1 use hir::{HasSource, HirDisplay, Module, ModuleDef, Semantics, TypeInfo};
4 defs::{Definition, NameRefClass},
8 use rustc_hash::{FxHashMap, FxHashSet};
9 use stdx::to_lower_snake_case;
13 edit::{AstNodeEdit, IndentLevel},
14 make, AstNode, CallExpr, HasArgList, HasModuleItem,
16 SyntaxKind, SyntaxNode, TextRange, TextSize,
20 utils::useless_type_special_case,
21 utils::{find_struct_impl, render_snippet, Cursor},
22 AssistContext, AssistId, AssistKind, Assists,
25 // Assist: generate_function
27 // Adds a stub function with a signature matching the function under the cursor.
31 // fn baz() -> Baz { Baz }
40 // fn baz() -> Baz { Baz }
45 // fn bar(arg: &str, baz: Baz) ${0:-> _} {
50 pub(crate) fn generate_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
51 gen_fn(acc, ctx).or_else(|| gen_method(acc, ctx))
54 fn gen_fn(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
55 let path_expr: ast::PathExpr = ctx.find_node_at_offset()?;
56 let call = path_expr.syntax().parent().and_then(ast::CallExpr::cast)?;
57 let path = path_expr.path()?;
58 let name_ref = path.segment()?.name_ref()?;
59 if ctx.sema.resolve_path(&path).is_some() {
60 // The function call already resolves, no need to add a function
64 let fn_name = &*name_ref.text();
66 let mut adt_name = None;
68 let (target, file, insert_offset) = match path.qualifier() {
69 Some(qualifier) => match ctx.sema.resolve_path(&qualifier) {
70 Some(hir::PathResolution::Def(hir::ModuleDef::Module(module))) => {
71 target_module = Some(module);
72 get_fn_target(ctx, &target_module, call.clone())?
74 Some(hir::PathResolution::Def(hir::ModuleDef::Adt(adt))) => {
75 let current_module = current_module(call.syntax(), ctx)?;
76 let module = adt.module(ctx.sema.db);
77 target_module = if current_module == module { None } else { Some(module) };
78 if current_module.krate() != module.krate() {
81 let (impl_, file) = get_adt_source(ctx, &adt, fn_name)?;
82 let (target, insert_offset) = get_method_target(ctx, &module, &impl_)?;
83 adt_name = if impl_.is_none() { Some(adt.name(ctx.sema.db)) } else { None };
84 (target, file, insert_offset)
92 get_fn_target(ctx, &target_module, call.clone())?
95 let function_builder = FunctionBuilder::from_call(ctx, &call, fn_name, target_module, target)?;
96 let text_range = call.syntax().text_range();
97 let label = format!("Generate {} function", function_builder.fn_name);
98 add_func_to_accumulator(
110 fn gen_method(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
111 let call: ast::MethodCallExpr = ctx.find_node_at_offset()?;
112 let fn_name = call.name_ref()?;
113 let adt = ctx.sema.type_of_expr(&call.receiver()?)?.original().strip_references().as_adt()?;
115 let current_module = current_module(call.syntax(), ctx)?;
116 let target_module = adt.module(ctx.sema.db);
118 if current_module.krate() != target_module.krate() {
121 let (impl_, file) = get_adt_source(ctx, &adt, fn_name.text().as_str())?;
122 let (target, insert_offset) = get_method_target(ctx, &target_module, &impl_)?;
123 let function_builder =
124 FunctionBuilder::from_method_call(ctx, &call, &fn_name, target_module, target)?;
125 let text_range = call.syntax().text_range();
126 let adt_name = if impl_.is_none() { Some(adt.name(ctx.sema.db)) } else { None };
127 let label = format!("Generate {} method", function_builder.fn_name);
128 add_func_to_accumulator(
140 fn add_func_to_accumulator(
143 text_range: TextRange,
144 function_builder: FunctionBuilder,
145 insert_offset: TextSize,
147 adt_name: Option<hir::Name>,
150 acc.add(AssistId("generate_function", AssistKind::Generate), label, text_range, |builder| {
151 let function_template = function_builder.render();
152 let mut func = function_template.to_string(ctx.config.snippet_cap);
153 if let Some(name) = adt_name {
154 func = format!("\nimpl {} {{\n{}\n}}", name, func);
156 builder.edit_file(file);
157 match ctx.config.snippet_cap {
