Move rendering tests to the render module

crates/completion/src/context.rs

@@ -245,19 +245,6 @@ impl<'a> CompletionContext<'a> {
         }
     }
 
-    pub(crate) fn active_name_and_type(&self) -> Option<(String, Type)> {
-        if let Some(record_field) = &self.record_field_syntax {
-            mark::hit!(record_field_type_match);
-            let (struct_field, _local) = self.sema.resolve_record_field(record_field)?;
-            Some((struct_field.name(self.db).to_string(), struct_field.signature_ty(self.db)))
-        } else if let Some(active_parameter) = &self.active_parameter {
-            mark::hit!(active_param_type_match);
-            Some((active_parameter.name.clone(), active_parameter.ty.clone()))
-        } else {
-            None
-        }
-    }
-
     fn fill_keyword_patterns(&mut self, file_with_fake_ident: &SyntaxNode, offset: TextSize) {
         let fake_ident_token = file_with_fake_ident.token_at_offset(offset).right_biased().unwrap();
         let syntax_element = NodeOrToken::Token(fake_ident_token);

crates/completion/src/render.rs

@@ -8,11 +8,15 @@ mod enum_variant;
 mod const_;
 mod type_alias;
 
-use hir::{Documentation, HasAttrs};
+use hir::{Documentation, HasAttrs, HirDisplay, Mutability, ScopeDef, Type};
 use ide_db::RootDatabase;
 use syntax::TextRange;
+use test_utils::mark;
 
-use crate::{config::SnippetCap, CompletionContext};
+use crate::{
+    config::SnippetCap, CompletionContext, CompletionItem, CompletionItemKind, CompletionKind,
+    CompletionScore,
+};
 
 pub(crate) use crate::render::{
     const_::ConstRender, enum_variant::EnumVariantRender, function::FunctionRender,
@@ -25,29 +29,42 @@ pub(crate) struct RenderContext<'a> {
 }
 
 impl<'a> RenderContext<'a> {
-    pub fn new(completion: &'a CompletionContext<'a>) -> RenderContext<'a> {
+    fn new(completion: &'a CompletionContext<'a>) -> RenderContext<'a> {
         RenderContext { completion }
     }
 
-    pub fn snippet_cap(&self) -> Option<SnippetCap> {
+    fn snippet_cap(&self) -> Option<SnippetCap> {
         self.completion.config.snippet_cap.clone()
     }
 
-    pub fn db(&self) -> &'a RootDatabase {
+    fn db(&self) -> &'a RootDatabase {
         &self.completion.db
     }
 
-    pub fn source_range(&self) -> TextRange {
+    fn source_range(&self) -> TextRange {
         self.completion.source_range()
     }
 
-    pub fn is_deprecated(&self, node: impl HasAttrs) -> bool {
+    fn is_deprecated(&self, node: impl HasAttrs) -> bool {
         node.attrs(self.db()).by_key("deprecated").exists()
     }
 
-    pub fn docs(&self, node: impl HasAttrs) -> Option<Documentation> {
+    fn docs(&self, node: impl HasAttrs) -> Option<Documentation> {
         node.docs(self.db())
     }
+
+    fn active_name_and_type(&self) -> Option<(String, Type)> {
+        if let Some(record_field) = &self.completion.record_field_syntax {
+            mark::hit!(record_field_type_match);
+            let (struct_field, _local) = self.completion.sema.resolve_record_field(record_field)?;
+            Some((struct_field.name(self.db()).to_string(), struct_field.signature_ty(self.db())))
+        } else if let Some(active_parameter) = &self.completion.active_parameter {
+            mark::hit!(active_param_type_match);
+            Some((active_parameter.name.clone(), active_parameter.ty.clone()))
+        } else {
+            None
+        }
+    }
 }
 
