2 files changed, 211 insertions, 101 deletions

diff --git a/crates/ra_assists/src/handlers/auto_import.rs b/crates/ra_assists/src/handlers/auto_import.rs
index a9778fab7..9a366414c 100644
--- a/crates/ra_assists/src/handlers/auto_import.rs
+++ b/crates/ra_assists/src/handlers/auto_import.rs
@@ -1,15 +1,17 @@
 use ra_ide_db::{imports_locator::ImportsLocator, RootDatabase};
-use ra_syntax::ast::{self, AstNode};
+use ra_syntax::{
+    ast::{self, AstNode},
+    SyntaxNode,
+};
 
 use crate::{
     assist_ctx::{Assist, AssistCtx},
     insert_use_statement, AssistId,
 };
-use ast::{FnDefOwner, ModuleItem, ModuleItemOwner};
 use hir::{
     db::{DefDatabase, HirDatabase},
-    Adt, AssocContainerId, Crate, Function, HasSource, InFile, ModPath, Module, ModuleDef,
-    PathResolution, SourceAnalyzer, SourceBinder, Trait,
+    AssocContainerId, AssocItem, Crate, Function, ModPath, Module, ModuleDef, PathResolution,
+    SourceAnalyzer, Trait, Type,
 };
 use rustc_hash::FxHashSet;
 use std::collections::BTreeSet;
@@ -34,36 +36,28 @@ use std::collections::BTreeSet;
 // # pub mod std { pub mod collections { pub struct HashMap { } } }
 // ```
 pub(crate) fn auto_import(ctx: AssistCtx) -> Option<Assist> {
-    let path_under_caret: ast::Path = ctx.find_node_at_offset()?;
-    if path_under_caret.syntax().ancestors().find_map(ast::UseItem::cast).is_some() {
-        return None;
-    }
-
-    let module = path_under_caret.syntax().ancestors().find_map(ast::Module::cast);
-    let position = match module.and_then(|it| it.item_list()) {
-        Some(item_list) => item_list.syntax().clone(),
-        None => {
-            let current_file =
-                path_under_caret.syntax().ancestors().find_map(ast::SourceFile::cast)?;
-            current_file.syntax().clone()
-        }
+    let auto_import_assets = if let Some(path_under_caret) = ctx.find_node_at_offset::<ast::Path>()
+    {
+        AutoImportAssets::for_regular_path(path_under_caret, &ctx)?
+    } else {
+        AutoImportAssets::for_method_call(ctx.find_node_at_offset()?, &ctx)?
     };
-    let source_analyzer = ctx.source_analyzer(&position, None);
-    let module_with_name_to_import = source_analyzer.module()?;
 
-    let import_candidate = ImportCandidate::new(&path_under_caret, &source_analyzer, ctx.db)?;
-    let proposed_imports = import_candidate.search_for_imports(ctx.db, module_with_name_to_import);
+    let proposed_imports = auto_import_assets
+        .search_for_imports(ctx.db, auto_import_assets.module_with_name_to_import);
     if proposed_imports.is_empty() {
         return None;
     }
 
-    let mut group = ctx.add_assist_group(format!("Import {}", import_candidate.get_search_query()));
+    let mut group =
+        // TODO kb create another method and add something about traits there
+        ctx.add_assist_group(format!("Import {}", auto_import_assets.get_search_query()));
     for import in proposed_imports {
         group.add_assist(AssistId("auto_import"), format!("Import `{}`", &import), |edit| {
-            edit.target(path_under_caret.syntax().text_range());
+            edit.target(auto_import_assets.syntax_under_caret.text_range());
             insert_use_statement(
-                &position,
-                path_under_caret.syntax(),
+                &auto_import_assets.syntax_under_caret,
+                &auto_import_assets.syntax_under_caret,
                 &import,
                 edit.text_edit_builder(),
             );
@@ -72,64 +66,55 @@ pub(crate) fn auto_import(ctx: AssistCtx) -> Option<Assist> {
     group.finish()
 }
 
