Rename ra_assists -> assists

1 files changed, 1088 insertions, 0 deletions

diff --git a/crates/assists/src/handlers/auto_import.rs b/crates/assists/src/handlers/auto_import.rs
new file mode 100644
index 000000000..cce789972
--- /dev/null
+++ b/crates/assists/src/handlers/auto_import.rs
@@ -0,0 +1,1088 @@
+use std::collections::BTreeSet;
+
+use either::Either;
+use hir::{
+    AsAssocItem, AssocItemContainer, ModPath, Module, ModuleDef, PathResolution, Semantics, Trait,
+    Type,
+};
+use ide_db::{imports_locator, RootDatabase};
+use rustc_hash::FxHashSet;
+use syntax::{
+    ast::{self, AstNode},
+    SyntaxNode,
+};
+
+use crate::{
+    utils::insert_use_statement, AssistContext, AssistId, AssistKind, Assists, GroupLabel,
+};
+
+// Assist: auto_import
+//
+// If the name is unresolved, provides all possible imports for it.
+//
+// ```
+// fn main() {
+//     let map = HashMap<|>::new();
+// }
+// # pub mod std { pub mod collections { pub struct HashMap { } } }
+// ```
+// ->
+// ```
+// use std::collections::HashMap;
+//
+// fn main() {
+//     let map = HashMap::new();
+// }
+// # pub mod std { pub mod collections { pub struct HashMap { } } }
+// ```
+pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let auto_import_assets = AutoImportAssets::new(ctx)?;
+    let proposed_imports = auto_import_assets.search_for_imports(ctx);
+    if proposed_imports.is_empty() {
+        return None;
+    }
+
+    let range = ctx.sema.original_range(&auto_import_assets.syntax_under_caret).range;
+    let group = auto_import_assets.get_import_group_message();
+    for import in proposed_imports {
+        acc.add_group(
+            &group,
+            AssistId("auto_import", AssistKind::QuickFix),
+            format!("Import `{}`", &import),
+            range,
+            |builder| {
+                insert_use_statement(
+                    &auto_import_assets.syntax_under_caret,
+                    &import,
+                    ctx,
+                    builder.text_edit_builder(),
+                );
+            },
+        );
+    }
+    Some(())
+}
+
+#[derive(Debug)]
+struct AutoImportAssets {
+    import_candidate: ImportCandidate,
+    module_with_name_to_import: Module,
+    syntax_under_caret: SyntaxNode,
+}
+
+impl AutoImportAssets {
+    fn new(ctx: &AssistContext) -> Option<Self> {
+        if let Some(path_under_caret) = ctx.find_node_at_offset_with_descend::<ast::Path>() {
+            Self::for_regular_path(path_under_caret, &ctx)
+        } else {
+            Self::for_method_call(ctx.find_node_at_offset_with_descend()?, &ctx)
+        }
+    }
+
+    fn for_method_call(method_call: ast::MethodCallExpr, ctx: &AssistContext) -> Option<Self> {
+        let syntax_under_caret = method_call.syntax().to_owned();
+        let module_with_name_to_import = ctx.sema.scope(&syntax_under_caret).module()?;
+        Some(Self {
+            import_candidate: ImportCandidate::for_method_call(&ctx.sema, &method_call)?,
+            module_with_name_to_import,
+            syntax_under_caret,
+        })
+    }
+
+    fn for_regular_path(path_under_caret: ast::Path, ctx: &AssistContext) -> Option<Self> {
+        let syntax_under_caret = path_under_caret.syntax().to_owned();
+        if syntax_under_caret.ancestors().find_map(ast::Use::cast).is_some() {
+            return None;
+        }
+
+        let module_with_name_to_import = ctx.sema.scope(&syntax_under_caret).module()?;
+        Some(Self {
+            import_candidate: ImportCandidate::for_regular_path(&ctx.sema, &path_under_caret)?,
+            module_with_name_to_import,
+            syntax_under_caret,
+        })
+    }
+
+    fn get_search_query(&self) -> &str {
+        match &self.import_candidate {
+            ImportCandidate::UnqualifiedName(name) => name,
+            ImportCandidate::QualifierStart(qualifier_start) => qualifier_start,
+            ImportCandidate::TraitAssocItem(_, trait_assoc_item_name) => trait_assoc_item_name,
+            ImportCandidate::TraitMethod(_, trait_method_name) => trait_method_name,
+        }
+    }
+
+    fn get_import_group_message(&self) -> GroupLabel {
+        let name = match &self.import_candidate {
+            ImportCandidate::UnqualifiedName(name) => format!("Import {}", name),
+            ImportCandidate::QualifierStart(qualifier_start) => {
+                format!("Import {}", qualifier_start)
+            }
+            ImportCandidate::TraitAssocItem(_, trait_assoc_item_name) => {
+                format!("Import a trait for item {}", trait_assoc_item_name)
+            }
