Auto merge of #12285 - Veykril:inlay-hints, r=Veykril

feat: Implement inlay hint tooltips

Currently this just delegates to hover request for some things, and otherwise fallsback to the label.
![image](https://user-images.githubusercontent.com/3757771/168816520-e015726f-53e1-4dac-a76e-8f1312f145d7.png)
![image](https://user-images.githubusercontent.com/3757771/168802753-43749b75-866c-40db-b106-aeaa542b87a3.png)
![image](https://user-images.githubusercontent.com/3757771/168816579-da2050f0-f198-4b3a-a9a1-53199fcaab61.png)
![image](https://user-images.githubusercontent.com/3757771/168818804-d4400ffe-0e6c-48a0-a872-f054e5f550fa.png)

Author: bors

crates/ide/src/inlay_hints.rs

@@ -80,7 +80,9 @@ pub use crate::{
     folding_ranges::{Fold, FoldKind},
     highlight_related::{HighlightRelatedConfig, HighlightedRange},
     hover::{HoverAction, HoverConfig, HoverDocFormat, HoverGotoTypeData, HoverResult},
-    inlay_hints::{InlayHint, InlayHintsConfig, InlayKind, LifetimeElisionHints, ReborrowHints},
+    inlay_hints::{
+        InlayHint, InlayHintsConfig, InlayKind, LifetimeElisionHints, RangeOrOffset, ReborrowHints,
+    },
     join_lines::JoinLinesConfig,
     markup::Markup,
     moniker::{MonikerKind, MonikerResult, PackageInformation},

crates/ide/src/lib.rs

@@ -4,7 +4,8 @@ use lsp_types::{
     CodeActionProviderCapability, CodeLensOptions, CompletionOptions, DeclarationCapability,
     DocumentOnTypeFormattingOptions, FileOperationFilter, FileOperationPattern,
     FileOperationPatternKind, FileOperationRegistrationOptions, FoldingRangeProviderCapability,
-    HoverProviderCapability, ImplementationProviderCapability, OneOf, RenameOptions, SaveOptions,
+    HoverProviderCapability, ImplementationProviderCapability, InlayHintOptions,
+    InlayHintServerCapabilities, OneOf, RenameOptions, SaveOptions,
     SelectionRangeProviderCapability, SemanticTokensFullOptions, SemanticTokensLegend,
     SemanticTokensOptions, ServerCapabilities, SignatureHelpOptions, TextDocumentSyncCapability,
     TextDocumentSyncKind, TextDocumentSyncOptions, TypeDefinitionProviderCapability,
@@ -112,7 +113,12 @@ pub fn server_capabilities(config: &Config) -> ServerCapabilities {
             .into(),
         ),
         moniker_provider: None,
-        inlay_hint_provider: Some(OneOf::Left(true)),
+        inlay_hint_provider: Some(OneOf::Right(InlayHintServerCapabilities::Options(
+            InlayHintOptions {
+                work_done_progress_options: Default::default(),
+                resolve_provider: Some(true),
+            },
+        ))),
         experimental: Some(json!({
             "externalDocs": true,
             "hoverRange": true,

crates/rust-analyzer/src/caps.rs

@@ -1343,11 +1343,54 @@ pub(crate) fn handle_inlay_hints(
         snap.analysis
             .inlay_hints(&inlay_hints_config, file_id, Some(range))?
             .into_iter()
-            .map(|it| to_proto::inlay_hint(inlay_hints_config.render_colons, &line_index, it))
+            .map(|it| {
+                to_proto::inlay_hint(
+                    &line_index,
+                    &params.text_document,
+                    inlay_hints_config.render_colons,
+                    it,
+                )
+            })
             .collect(),
     ))
 }
 
+pub(crate) fn handle_inlay_hints_resolve(
+    snap: GlobalStateSnapshot,
+    mut hint: InlayHint,
+) -> Result<InlayHint> {
+    let _p = profile::span("handle_inlay_hints_resolve");
+    let data = match hint.data.take() {
+        Some(it) => it,
+        None => return Ok(hint),
+    };
+
+    let resolve_data: lsp_ext::InlayHintResolveData = serde_json::from_value(data)?;
+
+    let file_range = from_proto::file_range(
+        &snap,
+        resolve_data.text_document,
+        match resolve_data.position {
+            PositionOrRange::Position(pos) => Range::new(pos, pos),
+            PositionOrRange::Range(range) => range,
+        },
+    )?;
+    let info = match snap.analysis.hover(&snap.config.hover(), file_range)? {
+        None => return Ok(hint),
+        Some(info) => info,
+    };
+
+    let markup_kind =
+        snap.config.hover().documentation.map_or(ide::HoverDocFormat::Markdown, |kind| kind);
+
+    // FIXME: hover actions?
+    hint.tooltip = Some(lsp_types::InlayHintTooltip::MarkupContent(to_proto::markup_content(
+        info.info.markup,
+        markup_kind,
+    )));
+    Ok(hint)
+}
+
 pub(crate) fn handle_call_hierarchy_prepare(
     snap: GlobalStateSnapshot,
     params: CallHierarchyPrepareParams,

crates/rust-analyzer/src/handlers.rs

@@ -518,6 +518,12 @@ pub struct CompletionResolveData {
     pub imports: Vec<CompletionImport>,
 }
 
