Implement location link for type inlay hints

Author: HKalbasi

crates/hir-ty/src/display.rs

@@ -16,7 +16,7 @@ use hir_def::{
     path::{Path, PathKind},
     type_ref::{ConstScalar, TraitBoundModifier, TypeBound, TypeRef},
     visibility::Visibility,
-    HasModule, ItemContainerId, Lookup, ModuleId, TraitId,
+    HasModule, ItemContainerId, Lookup, ModuleDefId, ModuleId, TraitId,
 };
 use hir_expand::{hygiene::Hygiene, name::Name};
 use itertools::Itertools;
@@ -35,16 +35,44 @@ use crate::{
     TraitRefExt, Ty, TyExt, TyKind, WhereClause,
 };
 
+pub trait HirWrite: fmt::Write {
+    fn start_location_link(&mut self, location: ModuleDefId);
+    fn end_location_link(&mut self);
+}
+
+// String will ignore link metadata
+impl HirWrite for String {
+    fn start_location_link(&mut self, _: ModuleDefId) {}
+
+    fn end_location_link(&mut self) {}
+}
+
+// `core::Formatter` will ignore metadata
+impl HirWrite for fmt::Formatter<'_> {
+    fn start_location_link(&mut self, _: ModuleDefId) {}
+    fn end_location_link(&mut self) {}
+}
+
 pub struct HirFormatter<'a> {
     pub db: &'a dyn HirDatabase,
-    fmt: &'a mut dyn fmt::Write,
+    fmt: &'a mut dyn HirWrite,
     buf: String,
     curr_size: usize,
     pub(crate) max_size: Option<usize>,
     omit_verbose_types: bool,
     display_target: DisplayTarget,
 }
 
+impl HirFormatter<'_> {
+    fn start_location_link(&mut self, location: ModuleDefId) {
+        self.fmt.start_location_link(location);
+    }
+
+    fn end_location_link(&mut self) {
+        self.fmt.end_location_link();
+    }
+}
+
 pub trait HirDisplay {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError>;
 
@@ -245,20 +273,26 @@ pub struct HirDisplayWrapper<'a, T> {
     display_target: DisplayTarget,
 }
 
-impl<'a, T> fmt::Display for HirDisplayWrapper<'a, T>
-where
-    T: HirDisplay,
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.t.hir_fmt(&mut HirFormatter {
+impl<T: HirDisplay> HirDisplayWrapper<'_, T> {
+    pub fn write_to<F: HirWrite>(&self, f: &mut F) -> Result<(), HirDisplayError> {
+        self.t.hir_fmt(&mut HirFormatter {
             db: self.db,
             fmt: f,
             buf: String::with_capacity(20),
             curr_size: 0,
             max_size: self.max_size,
             omit_verbose_types: self.omit_verbose_types,
             display_target: self.display_target,
-        }) {
+        })
+    }
+}
+
+impl<'a, T> fmt::Display for HirDisplayWrapper<'a, T>
+where
+    T: HirDisplay,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.write_to(f) {
             Ok(()) => Ok(()),
             Err(HirDisplayError::FmtError) => Err(fmt::Error),
             Err(HirDisplayError::DisplaySourceCodeError(_)) => {
@@ -530,6 +564,7 @@ impl HirDisplay for Ty {
                 }
             }
             TyKind::Adt(AdtId(def_id), parameters) => {
+                f.start_location_link((*def_id).into());
                 match f.display_target {
                     DisplayTarget::Diagnostics | DisplayTarget::Test => {
                         let name = match *def_id {
@@ -554,6 +589,7 @@ impl HirDisplay for Ty {
                         }
                     }
                 }
+                f.end_location_link();
 
                 if parameters.len(Interner) > 0 {
                     let parameters_to_write = if f.display_target.is_source_code()

crates/hir/src/lib.rs

@@ -114,12 +114,20 @@ pub use {
         path::{ModPath, PathKind},
         type_ref::{Mutability, TypeRef},
         visibility::Visibility,
+        // FIXME: This is here since it is input of a method in `HirWrite`
+        // and things outside of hir need to implement that trait. We probably
+        // should move whole `hir_ty::display` to this crate so we will become
+        // able to use `ModuleDef` or `Definition` instead of `ModuleDefId`.
+        ModuleDefId,
     },
     hir_expand::{
         name::{known, Name},
         ExpandResult, HirFileId, InFile, MacroFile, Origin,
     },
-    hir_ty::{display::HirDisplay, PointerCast, Safety},
+    hir_ty::{
+        display::{HirDisplay, HirWrite},
+        PointerCast, Safety,
+    },
 };
 
