1 files changed, 187 insertions, 43 deletions

diff --git a/crates/ide_completion/src/render.rs b/crates/ide_completion/src/render.rs
index 2514dda7c..4e4923e0d 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 +306,38 @@ 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 {
+    match ctx.expected_type.as_ref() {
+        Some(expected_type) => {
+            // 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()
+        }
+        None => 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 expected_type = ctx.expected_type.as_ref()?;
+    if completion_ty != expected_type {
+        let expected_type_without_ref = expected_type.remove_ref()?;
+        if 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
+            };
+            return Some(mutability);
+        };
+    }
+    None
 }
 
 #[cfg(test)]
@@ -432,6 +446,44 @@ 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 +529,11 @@ 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 +555,11 @@ 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 +570,7 @@ fn main() { let _: m::Spam = S$0 }
                             Function,
                         ),
                         lookup: "main",
-                        detail: "-> ()",
+                        detail: "fn()",
                     },
                 ]
             "#]],
@@ -537,7 +599,7 @@ fn main() { som$0 }
                             Function,
                         ),
                         lookup: "main",
-                        detail: "-> ()",
+                        detail: "fn()",
                     },
                     CompletionItem {
                         label: "something_deprecated()",
@@ -548,7 +610,7 @@ fn main() { som$0 }
                             Function,
                         ),
                         lookup: "something_deprecated",
-                        detail: "-> ()",
+                        detail: "fn()",
                         deprecated: true,
                     },
                     CompletionItem {
@@ -560,7 +622,7 @@ fn main() { som$0 }
                             Function,
                         ),
                         lookup: "something_else_deprecated",
-                        detail: "-> ()",
+                        detail: "fn()",
                         deprecated: true,
                     },
                 ]
@@ -611,7 +673,7 @@ impl S {
                         insert: "bar()$0",
                         kind: Method,
                         lookup: "bar",
-                        detail: "-> ()",
+                        detail: "fn(self)",
                         documentation: Documentation(
                             "Method docs",
                         ),
@@ -711,7 +773,7 @@ fn foo(s: S) { s.$0 }
                         insert: "the_method()$0",
                         kind: Method,
                         lookup: "the_method",
-                        detail: "-> ()",
+                        detail: "fn(&self)",
                     },
                 ]
             "#]],
@@ -1019,7 +1081,7 @@ fn main() {
                             Function,
                         ),
                         lookup: "foo",
-                        detail: "-> ()",
+                        detail: "fn(&mut S)",
                         trigger_call_info: true,
                     },
                     CompletionItem {
@@ -1031,7 +1093,7 @@ fn main() {
                             Function,
                         ),
                         lookup: "main",
-                        detail: "-> ()",
+                        detail: "fn()",
                     },
                     CompletionItem {
                         label: "s",
@@ -1169,4 +1231,86 @@ 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() []
+            "#]],
+        )
+    }
 }