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]>

12 files changed, 150 insertions, 43 deletions

diff --git a/crates/ra_ide/src/inlay_hints.rs b/crates/ra_ide/src/inlay_hints.rs
index cf0cbdbd0..59922e14c 100644
--- a/crates/ra_ide/src/inlay_hints.rs
+++ b/crates/ra_ide/src/inlay_hints.rs
@@ -10,7 +10,20 @@ use ra_syntax::{
 
 use crate::{FileId, FunctionSignature};
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct InlayConfig {
+    pub type_hints: bool,
+    pub parameter_hints: bool,
+    pub max_length: Option<usize>,
+}
+
+impl Default for InlayConfig {
+    fn default() -> Self {
+        Self { type_hints: true, parameter_hints: true, max_length: None }
+    }
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum InlayKind {
     TypeHint,
     ParameterHint,
@@ -26,7 +39,7 @@ pub struct InlayHint {
 pub(crate) fn inlay_hints(
     db: &RootDatabase,
     file_id: FileId,
-    max_inlay_hint_length: Option<usize>,
+    inlay_hint_opts: &InlayConfig,
 ) -> Vec<InlayHint> {
     let _p = profile("inlay_hints");
     let sema = Semantics::new(db);
@@ -36,9 +49,9 @@ pub(crate) fn inlay_hints(
     for node in file.syntax().descendants() {
         match_ast! {
             match node {
-                ast::CallExpr(it) => { get_param_name_hints(&mut res, &sema, ast::Expr::from(it)); },
-                ast::MethodCallExpr(it) => { get_param_name_hints(&mut res, &sema, ast::Expr::from(it)); },
-                ast::BindPat(it) => { get_bind_pat_hints(&mut res, &sema, max_inlay_hint_length, it); },
+                ast::CallExpr(it) => { get_param_name_hints(&mut res, &sema, inlay_hint_opts, ast::Expr::from(it)); },
+                ast::MethodCallExpr(it) => { get_param_name_hints(&mut res, &sema, inlay_hint_opts, ast::Expr::from(it)); },
+                ast::BindPat(it) => { get_bind_pat_hints(&mut res, &sema, inlay_hint_opts, it); },
                 _ => (),
             }
         }
@@ -49,8 +62,13 @@ pub(crate) fn inlay_hints(
 fn get_param_name_hints(
     acc: &mut Vec<InlayHint>,
     sema: &Semantics<RootDatabase>,
+    inlay_hint_opts: &InlayConfig,
     expr: ast::Expr,
 ) -> Option<()> {
+    if !inlay_hint_opts.parameter_hints {
+        return None;
+    }
+
     let args = match &expr {
         ast::Expr::CallExpr(expr) => expr.arg_list()?.args(),
         ast::Expr::MethodCallExpr(expr) => expr.arg_list()?.args(),
@@ -84,9 +102,13 @@ fn get_param_name_hints(
 fn get_bind_pat_hints(
     acc: &mut Vec<InlayHint>,
     sema: &Semantics<RootDatabase>,
-    max_inlay_hint_length: Option<usize>,
+    inlay_hint_opts: &InlayConfig,
     pat: ast::BindPat,
 ) -> Option<()> {
+    if !inlay_hint_opts.type_hints {
+        return None;
+    }
+
     let ty = sema.type_of_pat(&pat.clone().into())?;
 
     if should_not_display_type_hint(sema.db, &pat, &ty) {
@@ -96,7 +118,7 @@ fn get_bind_pat_hints(
     acc.push(InlayHint {
         range: pat.syntax().text_range(),
         kind: InlayKind::TypeHint,
-        label: ty.display_truncated(sema.db, max_inlay_hint_length).to_string().into(),
+        label: ty.display_truncated(sema.db, inlay_hint_opts.max_length).to_string().into(),
     });
     Some(())
 }
@@ -202,11 +224,66 @@ fn get_fn_signature(sema: &Semantics<RootDatabase>, expr: &ast::Expr) -> Option<
 