 impl<'a> From<&'a CompletionContext<'a>> for RenderContext<'a> {
@@ -55,3 +72,759 @@ impl<'a> From<&'a CompletionContext<'a>> for RenderContext<'a> {
         RenderContext::new(ctx)
     }
 }
+
+#[derive(Debug)]
+pub(crate) struct Render<'a> {
+    ctx: RenderContext<'a>,
+}
+
+impl<'a> Render<'a> {
+    pub(crate) fn new(ctx: RenderContext<'a>) -> Render<'a> {
+        Render { ctx }
+    }
+
+    pub(crate) fn add_field(&mut self, field: hir::Field, ty: &Type) -> CompletionItem {
+        let is_deprecated = self.ctx.is_deprecated(field);
+        let name = field.name(self.ctx.db());
+        let mut item = CompletionItem::new(
+            CompletionKind::Reference,
+            self.ctx.source_range(),
+            name.to_string(),
+        )
+        .kind(CompletionItemKind::Field)
+        .detail(ty.display(self.ctx.db()).to_string())
+        .set_documentation(field.docs(self.ctx.db()))
+        .set_deprecated(is_deprecated);
+
+        if let Some(score) = compute_score(&self.ctx, &ty, &name.to_string()) {
+            item = item.set_score(score);
+        }
+
+        return item.build();
+    }
+
+    pub(crate) fn add_tuple_field(&mut self, field: usize, ty: &Type) -> CompletionItem {
+        CompletionItem::new(CompletionKind::Reference, self.ctx.source_range(), field.to_string())
+            .kind(CompletionItemKind::Field)
+            .detail(ty.display(self.ctx.db()).to_string())
+            .build()
+    }
+
+    pub(crate) fn render_resolution(
+        self,
+        local_name: String,
+        resolution: &ScopeDef,
+    ) -> Option<CompletionItem> {
+        use hir::ModuleDef::*;
+
+        let completion_kind = match resolution {
+            ScopeDef::ModuleDef(BuiltinType(..)) => CompletionKind::BuiltinType,
+            _ => CompletionKind::Reference,
+        };
+
+        let kind = match resolution {
+            ScopeDef::ModuleDef(Function(func)) => {
+                let item = FunctionRender::new(self.ctx, Some(local_name), *func).render();
+                return Some(item);
+            }
+            ScopeDef::ModuleDef(EnumVariant(var)) => {
+                let item = EnumVariantRender::new(self.ctx, Some(local_name), *var, None).render();
+                return Some(item);
+            }
+            ScopeDef::MacroDef(mac) => {
+                let item = MacroRender::new(self.ctx, local_name, *mac).render();
+                return item;
+            }
+
+            ScopeDef::ModuleDef(Module(..)) => CompletionItemKind::Module,
+            ScopeDef::ModuleDef(Adt(hir::Adt::Struct(_))) => CompletionItemKind::Struct,
+            // FIXME: add CompletionItemKind::Union
+            ScopeDef::ModuleDef(Adt(hir::Adt::Union(_))) => CompletionItemKind::Struct,
+            ScopeDef::ModuleDef(Adt(hir::Adt::Enum(_))) => CompletionItemKind::Enum,
+            ScopeDef::ModuleDef(Const(..)) => CompletionItemKind::Const,
+            ScopeDef::ModuleDef(Static(..)) => CompletionItemKind::Static,
+            ScopeDef::ModuleDef(Trait(..)) => CompletionItemKind::Trait,
+            ScopeDef::ModuleDef(TypeAlias(..)) => CompletionItemKind::TypeAlias,
+            ScopeDef::ModuleDef(BuiltinType(..)) => CompletionItemKind::BuiltinType,
+            ScopeDef::GenericParam(..) => CompletionItemKind::TypeParam,
+            ScopeDef::Local(..) => CompletionItemKind::Binding,
+            // (does this need its own kind?)
+            ScopeDef::AdtSelfType(..) | ScopeDef::ImplSelfType(..) => CompletionItemKind::TypeParam,
+            ScopeDef::Unknown => {
+                let item = CompletionItem::new(
+                    CompletionKind::Reference,
+                    self.ctx.source_range(),
+                    local_name,
+                )
+                .kind(CompletionItemKind::UnresolvedReference)
+                .build();
+                return Some(item);
+            }
+        };
+
+        let docs = self.docs(resolution);
+
+        let mut item =
+            CompletionItem::new(completion_kind, self.ctx.source_range(), local_name.clone());
+        if let ScopeDef::Local(local) = resolution {
+            let ty = local.ty(self.ctx.db());
+            if !ty.is_unknown() {
+                item = item.detail(ty.display(self.ctx.db()).to_string());
+            }
+        };
+
+        let mut ref_match = None;
+        if let ScopeDef::Local(local) = resolution {
