12 files changed, 345 insertions, 154 deletions

diff --git a/crates/ide_completion/src/completions/dot.rs b/crates/ide_completion/src/completions/dot.rs
index 5ee9a9f07..cec2d0c3a 100644
--- a/crates/ide_completion/src/completions/dot.rs
+++ b/crates/ide_completion/src/completions/dot.rs
@@ -81,7 +81,7 @@ fn foo(s: S) { s.$0 }
 "#,
             expect![[r#"
                 fd foo   u32
-                me bar() -> ()
+                me bar() fn(&self)
             "#]],
         );
     }
@@ -97,7 +97,7 @@ impl S {
 "#,
             expect![[r#"
                 fd the_field (u32,)
-                me foo()     -> ()
+                me foo()     fn(self)
             "#]],
         )
     }
@@ -113,7 +113,7 @@ impl A {
 "#,
             expect![[r#"
                 fd the_field (u32, i32)
-                me foo()     -> ()
+                me foo()     fn(&self)
             "#]],
         )
     }
@@ -163,7 +163,7 @@ mod m {
 fn foo(a: A) { a.$0 }
 "#,
             expect![[r#"
-                me the_method() -> ()
+                me the_method() fn(&self)
             "#]],
         );
     }
@@ -196,7 +196,7 @@ impl A<i32> {
 fn foo(a: A<u32>) { a.$0 }
 "#,
             expect![[r#"
-                me the_method() -> ()
+                me the_method() fn(&self)
             "#]],
         )
     }
@@ -211,7 +211,7 @@ impl Trait for A {}
 fn foo(a: A) { a.$0 }
 "#,
             expect![[r#"
-                me the_method() -> ()
+                me the_method() fn(&self)
             "#]],
         );
     }
@@ -226,7 +226,7 @@ impl<T> Trait for T {}
 fn foo(a: &A) { a.$0 }
 ",
             expect![[r#"
-                me the_method() -> ()
+                me the_method() fn(&self)
             "#]],
         );
     }
@@ -244,7 +244,7 @@ impl Trait for A {}
 fn foo(a: A) { a.$0 }
 ",
             expect![[r#"
-                me the_method() -> ()
+                me the_method() fn(&self)
             "#]],
         );
     }
@@ -298,7 +298,7 @@ impl T {
 }
 "#,
             expect![[r#"
-                me blah() -> ()
+                me blah() fn(&self)
             "#]],
         );
     }
@@ -407,7 +407,7 @@ fn foo() {
 }
 "#,
             expect![[r#"
-                me the_method() -> ()
+                me the_method() fn(&self)
             "#]],
         );
     }
@@ -422,7 +422,7 @@ macro_rules! make_s { () => { S }; }
 fn main() { make_s!().f$0; }
 "#,
             expect![[r#"
-                me foo() -> ()
+                me foo() fn(&self)
             "#]],
         )
     }
@@ -450,7 +450,7 @@ mod foo {
 }
         "#,
             expect![[r#"
-                me private() -> ()
+                me private() fn(&self)
             "#]],
         );
     }
diff --git a/crates/ide_completion/src/completions/flyimport.rs b/crates/ide_completion/src/completions/flyimport.rs
index 391a11c91..08df2df3f 100644
--- a/crates/ide_completion/src/completions/flyimport.rs
+++ b/crates/ide_completion/src/completions/flyimport.rs
@@ -402,7 +402,7 @@ fn main() {
         check(
             fixture,
             expect![[r#"
-                fn weird_function() (dep::test_mod::TestTrait) -> ()
+                fn weird_function() (dep::test_mod::TestTrait) fn()
             "#]],
         );
 
@@ -495,7 +495,7 @@ fn main() {
         check(
             fixture,
             expect![[r#"
-                me random_method() (dep::test_mod::TestTrait) -> ()
+                me random_method() (dep::test_mod::TestTrait) fn(&self)
             "#]],
         );
 
@@ -665,7 +665,7 @@ fn main() {
 }
         "#,
             expect![[r#"
-                me random_method() (dep::test_mod::TestTrait) -> () DEPRECATED
+                me random_method() (dep::test_mod::TestTrait) fn(&self) DEPRECATED
             "#]],
         );
 
@@ -696,7 +696,7 @@ fn main() {
 "#,
             expect![[r#"
                 ct SPECIAL_CONST (dep::test_mod::TestTrait) DEPRECATED
-                fn weird_function() (dep::test_mod::TestTrait) -> () DEPRECATED
+                fn weird_function() (dep::test_mod::TestTrait) fn() DEPRECATED
             "#]],
         );
     }
diff --git a/crates/ide_completion/src/completions/fn_param.rs b/crates/ide_completion/src/completions/fn_param.rs
index 0243dce56..0ea558489 100644
--- a/crates/ide_completion/src/completions/fn_param.rs
+++ b/crates/ide_completion/src/completions/fn_param.rs
@@ -33,7 +33,7 @@ pub(crate) fn complete_fn_param(acc: &mut Completions, ctx: &CompletionContext)
         });
     };
 