158 Some(cap) => builder.insert_snippet(cap, insert_offset, func),
159 None => builder.insert(insert_offset, func),
164 fn current_module(current_node: &SyntaxNode, ctx: &AssistContext) -> Option<Module> {
165 ctx.sema.scope(current_node).module()
172 ) -> Option<(Option<ast::Impl>, FileId)> {
173 let range = adt.source(ctx.sema.db)?.syntax().original_file_range(ctx.sema.db);
174 let file = ctx.sema.parse(range.file_id);
176 ctx.sema.find_node_at_offset_with_macros(file.syntax(), range.range.start())?;
177 find_struct_impl(ctx, &adt_source, fn_name).map(|impl_| (impl_, range.file_id))
180 struct FunctionTemplate {
183 ret_type: Option<ast::RetType>,
184 should_focus_return_type: bool,
186 tail_expr: ast::Expr,
189 impl FunctionTemplate {
190 fn to_string(&self, cap: Option<SnippetCap>) -> String {
193 let cursor = if self.should_focus_return_type {
194 // Focus the return type if there is one
195 match self.ret_type {
196 Some(ref ret_type) => ret_type.syntax(),
197 None => self.tail_expr.syntax(),
200 self.tail_expr.syntax()
202 render_snippet(cap, self.fn_def.syntax(), Cursor::Replace(cursor))
204 None => self.fn_def.to_string(),
207 format!("{}{}{}", self.leading_ws, f, self.trailing_ws)
211 struct FunctionBuilder {
212 target: GeneratedFunctionTarget,
214 type_params: Option<ast::GenericParamList>,
215 params: ast::ParamList,
216 ret_type: Option<ast::RetType>,
217 should_focus_return_type: bool,
222 impl FunctionBuilder {
223 /// Prepares a generated function that matches `call`.
224 /// The function is generated in `target_module` or next to `call`
227 call: &ast::CallExpr,
229 target_module: Option<hir::Module>,
230 target: GeneratedFunctionTarget,
232 let needs_pub = target_module.is_some();
233 let target_module = target_module.or_else(|| current_module(target.syntax(), ctx))?;
234 let fn_name = make::name(fn_name);
235 let (type_params, params) =
236 fn_args(ctx, target_module, ast::CallableExpr::Call(call.clone()))?;
238 let await_expr = call.syntax().parent().and_then(ast::AwaitExpr::cast);
239 let is_async = await_expr.is_some();
241 let (ret_type, should_focus_return_type) =
242 make_return_type(ctx, &ast::Expr::CallExpr(call.clone()), target_module);
250 should_focus_return_type,
258 call: &ast::MethodCallExpr,
260 target_module: Module,
261 target: GeneratedFunctionTarget,
264 !module_is_descendant(¤t_module(call.syntax(), ctx)?, &target_module, ctx);
265 let fn_name = make::name(&name.text());
266 let (type_params, params) =
267 fn_args(ctx, target_module, ast::CallableExpr::MethodCall(call.clone()))?;
269 let await_expr = call.syntax().parent().and_then(ast::AwaitExpr::cast);
270 let is_async = await_expr.is_some();
272 let (ret_type, should_focus_return_type) =
273 make_return_type(ctx, &ast::Expr::MethodCallExpr(call.clone()), target_module);
281 should_focus_return_type,
287 fn render(self) -> FunctionTemplate {
288 let placeholder_expr = make::ext::expr_todo();
289 let fn_body = make::block_expr(vec![], Some(placeholder_expr));
290 let visibility = if self.needs_pub { Some(make::visibility_pub_crate()) } else { None };
291 let mut fn_def = make::fn_(
304 GeneratedFunctionTarget::BehindItem(it) => {
305 let indent = IndentLevel::from_node(&it);
306 leading_ws = format!("\n\n{}", indent);
307 fn_def = fn_def.indent(indent);
308 trailing_ws = String::new();
310 GeneratedFunctionTarget::InEmptyItemList(it) => {
311 let indent = IndentLevel::from_node(&it);
312 leading_ws = format!("\n{}", indent + 1);
313 fn_def = fn_def.indent(indent + 1);
314 trailing_ws = format!("\n{}", indent);
320 ret_type: fn_def.ret_type(),
321 // PANIC: we guarantee we always create a function body with a tail expr
322 tail_expr: fn_def.body().unwrap().tail_expr().unwrap(),
323 should_focus_return_type: self.should_focus_return_type,
330 /// Makes an optional return type along with whether the return type should be focused by the cursor.
