From 4c5fd19ee5734992344827b11c0d0e864b020b25 Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukastw97@gmail.com>
Date: Sun, 7 May 2023 09:42:50 +0200
Subject: [PATCH] Render places in capture inlay hints

---
 crates/hir-ty/src/display.rs                   |  1 -
 crates/hir-ty/src/infer/closure.rs             | 18 +-----------------
 crates/hir/src/lib.rs                          | 15 ++++++++-------
 crates/ide/src/hover/render.rs                 | 13 ++++++++++---
 crates/ide/src/inlay_hints/closure_captures.rs |  5 ++---
 5 files changed, 21 insertions(+), 31 deletions(-)

diff --git a/crates/hir-ty/src/display.rs b/crates/hir-ty/src/display.rs
index 22326990299c..3cfe78141d43 100644
--- a/crates/hir-ty/src/display.rs
+++ b/crates/hir-ty/src/display.rs
@@ -304,7 +304,6 @@ pub struct HirDisplayWrapper<'a, T> {
 pub enum ClosureStyle {
     /// `impl FnX(i32, i32) -> i32`, where `FnX` is the most special trait between `Fn`, `FnMut`, `FnOnce` that the
     /// closure implements. This is the default.
-    // FIXME: Allow rendering non capturing closures as plain function pointers?
     ImplFn,
     /// `|i32, i32| -> i32`
     RANotation,
diff --git a/crates/hir-ty/src/infer/closure.rs b/crates/hir-ty/src/infer/closure.rs
index a2c72e5751df..6d03c76eb6ab 100644
--- a/crates/hir-ty/src/infer/closure.rs
+++ b/crates/hir-ty/src/infer/closure.rs
@@ -170,23 +170,7 @@ impl CapturedItem {
         self.kind
     }
 
-    pub fn display_kind(&self) -> &'static str {
-        match self.kind {
-            CaptureKind::ByRef(k) => match k {
-                BorrowKind::Shared => "immutable borrow",
-                BorrowKind::Shallow => {
-                    never!("shallow borrow should not happen in closure captures");
-                    "shallow borrow"
-                },
-                BorrowKind::Unique => "unique immutable borrow ([read more](https://doc.rust-lang.org/stable/reference/types/closure.html#unique-immutable-borrows-in-captures))",
-                BorrowKind::Mut { .. } => "mutable borrow",
-            },
-            CaptureKind::ByValue => "move",
-        }
-    }
-
-    pub fn display_place(&self, owner: ClosureId, db: &dyn HirDatabase) -> String {
-        let owner = db.lookup_intern_closure(owner.into()).0;
+    pub fn display_place(&self, owner: DefWithBodyId, db: &dyn HirDatabase) -> String {
         let body = db.body(owner);
         let mut result = body[self.place.local].name.to_string();
         let mut field_need_paren = false;
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 84608777054f..1fac95ae5e37 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -3214,7 +3214,11 @@ impl Closure {
         let owner = db.lookup_intern_closure((self.id).into()).0;
         let infer = &db.infer(owner);
         let info = infer.closure_info(&self.id);
-        info.0.iter().cloned().map(|capture| ClosureCapture { owner, capture }).collect()
+        info.0
+            .iter()
+            .cloned()
+            .map(|capture| ClosureCapture { owner, closure: self.id, capture })
+            .collect()
     }
 
     pub fn fn_trait(&self, db: &dyn HirDatabase) -> FnTrait {
@@ -3228,6 +3232,7 @@ impl Closure {
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct ClosureCapture {
     owner: DefWithBodyId,
+    closure: ClosureId,
     capture: hir_ty::CapturedItem,
 }
 
@@ -3251,12 +3256,8 @@ impl ClosureCapture {
         }
     }
 
-    pub fn display_kind(&self) -> &'static str {
-        self.capture.display_kind()
-    }
-
-    pub fn display_place(&self, owner: ClosureId, db: &dyn HirDatabase) -> String {
-        self.capture.display_place(owner, db)
+    pub fn display_place(&self, db: &dyn HirDatabase) -> String {
+        self.capture.display_place(self.owner, db)
     }
 }
 
diff --git a/crates/ide/src/hover/render.rs b/crates/ide/src/hover/render.rs
index 8f8cdcce515c..9bbedec44a2d 100644
--- a/crates/ide/src/hover/render.rs
+++ b/crates/ide/src/hover/render.rs
@@ -3,7 +3,8 @@ use std::fmt::Display;
 
 use either::Either;
 use hir::{
-    Adt, AsAssocItem, AttributeTemplate, HasAttrs, HasSource, HirDisplay, Semantics, TypeInfo,
+    Adt, AsAssocItem, AttributeTemplate, CaptureKind, HasAttrs, HasSource, HirDisplay, Semantics,
+    TypeInfo,
 };
 use ide_db::{
     base_db::SourceDatabase,
@@ -54,8 +55,14 @@ pub(super) fn closure_expr(
     let mut captures = c
         .captured_items(sema.db)
         .into_iter()
-        .map(|x| {
-            format!("* `{}` by {}", x.display_place(c.clone().into(), sema.db), x.display_kind())
+        .map(|it| {
+            let borrow_kind=   match it.kind() {
+                CaptureKind::SharedRef => "immutable borrow",
+                CaptureKind::UniqueSharedRef => "unique immutable borrow ([read more](https://doc.rust-lang.org/stable/reference/types/closure.html#unique-immutable-borrows-in-captures))",
+                CaptureKind::MutableRef => "mutable borrow",
+                CaptureKind::Move => "move",
+            };
+            format!("* `{}` by {}", it.display_place(sema.db), borrow_kind)
         })
         .join("\n");
     if captures.trim().is_empty() {
diff --git a/crates/ide/src/inlay_hints/closure_captures.rs b/crates/ide/src/inlay_hints/closure_captures.rs
index d7e5332c41da..60c4fe411f4f 100644
--- a/crates/ide/src/inlay_hints/closure_captures.rs
+++ b/crates/ide/src/inlay_hints/closure_captures.rs
@@ -65,7 +65,7 @@ pub(super) fn hints(
                         hir::CaptureKind::MutableRef => "&mut ",
                         hir::CaptureKind::Move => "",
                     },
-                    local.name(sema.db)
+                    capture.display_place(sema.db)
                 ),
                 None,
                 source.name().and_then(|name| sema.original_range_opt(name.syntax())),
@@ -156,13 +156,12 @@ fn main() {
 // ^ )
         &mut baz;
     };
-    // FIXME: &mut qux should be &unique qux
     || {
 // ^ move
 // ^ (
 // ^ &mut baz
 // ^ , $
-// ^ &mut qux
+// ^ &mut *qux
 // ^ )
         baz = NonCopy;
         *qux = NonCopy;