-    for node in ctx.token.parent().ancestors() {
+    for node in ctx.token.ancestors() {
         match_ast! {
             match node {
                 ast::SourceFile(it) => it.items().filter_map(|item| match item {
diff --git a/crates/ide_completion/src/completions/qualified_path.rs b/crates/ide_completion/src/completions/qualified_path.rs
index df74b739e..105ff6013 100644
--- a/crates/ide_completion/src/completions/qualified_path.rs
+++ b/crates/ide_completion/src/completions/qualified_path.rs
@@ -359,8 +359,8 @@ impl S {
 fn foo() { let _ = S::$0 }
 "#,
             expect![[r#"
-                fn a()  -> ()
-                me b(…) -> ()
+                fn a()  fn()
+                me b(…) fn(&self)
                 ct C    const C: i32 = 42;
                 ta T    type T = i32;
             "#]],
@@ -387,7 +387,7 @@ mod m {
 fn foo() { let _ = S::$0 }
 "#,
             expect![[r#"
-                fn public_method() -> ()
+                fn public_method() fn()
                 ct PUBLIC_CONST    pub(crate) const PUBLIC_CONST: u32 = 1;
                 ta PublicType      pub(crate) type PublicType = u32;
             "#]],
@@ -404,7 +404,7 @@ impl E { fn m() { } }
 fn foo() { let _ = E::$0 }
         "#,
             expect![[r#"
-                fn m() -> ()
+                fn m() fn()
             "#]],
         );
     }
@@ -419,7 +419,7 @@ impl U { fn m() { } }
 fn foo() { let _ = U::$0 }
 "#,
             expect![[r#"
-                fn m() -> ()
+                fn m() fn()
             "#]],
         );
     }
@@ -449,7 +449,7 @@ trait Trait { fn m(); }
 fn foo() { let _ = Trait::$0 }
 "#,
             expect![[r#"
-                fn m() -> ()
+                fn m() fn()
             "#]],
         );
     }
@@ -466,7 +466,7 @@ impl Trait for S {}
 fn foo() { let _ = S::$0 }
 "#,
             expect![[r#"
-                fn m() -> ()
+                fn m() fn()
             "#]],
         );
     }
@@ -483,7 +483,7 @@ impl Trait for S {}
 fn foo() { let _ = <S as Trait>::$0 }
 "#,
             expect![[r#"
-                fn m() -> ()
+                fn m() fn()
             "#]],
         );
     }
@@ -512,11 +512,11 @@ fn foo<T: Sub>() { T::$0 }
                 ta SubTy        type SubTy;
                 ta Ty           type Ty;
                 ct C2           const C2: ();
-                fn subfunc()    -> ()
-                me submethod(…) -> ()
+                fn subfunc()    fn()
+                me submethod(…) fn(&self)
                 ct CONST        const CONST: u8;
-                fn func()       -> ()
-                me method(…)    -> ()
+                fn func()       fn()
+                me method(…)    fn(&self)
             "#]],
         );
     }
@@ -552,11 +552,11 @@ impl<T> Sub for Wrap<T> {
                 ta SubTy        type SubTy;
                 ta Ty           type Ty;
                 ct CONST        const CONST: u8 = 0;
-                fn func()       -> ()
-                me method(…)    -> ()
+                fn func()       fn()
+                me method(…)    fn(&self)
                 ct C2           const C2: () = ();
-                fn subfunc()    -> ()
-                me submethod(…) -> ()
+                fn subfunc()    fn()
+                me submethod(…) fn(&self)
             "#]],
         );
     }
@@ -573,8 +573,8 @@ impl T { fn bar() {} }
 fn main() { T::$0; }
 "#,
             expect![[r#"
-                fn foo() -> ()
-                fn bar() -> ()
+                fn foo() fn()
+                fn bar() fn()
             "#]],
         );
     }
@@ -589,7 +589,7 @@ macro_rules! foo { () => {} }
 fn main() { let _ = crate::$0 }
         "#,
             expect![[r##"
-                fn main()  -> ()
+                fn main()  fn()
                 ma foo!(…) #[macro_export] macro_rules! foo
             "##]],
         );
@@ -633,7 +633,7 @@ mod p {
 "#,
             expect![[r#"
                 ct RIGHT_CONST
-                fn right_fn()  -> ()
+                fn right_fn()  fn()
                 st RightType
             "#]],
         );
@@ -680,8 +680,8 @@ fn main() { m!(self::f$0); }
 fn foo() {}
 "#,
             expect![[r#"
-                fn main() -> ()
-                fn foo()  -> ()
+                fn main() fn()
+                fn foo()  fn()
             "#]],
         );
     }
@@ -699,7 +699,7 @@ mod m {
 "#,
             expect![[r#"
                 md z
-                fn z() -> ()
+                fn z() fn()
             "#]],
         );
     }
@@ -719,7 +719,7 @@ fn foo() {
 }
 "#,
             expect![[r#"
-                fn new() -> HashMap<K, V, RandomState>
+                fn new() fn() -> HashMap<K, V, RandomState>
             "#]],
         );
     }
@@ -752,8 +752,8 @@ fn main() {
 }
 "#,
             expect![[r#"
-                fn main() -> ()
-                fn foo(…) -> ()
+                fn main() fn()
+                fn foo(…) fn(i32, i32)
             "#]],
         );
     }
@@ -776,7 +776,7 @@ impl Foo {
             expect![[r#"
                 ev Bar    ()
                 ev Baz    ()
-                me foo(…) -> ()
+                me foo(…) fn(self)
             "#]],
         );
     }
@@ -800,7 +800,7 @@ impl u8 {
 "#,
             expect![[r#"
                 ct MAX     pub const MAX: Self = 255;
-                me func(…) -> ()
+                me func(…) fn(self)
             "#]],
         );
     }
diff --git a/crates/ide_completion/src/completions/trait_impl.rs b/crates/ide_completion/src/completions/trait_impl.rs
index 5a7361f8e..a26fe7c6c 100644
--- a/crates/ide_completion/src/completions/trait_impl.rs
+++ b/crates/ide_completion/src/completions/trait_impl.rs
@@ -82,13 +82,14 @@ pub(crate) fn complete_trait_impl(acc: &mut Completions, ctx: &CompletionContext
 