 #[cfg(test)]
 mod tests {
+    use crate::inlay_hints::InlayConfig;
     use insta::assert_debug_snapshot;
 
     use crate::mock_analysis::single_file;
 
     #[test]
+    fn param_hints_only() {
+        let (analysis, file_id) = single_file(
+            r#"
+            fn foo(a: i32, b: i32) -> i32 { a + b }
+            fn main() {
+                let _x = foo(4, 4);
+            }"#,
+        );
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig{ parameter_hints: true, type_hints: false, max_length: None}).unwrap(), @r###"
+        [
+            InlayHint {
+                range: [106; 107),
+                kind: ParameterHint,
+                label: "a",
+            },
+            InlayHint {
+                range: [109; 110),
+                kind: ParameterHint,
+                label: "b",
+            },
+        ]"###);
+    }
+
+    #[test]
+    fn hints_disabled() {
+        let (analysis, file_id) = single_file(
+            r#"
+            fn foo(a: i32, b: i32) -> i32 { a + b }
+            fn main() {
+                let _x = foo(4, 4);
+            }"#,
+        );
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig{ type_hints: false, parameter_hints: false, max_length: None}).unwrap(), @r###"[]"###);
+    }
+
+    #[test]
+    fn type_hints_only() {
+        let (analysis, file_id) = single_file(
+            r#"
+            fn foo(a: i32, b: i32) -> i32 { a + b }
+            fn main() {
+                let _x = foo(4, 4);
+            }"#,
+        );
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig{ type_hints: true, parameter_hints: false, max_length: None}).unwrap(), @r###"
+        [
+            InlayHint {
+                range: [97; 99),
+                kind: TypeHint,
+                label: "i32",
+            },
+        ]"###);
+    }
+    #[test]
     fn default_generic_types_should_not_be_displayed() {
         let (analysis, file_id) = single_file(
             r#"
@@ -221,7 +298,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig::default()).unwrap(), @r###"
         [
             InlayHint {
                 range: [69; 71),
@@ -278,7 +355,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig::default()).unwrap(), @r###"
         [
             InlayHint {
                 range: [193; 197),
@@ -358,7 +435,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig::default()).unwrap(), @r###"
         [
             InlayHint {
                 range: [21; 30),
@@ -422,7 +499,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig::default()).unwrap(), @r###"
         [
             InlayHint {
                 range: [21; 30),
@@ -472,7 +549,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig::default()).unwrap(), @r###"
         [
             InlayHint {
                 range: [188; 192),
@@ -567,7 +644,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig::default()).unwrap(), @r###"
         [
             InlayHint {
                 range: [188; 192),
@@ -662,7 +739,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig::default()).unwrap(), @r###"
         [
             InlayHint {
                 range: [252; 256),
@@ -734,7 +811,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, Some(8)).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig { max_length: Some(8), ..Default::default() }).unwrap(), @r###"
         [
             InlayHint {
                 range: [74; 75),
@@ -822,7 +899,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig::default()).unwrap(), @r###"
         [
             InlayHint {
                 range: [798; 809),
@@ -944,7 +1021,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, Some(8)).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig { max_length: Some(8), ..Default::default() }).unwrap(), @r###"
         []
         "###
         );
@@ -970,7 +1047,7 @@ fn main() {
 }"#,
         );
 