-#[derive(Debug)]
-// TODO kb rustdocs
-enum ImportCandidate {
-    UnqualifiedName(ast::NameRef),
-    QualifierStart(ast::NameRef),
-    TraitFunction(Adt, ast::PathSegment),
+struct AutoImportAssets {
+    import_candidate: ImportCandidate,
+    module_with_name_to_import: Module,
+    syntax_under_caret: SyntaxNode,
 }
 
-impl ImportCandidate {
-    // TODO kb refactor this mess
-    fn new(
-        path_under_caret: &ast::Path,
-        source_analyzer: &SourceAnalyzer,
-        db: &impl HirDatabase,
-    ) -> Option<Self> {
-        if source_analyzer.resolve_path(db, path_under_caret).is_some() {
+impl AutoImportAssets {
+    fn for_method_call(method_call: ast::MethodCallExpr, ctx: &AssistCtx) -> Option<Self> {
+        let syntax_under_caret = method_call.syntax().to_owned();
+        let source_analyzer = ctx.source_analyzer(&syntax_under_caret, None);
+        let module_with_name_to_import = source_analyzer.module()?;
+        Some(Self {
+            import_candidate: ImportCandidate::for_method_call(
+                &method_call,
+                &source_analyzer,
+                ctx.db,
+            )?,
+            module_with_name_to_import,
+            syntax_under_caret,
+        })
+    }
+
+    fn for_regular_path(path_under_caret: ast::Path, ctx: &AssistCtx) -> Option<Self> {
+        let syntax_under_caret = path_under_caret.syntax().to_owned();
+        if syntax_under_caret.ancestors().find_map(ast::UseItem::cast).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) =
-                source_analyzer.resolve_path(db, &qualifier_start_path)
-            {
-                let qualifier_resolution = if &qualifier_start_path == path_under_caret {
-                    qualifier_start_resolution
-                } else {
-                    source_analyzer.resolve_path(db, &qualifier)?
-                };
-                if let PathResolution::Def(ModuleDef::Adt(function_callee)) = qualifier_resolution {
-                    Some(ImportCandidate::TraitFunction(function_callee, segment))
-                } else {
-                    None
-                }
-            } else {
-                Some(ImportCandidate::QualifierStart(qualifier_start))
-            }
-        } else {
-            if source_analyzer.resolve_path(db, path_under_caret).is_none() {
-                Some(ImportCandidate::UnqualifiedName(
-                    segment.syntax().descendants().find_map(ast::NameRef::cast)?,
-                ))
-            } else {
-                None
-            }
-        }
+        let source_analyzer = ctx.source_analyzer(&syntax_under_caret, None);
+        let module_with_name_to_import = source_analyzer.module()?;
+        Some(Self {
+            import_candidate: ImportCandidate::for_regular_path(
+                &path_under_caret,
+                &source_analyzer,
+                ctx.db,
+            )?,
+            module_with_name_to_import,
+            syntax_under_caret,
+        })
     }
 
     fn get_search_query(&self) -> String {
-        match self {
+        match &self.import_candidate {
             ImportCandidate::UnqualifiedName(name_ref)
             | ImportCandidate::QualifierStart(name_ref) => name_ref.syntax().to_string(),
             ImportCandidate::TraitFunction(_, trait_function) => {
                 trait_function.syntax().to_string()
             }
+            ImportCandidate::TraitMethod(_, trait_method) => trait_method.syntax().to_string(),
         }
     }
 
@@ -141,7 +126,7 @@ impl ImportCandidate {
         ImportsLocator::new(db)
             .find_imports(&self.get_search_query())
             .into_iter()
-            .map(|module_def| match self {
+            .map(|module_def| match &self.import_candidate {
                 ImportCandidate::TraitFunction(function_callee, _) => {
                     let mut applicable_traits = Vec::new();
                     if let ModuleDef::Function(located_function) = module_def {
@@ -154,7 +139,7 @@ impl ImportCandidate {
                         .map(|trait_candidate| trait_candidate.into())
                         .collect();
 