 fn completion_match(ctx: &CompletionContext) -> Option<(ImplCompletionKind, SyntaxNode, Impl)> {
     let mut token = ctx.token.clone();
-    // For keywork without name like `impl .. { fn $0 }`, the current position is inside
+    // For keyword without name like `impl .. { fn $0 }`, the current position is inside
     // the whitespace token, which is outside `FN` syntax node.
     // We need to follow the previous token in this case.
     if token.kind() == SyntaxKind::WHITESPACE {
         token = token.prev_token()?;
     }
 
+    let parent_kind = token.parent().map_or(SyntaxKind::EOF, |it| it.kind());
     let impl_item_offset = match token.kind() {
         // `impl .. { const $0 }`
         // ERROR      0
@@ -102,14 +103,14 @@ fn completion_match(ctx: &CompletionContext) -> Option<(ImplCompletionKind, Synt
         // FN/TYPE_ALIAS/CONST  1
         //  NAME                0
         //    IDENT             <- *
-        SyntaxKind::IDENT if token.parent().kind() == SyntaxKind::NAME => 1,
+        SyntaxKind::IDENT if parent_kind == SyntaxKind::NAME => 1,
         // `impl .. { foo$0 }`
         // MACRO_CALL       3
         //  PATH            2
         //    PATH_SEGMENT  1
         //      NAME_REF    0
         //        IDENT     <- *
-        SyntaxKind::IDENT if token.parent().kind() == SyntaxKind::NAME_REF => 3,
+        SyntaxKind::IDENT if parent_kind == SyntaxKind::NAME_REF => 3,
         _ => return None,
     };
 