-        assert_debug_snapshot!(analysis.inlay_hints(file_id, Some(8)).unwrap(), @r###"
+        assert_debug_snapshot!(analysis.inlay_hints(file_id, &InlayConfig { max_length: Some(8), ..Default::default() }).unwrap(), @r###"
         []
         "###
         );
diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index 015fae195..922e4caa8 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -68,7 +68,7 @@ pub use crate::{
     expand_macro::ExpandedMacro,
     folding_ranges::{Fold, FoldKind},
     hover::HoverResult,
-    inlay_hints::{InlayHint, InlayKind},
+    inlay_hints::{InlayConfig, InlayHint, InlayKind},
     references::{Declaration, Reference, ReferenceAccess, ReferenceKind, ReferenceSearchResult},
     runnables::{Runnable, RunnableKind, TestId},
     source_change::{FileSystemEdit, SourceChange, SourceFileEdit},
@@ -319,9 +319,9 @@ impl Analysis {
     pub fn inlay_hints(
         &self,
         file_id: FileId,
-        max_inlay_hint_length: Option<usize>,
+        inlay_hint_opts: &InlayConfig,
     ) -> Cancelable<Vec<InlayHint>> {
-        self.with_db(|db| inlay_hints::inlay_hints(db, file_id, max_inlay_hint_length))
+        self.with_db(|db| inlay_hints::inlay_hints(db, file_id, inlay_hint_opts))
     }
 
     /// Returns the set of folding ranges.
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index a8bf29ddf..bd5904db0 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -7,6 +7,8 @@
 //! configure the server itself, feature flags are passed into analysis, and
 //! tweak things like automatic insertion of `()` in completions.
 
+use crate::req::InlayConfigDef;
+use ra_ide::InlayConfig;
 use rustc_hash::FxHashMap;
 
 use ra_project_model::CargoFeatures;
@@ -30,7 +32,8 @@ pub struct ServerConfig {
 
     pub lru_capacity: Option<usize>,
 
-    pub max_inlay_hint_length: Option<usize>,
+    #[serde(with = "InlayConfigDef")]
+    pub inlay_hints: InlayConfig,
 
     pub cargo_watch_enable: bool,
     pub cargo_watch_args: Vec<String>,
@@ -60,7 +63,7 @@ impl Default for ServerConfig {
             exclude_globs: Vec::new(),
             use_client_watching: false,
             lru_capacity: None,
-            max_inlay_hint_length: None,
+            inlay_hints: Default::default(),
             cargo_watch_enable: true,
             cargo_watch_args: Vec::new(),
             cargo_watch_command: "check".to_string(),
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 4f7aac754..495056da3 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -177,7 +177,7 @@ pub fn main_loop(
                     .and_then(|it| it.folding_range.as_ref())
                     .and_then(|it| it.line_folding_only)
                     .unwrap_or(false),
-                max_inlay_hint_length: config.max_inlay_hint_length,
+                inlay_hints: config.inlay_hints,
                 cargo_watch: CheckOptions {
                     enable: config.cargo_watch_enable,
                     args: config.cargo_watch_args,
diff --git a/crates/rust-analyzer/src/main_loop/handlers.rs b/crates/rust-analyzer/src/main_loop/handlers.rs
index fcb40432d..921990da0 100644
--- a/crates/rust-analyzer/src/main_loop/handlers.rs
+++ b/crates/rust-analyzer/src/main_loop/handlers.rs
@@ -37,7 +37,7 @@ use crate::{
     },
     diagnostics::DiagnosticTask,
     from_json,
-    req::{self, Decoration, InlayHint, InlayHintsParams, InlayKind},
+    req::{self, Decoration, InlayHint, InlayHintsParams},
     semantic_tokens::SemanticTokensBuilder,
     world::WorldSnapshot,
     LspError, Result,
@@ -997,15 +997,12 @@ pub fn handle_inlay_hints(
     let analysis = world.analysis();
     let line_index = analysis.file_line_index(file_id)?;
     Ok(analysis
-        .inlay_hints(file_id, world.options.max_inlay_hint_length)?
+        .inlay_hints(file_id, &world.options.inlay_hints)?
         .into_iter()
         .map(|api_type| InlayHint {
             label: api_type.label.to_string(),
             range: api_type.range.conv_with(&line_index),
-            kind: match api_type.kind {
-                ra_ide::InlayKind::TypeHint => InlayKind::TypeHint,
-                ra_ide::InlayKind::ParameterHint => InlayKind::ParameterHint,
-            },
+            kind: api_type.kind,
         })
         .collect())
 }
diff --git a/crates/rust-analyzer/src/req.rs b/crates/rust-analyzer/src/req.rs
index a3efe3b9f..1dcab2703 100644
--- a/crates/rust-analyzer/src/req.rs
+++ b/crates/rust-analyzer/src/req.rs
@@ -4,6 +4,8 @@ use lsp_types::{Location, Position, Range, TextDocumentIdentifier, Url};
 use rustc_hash::FxHashMap;
 use serde::{Deserialize, Serialize};
 