+            ImportCandidate::TraitMethod(_, trait_method_name) => {
+                format!("Import a trait for method {}", trait_method_name)
+            }
+        };
+        GroupLabel(name)
+    }
+
+    fn search_for_imports(&self, ctx: &AssistContext) -> BTreeSet<ModPath> {
+        let _p = profile::span("auto_import::search_for_imports");
+        let db = ctx.db();
+        let current_crate = self.module_with_name_to_import.krate();
+        imports_locator::find_imports(&ctx.sema, current_crate, &self.get_search_query())
+            .into_iter()
+            .filter_map(|candidate| match &self.import_candidate {
+                ImportCandidate::TraitAssocItem(assoc_item_type, _) => {
+                    let located_assoc_item = match candidate {
+                        Either::Left(ModuleDef::Function(located_function)) => located_function
+                            .as_assoc_item(db)
+                            .map(|assoc| assoc.container(db))
+                            .and_then(Self::assoc_to_trait),
+                        Either::Left(ModuleDef::Const(located_const)) => located_const
+                            .as_assoc_item(db)
+                            .map(|assoc| assoc.container(db))
+                            .and_then(Self::assoc_to_trait),
+                        _ => None,
+                    }?;
+
+                    let mut trait_candidates = FxHashSet::default();
+                    trait_candidates.insert(located_assoc_item.into());
+
+                    assoc_item_type
+                        .iterate_path_candidates(
+                            db,
+                            current_crate,
+                            &trait_candidates,
+                            None,
+                            |_, assoc| Self::assoc_to_trait(assoc.container(db)),
+                        )
+                        .map(ModuleDef::from)
+                        .map(Either::Left)
+                }
+                ImportCandidate::TraitMethod(function_callee, _) => {
+                    let located_assoc_item =
+                        if let Either::Left(ModuleDef::Function(located_function)) = candidate {
+                            located_function
+                                .as_assoc_item(db)
+                                .map(|assoc| assoc.container(db))
+                                .and_then(Self::assoc_to_trait)
+                        } else {
+                            None
+                        }?;
+
+                    let mut trait_candidates = FxHashSet::default();
+                    trait_candidates.insert(located_assoc_item.into());
+
+                    function_callee
+                        .iterate_method_candidates(
+                            db,
+                            current_crate,
+                            &trait_candidates,
+                            None,
+                            |_, function| {
+                                Self::assoc_to_trait(function.as_assoc_item(db)?.container(db))
+                            },
+                        )
+                        .map(ModuleDef::from)
+                        .map(Either::Left)
+                }
+                _ => Some(candidate),
+            })
+            .filter_map(|candidate| match candidate {
+                Either::Left(module_def) => {
+                    self.module_with_name_to_import.find_use_path(db, module_def)
+                }
+                Either::Right(macro_def) => {
+                    self.module_with_name_to_import.find_use_path(db, macro_def)
+                }
+            })
+            .filter(|use_path| !use_path.segments.is_empty())
+            .take(20)
+            .collect::<BTreeSet<_>>()
+    }
+
+    fn assoc_to_trait(assoc: AssocItemContainer) -> Option<Trait> {
+        if let AssocItemContainer::Trait(extracted_trait) = assoc {
+            Some(extracted_trait)
+        } else {
+            None
+        }
+    }
+}
+
+#[derive(Debug)]
+enum ImportCandidate {
+    /// Simple name like 'HashMap'
+    UnqualifiedName(String),
+    /// First part of the qualified name.
+    /// For 'std::collections::HashMap', that will be 'std'.
+    QualifierStart(String),
+    /// A trait associated function (with no self parameter) or associated constant.
+    /// For 'test_mod::TestEnum::test_function', `Type` is the `test_mod::TestEnum` expression type
+    /// and `String` is the `test_function`
+    TraitAssocItem(Type, String),
+    /// A trait method with self parameter.