diff --git a/crates/ide_completion/src/completions/unqualified_path.rs b/crates/ide_completion/src/completions/unqualified_path.rs
index 5ef80f6a7..1b8b063e7 100644
--- a/crates/ide_completion/src/completions/unqualified_path.rs
+++ b/crates/ide_completion/src/completions/unqualified_path.rs
@@ -135,7 +135,7 @@ fn quux(x: i32) {
             expect![[r#"
                 lc y       i32
                 lc x       i32
-                fn quux(…) -> ()
+                fn quux(…) fn(i32)
             "#]],
         );
     }
@@ -157,7 +157,7 @@ fn quux() {
             expect![[r#"
                 lc b      i32
                 lc a
-                fn quux() -> ()
+                fn quux() fn()
             "#]],
         );
     }
@@ -172,7 +172,7 @@ fn quux() {
 "#,
             expect![[r#"
                 lc x
-                fn quux() -> ()
+                fn quux() fn()
             "#]],
         );
     }
@@ -203,14 +203,14 @@ fn main() {
             r#"fn quux<T>() { $0 }"#,
             expect![[r#"
                 tp T
-                fn quux() -> ()
+                fn quux() fn()
             "#]],
         );
         check(
             r#"fn quux<const C: usize>() { $0 }"#,
             expect![[r#"
                 cp C
-                fn quux() -> ()
+                fn quux() fn()
             "#]],
         );
     }
@@ -221,7 +221,7 @@ fn main() {
         check(
             r#"fn quux<'a>() { $0 }"#,
             expect![[r#"
-                fn quux() -> ()
+                fn quux() fn()
             "#]],
         );
     }
@@ -259,7 +259,7 @@ fn quux() { $0 }
 "#,
             expect![[r#"
                 st S
-                fn quux() -> ()
+                fn quux() fn()
                 en E
             "#]],
         );
@@ -312,7 +312,7 @@ mod m {
 }
 "#,
             expect![[r#"
-                fn quux() -> ()
+                fn quux() fn()
                 st Bar
             "#]],
         );
@@ -327,7 +327,7 @@ fn x() -> $0
 "#,
             expect![[r#"
                 st Foo
-                fn x() -> ()
+                fn x() fn()
             "#]],
         );
     }
@@ -348,7 +348,7 @@ fn foo() {
             expect![[r#"
                 lc bar   i32
                 lc bar   i32
-                fn foo() -> ()
+                fn foo() fn()
             "#]],
         );
     }
@@ -378,7 +378,7 @@ use prelude::*;
 mod prelude { struct Option; }
 "#,
             expect![[r#"
-                fn foo()  -> ()
+                fn foo()  fn()
                 md std
                 st Option
             "#]],
@@ -408,7 +408,7 @@ mod macros {
 }
 "#,
             expect![[r##"
-                fn f()        -> ()
+                fn f()        fn()
                 ma concat!(…) #[macro_export] macro_rules! concat
                 md std
             "##]],
@@ -435,7 +435,7 @@ use prelude::*;
 mod prelude { struct String; }
 "#,
             expect![[r#"
-                fn foo()  -> ()
+                fn foo()  fn()
                 md std
                 md core
                 st String
@@ -466,7 +466,7 @@ fn main() { let v = $0 }
             expect![[r##"
                 md m1
                 ma baz!(…) #[macro_export] macro_rules! baz
-                fn main()  -> ()
+                fn main()  fn()
                 md m2
                 ma bar!(…) macro_rules! bar
                 ma foo!(…) macro_rules! foo
@@ -482,7 +482,7 @@ macro_rules! foo { () => {} }
 fn foo() { $0 }
 "#,
             expect![[r#"
-                fn foo()   -> ()
+                fn foo()   fn()
                 ma foo!(…) macro_rules! foo
             "#]],
         );
@@ -496,7 +496,7 @@ macro_rules! foo { () => {} }
 fn main() { let x: $0 }
 "#,
             expect![[r#"
-                fn main()  -> ()
+                fn main()  fn()
                 ma foo!(…) macro_rules! foo
             "#]],
         );
@@ -510,7 +510,7 @@ macro_rules! foo { () => {} }
 fn main() { $0 }
 "#,
             expect![[r#"
-                fn main()  -> ()
+                fn main()  fn()
                 ma foo!(…) macro_rules! foo
             "#]],
         );
@@ -526,8 +526,8 @@ fn main() {
 }
 "#,
             expect![[r#"
-                fn frobnicate() -> ()
-                fn main()       -> ()
+                fn frobnicate() fn()
+                fn main()       fn()
             "#]],
         );
     }
@@ -545,7 +545,7 @@ fn quux(x: i32) {
             expect![[r#"
                 lc y       i32
                 lc x       i32
-                fn quux(…) -> ()
+                fn quux(…) fn(i32)
                 ma m!(…)   macro_rules! m
             "#]],
         );
@@ -564,7 +564,7 @@ fn quux(x: i32) {
             expect![[r#"
                 lc y       i32
                 lc x       i32
-                fn quux(…) -> ()
+                fn quux(…) fn(i32)
                 ma m!(…)   macro_rules! m
             "#]],
         );
@@ -583,7 +583,7 @@ fn quux(x: i32) {
             expect![[r#"
                 lc y       i32
                 lc x       i32
-                fn quux(…) -> ()
+                fn quux(…) fn(i32)
                 ma m!(…)   macro_rules! m
             "#]],
         );
@@ -598,7 +598,7 @@ use spam::Quux;
 fn main() { $0 }
 "#,
             expect![[r#"
-                fn main() -> ()
+                fn main() fn()
                 ?? Quux
             "#]],
         );
@@ -616,7 +616,7 @@ fn main() { let foo: Foo = Q$0 }
                 ev Foo::Baz  ()
                 ev Foo::Quux ()
                 en Foo
-                fn main()    -> ()
+                fn main()    fn()
             "#]],
         )
     }
@@ -631,7 +631,7 @@ fn f() -> m::E { V$0 }
             expect![[r#"
                 ev m::E::V ()
                 md m
-                fn f()     -> E
+                fn f()     fn() -> E
             "#]],
         )
     }
diff --git a/crates/ide_completion/src/context.rs b/crates/ide_completion/src/context.rs
index 5a081de7e..6d57da06a 100644
--- a/crates/ide_completion/src/context.rs
+++ b/crates/ide_completion/src/context.rs
@@ -120,7 +120,7 @@ impl<'a> CompletionContext<'a> {
         let original_token =
             original_file.syntax().token_at_offset(position.offset).left_biased()?;
         let token = sema.descend_into_macros(original_token.clone());
-        let scope = sema.scope_at_offset(&token.parent(), position.offset);
+        let scope = sema.scope_at_offset(&token, position.offset);
         let mut locals = vec![];
         scope.process_all_names(&mut |name, scope| {
             if let ScopeDef::Local(local) = scope {
@@ -281,7 +281,7 @@ impl<'a> CompletionContext<'a> {
     fn fill_impl_def(&mut self) {
         self.impl_def = self
             .sema
-            .ancestors_with_macros(self.token.parent())
+            .token_ancestors_with_macros(self.token.clone())
             .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
             .find_map(ast::Impl::cast);
     }
@@ -293,7 +293,10 @@ impl<'a> CompletionContext<'a> {
         offset: TextSize,
     ) {
         let expected = {
-            let mut node = self.token.parent();
+            let mut node = match self.token.parent() {
+                Some(it) => it,
+                None => return,
+            };
             loop {
                 let ret = match_ast! {
                     match node {
@@ -474,17 +477,17 @@ impl<'a> CompletionContext<'a> {
         }
 
