,
completion, and hover returned INVALID_PARAMS for the same failure.
All six now return the error, which is what JSON-RPC prescribes and
makes a client bug visible instead of looking like an empty
document.

src/server.rs

@@ -544,18 +544,26 @@ impl Server {
         id: Value,
         params: Option<Value>,
     ) -> Vec<Outgoing> {
-        let items = parse_params::<DocumentSymbolParams>(params)
-            .ok()
-            .and_then(|p| self.documents.get(&p.text_document.uri))
+        let params: DocumentSymbolParams = match require_params(&id, params) {
+            Ok(params) => params,
+            Err(out) => return out,
+        };
+        let items = self
+            .documents
+            .get(&params.text_document.uri)
             .map(|doc| symbols::document_symbols(doc, self.encoding))
             .unwrap_or_default();
         ok(id, items)
     }
 
     fn on_code_lens(&self, id: Value, params: Option<Value>) -> Vec<Outgoing> {
-        let lenses = parse_params::<CodeLensParams>(params)
-            .ok()
-            .and_then(|p| self.documents.get(&p.text_document.uri))
+        let params: CodeLensParams = match require_params(&id, params) {
+            Ok(params) => params,
+            Err(out) => return out,
+        };
+        let lenses = self
+            .documents
+            .get(&params.text_document.uri)
             .map(|doc| {
                 schema_action::code_lenses(
                     doc,
@@ -572,16 +580,20 @@ impl Server {
         id: Value,
         params: Option<Value>,
     ) -> Vec<Outgoing> {
-        let actions = parse_params::<CodeActionParams>(params)
-            .ok()
-            .and_then(|p| {
-                let doc = self.documents.get(&p.text_document.uri)?;
-                Some(schema_action::code_actions(
+        let params: CodeActionParams = match require_params(&id, params) {
+            Ok(params) => params,
+            Err(out) => return out,
+        };
+        let actions = self
+            .documents
+            .get(&params.text_document.uri)
+            .map(|doc| {
+                schema_action::code_actions(
                     doc,
                     &self.schema_store,
                     self.encoding,
-                    p.range,
-                ))
+                    params.range,
+                )
             })
             .unwrap_or_default();
         ok(id, actions)