-                        function_callee.ty(db).iterate_path_candidates(
+                        function_callee.iterate_path_candidates(
                             db,
                             module_with_name_to_import.krate(),
                             &trait_candidates,
@@ -172,6 +157,42 @@ impl ImportCandidate {
                     }
                     applicable_traits
                 }
+                ImportCandidate::TraitMethod(function_callee, _) => {
+                    let mut applicable_traits = Vec::new();
+                    if let ModuleDef::Function(located_function) = module_def {
+                        let trait_candidates: FxHashSet<_> = Self::get_trait_candidates(
+                            db,
+                            located_function,
+                            module_with_name_to_import.krate(),
+                        )
+                        .into_iter()
+                        .map(|trait_candidate| trait_candidate.into())
+                        .collect();
+
+                        if !trait_candidates.is_empty() {
+                            function_callee.iterate_method_candidates(
+                                db,
+                                module_with_name_to_import.krate(),
+                                &trait_candidates,
+                                None,
+                                |_, funciton| {
+                                    if let AssocContainerId::TraitId(trait_id) =
+                                        funciton.container(db)
+                                    {
+                                        applicable_traits.push(
+                                            module_with_name_to_import.find_use_path(
+                                                db,
+                                                ModuleDef::Trait(trait_id.into()),
+                                            ),
+                                        );
+                                    };
+                                    None::<()>
+                                },
+                            );
+                        }
+                    }
+                    applicable_traits
+                }
                 _ => vec![module_with_name_to_import.find_use_path(db, module_def)],
             })
             .flatten()
@@ -186,7 +207,6 @@ impl ImportCandidate {
         called_function: Function,
         root_crate: Crate,
     ) -> FxHashSet<Trait> {
-        let mut source_binder = SourceBinder::new(db);
         root_crate
             .dependencies(db)
             .into_iter()
@@ -196,28 +216,22 @@ impl ImportCandidate {
                 crate_def_map
                     .modules
                     .iter()
-                    .filter_map(|(_, module_data)| module_data.declaration_source(db))
-                    .filter_map(|in_file_module| {
-                        Some((in_file_module.file_id, in_file_module.value.item_list()?.items()))
-                    })
-                    .map(|(file_id, item_list)| {
-                        let mut if_file_trait_defs = Vec::new();
-                        for module_item in item_list {
-                            if let ModuleItem::TraitDef(trait_def) = module_item {
-                                if let Some(item_list) = trait_def.item_list() {
-                                    if item_list
-                                        .functions()
-                                        .any(|fn_def| fn_def == called_function.source(db).value)
-                                    {
-                                        if_file_trait_defs.push(InFile::new(file_id, trait_def))
-                                    }
+                    .map(|(_, module_data)| {
+                        let mut traits = Vec::new();
+                        for module_def_id in module_data.scope.declarations() {
+                            if let ModuleDef::Trait(trait_candidate) = module_def_id.into() {
+                                if trait_candidate
+                                    .items(db)
+                                    .into_iter()
+                                    .any(|item| item == AssocItem::Function(called_function))
+                                {
+                                    traits.push(trait_candidate)
                                 }
                             }
                         }
-                        if_file_trait_defs
+                        traits
                     })
                     .flatten()
-                    .filter_map(|in_file_trait_def| source_binder.to_def(in_file_trait_def))
                     .collect::<FxHashSet<_>>()
             })
             .flatten()
@@ -225,6 +239,72 @@ impl ImportCandidate {
     }
 }
 