+use ra_ide::{InlayConfig, InlayKind};
+
 pub use lsp_types::{
     notification::*, request::*, ApplyWorkspaceEditParams, CodeActionParams, CodeLens,
     CodeLensParams, CompletionParams, CompletionResponse, DiagnosticTag,
@@ -196,14 +198,24 @@ pub struct InlayHintsParams {
 }
 
 #[derive(Debug, PartialEq, Eq, Deserialize, Serialize)]
-pub enum InlayKind {
+#[serde(remote = "InlayKind")]
+pub enum InlayKindDef {
     TypeHint,
     ParameterHint,
 }
 
+#[derive(Deserialize)]
+#[serde(remote = "InlayConfig", rename_all = "camelCase")]
+pub struct InlayConfigDef {
+    pub type_hints: bool,
+    pub parameter_hints: bool,
+    pub max_length: Option<usize>,
+}
+
 #[derive(Debug, Deserialize, Serialize)]
 pub struct InlayHint {
     pub range: Range,
+    #[serde(with = "InlayKindDef")]
     pub kind: InlayKind,
     pub label: String,
 }
diff --git a/crates/rust-analyzer/src/world.rs b/crates/rust-analyzer/src/world.rs
index 9ef368529..d358f6b47 100644
--- a/crates/rust-analyzer/src/world.rs
+++ b/crates/rust-analyzer/src/world.rs
@@ -13,7 +13,8 @@ use lsp_types::Url;
 use parking_lot::RwLock;
 use ra_cargo_watch::{url_from_path_with_drive_lowercasing, CheckOptions, CheckWatcher};
 use ra_ide::{
-    Analysis, AnalysisChange, AnalysisHost, CrateGraph, FileId, LibraryData, SourceRootId,
+    Analysis, AnalysisChange, AnalysisHost, CrateGraph, FileId, InlayConfig, LibraryData,
+    SourceRootId,
 };
 use ra_project_model::{get_rustc_cfg_options, ProjectWorkspace};
 use ra_vfs::{LineEndings, RootEntry, Vfs, VfsChange, VfsFile, VfsRoot, VfsTask, Watch};
@@ -34,7 +35,7 @@ pub struct Options {
     pub publish_decorations: bool,
     pub supports_location_link: bool,
     pub line_folding_only: bool,
-    pub max_inlay_hint_length: Option<usize>,
+    pub inlay_hints: InlayConfig,
     pub rustfmt_args: Vec<String>,
     pub cargo_watch: CheckOptions,
 }
diff --git a/docs/user/features.md b/docs/user/features.md
index ba4d50fa8..06bc7ded5 100644
--- a/docs/user/features.md
+++ b/docs/user/features.md
@@ -191,8 +191,8 @@ Two types of inlay hints are displayed currently:
 
 In VS Code, the following settings can be used to configure the inlay hints:
 
-* `rust-analyzer.displayInlayHints` — toggles inlay hints display on or off
-* `rust-analyzer.maxInlayHintLength` — shortens the hints if their length exceeds the value specified. If no value is specified (`null`), no shortening is applied.
+* `rust-analyzer.inlayHintOpts.displayType` configure which types of inlay hints are shown.
+* `rust-analyzer.inlayHintOpts.maxLength` — shortens the hints if their length exceeds the value specified. If no value is specified (`null`), no shortening is applied.
 
 **Note:** VS Code does not have native support for inlay hints [yet](https://github.com/microsoft/vscode/issues/16221) and the hints are implemented using decorations.
 This approach has limitations, the caret movement and bracket highlighting near the edges of the hint may be weird:
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);