         self.use_item_syntax =
-            self.sema.ancestors_with_macros(self.token.parent()).find_map(ast::Use::cast);
+            self.sema.token_ancestors_with_macros(self.token.clone()).find_map(ast::Use::cast);
 
         self.function_syntax = self
             .sema
-            .ancestors_with_macros(self.token.parent())
+            .token_ancestors_with_macros(self.token.clone())
             .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
             .find_map(ast::Fn::cast);
 
         self.record_field_syntax = self
             .sema
-            .ancestors_with_macros(self.token.parent())
+            .token_ancestors_with_macros(self.token.clone())
             .take_while(|it| {
                 it.kind() != SOURCE_FILE && it.kind() != MODULE && it.kind() != CALL_EXPR
             })
diff --git a/crates/ide_completion/src/lib.rs b/crates/ide_completion/src/lib.rs
index 263554ecf..5b7ad38d5 100644
--- a/crates/ide_completion/src/lib.rs
+++ b/crates/ide_completion/src/lib.rs
@@ -230,7 +230,7 @@ fn foo() {
     bar.fo$0;
 }
 "#,
-            DetailAndDocumentation { detail: "-> ()", documentation: "Do the foo" },
+            DetailAndDocumentation { detail: "fn(&self)", documentation: "Do the foo" },
         );
     }
 
@@ -255,7 +255,7 @@ fn foo() {
     bar.fo$0;
 }
 "#,
-            DetailAndDocumentation { detail: "-> ()", documentation: " Do the foo" },
+            DetailAndDocumentation { detail: "fn(&self)", documentation: " Do the foo" },
         );
     }
 
@@ -273,7 +273,7 @@ fn bar() {
     for c in fo$0
 }
 "#,
-            DetailAndDocumentation { detail: "-> &str", documentation: "Do the foo" },
+            DetailAndDocumentation { detail: "fn() -> &str", documentation: "Do the foo" },
         );
     }
 }
diff --git a/crates/ide_completion/src/patterns.rs b/crates/ide_completion/src/patterns.rs
index f3ce91dd1..cf5ef07b7 100644
--- a/crates/ide_completion/src/patterns.rs
+++ b/crates/ide_completion/src/patterns.rs
@@ -184,11 +184,7 @@ fn test_has_impl_as_prev_sibling() {
 }
 
 pub(crate) fn is_in_loop_body(element: SyntaxElement) -> bool {
-    let leaf = match element {
-        NodeOrToken::Node(node) => node,
-        NodeOrToken::Token(token) => token.parent(),
-    };
-    for node in leaf.ancestors() {
+    for node in element.ancestors() {
         if node.kind() == FN || node.kind() == CLOSURE_EXPR {
             break;
         }
@@ -201,7 +197,7 @@ pub(crate) fn is_in_loop_body(element: SyntaxElement) -> bool {
             }
         };
         if let Some(body) = loop_body {
-            if body.syntax().text_range().contains_range(leaf.text_range()) {
+            if body.syntax().text_range().contains_range(element.text_range()) {
                 return true;
             }
         }
@@ -235,12 +231,8 @@ fn previous_sibling_or_ancestor_sibling(element: SyntaxElement) -> Option<Syntax
         Some(sibling)
     } else {
         // if not trying to find first ancestor which has such a sibling
-        let node = match element {
-            NodeOrToken::Node(node) => node,
-            NodeOrToken::Token(token) => token.parent(),
-        };
-        let range = node.text_range();
-        let top_node = node.ancestors().take_while(|it| it.text_range() == range).last()?;
+        let range = element.text_range();
+        let top_node = element.ancestors().take_while(|it| it.text_range() == range).last()?;
         let prev_sibling_node = top_node.ancestors().find(|it| {
             non_trivia_sibling(NodeOrToken::Node(it.to_owned()), Direction::Prev).is_some()
         })?;
diff --git a/crates/ide_completion/src/render.rs b/crates/ide_completion/src/render.rs
index 2514dda7c..36655667c 100644
--- a/crates/ide_completion/src/render.rs
+++ b/crates/ide_completion/src/render.rs
@@ -10,10 +10,8 @@ pub(crate) mod type_alias;
 
 mod builder_ext;
 
-use base_db::Upcast;
 use hir::{
-    db::HirDatabase, AsAssocItem, Documentation, HasAttrs, HirDisplay, ModuleDef, Mutability,
-    ScopeDef, Type,
+    AsAssocItem, Documentation, HasAttrs, HirDisplay, ModuleDef, Mutability, ScopeDef, Type,
 };
 use ide_db::{
     helpers::{item_name, SnippetCap},
@@ -22,8 +20,8 @@ use ide_db::{
 use syntax::TextRange;
 
 use crate::{
-    item::{CompletionRelevance, ImportEdit},
-    CompletionContext, CompletionItem, CompletionItemKind, CompletionKind,
+    item::ImportEdit, CompletionContext, CompletionItem, CompletionItemKind, CompletionKind,
+    CompletionRelevance,
 };
 
 use crate::render::{enum_variant::render_variant, function::render_fn, macro_::render_macro};
@@ -144,7 +142,15 @@ impl<'a> Render<'a> {
             .set_documentation(field.docs(self.ctx.db()))
             .set_deprecated(is_deprecated);
 