+#[derive(Debug)]
+// TODO kb rustdocs
+enum ImportCandidate {
+    UnqualifiedName(ast::NameRef),
+    QualifierStart(ast::NameRef),
+    TraitFunction(Type, ast::PathSegment),
+    TraitMethod(Type, ast::NameRef),
+}
+
+impl ImportCandidate {
+    fn for_method_call(
+        method_call: &ast::MethodCallExpr,
+        source_analyzer: &SourceAnalyzer,
+        db: &impl HirDatabase,
+    ) -> Option<Self> {
+        if source_analyzer.resolve_method_call(method_call).is_some() {
+            return None;
+        }
+        Some(Self::TraitMethod(
+            source_analyzer.type_of(db, &method_call.expr()?)?,
+            method_call.name_ref()?,
+        ))
+    }
+
+    fn for_regular_path(
+        path_under_caret: &ast::Path,
+        source_analyzer: &SourceAnalyzer,
+        db: &impl HirDatabase,
+    ) -> Option<Self> {
+        if source_analyzer.resolve_path(db, 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) =
+                source_analyzer.resolve_path(db, &qualifier_start_path)
+            {
+                let qualifier_resolution = if &qualifier_start_path == path_under_caret {
+                    qualifier_start_resolution
+                } else {
+                    source_analyzer.resolve_path(db, &qualifier)?
+                };
+                if let PathResolution::Def(ModuleDef::Adt(function_callee)) = qualifier_resolution {
+                    Some(ImportCandidate::TraitFunction(function_callee.ty(db), segment))
+                } else {
+                    None
+                }
+            } else {
+                Some(ImportCandidate::QualifierStart(qualifier_start))
+            }
+        } else {
+            if source_analyzer.resolve_path(db, path_under_caret).is_none() {
+                Some(ImportCandidate::UnqualifiedName(
+                    segment.syntax().descendants().find_map(ast::NameRef::cast)?,
+                ))
+            } else {
+                None
+            }
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::helpers::{check_assist, check_assist_not_applicable, check_assist_target};
@@ -525,32 +605,25 @@ mod tests {
     }
 
     #[test]
-    fn not_applicable_for_imported_trait() {
+    fn not_applicable_for_imported_trait_for_function() {
         check_assist_not_applicable(
             auto_import,
             r"
             mod test_mod {
                 pub trait TestTrait {
-                    fn test_method(&self);
                     fn test_function();
                 }
-
                 pub trait TestTrait2 {
-                    fn test_method(&self);
                     fn test_function();
                 }
                 pub enum TestEnum {
                     One,
                     Two,
                 }
-
                 impl TestTrait2 for TestEnum {
-                    fn test_method(&self) {}
                     fn test_function() {}
                 }
-
                 impl TestTrait for TestEnum {
-                    fn test_method(&self) {}
                     fn test_function() {}
                 }
             }
@@ -580,7 +653,7 @@ mod tests {
 
             fn main() {
                 let test_struct = test_mod::TestStruct {};
-                test_struct.test_method<|>
+                test_struct.test_meth<|>od()
             }
             ",
             r"
@@ -598,9 +671,42 @@ mod tests {
 
             fn main() {
                 let test_struct = test_mod::TestStruct {};
-                test_struct.test_method<|>
+                test_struct.test_meth<|>od()
             }
             ",
         );
     }
+
+    #[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();
+            }
+            ",
+        )
+    }
 }
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 73158b8bd..140b3a87f 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -548,6 +548,10 @@ impl Function {
         let mut validator = ExprValidator::new(self.id, infer, sink);
         validator.validate_body(db);
     }
+
+    pub fn container(self, db: &impl DefDatabase) -> AssocContainerId {
+        self.id.lookup(db).container
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -699,7 +703,7 @@ impl AssocItem {
 
     pub fn container(self, db: &impl DefDatabase) -> AssocContainerId {
         match self {
-            AssocItem::Function(f) => f.id.lookup(db).container,
+            AssocItem::Function(f) => f.container(db),
             AssocItem::Const(c) => c.id.lookup(db).container,
             AssocItem::TypeAlias(t) => t.id.lookup(db).container,
         }