Parameter inlay hint separate from variable type inlay? #2876

Add setting to allow enabling either type inlay hints or parameter
inlay hints or both. Group the the max inlay hint length option
into the object.

- Add a new type for the inlayHint options.
- Add tests to ensure the inlays don't happen on the server side

editors/code/package.json

@@ -307,12 +307,24 @@
                     "exclusiveMinimum": true,
                     "description": "Number of syntax trees rust-analyzer keeps in memory"
                 },
-                "rust-analyzer.displayInlayHints": {
-                    "type": "boolean",
-                    "default": true,
+                "rust-analyzer.inlayHintOpts.displayType": {
+                    "type": "string",
+                    "enum": [
+                        "off",
+                        "typeHints",
+                        "parameterHints",
+                        "full"
+                    ],
+                    "enumDescriptions": [
+                        "No type inlay hints",
+                        "Type inlays hints only",
+                        "Parameter inlays hints only",
+                        "All inlay hints types"
+                    ],
+                    "default": "full",
                     "description": "Display additional type and parameter information in the editor"
                 },
-                "rust-analyzer.maxInlayHintLength": {
+                "rust-analyzer.inlayHintOpts.maxLength": {
                     "type": [
                         "null",
                         "integer"

editors/code/src/client.ts

@@ -29,7 +29,7 @@ export async function createClient(config: Config, serverPath: string): Promise<
         initializationOptions: {
             publishDecorations: !config.highlightingSemanticTokens,
             lruCapacity: config.lruCapacity,
-            maxInlayHintLength: config.maxInlayHintLength,
+            inlayHintOpts: config.inlayHintOpts,
             cargoWatchEnable: cargoWatchOpts.enable,
             cargoWatchArgs: cargoWatchOpts.arguments,
             cargoWatchCommand: cargoWatchOpts.command,

editors/code/src/config.ts

@@ -5,6 +5,11 @@ import { log } from "./util";
 
 const RA_LSP_DEBUG = process.env.__RA_LSP_SERVER_DEBUG;
 
+export interface InlayHintOptions {
+    displayType: string;
+    maxLength: number;
+}
+
 export interface CargoWatchOptions {
     enable: boolean;
     arguments: string[];
@@ -149,8 +154,12 @@ export class Config {
     get highlightingOn() { return this.cfg.get("highlightingOn") as boolean; }
     get rainbowHighlightingOn() { return this.cfg.get("rainbowHighlightingOn") as boolean; }
     get lruCapacity() { return this.cfg.get("lruCapacity") as null | number; }
-    get displayInlayHints() { return this.cfg.get("displayInlayHints") as boolean; }
-    get maxInlayHintLength() { return this.cfg.get("maxInlayHintLength") as number; }
+    get inlayHintOpts(): InlayHintOptions {
+        return {
+            displayType: this.cfg.get("inlayHintOpts.displayType") as string,
+            maxLength: this.cfg.get("inlayHintOpts.maxLength") as number,
+        };
+    }
     get excludeGlobs() { return this.cfg.get("excludeGlobs") as string[]; }
     get useClientWatching() { return this.cfg.get("useClientWatching") as boolean; }
     get featureFlags() { return this.cfg.get("featureFlags") as Record<string, boolean>; }

editors/code/src/inlay_hints.ts

@@ -10,7 +10,7 @@ export function activateInlayHints(ctx: Ctx) {
     const maybeUpdater = {
         updater: null as null | HintsUpdater,
         onConfigChange() {
-            if (!ctx.config.displayInlayHints) {
+            if (ctx.config.inlayHintOpts.displayType === 'off') {
                 return this.dispose();
             }
             if (!this.updater) this.updater = new HintsUpdater(ctx);