+            if let Some((active_name, active_type)) = self.ctx.active_name_and_type() {
+                let ty = local.ty(self.ctx.db());
+                if let Some(score) =
+                    compute_score_from_active(&active_type, &active_name, &ty, &local_name)
+                {
+                    item = item.set_score(score);
+                }
+                ref_match = refed_type_matches(&active_type, &active_name, &ty, &local_name);
+            }
+        }
+
+        // Add `<>` for generic types
+        if self.ctx.completion.is_path_type
+            && !self.ctx.completion.has_type_args
+            && self.ctx.completion.config.add_call_parenthesis
+        {
+            if let Some(cap) = self.ctx.snippet_cap() {
+                let has_non_default_type_params = match resolution {
+                    ScopeDef::ModuleDef(Adt(it)) => it.has_non_default_type_params(self.ctx.db()),
+                    ScopeDef::ModuleDef(TypeAlias(it)) => {
+                        it.has_non_default_type_params(self.ctx.db())
+                    }
+                    _ => false,
+                };
+                if has_non_default_type_params {
+                    mark::hit!(inserts_angle_brackets_for_generics);
+                    item = item
+                        .lookup_by(local_name.clone())
+                        .label(format!("{}<…>", local_name))
+                        .insert_snippet(cap, format!("{}<$0>", local_name));
+                }
+            }
+        }
+
+        let item = item.kind(kind).set_documentation(docs).set_ref_match(ref_match).build();
+        Some(item)
+    }
+
+    fn docs(&self, resolution: &ScopeDef) -> Option<Documentation> {
+        use hir::ModuleDef::*;
+        match resolution {
+            ScopeDef::ModuleDef(Module(it)) => it.docs(self.ctx.db()),
+            ScopeDef::ModuleDef(Adt(it)) => it.docs(self.ctx.db()),
+            ScopeDef::ModuleDef(EnumVariant(it)) => it.docs(self.ctx.db()),
+            ScopeDef::ModuleDef(Const(it)) => it.docs(self.ctx.db()),
+            ScopeDef::ModuleDef(Static(it)) => it.docs(self.ctx.db()),
+            ScopeDef::ModuleDef(Trait(it)) => it.docs(self.ctx.db()),
+            ScopeDef::ModuleDef(TypeAlias(it)) => it.docs(self.ctx.db()),
+            _ => None,
+        }
+    }
+}
+
+fn compute_score_from_active(
+    active_type: &Type,
+    active_name: &str,
+    ty: &Type,
+    name: &str,
+) -> Option<CompletionScore> {
+    // Compute score
+    // For the same type
+    if active_type != ty {
+        return None;
+    }
+
+    let mut res = CompletionScore::TypeMatch;
+
+    // If same type + same name then go top position
+    if active_name == name {
+        res = CompletionScore::TypeAndNameMatch
+    }
+
+    Some(res)
+}
+fn refed_type_matches(
+    active_type: &Type,
+    active_name: &str,
+    ty: &Type,
+    name: &str,
+) -> Option<(Mutability, CompletionScore)> {
+    let derefed_active = active_type.remove_ref()?;
+    let score = compute_score_from_active(&derefed_active, &active_name, &ty, &name)?;
+    Some((
+        if active_type.is_mutable_reference() { Mutability::Mut } else { Mutability::Shared },
+        score,
+    ))
+}
+
+fn compute_score(ctx: &RenderContext, ty: &Type, name: &str) -> Option<CompletionScore> {
+    let (active_name, active_type) = ctx.active_name_and_type()?;
+    compute_score_from_active(&active_type, &active_name, ty, name)
+}
+
+#[cfg(test)]
+mod tests {
+    use std::cmp::Reverse;
+
+    use expect_test::{expect, Expect};
+    use test_utils::mark;
+
+    use crate::{
+        test_utils::{check_edit, do_completion, get_all_items},
+        CompletionConfig, CompletionKind, CompletionScore,
+    };
+
+    fn check(ra_fixture: &str, expect: Expect) {
+        let actual = do_completion(ra_fixture, CompletionKind::Reference);
+        expect.assert_debug_eq(&actual);
+    }
+
+    fn check_scores(ra_fixture: &str, expect: Expect) {
+        fn display_score(score: Option<CompletionScore>) -> &'static str {
+            match score {
+                Some(CompletionScore::TypeMatch) => "[type]",
+                Some(CompletionScore::TypeAndNameMatch) => "[type+name]",
+                None => "[]".into(),
+            }
+        }
+
+        let mut completions = get_all_items(CompletionConfig::default(), ra_fixture);
+        completions.sort_by_key(|it| (Reverse(it.score()), it.label().to_string()));