-        item.set_relevance(compute_relevance(&self.ctx, &ty, &name.to_string()));
+        item.set_relevance(CompletionRelevance {
+            exact_type_match: compute_exact_type_match(self.ctx.completion, ty),
+            exact_name_match: compute_exact_name_match(self.ctx.completion, name.to_string()),
+            ..CompletionRelevance::default()
+        });
+
+        if let Some(ref_match) = compute_ref_match(self.ctx.completion, ty) {
+            item.ref_match(ref_match);
+        }
 
         item.build()
     }
@@ -234,31 +240,18 @@ impl<'a> Render<'a> {
             if !ty.is_unknown() {
                 item.detail(ty.display(self.ctx.db()).to_string());
             }
-        };
 
-        if let ScopeDef::Local(local) = resolution {
-            let ty = local.ty(self.ctx.db());
+            item.set_relevance(CompletionRelevance {
+                exact_type_match: compute_exact_type_match(self.ctx.completion, &ty),
+                exact_name_match: compute_exact_name_match(self.ctx.completion, local_name.clone()),
+                is_local: true,
+                ..CompletionRelevance::default()
+            });
 
-            let mut relevance = compute_relevance(&self.ctx, &ty, &local_name);
-            relevance.is_local = true;
-            item.set_relevance(relevance);
-
-            if let Some(expected_type) = self.ctx.completion.expected_type.as_ref() {
-                if &ty != expected_type {
-                    if let Some(ty_without_ref) = expected_type.remove_ref() {
-                        if relevance_type_match(self.ctx.db().upcast(), &ty, &ty_without_ref) {
-                            cov_mark::hit!(suggest_ref);
-                            let mutability = if expected_type.is_mutable_reference() {
-                                Mutability::Mut
-                            } else {
-                                Mutability::Shared
-                            };
-                            item.ref_match(mutability);
-                        }
-                    }
-                }
+            if let Some(ref_match) = compute_ref_match(self.ctx.completion, &ty) {
+                item.ref_match(ref_match);
             }
-        }
+        };
 
         // Add `<>` for generic types
         if self.ctx.completion.is_path_type
@@ -313,17 +306,44 @@ impl<'a> Render<'a> {
     }
 }
 
-fn compute_relevance(ctx: &RenderContext, ty: &Type, name: &str) -> CompletionRelevance {
-    let mut res = CompletionRelevance::default();
+fn compute_exact_type_match(ctx: &CompletionContext, completion_ty: &hir::Type) -> bool {
+    if let Some(expected_type) = ctx.expected_type.as_ref() {
+        // We don't ever consider unit type to be an exact type match, since
+        // nearly always this is not meaningful to the user.
+        completion_ty == expected_type && !expected_type.is_unit()
+    } else {
+        false
+    }
+}
 
-    res.exact_type_match = Some(ty) == ctx.completion.expected_type.as_ref();
-    res.exact_name_match = Some(name) == ctx.completion.expected_name.as_deref();
+fn compute_exact_name_match(ctx: &CompletionContext, completion_name: impl Into<String>) -> bool {
+    let completion_name = completion_name.into();
 
-    res
+    Some(&completion_name) == ctx.expected_name.as_ref()
 }
 
-fn relevance_type_match(db: &dyn HirDatabase, ty: &Type, expected_type: &Type) -> bool {
-    ty == expected_type || ty.autoderef(db).any(|deref_ty| &deref_ty == expected_type)
+fn compute_ref_match(ctx: &CompletionContext, completion_ty: &hir::Type) -> Option<Mutability> {
+    let mut ref_match = None;
+    if let Some(expected_type) = &ctx.expected_type {
+        if completion_ty != expected_type {
+            if let Some(expected_type_without_ref) = expected_type.remove_ref() {
+                if completion_ty == &expected_type_without_ref
+                    || completion_ty
+                        .autoderef(ctx.db)
+                        .any(|deref_ty| deref_ty == expected_type_without_ref)
+                {
+                    cov_mark::hit!(suggest_ref);
+                    let mutability = if expected_type.is_mutable_reference() {
+                        Mutability::Mut
+                    } else {
+                        Mutability::Shared
+                    };
+                    ref_match = Some(mutability);
+                }
+            }
+        }
+    };
+    ref_match
 }
 