331 /// If we cannot infer what the return type should be, we create a placeholder type.
333 /// The rule for whether we focus a return type or not (and thus focus the function body),
334 /// is rather simple:
335 /// * If we could *not* infer what the return type should be, focus it (so the user can fill-in
336 /// the correct return type).
337 /// * If we could infer the return type, don't focus it (and thus focus the function body) so the
338 /// user can change the `todo!` function body.
342 target_module: Module,
343 ) -> (Option<ast::RetType>, bool) {
344 let (ret_ty, should_focus_return_type) = {
345 match ctx.sema.type_of_expr(call).map(TypeInfo::original) {
346 Some(ty) if ty.is_unknown() => (Some(make::ty_placeholder()), true),
347 None => (Some(make::ty_placeholder()), true),
348 Some(ty) if ty.is_unit() => (None, false),
350 let rendered = ty.display_source_code(ctx.db(), target_module.into());
352 Ok(rendered) => (Some(make::ty(&rendered)), false),
353 Err(_) => (Some(make::ty_placeholder()), true),
358 let ret_type = ret_ty.map(make::ret_type);
359 (ret_type, should_focus_return_type)
364 target_module: &Option<Module>,
366 ) -> Option<(GeneratedFunctionTarget, FileId, TextSize)> {
367 let mut file = ctx.frange.file_id;
368 let target = match target_module {
369 Some(target_module) => {
370 let module_source = target_module.definition_source(ctx.db());
371 let (in_file, target) = next_space_for_fn_in_module(ctx.sema.db, &module_source)?;
375 None => next_space_for_fn_after_call_site(ast::CallableExpr::Call(call))?,
377 Some((target.clone(), file, get_insert_offset(&target)))
380 fn get_method_target(
382 target_module: &Module,
383 impl_: &Option<ast::Impl>,
384 ) -> Option<(GeneratedFunctionTarget, TextSize)> {
385 let target = match impl_ {
386 Some(impl_) => next_space_for_fn_in_impl(impl_)?,
388 next_space_for_fn_in_module(ctx.sema.db, &target_module.definition_source(ctx.sema.db))?
392 Some((target.clone(), get_insert_offset(&target)))
395 fn get_insert_offset(target: &GeneratedFunctionTarget) -> TextSize {
397 GeneratedFunctionTarget::BehindItem(it) => it.text_range().end(),
398 GeneratedFunctionTarget::InEmptyItemList(it) => it.text_range().start() + TextSize::of('{'),
403 enum GeneratedFunctionTarget {
404 BehindItem(SyntaxNode),
405 InEmptyItemList(SyntaxNode),
408 impl GeneratedFunctionTarget {
409 fn syntax(&self) -> &SyntaxNode {
411 GeneratedFunctionTarget::BehindItem(it) => it,
412 GeneratedFunctionTarget::InEmptyItemList(it) => it,
417 /// Computes the type variables and arguments required for the generated function
420 target_module: hir::Module,
421 call: ast::CallableExpr,
422 ) -> Option<(Option<ast::GenericParamList>, ast::ParamList)> {
423 let mut arg_names = Vec::new();
424 let mut arg_types = Vec::new();
425 for arg in call.arg_list()?.args() {
426 arg_names.push(fn_arg_name(&ctx.sema, &arg));
427 arg_types.push(match fn_arg_type(ctx, target_module, &arg) {
429 if !ty.is_empty() && ty.starts_with('&') {
430 match useless_type_special_case("", &ty[1..].to_owned()) {
431 Some((new_ty, _)) => new_ty,
438 None => String::from("_"),
441 deduplicate_arg_names(&mut arg_names);
442 let params = arg_names.into_iter().zip(arg_types).map(|(name, ty)| {
443 make::param(make::ext::simple_ident_pat(make::name(&name)).into(), make::ty(&ty))
450 ast::CallableExpr::Call(_) => None,
451 ast::CallableExpr::MethodCall(_) => Some(make::self_param()),
458 /// Makes duplicate argument names unique by appending incrementing numbers.