+        let actual = completions
+            .into_iter()
+            .filter(|it| it.completion_kind == CompletionKind::Reference)
+            .map(|it| {
+                let tag = it.kind().unwrap().tag();
+                let score = display_score(it.score());
+                format!("{} {} {}\n", tag, it.label(), score)
+            })
+            .collect::<String>();
+        expect.assert_eq(&actual);
+    }
+
+    #[test]
+    fn enum_detail_includes_record_fields() {
+        check(
+            r#"
+enum Foo { Foo { x: i32, y: i32 } }
+
+fn main() { Foo::Fo<|> }
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "Foo",
+                        source_range: 54..56,
+                        delete: 54..56,
+                        insert: "Foo",
+                        kind: EnumVariant,
+                        detail: "{ x: i32, y: i32 }",
+                    },
+                ]
+            "#]],
+        );
+    }
+
+    #[test]
+    fn enum_detail_doesnt_include_tuple_fields() {
+        check(
+            r#"
+enum Foo { Foo (i32, i32) }
+
+fn main() { Foo::Fo<|> }
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "Foo(…)",
+                        source_range: 46..48,
+                        delete: 46..48,
+                        insert: "Foo($0)",
+                        kind: EnumVariant,
+                        lookup: "Foo",
+                        detail: "(i32, i32)",
+                        trigger_call_info: true,
+                    },
+                ]
+            "#]],
+        );
+    }
+
+    #[test]
+    fn enum_detail_just_parentheses_for_unit() {
+        check(
+            r#"
+enum Foo { Foo }
+
+fn main() { Foo::Fo<|> }
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "Foo",
+                        source_range: 35..37,
+                        delete: 35..37,
+                        insert: "Foo",
+                        kind: EnumVariant,
+                        detail: "()",
+                    },
+                ]
+            "#]],
+        );
+    }
+
+    #[test]
+    fn lookup_enums_by_two_qualifiers() {
+        check(
+            r#"
+mod m {
+    pub enum Spam { Foo, Bar(i32) }
+}
+fn main() { let _: m::Spam = S<|> }
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "Spam::Bar(…)",
+                        source_range: 75..76,
+                        delete: 75..76,
+                        insert: "Spam::Bar($0)",
+                        kind: EnumVariant,
+                        lookup: "Spam::Bar",
+                        detail: "(i32)",
+                        trigger_call_info: true,
+                    },
+                    CompletionItem {
+                        label: "m",
+                        source_range: 75..76,
+                        delete: 75..76,
+                        insert: "m",
+                        kind: Module,
+                    },
+                    CompletionItem {
+                        label: "m::Spam::Foo",
+                        source_range: 75..76,
+                        delete: 75..76,
+                        insert: "m::Spam::Foo",
+                        kind: EnumVariant,
+                        lookup: "Spam::Foo",
+                        detail: "()",
+                    },
+                    CompletionItem {
+                        label: "main()",
+                        source_range: 75..76,
+                        delete: 75..76,
+                        insert: "main()$0",
+                        kind: Function,
+                        lookup: "main",
+                        detail: "fn main()",
+                    },
+                ]
+            "#]],
+        )
+    }
+
+    #[test]
+    fn sets_deprecated_flag_in_items() {
+        check(
+            r#"
+#[deprecated]
+fn something_deprecated() {}
+#[deprecated(since = "1.0.0")]
+fn something_else_deprecated() {}
+
+fn main() { som<|> }
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "main()",
+                        source_range: 121..124,
+                        delete: 121..124,
+                        insert: "main()$0",
+                        kind: Function,
+                        lookup: "main",
+                        detail: "fn main()",
+                    },
+                    CompletionItem {
+                        label: "something_deprecated()",
+                        source_range: 121..124,
