Compute closure captures

crates/ide/src/hover/tests.rs

@@ -225,7 +225,7 @@ fn main() {
                 *iter*
 
                 ```rust
-                let mut iter: Iter<Scan<OtherStruct<OtherStruct<i32>>, |&mut u32, &u32, &mut u32| -> Option<u32>, u32>>
+                let mut iter: Iter<Scan<OtherStruct<OtherStruct<i32>>, impl Fn(&mut u32, &u32, &mut u32) -> Option<u32>, u32>>
                 ```
             "#]],
     );

crates/ide/src/inlay_hints.rs

@@ -5,7 +5,8 @@ use std::{
 
 use either::Either;
 use hir::{
-    known, HasVisibility, HirDisplay, HirDisplayError, HirWrite, ModuleDef, ModuleDefId, Semantics,
+    known, ClosureStyle, HasVisibility, HirDisplay, HirDisplayError, HirWrite, ModuleDef,
+    ModuleDefId, Semantics,
 };
 use ide_db::{base_db::FileRange, famous_defs::FamousDefs, RootDatabase};
 use itertools::Itertools;
@@ -45,6 +46,7 @@ pub struct InlayHintsConfig {
     pub param_names_for_lifetime_elision_hints: bool,
     pub hide_named_constructor_hints: bool,
     pub hide_closure_initialization_hints: bool,
+    pub closure_style: ClosureStyle,
     pub max_length: Option<usize>,
     pub closing_brace_hints_min_lines: Option<usize>,
 }
@@ -291,6 +293,7 @@ fn label_of_ty(
         mut max_length: Option<usize>,
         ty: hir::Type,
         label_builder: &mut InlayHintLabelBuilder<'_>,
+        config: &InlayHintsConfig,
     ) -> Result<(), HirDisplayError> {
         let iter_item_type = hint_iterator(sema, famous_defs, &ty);
         match iter_item_type {
@@ -321,11 +324,14 @@ fn label_of_ty(
                 label_builder.write_str(LABEL_ITEM)?;
                 label_builder.end_location_link();
                 label_builder.write_str(LABEL_MIDDLE2)?;
-                rec(sema, famous_defs, max_length, ty, label_builder)?;
+                rec(sema, famous_defs, max_length, ty, label_builder, config)?;
                 label_builder.write_str(LABEL_END)?;
                 Ok(())
             }
-            None => ty.display_truncated(sema.db, max_length).write_to(label_builder),
+            None => ty
+                .display_truncated(sema.db, max_length)
+                .with_closure_style(config.closure_style)
+                .write_to(label_builder),
         }
     }
 
@@ -335,7 +341,7 @@ fn label_of_ty(
         location: None,
         result: InlayHintLabel::default(),
     };
-    let _ = rec(sema, famous_defs, config.max_length, ty, &mut label_builder);
+    let _ = rec(sema, famous_defs, config.max_length, ty, &mut label_builder, config);
     let r = label_builder.finish();
     Some(r)
 }
@@ -481,6 +487,7 @@ fn closure_has_block_body(closure: &ast::ClosureExpr) -> bool {
 #[cfg(test)]
 mod tests {
     use expect_test::Expect;
+    use hir::ClosureStyle;
     use itertools::Itertools;
     use test_utils::extract_annotations;
 
@@ -504,6 +511,7 @@ mod tests {
         binding_mode_hints: false,
         hide_named_constructor_hints: false,
         hide_closure_initialization_hints: false,
+        closure_style: ClosureStyle::ImplFn,
         param_names_for_lifetime_elision_hints: false,
         max_length: None,
         closing_brace_hints_min_lines: None,

crates/ide/src/inlay_hints/bind_pat.rs

@@ -176,6 +176,7 @@ fn pat_is_enum_variant(db: &RootDatabase, bind_pat: &ast::IdentPat, pat_ty: &hir
 mod tests {
     // This module also contains tests for super::closure_ret
 
+    use hir::ClosureStyle;
     use syntax::{TextRange, TextSize};
     use test_utils::extract_annotations;
 
@@ -235,7 +236,7 @@ fn main() {
     let zz_ref = &zz;
       //^^^^^^ &Test<i32>
     let test = || zz;
-      //^^^^ || -> Test<i32>
+      //^^^^ impl FnOnce() -> Test<i32>
 }"#,
         );
     }
@@ -753,7 +754,7 @@ fn main() {
     let func = times2;
     //  ^^^^ fn times2(i32) -> i32
     let closure = |x: i32| x * 2;
-    //  ^^^^^^^ |i32| -> i32
+    //  ^^^^^^^ impl Fn(i32) -> i32
 }
 
 fn fallible() -> ControlFlow<()> {
@@ -821,7 +822,7 @@ fn main() {
                    //^^^^^^^^^ i32
 
     let multiply =
-      //^^^^^^^^ |i32, i32| -> i32
+      //^^^^^^^^ impl Fn(i32, i32) -> i32
       | a,     b| a * b
       //^ i32  ^ i32
 