+    /// For 'test_enum.test_method()', `Type` is the `test_enum` expression type
+    /// and `String` is the `test_method`
+    TraitMethod(Type, String),
+}
+
+impl ImportCandidate {
+    fn for_method_call(
+        sema: &Semantics<RootDatabase>,
+        method_call: &ast::MethodCallExpr,
+    ) -> Option<Self> {
+        if sema.resolve_method_call(method_call).is_some() {
+            return None;
+        }
+        Some(Self::TraitMethod(
+            sema.type_of_expr(&method_call.expr()?)?,
+            method_call.name_ref()?.syntax().to_string(),
+        ))
+    }
+
+    fn for_regular_path(
+        sema: &Semantics<RootDatabase>,
+        path_under_caret: &ast::Path,
+    ) -> Option<Self> {
+        if sema.resolve_path(path_under_caret).is_some() {
+            return None;
+        }
+
+        let segment = path_under_caret.segment()?;
+        if let Some(qualifier) = path_under_caret.qualifier() {
+            let qualifier_start = qualifier.syntax().descendants().find_map(ast::NameRef::cast)?;
+            let qualifier_start_path =
+                qualifier_start.syntax().ancestors().find_map(ast::Path::cast)?;
+            if let Some(qualifier_start_resolution) = sema.resolve_path(&qualifier_start_path) {
+                let qualifier_resolution = if qualifier_start_path == qualifier {
+                    qualifier_start_resolution
+                } else {
+                    sema.resolve_path(&qualifier)?
+                };
+                if let PathResolution::Def(ModuleDef::Adt(assoc_item_path)) = qualifier_resolution {
+                    Some(ImportCandidate::TraitAssocItem(
+                        assoc_item_path.ty(sema.db),
+                        segment.syntax().to_string(),
+                    ))
+                } else {
+                    None
+                }
+            } else {
+                Some(ImportCandidate::QualifierStart(qualifier_start.syntax().to_string()))
+            }
+        } else {
+            Some(ImportCandidate::UnqualifiedName(
+                segment.syntax().descendants().find_map(ast::NameRef::cast)?.syntax().to_string(),
+            ))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    #[test]
+    fn applicable_when_found_an_import() {
+        check_assist(
+            auto_import,
+            r"
+            <|>PubStruct
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            use PubMod::PubStruct;
+
+            PubStruct
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn applicable_when_found_an_import_in_macros() {
+        check_assist(
+            auto_import,
+            r"
+            macro_rules! foo {
+                ($i:ident) => { fn foo(a: $i) {} }
+            }
+            foo!(Pub<|>Struct);
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            use PubMod::PubStruct;
+
+            macro_rules! foo {
+                ($i:ident) => { fn foo(a: $i) {} }
+            }
+            foo!(PubStruct);
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn auto_imports_are_merged() {
+        check_assist(
+            auto_import,
+            r"
+            use PubMod::PubStruct1;
+
+            struct Test {
+                test: Pub<|>Struct2<u8>,
+            }
+
+            pub mod PubMod {
+                pub struct PubStruct1;
+                pub struct PubStruct2<T> {
+                    _t: T,
+                }
+            }
+            ",
+            r"
+            use PubMod::{PubStruct2, PubStruct1};
+
+            struct Test {
+                test: PubStruct2<u8>,
+            }
+
+            pub mod PubMod {
+                pub struct PubStruct1;
+                pub struct PubStruct2<T> {
+                    _t: T,
+                }
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn applicable_when_found_multiple_imports() {
+        check_assist(
+            auto_import,
+            r"
+            PubSt<|>ruct
+
+            pub mod PubMod1 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod2 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod3 {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            use PubMod3::PubStruct;
+
+            PubStruct
+
+            pub mod PubMod1 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod2 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod3 {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_already_imported_types() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            use PubMod::PubStruct;
+
+            PubStruct<|>
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_types_with_private_paths() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            PrivateStruct<|>
+
+            pub mod PubMod {
+                struct PrivateStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_when_no_imports_found() {
+        check_assist_not_applicable(
+            auto_import,
+            "
+            PubStruct<|>",
+        );
+    }
+
+    #[test]
+    fn not_applicable_in_import_statements() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            use PubStruct<|>;
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }",
+        );
+    }
+
+    #[test]
+    fn function_import() {
+        check_assist(
+            auto_import,
+            r"
+            test_function<|>
+
+            pub mod PubMod {
+                pub fn test_function() {};
+            }
+            ",
+            r"
+            use PubMod::test_function;
+
+            test_function
+
+            pub mod PubMod {
+                pub fn test_function() {};
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn macro_import() {
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:crate_with_macro
+#[macro_export]
+macro_rules! foo {
+    () => ()
+}
+
+//- /main.rs crate:main deps:crate_with_macro
+fn main() {
+    foo<|>
+}
+",
+            r"use crate_with_macro::foo;
+
+fn main() {
+    foo
+}
+",
+        );
+    }
+
+    #[test]
+    fn auto_import_target() {
+        check_assist_target(
+            auto_import,
+            r"
+            struct AssistInfo {
+                group_label: Option<<|>GroupLabel>,
+            }
+
+            mod m { pub struct GroupLabel; }
+            ",
+            "GroupLabel",
+        )
+    }
+
+    #[test]
+    fn not_applicable_when_path_start_is_imported() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            pub mod mod1 {
+                pub mod mod2 {
+                    pub mod mod3 {