+                        delete: 121..124,
+                        insert: "something_deprecated()$0",
+                        kind: Function,
+                        lookup: "something_deprecated",
+                        detail: "fn something_deprecated()",
+                        deprecated: true,
+                    },
+                    CompletionItem {
+                        label: "something_else_deprecated()",
+                        source_range: 121..124,
+                        delete: 121..124,
+                        insert: "something_else_deprecated()$0",
+                        kind: Function,
+                        lookup: "something_else_deprecated",
+                        detail: "fn something_else_deprecated()",
+                        deprecated: true,
+                    },
+                ]
+            "#]],
+        );
+
+        check(
+            r#"
+struct A { #[deprecated] the_field: u32 }
+fn foo() { A { the<|> } }
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "the_field",
+                        source_range: 57..60,
+                        delete: 57..60,
+                        insert: "the_field",
+                        kind: Field,
+                        detail: "u32",
+                        deprecated: true,
+                    },
+                ]
+            "#]],
+        );
+    }
+
+    #[test]
+    fn renders_docs() {
+        check(
+            r#"
+struct S {
+    /// Field docs
+    foo:
+}
+impl S {
+    /// Method docs
+    fn bar(self) { self.<|> }
+}"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "bar()",
+                        source_range: 94..94,
+                        delete: 94..94,
+                        insert: "bar()$0",
+                        kind: Method,
+                        lookup: "bar",
+                        detail: "fn bar(self)",
+                        documentation: Documentation(
+                            "Method docs",
+                        ),
+                    },
+                    CompletionItem {
+                        label: "foo",
+                        source_range: 94..94,
+                        delete: 94..94,
+                        insert: "foo",
+                        kind: Field,
+                        detail: "{unknown}",
+                        documentation: Documentation(
+                            "Field docs",
+                        ),
+                    },
+                ]
+            "#]],
+        );
+
+        check(
+            r#"
+use self::my<|>;
+
+/// mod docs
+mod my { }
+
+/// enum docs
+enum E {
+    /// variant docs
+    V
+}
+use self::E::*;
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "E",
+                        source_range: 10..12,
+                        delete: 10..12,
+                        insert: "E",
+                        kind: Enum,
+                        documentation: Documentation(
+                            "enum docs",
+                        ),
+                    },
+                    CompletionItem {
+                        label: "V",
+                        source_range: 10..12,
+                        delete: 10..12,
+                        insert: "V",
+                        kind: EnumVariant,
+                        detail: "()",
+                        documentation: Documentation(
+                            "variant docs",
+                        ),
+                    },
+                    CompletionItem {
+                        label: "my",
+                        source_range: 10..12,
+                        delete: 10..12,
+                        insert: "my",
+                        kind: Module,
+                        documentation: Documentation(
+                            "mod docs",
+                        ),
+                    },
+                ]
+            "#]],
+        )
+    }
+
+    #[test]
+    fn dont_render_attrs() {
+        check(
+            r#"
+struct S;
+impl S {
+    #[inline]
+    fn the_method(&self) { }
+}
+fn foo(s: S) { s.<|> }
+"#,
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "the_method()",
+                        source_range: 81..81,
+                        delete: 81..81,
+                        insert: "the_method()$0",
+                        kind: Method,
+                        lookup: "the_method",
