Merge #3543

3543: Parameter inlay hint separate from variable type inlay? #2876 r=matklad a=slyngbaek

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

Co-authored-by: Steffen Lyngbaek <[email protected]>

4 files changed, 25 insertions, 8 deletions

diff --git a/editors/code/package.json b/editors/code/package.json
index 09dfc404d..3aaae357a 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -312,12 +312,17 @@
                     "exclusiveMinimum": true,
                     "description": "Number of syntax trees rust-analyzer keeps in memory"
                 },
-                "rust-analyzer.displayInlayHints": {
+                "rust-analyzer.inlayHints.typeHints": {
                     "type": "boolean",
                     "default": true,
-                    "description": "Display additional type and parameter information in the editor"
+                    "description": "Whether to show inlay type hints"
                 },
-                "rust-analyzer.maxInlayHintLength": {
+                "rust-analyzer.inlayHints.parameterHints": {
+                    "type": "boolean",
+                    "default": true,
+                    "description": "Whether to show function parameter name inlay hints at the call site"
+                },
+                "rust-analyzer.inlayHints.maxLength": {
                     "type": [
                         "null",
                         "integer"
diff --git a/editors/code/src/client.ts b/editors/code/src/client.ts
index 6ce3b9235..e9f261c24 100644
--- a/editors/code/src/client.ts
+++ b/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,
+            inlayHints: config.inlayHints,
             cargoWatchEnable: cargoWatchOpts.enable,
             cargoWatchArgs: cargoWatchOpts.arguments,
             cargoWatchCommand: cargoWatchOpts.command,
diff --git a/editors/code/src/config.ts b/editors/code/src/config.ts
index 3ade7e900..6db073bec 100644
--- a/editors/code/src/config.ts
+++ b/editors/code/src/config.ts
@@ -5,6 +5,12 @@ import { log } from "./util";
 
 const RA_LSP_DEBUG = process.env.__RA_LSP_SERVER_DEBUG;
 
+export interface InlayHintOptions {
+    typeHints: boolean;
+    parameterHints: boolean;
+    maxLength: number | null;
+}
+
 export interface CargoWatchOptions {
     enable: boolean;
     arguments: string[];
@@ -22,7 +28,8 @@ export class Config {
     private static readonly requiresReloadOpts = [
         "cargoFeatures",
         "cargo-watch",
-        "highlighting.semanticTokens"
+        "highlighting.semanticTokens",
+        "inlayHints",
     ]
         .map(opt => `${Config.rootSection}.${opt}`);
 
@@ -149,8 +156,13 @@ 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 inlayHints(): InlayHintOptions {
+        return {
+            typeHints: this.cfg.get("inlayHints.typeHints") as boolean,
+            parameterHints: this.cfg.get("inlayHints.parameterHints") as boolean,
+            maxLength: this.cfg.get("inlayHints.maxLength") as null | 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>; }
diff --git a/editors/code/src/inlay_hints.ts b/editors/code/src/inlay_hints.ts
index e1a82e03e..b19b09ad5 100644
--- a/editors/code/src/inlay_hints.ts
+++ b/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.inlayHints.typeHints && !ctx.config.inlayHints.parameterHints) {
                 return this.dispose();
             }
             if (!this.updater) this.updater = new HintsUpdater(ctx);