 #[cfg(test)]
@@ -432,6 +452,44 @@ fn main() { Foo::Fo$0 }
     }
 
     #[test]
+    fn fn_detail_includes_args_and_return_type() {
+        check(
+            r#"
+fn foo<T>(a: u32, b: u32, t: T) -> (u32, T) { (a, t) }
+
+fn main() { fo$0 }
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "foo(…)",
+                        source_range: 68..70,
+                        delete: 68..70,
+                        insert: "foo(${1:a}, ${2:b}, ${3:t})$0",
+                        kind: SymbolKind(
+                            Function,
+                        ),
+                        lookup: "foo",
+                        detail: "fn(u32, u32, T) -> (u32, T)",
+                        trigger_call_info: true,
+                    },
+                    CompletionItem {
+                        label: "main()",
+                        source_range: 68..70,
+                        delete: 68..70,
+                        insert: "main()$0",
+                        kind: SymbolKind(
+                            Function,
+                        ),
+                        lookup: "main",
+                        detail: "fn()",
+                    },
+                ]
+            "#]],
+        );
+    }
+
+    #[test]
     fn enum_detail_just_parentheses_for_unit() {
         check(
             r#"
@@ -477,6 +535,11 @@ fn main() { let _: m::Spam = S$0 }
                         ),
                         lookup: "Spam::Bar",
                         detail: "(i32)",
+                        relevance: CompletionRelevance {
+                            exact_name_match: false,
+                            exact_type_match: true,
+                            is_local: false,
+                        },
                         trigger_call_info: true,
                     },
                     CompletionItem {
@@ -498,6 +561,11 @@ fn main() { let _: m::Spam = S$0 }
                         ),
                         lookup: "Spam::Foo",
                         detail: "()",
+                        relevance: CompletionRelevance {
+                            exact_name_match: false,
+                            exact_type_match: true,
+                            is_local: false,
+                        },
                     },
                     CompletionItem {
                         label: "main()",
@@ -508,7 +576,7 @@ fn main() { let _: m::Spam = S$0 }
                             Function,
                         ),
                         lookup: "main",
-                        detail: "-> ()",
+                        detail: "fn()",
                     },
                 ]
             "#]],
@@ -537,7 +605,7 @@ fn main() { som$0 }
                             Function,
                         ),
                         lookup: "main",
-                        detail: "-> ()",
+                        detail: "fn()",
                     },
                     CompletionItem {
                         label: "something_deprecated()",
@@ -548,7 +616,7 @@ fn main() { som$0 }
                             Function,
                         ),
                         lookup: "something_deprecated",
-                        detail: "-> ()",
+                        detail: "fn()",
                         deprecated: true,
                     },
                     CompletionItem {
@@ -560,7 +628,7 @@ fn main() { som$0 }
                             Function,
                         ),
                         lookup: "something_else_deprecated",
-                        detail: "-> ()",
+                        detail: "fn()",
                         deprecated: true,
                     },
                 ]
@@ -611,7 +679,7 @@ impl S {
                         insert: "bar()$0",
                         kind: Method,
                         lookup: "bar",
-                        detail: "-> ()",
+                        detail: "fn(self)",
                         documentation: Documentation(
                             "Method docs",
                         ),
@@ -711,7 +779,7 @@ fn foo(s: S) { s.$0 }
                         insert: "the_method()$0",
                         kind: Method,
                         lookup: "the_method",
-                        detail: "-> ()",
+                        detail: "fn(&self)",
                     },
                 ]
             "#]],
@@ -1019,7 +1087,7 @@ fn main() {
                             Function,
                         ),
                         lookup: "foo",
-                        detail: "-> ()",
+                        detail: "fn(&mut S)",
                         trigger_call_info: true,
                     },
                     CompletionItem {
@@ -1031,7 +1099,7 @@ fn main() {
                             Function,
                         ),
                         lookup: "main",
-                        detail: "-> ()",
+                        detail: "fn()",
                     },
                     CompletionItem {
                         label: "s",
@@ -1169,4 +1237,86 @@ fn foo(bar: u32) {
             "#]],
         );
     }
+
+    #[test]
+    fn enum_owned() {
+        check_relevance(
+            r#"
+enum Foo { A, B }
+fn foo() {
+    bar($0);
+}
+fn bar(t: Foo) {}
+"#,
+            expect![[r#"
+                ev Foo::A [type]
+                ev Foo::B [type]
+                en Foo []
+                fn bar(…) []
+                fn foo() []
+            "#]],
+        );
+    }
+
+    #[test]
+    fn enum_ref() {
+        check_relevance(
+            r#"
+enum Foo { A, B }
+fn foo() {
+    bar($0);
+}
+fn bar(t: &Foo) {}
+"#,
+            expect![[r#"
+                ev Foo::A []
+                ev &Foo::A [type]
+                ev Foo::B []
+                ev &Foo::B [type]
+                en Foo []
+                fn bar(…) []
+                fn foo() []
+            "#]],
+        );
+    }
+
+    #[test]
+    fn suggest_deref_fn_ret() {
+        check_relevance(
+            r#"
+#[lang = "deref"]
+trait Deref {
+    type Target;
+    fn deref(&self) -> &Self::Target;
+}
+
+struct S;
+struct T(S);
+
+impl Deref for T {
+    type Target = S;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+fn foo(s: &S) {}
+fn bar() -> T {}
+
+fn main() {
+    foo($0);
+}
+            "#,
+            expect![[r#"
+                tt Deref []
+                fn bar() []
+                fn &bar() [type]
+                fn foo(…) []
+                st T []
+                st S []
+                fn main() []
+            "#]],
+        )
+    }
 }
diff --git a/crates/ide_completion/src/render/enum_variant.rs b/crates/ide_completion/src/render/enum_variant.rs
index e8cfcc0c7..374247b05 100644
--- a/crates/ide_completion/src/render/enum_variant.rs
+++ b/crates/ide_completion/src/render/enum_variant.rs
@@ -6,7 +6,8 @@ use itertools::Itertools;
 
 use crate::{
     item::{CompletionItem, CompletionKind, ImportEdit},
-    render::{builder_ext::Params, RenderContext},
+    render::{builder_ext::Params, compute_exact_type_match, compute_ref_match, RenderContext},
+    CompletionRelevance,
 };
 
 pub(crate) fn render_variant<'a>(
@@ -74,6 +75,16 @@ impl<'a> EnumRender<'a> {
             item.lookup_by(self.short_qualified_name);
         }
 