+                        detail: "fn the_method(&self)",
+                    },
+                ]
+            "#]],
+        )
+    }
+
+    #[test]
+    fn no_call_parens_if_fn_ptr_needed() {
+        mark::check!(no_call_parens_if_fn_ptr_needed);
+        check_edit(
+            "foo",
+            r#"
+fn foo(foo: u8, bar: u8) {}
+struct ManualVtable { f: fn(u8, u8) }
+
+fn main() -> ManualVtable {
+    ManualVtable { f: f<|> }
+}
+"#,
+            r#"
+fn foo(foo: u8, bar: u8) {}
+struct ManualVtable { f: fn(u8, u8) }
+
+fn main() -> ManualVtable {
+    ManualVtable { f: foo }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn no_parens_in_use_item() {
+        mark::check!(no_parens_in_use_item);
+        check_edit(
+            "foo",
+            r#"
+mod m { pub fn foo() {} }
+use crate::m::f<|>;
+"#,
+            r#"
+mod m { pub fn foo() {} }
+use crate::m::foo;
+"#,
+        );
+    }
+
+    #[test]
+    fn no_parens_in_call() {
+        check_edit(
+            "foo",
+            r#"
+fn foo(x: i32) {}
+fn main() { f<|>(); }
+"#,
+            r#"
+fn foo(x: i32) {}
+fn main() { foo(); }
+"#,
+        );
+        check_edit(
+            "foo",
+            r#"
+struct Foo;
+impl Foo { fn foo(&self){} }
+fn f(foo: &Foo) { foo.f<|>(); }
+"#,
+            r#"
+struct Foo;
+impl Foo { fn foo(&self){} }
+fn f(foo: &Foo) { foo.foo(); }
+"#,
+        );
+    }
+
+    #[test]
+    fn inserts_angle_brackets_for_generics() {
+        mark::check!(inserts_angle_brackets_for_generics);
+        check_edit(
+            "Vec",
+            r#"
+struct Vec<T> {}
+fn foo(xs: Ve<|>)
+"#,
+            r#"
+struct Vec<T> {}
+fn foo(xs: Vec<$0>)
+"#,
+        );
+        check_edit(
+            "Vec",
+            r#"
+type Vec<T> = (T,);
+fn foo(xs: Ve<|>)
+"#,
+            r#"
+type Vec<T> = (T,);
+fn foo(xs: Vec<$0>)
+"#,
+        );
+        check_edit(
+            "Vec",
+            r#"
+struct Vec<T = i128> {}
+fn foo(xs: Ve<|>)
+"#,
+            r#"
+struct Vec<T = i128> {}
+fn foo(xs: Vec)
+"#,
+        );
+        check_edit(
+            "Vec",
+            r#"
+struct Vec<T> {}
+fn foo(xs: Ve<|><i128>)
+"#,
+            r#"
+struct Vec<T> {}
+fn foo(xs: Vec<i128>)
+"#,
+        );
+    }
+
+    #[test]
+    fn active_param_score() {
+        mark::check!(active_param_type_match);
+        check_scores(
+            r#"
+struct S { foo: i64, bar: u32, baz: u32 }
+fn test(bar: u32) { }
+fn foo(s: S) { test(s.<|>) }
+"#,
+            expect![[r#"
+                fd bar [type+name]
+                fd baz [type]
+                fd foo []
+            "#]],
+        );
+    }
+
+    #[test]
+    fn record_field_scores() {
+        mark::check!(record_field_type_match);
+        check_scores(
+            r#"
+struct A { foo: i64, bar: u32, baz: u32 }
+struct B { x: (), y: f32, bar: u32 }
+fn foo(a: A) { B { bar: a.<|> }; }
+"#,
+            expect![[r#"
+                fd bar [type+name]
+                fd baz [type]
+                fd foo []
+            "#]],
+        )
+    }
+
+    #[test]
+    fn record_field_and_call_scores() {
+        check_scores(
+            r#"
+struct A { foo: i64, bar: u32, baz: u32 }
+struct B { x: (), y: f32, bar: u32 }
+fn f(foo: i64) {  }
+fn foo(a: A) { B { bar: f(a.<|>) }; }
+"#,
+            expect![[r#"
+                fd foo [type+name]
+                fd bar []
+                fd baz []
+            "#]],
+        );
+        check_scores(
+            r#"
+struct A { foo: i64, bar: u32, baz: u32 }
+struct B { x: (), y: f32, bar: u32 }
+fn f(foo: i64) {  }
+fn foo(a: A) { f(B { bar: a.<|> }); }
+"#,
+            expect![[r#"
+                fd bar [type+name]
+                fd baz [type]
+                fd foo []
+            "#]],
+        );
+    }
+
+    #[test]
+    fn prioritize_exact_ref_match() {
+        check_scores(
+            r#"
+struct WorldSnapshot { _f: () };
+fn go(world: &WorldSnapshot) { go(w<|>) }
+"#,
+            expect![[r#"
+                bn world [type+name]
+                st WorldSnapshot []
+                fn go(…) []
+            "#]],
+        );
+    }
+
+    #[test]
+    fn too_many_arguments() {
+        check_scores(
+            r#"
+struct Foo;
+fn f(foo: &Foo) { f(foo, w<|>) }
+"#,
+            expect![[r#"
+                st Foo []
+                fn f(…) []
+                bn foo []
+            "#]],
+        );
+    }
+}