 // These are negative re-exports: pub using these names is forbidden, they

crates/ide/src/inlay_hints.rs

@@ -1,23 +1,23 @@
-use std::fmt;
+use std::{fmt, mem::take};
 
 use either::Either;
 use hir::{
-    known, Adjust, AutoBorrow, Callable, HasVisibility, HirDisplay, Mutability, OverloadedDeref,
-    PointerCast, Safety, Semantics, TypeInfo,
+    known, Adjust, AutoBorrow, Callable, HasVisibility, HirDisplay, HirWrite, ModuleDef,
+    ModuleDefId, Mutability, OverloadedDeref, PointerCast, Safety, Semantics, TypeInfo,
 };
 use ide_db::{
     base_db::FileRange, famous_defs::FamousDefs, syntax_helpers::node_ext::walk_ty, FxHashMap,
     RootDatabase,
 };
 use itertools::Itertools;
-use stdx::to_lower_snake_case;
+use stdx::{never, to_lower_snake_case};
 use syntax::{
     ast::{self, AstNode, HasArgList, HasGenericParams, HasName, UnaryOp},
     match_ast, Direction, NodeOrToken, SmolStr, SyntaxKind, SyntaxNode, SyntaxToken, TextRange,
     TextSize, T,
 };
 
-use crate::FileId;
+use crate::{navigation_target::TryToNav, FileId};
 
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct InlayHintsConfig {
@@ -86,6 +86,7 @@ pub enum InlayTooltip {
     HoverOffset(FileId, TextSize),
 }
 
+#[derive(Default)]
 pub struct InlayHintLabel {
     pub parts: Vec<InlayHintLabelPart>,
 }
@@ -886,6 +887,51 @@ fn binding_mode_hints(
     Some(())
 }
 
+#[derive(Debug)]
+struct InlayHintLabelBuilder<'a> {
+    db: &'a RootDatabase,
+    result: InlayHintLabel,
+    last_part: String,
+    location: Option<FileRange>,
+}
+
+impl fmt::Write for InlayHintLabelBuilder<'_> {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.last_part.write_str(s)
+    }
+}
+
+impl HirWrite for InlayHintLabelBuilder<'_> {
+    fn start_location_link(&mut self, def: ModuleDefId) {
+        if self.location.is_some() {
+            never!("location link is already started");
+        }
+        self.make_new_part();
+        let Some(location) = ModuleDef::from(def).try_to_nav(self.db) else { return };
+        let location =
+            FileRange { file_id: location.file_id, range: location.focus_or_full_range() };
+        self.location = Some(location);
+    }
+
+    fn end_location_link(&mut self) {
+        self.make_new_part();
+    }
+}
+
+impl InlayHintLabelBuilder<'_> {
+    fn make_new_part(&mut self) {
+        self.result.parts.push(InlayHintLabelPart {
+            text: take(&mut self.last_part),
+            linked_location: self.location.take(),
+        });
+    }
+
+    fn finish(mut self) -> InlayHintLabel {
+        self.make_new_part();
+        self.result
+    }
+}
+
 fn bind_pat_hints(
     acc: &mut Vec<InlayHint>,
     sema: &Semantics<'_, RootDatabase>,
@@ -907,18 +953,27 @@ fn bind_pat_hints(
 
     let krate = sema.scope(desc_pat.syntax())?.krate();
     let famous_defs = FamousDefs(sema, krate);
+
+    let mut label_builder = InlayHintLabelBuilder {
+        db: sema.db,
+        last_part: String::new(),
+        location: None,
+        result: InlayHintLabel::default(),
+    };
+
     let label = hint_iterator(sema, &famous_defs, config, &ty);
 
     let label = match label {
-        Some(label) => label,
+        Some(label) => label.into(),
         None => {
-            let ty_name = ty.display_truncated(sema.db, config.max_length).to_string();
+            let _ = ty.display_truncated(sema.db, config.max_length).write_to(&mut label_builder);
+            let r = label_builder.finish();
             if config.hide_named_constructor_hints
-                && is_named_constructor(sema, pat, &ty_name).is_some()
+                && is_named_constructor(sema, pat, &r.to_string()).is_some()
             {
                 return None;
             }
-            ty_name
+            r
         }
     };
 
@@ -928,7 +983,7 @@ fn bind_pat_hints(
             None => pat.syntax().text_range(),
         },
         kind: InlayKind::TypeHint,
-        label: label.into(),
+        label,
         tooltip: pat
             .name()
             .map(|it| it.syntax().text_range())
@@ -2736,7 +2791,19 @@ fn main() {
                         range: 124..130,
                         kind: TypeHint,
                         label: [
-                            "Struct",
+                            "",
+                            InlayHintLabelPart {
+                                text: "Struct",
+                                linked_location: Some(
+                                    FileRange {
+                                        file_id: FileId(
+                                            0,
+                                        ),
+                                        range: 7..13,
+                                    },
+                                ),
+                            },
+                            "",
                         ],
                         tooltip: Some(
                             HoverRanged(