@@ -830,10 +831,10 @@ fn main() {
     let _: i32 = multiply(1,  2);
                         //^ a ^ b
     let multiply_ref = &multiply;
-      //^^^^^^^^^^^^ &|i32, i32| -> i32
+      //^^^^^^^^^^^^ &impl Fn(i32, i32) -> i32
 
     let return_42 = || 42;
-      //^^^^^^^^^ || -> i32
+      //^^^^^^^^^ impl Fn() -> i32
       || { 42 };
     //^^ i32
 }"#,
@@ -857,6 +858,94 @@ fn main() {
         );
     }
 
+    #[test]
+    fn closure_style() {
+        check_with_config(
+            InlayHintsConfig { type_hints: true, ..DISABLED_CONFIG },
+            r#"
+//- minicore: fn
+fn main() {
+    let x = || 2;
+      //^ impl Fn() -> i32
+    let y = |t: i32| x() + t;
+      //^ impl Fn(i32) -> i32
+    let mut t = 5;
+          //^ i32
+    let z = |k: i32| { t += k; };
+      //^ impl FnMut(i32)
+    let p = (y, z);
+      //^ (impl Fn(i32) -> i32, impl FnMut(i32))
+}
+            "#,
+        );
+        check_with_config(
+            InlayHintsConfig {
+                type_hints: true,
+                closure_style: ClosureStyle::RANotation,
+                ..DISABLED_CONFIG
+            },
+            r#"
+//- minicore: fn
+fn main() {
+    let x = || 2;
+      //^ || -> i32
+    let y = |t: i32| x() + t;
+      //^ |i32| -> i32
+    let mut t = 5;
+          //^ i32
+    let z = |k: i32| { t += k; };
+      //^ |i32| -> ()
+    let p = (y, z);
+      //^ (|i32| -> i32, |i32| -> ())
+}
+            "#,
+        );
+        check_with_config(
+            InlayHintsConfig {
+                type_hints: true,
+                closure_style: ClosureStyle::ClosureWithId,
+                ..DISABLED_CONFIG
+            },
+            r#"
+//- minicore: fn
+fn main() {
+    let x = || 2;
+      //^ {closure#0}
+    let y = |t: i32| x() + t;
+      //^ {closure#1}
+    let mut t = 5;
+          //^ i32
+    let z = |k: i32| { t += k; };
+      //^ {closure#2}
+    let p = (y, z);
+      //^ ({closure#1}, {closure#2})
+}
+            "#,
+        );
+        check_with_config(
+            InlayHintsConfig {
+                type_hints: true,
+                closure_style: ClosureStyle::Hide,
+                ..DISABLED_CONFIG
+            },
+            r#"
+//- minicore: fn
+fn main() {
+    let x = || 2;
+      //^ …
+    let y = |t: i32| x() + t;
+      //^ …
+    let mut t = 5;
+          //^ i32
+    let z = |k: i32| { t += k; };
+      //^ …
+    let p = (y, z);
+      //^ (…, …)
+}
+            "#,
+        );
+    }
+
     #[test]
     fn skip_closure_type_hints() {
         check_with_config(
@@ -871,13 +960,13 @@ fn main() {
     let multiple_2 = |x: i32| { x * 2 };
 
     let multiple_2 = |x: i32| x * 2;
-    //  ^^^^^^^^^^ |i32| -> i32
+    //  ^^^^^^^^^^ impl Fn(i32) -> i32
 
     let (not) = (|x: bool| { !x });
-    //   ^^^ |bool| -> bool
+    //   ^^^ impl Fn(bool) -> bool
 
     let (is_zero, _b) = (|x: usize| { x == 0 }, false);
-    //   ^^^^^^^ |usize| -> bool
+    //   ^^^^^^^ impl Fn(usize) -> bool
     //            ^^ bool
 
     let plus_one = |x| { x + 1 };

crates/ide/src/signature_help.rs

@@ -1227,6 +1227,24 @@ fn main() {
         )
     }
 
+    #[test]
+    fn call_info_for_fn_def_over_reference() {
+        check(
+            r#"
+struct S;
+fn foo(s: S) -> i32 { 92 }
+fn main() {
+    let bar = &&&&&foo;
+    bar($0);
+}
+        "#,
+            expect![[r#"
+                fn foo(s: S) -> i32
+                       ^^^^
+            "#]],
+        )
+    }
+
     #[test]
     fn call_info_for_fn_ptr() {
         check(

crates/ide/src/static_index.rs

@@ -118,6 +118,7 @@ impl StaticIndex<'_> {
                     adjustment_hints_hide_outside_unsafe: false,
                     hide_named_constructor_hints: false,
                     hide_closure_initialization_hints: false,
+                    closure_style: hir::ClosureStyle::ImplFn,
                     param_names_for_lifetime_elision_hints: false,
                     binding_mode_hints: false,
                     max_length: Some(25),