crates/completion/src/render/enum_variant.rs

@@ -93,3 +93,77 @@ impl<'a> EnumVariantRender<'a> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::test_utils::check_edit;
+
+    #[test]
+    fn inserts_parens_for_tuple_enums() {
+        mark::check!(inserts_parens_for_tuple_enums);
+        check_edit(
+            "Some",
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+fn main() -> Option<i32> {
+    Som<|>
+}
+"#,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+fn main() -> Option<i32> {
+    Some($0)
+}
+"#,
+        );
+        check_edit(
+            "Some",
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+fn main(value: Option<i32>) {
+    match value {
+        Som<|>
+    }
+}
+"#,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+fn main(value: Option<i32>) {
+    match value {
+        Some($0)
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn dont_duplicate_pattern_parens() {
+        mark::check!(dont_duplicate_pattern_parens);
+        check_edit(
+            "Var",
+            r#"
+enum E { Var(i32) }
+fn main() {
+    match E::Var(92) {
+        E::<|>(92) => (),
+    }
+}
+"#,
+            r#"
+enum E { Var(i32) }
+fn main() {
+    match E::Var(92) {
+        E::Var(92) => (),
+    }
+}
+"#,
+        );
+    }
+}

crates/completion/src/render/function.rs

@@ -81,3 +81,213 @@ impl<'a> FunctionRender<'a> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::{
+        test_utils::{check_edit, check_edit_with_config},
+        CompletionConfig,
+    };
+
+    #[test]
+    fn inserts_parens_for_function_calls() {
+        mark::check!(inserts_parens_for_function_calls);
+        check_edit(
+            "no_args",
+            r#"
+fn no_args() {}
+fn main() { no_<|> }
+"#,
+            r#"
+fn no_args() {}
+fn main() { no_args()$0 }
+"#,
+        );
+
+        check_edit(
+            "with_args",
+            r#"
+fn with_args(x: i32, y: String) {}
+fn main() { with_<|> }
+"#,
+            r#"
+fn with_args(x: i32, y: String) {}
+fn main() { with_args(${1:x}, ${2:y})$0 }
+"#,
+        );
+
+        check_edit(
+            "foo",
+            r#"
+struct S;
+impl S {
+    fn foo(&self) {}
+}
+fn bar(s: &S) { s.f<|> }
+"#,
+            r#"
+struct S;
+impl S {
+    fn foo(&self) {}
+}
+fn bar(s: &S) { s.foo()$0 }
+"#,
+        );
+
+        check_edit(
+            "foo",
+            r#"
+struct S {}
+impl S {
+    fn foo(&self, x: i32) {}
+}
+fn bar(s: &S) {
+    s.f<|>
+}
+"#,
+            r#"
+struct S {}
+impl S {
+    fn foo(&self, x: i32) {}
+}
+fn bar(s: &S) {
+    s.foo(${1:x})$0
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn suppress_arg_snippets() {
+        mark::check!(suppress_arg_snippets);
+        check_edit_with_config(
+            CompletionConfig { add_call_argument_snippets: false, ..CompletionConfig::default() },
+            "with_args",
+            r#"
+fn with_args(x: i32, y: String) {}
+fn main() { with_<|> }
+"#,
+            r#"
+fn with_args(x: i32, y: String) {}
+fn main() { with_args($0) }
+"#,
+        );
+    }
+
+    #[test]
+    fn strips_underscores_from_args() {
+        check_edit(
+            "foo",
+            r#"
+fn foo(_foo: i32, ___bar: bool, ho_ge_: String) {}
+fn main() { f<|> }
+"#,
+            r#"
+fn foo(_foo: i32, ___bar: bool, ho_ge_: String) {}
+fn main() { foo(${1:foo}, ${2:bar}, ${3:ho_ge_})$0 }
+"#,
+        );
+    }
+
+    #[test]
+    fn insert_ref_when_matching_local_in_scope() {
+        check_edit(
+            "ref_arg",
+            r#"
+struct Foo {}
+fn ref_arg(x: &Foo) {}
+fn main() {
+    let x = Foo {};
+    ref_ar<|>
+}
+"#,
+            r#"
+struct Foo {}
+fn ref_arg(x: &Foo) {}
+fn main() {
+    let x = Foo {};
+    ref_arg(${1:&x})$0
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn insert_mut_ref_when_matching_local_in_scope() {
+        check_edit(
+            "ref_arg",
+            r#"
+struct Foo {}
+fn ref_arg(x: &mut Foo) {}
+fn main() {
+    let x = Foo {};
+    ref_ar<|>
+}
+"#,
+            r#"
+struct Foo {}
+fn ref_arg(x: &mut Foo) {}
+fn main() {
+    let x = Foo {};
+    ref_arg(${1:&mut x})$0
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn insert_ref_when_matching_local_in_scope_for_method() {
+        check_edit(
+            "apply_foo",
+            r#"
+struct Foo {}
+struct Bar {}
+impl Bar {
+    fn apply_foo(&self, x: &Foo) {}
+}
+
+fn main() {
+    let x = Foo {};
+    let y = Bar {};
+    y.<|>
+}
+"#,
+            r#"
+struct Foo {}
+struct Bar {}
+impl Bar {
+    fn apply_foo(&self, x: &Foo) {}
+}
+
+fn main() {
+    let x = Foo {};
+    let y = Bar {};
+    y.apply_foo(${1:&x})$0
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn trim_mut_keyword_in_func_completion() {
+        check_edit(
+            "take_mutably",
+            r#"
+fn take_mutably(mut x: &i32) {}
+
+fn main() {
+    take_m<|>
+}
+"#,
+            r#"
+fn take_mutably(mut x: &i32) {}
+
+fn main() {
+    take_mutably(${1:x})$0
+}
+"#,
+        );
+    }
+}