+#[derive(Debug, Serialize, Deserialize)]
+pub struct InlayHintResolveData {
+    pub text_document: TextDocumentIdentifier,
+    pub position: PositionOrRange,
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 pub struct CompletionImport {
     pub full_import_path: String,

crates/rust-analyzer/src/lsp_ext.rs

@@ -612,6 +612,7 @@ impl GlobalState {
             .on::<lsp_types::request::GotoImplementation>(handlers::handle_goto_implementation)
             .on::<lsp_types::request::GotoTypeDefinition>(handlers::handle_goto_type_definition)
             .on::<lsp_types::request::InlayHintRequest>(handlers::handle_inlay_hints)
+            .on::<lsp_types::request::InlayHintResolveRequest>(handlers::handle_inlay_hints_resolve)
             .on::<lsp_types::request::Completion>(handlers::handle_completion)
             .on::<lsp_types::request::ResolveCompletionItem>(handlers::handle_completion_resolve)
             .on::<lsp_types::request::CodeLensRequest>(handlers::handle_code_lens)

crates/rust-analyzer/src/main_loop.rs

@@ -415,8 +415,9 @@ pub(crate) fn signature_help(
 }
 
 pub(crate) fn inlay_hint(
-    render_colons: bool,
     line_index: &LineIndex,
+    text_document: &lsp_types::TextDocumentIdentifier,
+    render_colons: bool,
     inlay_hint: InlayHint,
 ) -> lsp_types::InlayHint {
     lsp_types::InlayHint {
@@ -433,24 +434,6 @@ pub(crate) fn inlay_hint(
             | InlayKind::LifetimeHint
             | InlayKind::ClosingBraceHint => position(line_index, inlay_hint.range.end()),
         },
-        label: lsp_types::InlayHintLabel::String(match inlay_hint.kind {
-            InlayKind::ParameterHint if render_colons => format!("{}:", inlay_hint.label),
-            InlayKind::TypeHint if render_colons => format!(": {}", inlay_hint.label),
-            InlayKind::ClosureReturnTypeHint => format!(" -> {}", inlay_hint.label),
-            _ => inlay_hint.label.to_string(),
-        }),
-        kind: match inlay_hint.kind {
-            InlayKind::ParameterHint => Some(lsp_types::InlayHintKind::PARAMETER),
-            InlayKind::ClosureReturnTypeHint | InlayKind::TypeHint | InlayKind::ChainingHint => {
-                Some(lsp_types::InlayHintKind::TYPE)
-            }
-            InlayKind::BindingModeHint
-            | InlayKind::GenericParamListHint
-            | InlayKind::LifetimeHint
-            | InlayKind::ImplicitReborrowHint
-            | InlayKind::ClosingBraceHint => None,
-        },
-        tooltip: None,
         padding_left: Some(match inlay_hint.kind {
             InlayKind::TypeHint => !render_colons,
             InlayKind::ChainingHint | InlayKind::ClosingBraceHint => true,
@@ -471,8 +454,39 @@ pub(crate) fn inlay_hint(
             InlayKind::BindingModeHint => inlay_hint.label != "&",
             InlayKind::ParameterHint | InlayKind::LifetimeHint => true,
         }),
+        label: lsp_types::InlayHintLabel::String(match inlay_hint.kind {
+            InlayKind::ParameterHint if render_colons => format!("{}:", inlay_hint.label),
+            InlayKind::TypeHint if render_colons => format!(": {}", inlay_hint.label),
+            InlayKind::ClosureReturnTypeHint => format!(" -> {}", inlay_hint.label),
+            _ => inlay_hint.label.clone(),
+        }),
+        kind: match inlay_hint.kind {
+            InlayKind::ParameterHint => Some(lsp_types::InlayHintKind::PARAMETER),
+            InlayKind::ClosureReturnTypeHint | InlayKind::TypeHint | InlayKind::ChainingHint => {
+                Some(lsp_types::InlayHintKind::TYPE)
+            }
+            InlayKind::BindingModeHint
+            | InlayKind::GenericParamListHint
+            | InlayKind::LifetimeHint
+            | InlayKind::ImplicitReborrowHint
+            | InlayKind::ClosingBraceHint => None,
+        },
         text_edits: None,
-        data: None,
+        tooltip: Some(lsp_types::InlayHintTooltip::String(inlay_hint.label)),
+        data: inlay_hint.hover_trigger.map(|range_or_offset| {
+            to_value(lsp_ext::InlayHintResolveData {
+                text_document: text_document.clone(),
+                position: match range_or_offset {
+                    ide::RangeOrOffset::Offset(offset) => {
+                        lsp_ext::PositionOrRange::Position(position(line_index, offset))
+                    }
+                    ide::RangeOrOffset::Range(text_range) => {
+                        lsp_ext::PositionOrRange::Range(range(line_index, text_range))
+                    }
+                },
+            })
+            .unwrap()
+        }),
     }
 }
 

crates/rust-analyzer/src/to_proto.rs

@@ -1,5 +1,5 @@
 <!---
-lsp_ext.rs hash: 7a34bc3f38e2a7d8
+lsp_ext.rs hash: 44e8238e4fbd4128
 
 If you need to change the above hash to make the test pass, please check if you
 need to adjust this doc as well and ping this issue: