Auto merge of #16089 - SomeoneToIgnore:fix-parameter-inlay-hints-resolution, r=Veykril

Query for nearest parent block around the hint to resolve

This way, parameter hints will be found for resolution and #15522 (comment) will be fixed

Hopefully that also helps with whatever else (lifetimes', etc.) hints in
#13962

> hints are resolved by querying for textDocument/inlayHint with hint's position turned into a [position-1, position+1] range (instead of the original, much wider document range).
>
> This might lead to issues in the future, with e.g. lifetime hints (currently there's nothing to resolve for them and it's fine) that belong to a certain position, but need to have textDocument/inlayHint query for much bigger range than their position+/-1

Author: bors

crates/ide/src/inlay_hints.rs

@@ -422,6 +422,11 @@ fn ty_to_text_edit(
     Some(builder.finish())
 }
 
+pub enum RangeLimit {
+    Fixed(TextRange),
+    NearestParent(TextSize),
+}
+
 // Feature: Inlay Hints
 //
 // rust-analyzer shows additional information inline with the source code.
@@ -443,7 +448,7 @@ fn ty_to_text_edit(
 pub(crate) fn inlay_hints(
     db: &RootDatabase,
     file_id: FileId,
-    range_limit: Option<TextRange>,
+    range_limit: Option<RangeLimit>,
     config: &InlayHintsConfig,
 ) -> Vec<InlayHint> {
     let _p = profile::span("inlay_hints");
@@ -458,13 +463,31 @@ pub(crate) fn inlay_hints(
 
         let hints = |node| hints(&mut acc, &famous_defs, config, file_id, node);
         match range_limit {
-            Some(range) => match file.covering_element(range) {
+            Some(RangeLimit::Fixed(range)) => match file.covering_element(range) {
                 NodeOrToken::Token(_) => return acc,
                 NodeOrToken::Node(n) => n
                     .descendants()
                     .filter(|descendant| range.intersect(descendant.text_range()).is_some())
                     .for_each(hints),
             },
+            Some(RangeLimit::NearestParent(position)) => {
+                match file.token_at_offset(position).left_biased() {
+                    Some(token) => {
+                        if let Some(parent_block) =
+                            token.parent_ancestors().find_map(ast::BlockExpr::cast)
+                        {
+                            parent_block.syntax().descendants().for_each(hints)
+                        } else if let Some(parent_item) =
+                            token.parent_ancestors().find_map(ast::Item::cast)
+                        {
+                            parent_item.syntax().descendants().for_each(hints)
+                        } else {
+                            return acc;
+                        }
+                    }
+                    None => return acc,
+                }
+            }
             None => file.descendants().for_each(hints),
         };
     }

crates/ide/src/inlay_hints/bind_pat.rs

@@ -177,7 +177,11 @@ mod tests {
     use syntax::{TextRange, TextSize};
     use test_utils::extract_annotations;
 
-    use crate::{fixture, inlay_hints::InlayHintsConfig, ClosureReturnTypeHints};
+    use crate::{
+        fixture,
+        inlay_hints::{InlayHintsConfig, RangeLimit},
+        ClosureReturnTypeHints,
+    };
 
     use crate::inlay_hints::tests::{
         check, check_edit, check_no_edit, check_with_config, DISABLED_CONFIG, TEST_CONFIG,
@@ -400,7 +404,7 @@ fn main() {
             .inlay_hints(
                 &InlayHintsConfig { type_hints: true, ..DISABLED_CONFIG },
                 file_id,
-                Some(TextRange::new(TextSize::from(500), TextSize::from(600))),
+                Some(RangeLimit::Fixed(TextRange::new(TextSize::from(500), TextSize::from(600)))),
             )
             .unwrap();
         let actual =

crates/ide/src/lib.rs

@@ -94,7 +94,7 @@ pub use crate::{
     inlay_hints::{
         AdjustmentHints, AdjustmentHintsMode, ClosureReturnTypeHints, DiscriminantHints,
         InlayFieldsToResolve, InlayHint, InlayHintLabel, InlayHintLabelPart, InlayHintPosition,
-        InlayHintsConfig, InlayKind, InlayTooltip, LifetimeElisionHints,
+        InlayHintsConfig, InlayKind, InlayTooltip, LifetimeElisionHints, RangeLimit,
     },
     join_lines::JoinLinesConfig,
     markup::Markup,
@@ -397,7 +397,7 @@ impl Analysis {
         &self,
         config: &InlayHintsConfig,
         file_id: FileId,
-        range: Option<TextRange>,
+        range: Option<RangeLimit>,
     ) -> Cancellable<Vec<InlayHint>> {
         self.with_db(|db| inlay_hints::inlay_hints(db, file_id, range, config))
     }

crates/rust-analyzer/src/handlers/request.rs

@@ -12,8 +12,8 @@ use anyhow::Context;
 
 use ide::{
     AnnotationConfig, AssistKind, AssistResolveStrategy, Cancellable, FilePosition, FileRange,
-    HoverAction, HoverGotoTypeData, InlayFieldsToResolve, Query, RangeInfo, ReferenceCategory,
-    Runnable, RunnableKind, SingleResolve, SourceChange, TextEdit,
+    HoverAction, HoverGotoTypeData, InlayFieldsToResolve, Query, RangeInfo, RangeLimit,
+    ReferenceCategory, Runnable, RunnableKind, SingleResolve, SourceChange, TextEdit,
 };
 use ide_db::SymbolKind;
 use lsp_server::ErrorCode;
@@ -1409,7 +1409,7 @@ pub(crate) fn handle_inlay_hints(
     let inlay_hints_config = snap.config.inlay_hints();
     Ok(Some(
         snap.analysis
-            .inlay_hints(&inlay_hints_config, file_id, Some(range))?
+            .inlay_hints(&inlay_hints_config, file_id, Some(RangeLimit::Fixed(range)))?
             .into_iter()
             .map(|it| {
                 to_proto::inlay_hint(
@@ -1440,22 +1440,13 @@ pub(crate) fn handle_inlay_hints_resolve(
     anyhow::ensure!(snap.file_exists(file_id), "Invalid LSP resolve data");
 
     let line_index = snap.file_line_index(file_id)?;
-    let range = from_proto::text_range(
-        &line_index,
-        lsp_types::Range { start: original_hint.position, end: original_hint.position },
-    )?;
-    let range_start = range.start();
-    let range_end = range.end();
-    let large_range = TextRange::new(
-        range_start.checked_sub(1.into()).unwrap_or(range_start),
-        range_end.checked_add(1.into()).unwrap_or(range_end),
-    );
+    let hint_position = from_proto::offset(&line_index, original_hint.position)?;
     let mut forced_resolve_inlay_hints_config = snap.config.inlay_hints();
     forced_resolve_inlay_hints_config.fields_to_resolve = InlayFieldsToResolve::empty();
     let resolve_hints = snap.analysis.inlay_hints(
         &forced_resolve_inlay_hints_config,
         file_id,
-        Some(large_range),
+        Some(RangeLimit::NearestParent(hint_position)),
     )?;
 
     let mut resolved_hints = resolve_hints