461 /// let mut names: Vec<String> =
462 /// vec!["foo".into(), "foo".into(), "bar".into(), "baz".into(), "bar".into()];
463 /// deduplicate_arg_names(&mut names);
464 /// let expected: Vec<String> =
465 /// vec!["foo_1".into(), "foo_2".into(), "bar_1".into(), "baz".into(), "bar_2".into()];
466 /// assert_eq!(names, expected);
468 fn deduplicate_arg_names(arg_names: &mut Vec<String>) {
469 let arg_name_counts = arg_names.iter().fold(FxHashMap::default(), |mut m, name| {
470 *m.entry(name).or_insert(0) += 1;
473 let duplicate_arg_names: FxHashSet<String> = arg_name_counts
475 .filter(|(_, count)| *count >= 2)
476 .map(|(name, _)| name.clone())
479 let mut counter_per_name = FxHashMap::default();
480 for arg_name in arg_names.iter_mut() {
481 if duplicate_arg_names.contains(arg_name) {
482 let counter = counter_per_name.entry(arg_name.clone()).or_insert(1);
484 arg_name.push_str(&counter.to_string());
490 fn fn_arg_name(sema: &Semantics<RootDatabase>, arg_expr: &ast::Expr) -> String {
491 let name = (|| match arg_expr {
492 ast::Expr::CastExpr(cast_expr) => Some(fn_arg_name(sema, &cast_expr.expr()?)),
494 let name_ref = expr.syntax().descendants().filter_map(ast::NameRef::cast).last()?;
495 if let Some(NameRefClass::Definition(Definition::ModuleDef(
496 ModuleDef::Const(_) | ModuleDef::Static(_),
497 ))) = NameRefClass::classify(sema, &name_ref)
499 return Some(name_ref.to_string().to_lowercase());
501 Some(to_lower_snake_case(&name_ref.to_string()))
505 Some(mut name) if name.starts_with(|c: char| c.is_ascii_digit()) => {
506 name.insert_str(0, "arg");
510 None => "arg".to_string(),
516 target_module: hir::Module,
518 ) -> Option<String> {
519 let ty = ctx.sema.type_of_expr(fn_arg)?.adjusted();
524 ty.display_source_code(ctx.db(), target_module.into()).ok()
527 /// Returns the position inside the current mod or file
528 /// directly after the current block
529 /// We want to write the generated function directly after
530 /// fns, impls or macro calls, but inside mods
531 fn next_space_for_fn_after_call_site(expr: ast::CallableExpr) -> Option<GeneratedFunctionTarget> {
532 let mut ancestors = expr.syntax().ancestors().peekable();
533 let mut last_ancestor: Option<SyntaxNode> = None;
534 while let Some(next_ancestor) = ancestors.next() {
535 match next_ancestor.kind() {
536 SyntaxKind::SOURCE_FILE => {
539 SyntaxKind::ITEM_LIST => {
540 if ancestors.peek().map(|a| a.kind()) == Some(SyntaxKind::MODULE) {
546 last_ancestor = Some(next_ancestor);
548 last_ancestor.map(GeneratedFunctionTarget::BehindItem)
551 fn next_space_for_fn_in_module(
552 db: &dyn hir::db::AstDatabase,
553 module_source: &hir::InFile<hir::ModuleSource>,
554 ) -> Option<(FileId, GeneratedFunctionTarget)> {
555 let file = module_source.file_id.original_file(db);
556 let assist_item = match &module_source.value {
557 hir::ModuleSource::SourceFile(it) => match it.items().last() {
558 Some(last_item) => GeneratedFunctionTarget::BehindItem(last_item.syntax().clone()),
559 None => GeneratedFunctionTarget::BehindItem(it.syntax().clone()),
561 hir::ModuleSource::Module(it) => match it.item_list().and_then(|it| it.items().last()) {
562 Some(last_item) => GeneratedFunctionTarget::BehindItem(last_item.syntax().clone()),
563 None => GeneratedFunctionTarget::InEmptyItemList(it.item_list()?.syntax().clone()),