+        let ty = self.variant.parent_enum(self.ctx.completion.db).ty(self.ctx.completion.db);
+        item.set_relevance(CompletionRelevance {
+            exact_type_match: compute_exact_type_match(self.ctx.completion, &ty),
+            ..CompletionRelevance::default()
+        });
+
+        if let Some(ref_match) = compute_ref_match(self.ctx.completion, &ty) {
+            item.ref_match(ref_match);
+        }
+
         item.build()
     }
 
diff --git a/crates/ide_completion/src/render/function.rs b/crates/ide_completion/src/render/function.rs
index 47e26a5d8..010303182 100644
--- a/crates/ide_completion/src/render/function.rs
+++ b/crates/ide_completion/src/render/function.rs
@@ -2,11 +2,15 @@
 
 use hir::{HasSource, HirDisplay, Type};
 use ide_db::SymbolKind;
+use itertools::Itertools;
 use syntax::ast::Fn;
 
 use crate::{
     item::{CompletionItem, CompletionItemKind, CompletionKind, CompletionRelevance, ImportEdit},
-    render::{builder_ext::Params, RenderContext},
+    render::{
+        builder_ext::Params, compute_exact_name_match, compute_exact_type_match, compute_ref_match,
+        RenderContext,
+    },
 };
 
 pub(crate) fn render_fn<'a>(
@@ -52,30 +56,60 @@ impl<'a> FunctionRender<'a> {
                 self.ctx.is_deprecated(self.func) || self.ctx.is_deprecated_assoc_item(self.func),
             )
             .detail(self.detail())
-            .add_call_parens(self.ctx.completion, self.name, params)
+            .add_call_parens(self.ctx.completion, self.name.clone(), params)
             .add_import(import_to_add);
 
-        let mut relevance = CompletionRelevance::default();
-        if let Some(expected_type) = &self.ctx.completion.expected_type {
-            let ret_ty = self.func.ret_type(self.ctx.db());
+        let ret_type = self.func.ret_type(self.ctx.db());
+        item.set_relevance(CompletionRelevance {
+            exact_type_match: compute_exact_type_match(self.ctx.completion, &ret_type),
+            exact_name_match: compute_exact_name_match(self.ctx.completion, self.name.clone()),
+            ..CompletionRelevance::default()
+        });
 
-            // We don't ever consider a function which returns unit type to be an
-            // exact type match, since nearly always this is not meaningful to the
-            // user.
-            relevance.exact_type_match = &ret_ty == expected_type && !ret_ty.is_unit();
+        if let Some(ref_match) = compute_ref_match(self.ctx.completion, &ret_type) {
+            item.ref_match(ref_match);
         }
-        if let Some(expected_name) = &self.ctx.completion.expected_name {
-            relevance.exact_name_match =
-                expected_name == &self.func.name(self.ctx.db()).to_string();
-        }
-        item.set_relevance(relevance);
 
         item.build()
     }
 
     fn detail(&self) -> String {
-        let ty = self.func.ret_type(self.ctx.db());
-        format!("-> {}", ty.display(self.ctx.db()))
+        let ret_ty = self.func.ret_type(self.ctx.db());
+        let ret = if ret_ty.is_unit() {
+            // Omit the return type if it is the unit type
+            String::new()
+        } else {
+            format!(" {}", self.ty_display())
+        };
+
+        format!("fn({}){}", self.params_display(), ret)
+    }
+
+    fn params_display(&self) -> String {
+        if let Some(self_param) = self.func.self_param(self.ctx.db()) {
+            let params = self
+                .func
+                .assoc_fn_params(self.ctx.db())
+                .into_iter()
+                .skip(1) // skip the self param because we are manually handling that
+                .map(|p| p.ty().display(self.ctx.db()).to_string());
+
+            std::iter::once(self_param.display(self.ctx.db()).to_owned()).chain(params).join(", ")
+        } else {
+            let params = self
+                .func
+                .assoc_fn_params(self.ctx.db())
+                .into_iter()
+                .map(|p| p.ty().display(self.ctx.db()).to_string())
+                .join(", ");
+            params
+        }
+    }
+
+    fn ty_display(&self) -> String {
+        let ret_ty = self.func.ret_type(self.ctx.db());
+
+        format!("-> {}", ret_ty.display(self.ctx.db()))
     }
 
     fn add_arg(&self, arg: &str, ty: &Type) -> String {