+                        pub struct TestStruct;
+                    }
+                }
+            }
+
+            use mod1::mod2;
+            fn main() {
+                mod2::mod3::TestStruct<|>
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_function() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            pub mod test_mod {
+                pub fn test_function() {}
+            }
+
+            use test_mod::test_function;
+            fn main() {
+                test_function<|>
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_struct_function() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    pub fn test_function() {}
+                }
+            }
+
+            fn main() {
+                TestStruct::test_function<|>
+            }
+            ",
+            r"
+            use test_mod::TestStruct;
+
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    pub fn test_function() {}
+                }
+            }
+
+            fn main() {
+                TestStruct::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_struct_const() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                TestStruct::TEST_CONST<|>
+            }
+            ",
+            r"
+            use test_mod::TestStruct;
+
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                TestStruct::TEST_CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_trait_function() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::test_function<|>
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_function() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub trait TestTrait2 {
+                    fn test_function();
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    fn test_function() {}
+                }
+                impl TestTrait for TestEnum {
+                    fn test_function() {}
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                test_mod::TestEnum::test_function<|>;
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn associated_trait_const() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::TEST_CONST<|>
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::TEST_CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_const() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub trait TestTrait2 {
+                    const TEST_CONST: f64;
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    const TEST_CONST: f64 = 42.0;
+                }
+                impl TestTrait for TestEnum {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                test_mod::TestEnum::TEST_CONST<|>;
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn trait_method() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_meth<|>od()
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_method()
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn trait_method_cross_crate() {
+        check_assist(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_meth<|>od()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+            ",
+            r"
+            use dep::test_mod::TestTrait;
+
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_method()
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_fn_cross_crate() {
+        check_assist(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                dep::test_mod::TestStruct::test_func<|>tion
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+            ",
+            r"
+            use dep::test_mod::TestTrait;
+
+            fn main() {
+                dep::test_mod::TestStruct::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_const_cross_crate() {
+        check_assist(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                dep::test_mod::TestStruct::CONST<|>
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    const CONST: bool;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const CONST: bool = true;
+                }
+            }
+            ",
+            r"
+            use dep::test_mod::TestTrait;
+
+            fn main() {
+                dep::test_mod::TestStruct::CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_fn_as_method_cross_crate() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_func<|>tion()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn private_trait_cross_crate() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_meth<|>od()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_method() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub trait TestTrait2 {
+                    fn test_method(&self);
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    fn test_method(&self) {}
+                }
+                impl TestTrait for TestEnum {
+                    fn test_method(&self) {}
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                let one = test_mod::TestEnum::One;
+                one.test<|>_method();
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn dep_import() {
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:dep
+pub struct Struct;
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    Struct<|>
+}
+",
+            r"use dep::Struct;
+
+fn main() {
+    Struct
+}
+",
+        );
+    }
+
+    #[test]
+    fn whole_segment() {
+        // Tests that only imports whose last segment matches the identifier get suggested.
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:dep
+pub mod fmt {
+    pub trait Display {}
+}
+
+pub fn panic_fmt() {}
+
+//- /main.rs crate:main deps:dep
+struct S;
+
+impl f<|>mt::Display for S {}
+",
+            r"use dep::fmt;
+
+struct S;
+
+impl fmt::Display for S {}
+",
+        );
+    }
+
+    #[test]
+    fn macro_generated() {
+        // Tests that macro-generated items are suggested from external crates.
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:dep
+macro_rules! mac {
+    () => {
+        pub struct Cheese;
+    };
+}
+
+mac!();
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    Cheese<|>;
+}
+",
+            r"use dep::Cheese;
+
+fn main() {
+    Cheese;
+}
+",
+        );
+    }
+
+    #[test]
+    fn casing() {
+        // Tests that differently cased names don't interfere and we only suggest the matching one.
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:dep
+pub struct FMT;
+pub struct fmt;
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    FMT<|>;
+}
+",
+            r"use dep::FMT;
+
+fn main() {
+    FMT;
+}
+",
+        );
+    }
+}