crates/completion/src/render/macro_.rs

@@ -114,3 +114,93 @@ fn guess_macro_braces(macro_name: &str, docs: &str) -> (&'static str, &'static s
         .unwrap();
     (*bra, *ket)
 }
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::test_utils::check_edit;
+
+    #[test]
+    fn dont_insert_macro_call_parens_unncessary() {
+        mark::check!(dont_insert_macro_call_parens_unncessary);
+        check_edit(
+            "frobnicate!",
+            r#"
+//- /main.rs crate:main deps:foo
+use foo::<|>;
+//- /foo/lib.rs crate:foo
+#[macro_export]
+macro_rules frobnicate { () => () }
+"#,
+            r#"
+use foo::frobnicate;
+"#,
+        );
+
+        check_edit(
+            "frobnicate!",
+            r#"
+macro_rules frobnicate { () => () }
+fn main() { frob<|>!(); }
+"#,
+            r#"
+macro_rules frobnicate { () => () }
+fn main() { frobnicate!(); }
+"#,
+        );
+    }
+
+    #[test]
+    fn guesses_macro_braces() {
+        check_edit(
+            "vec!",
+            r#"
+/// Creates a [`Vec`] containing the arguments.
+///
+/// ```
+/// let v = vec![1, 2, 3];
+/// assert_eq!(v[0], 1);
+/// assert_eq!(v[1], 2);
+/// assert_eq!(v[2], 3);
+/// ```
+macro_rules! vec { () => {} }
+
+fn fn main() { v<|> }
+"#,
+            r#"
+/// Creates a [`Vec`] containing the arguments.
+///
+/// ```
+/// let v = vec![1, 2, 3];
+/// assert_eq!(v[0], 1);
+/// assert_eq!(v[1], 2);
+/// assert_eq!(v[2], 3);
+/// ```
+macro_rules! vec { () => {} }
+
+fn fn main() { vec![$0] }
+"#,
+        );
+
+        check_edit(
+            "foo!",
+            r#"
+/// Foo
+///
+/// Don't call `fooo!()` `fooo!()`, or `_foo![]` `_foo![]`,
+/// call as `let _=foo!  { hello world };`
+macro_rules! foo { () => {} }
+fn main() { <|> }
+"#,
+            r#"
+/// Foo
+///
+/// Don't call `fooo!()` `fooo!()`, or `_foo![]` `_foo![]`,
+/// call as `let _=foo!  { hello world };`
+macro_rules! foo { () => {} }
+fn main() { foo! {$0} }
+"#,
+        )
+    }
+}