565 hir::ModuleSource::BlockExpr(it) => {
566 if let Some(last_item) =
567 it.statements().take_while(|stmt| matches!(stmt, ast::Stmt::Item(_))).last()
569 GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
571 GeneratedFunctionTarget::InEmptyItemList(it.syntax().clone())
575 Some((file, assist_item))
578 fn next_space_for_fn_in_impl(impl_: &ast::Impl) -> Option<GeneratedFunctionTarget> {
579 if let Some(last_item) = impl_.assoc_item_list().and_then(|it| it.assoc_items().last()) {
580 Some(GeneratedFunctionTarget::BehindItem(last_item.syntax().clone()))
582 Some(GeneratedFunctionTarget::InEmptyItemList(impl_.assoc_item_list()?.syntax().clone()))
586 fn module_is_descendant(module: &hir::Module, ans: &hir::Module, ctx: &AssistContext) -> bool {
590 for c in ans.children(ctx.sema.db) {
591 if module_is_descendant(module, &c, ctx) {
600 use crate::tests::{check_assist, check_assist_not_applicable};
605 fn add_function_with_no_args() {
626 fn add_function_from_method() {
627 // This ensures that the function is correctly generated
628 // in the next outer mod or file
653 fn add_function_directly_after_current_block() {
654 // The new fn should not be created at the end of the file or module
679 fn add_function_with_no_args_in_same_module() {
704 fn add_function_with_upper_camel_case_arg() {
719 fn bar(baz_baz: BazBaz) ${0:-> _} {
727 fn add_function_with_upper_camel_case_arg_as_cast() {
733 bar$0(&BazBaz as *const BazBaz);
739 bar(&BazBaz as *const BazBaz);
742 fn bar(baz_baz: *const BazBaz) ${0:-> _} {
750 fn add_function_with_function_call_arg() {
755 fn baz() -> Baz { todo!() }
762 fn baz() -> Baz { todo!() }
767 fn bar(baz: Baz) ${0:-> _} {
775 fn add_function_with_method_call_arg() {
781 fn foo(&self) -> Baz {
784 fn baz(&self) -> Baz {
792 fn foo(&self) -> Baz {
795 fn baz(&self) -> Baz {
800 fn bar(baz: Baz) -> Baz {
808 fn add_function_with_string_literal_arg() {
829 fn add_function_with_char_literal_arg() {
850 fn add_function_with_int_literal_arg() {
871 fn add_function_with_cast_int_literal_arg() {
892 fn name_of_cast_variable_is_used() {
893 // Ensures that the name of the cast type isn't used
894 // in the generated function signature.
917 fn add_function_with_variable_arg() {
940 fn add_function_with_impl_trait_arg() {
946 fn foo() -> impl Foo {
955 fn foo() -> impl Foo {
962 fn bar(foo: impl Foo) {
975 fn baz() -> Baz { todo!() }
983 fn baz() -> Baz { todo!() }
997 fn add_function_with_qualified_path_arg() {
1003 pub fn baz() -> Bof { Bof }
1012 pub fn baz() -> Bof { Bof }
1018 fn bar(baz: Baz::Bof) {
1026 fn add_function_with_generic_arg() {
1027 // FIXME: This is wrong, generated `bar` should include generic parameter.
1048 fn add_function_with_fn_arg() {
1049 // FIXME: The argument in `bar` is wrong.
1055 fn new() -> Self { Baz }
1064 fn new() -> Self { Baz }
1070 fn bar(new: fn) ${0:-> _} {
1078 fn add_function_with_closure_arg() {
1079 // FIXME: The argument in `bar` is wrong.
1084 let closure = |x: i64| x - 1;
1090 let closure = |x: i64| x - 1;
1094 fn bar(closure: _) {
1102 fn unresolveable_types_default_to_placeholder() {
1123 fn arg_names_dont_overlap() {
1128 fn baz() -> Baz { Baz }
1135 fn baz() -> Baz { Baz }
1140 fn bar(baz_1: Baz, baz_2: Baz) {
1148 fn arg_name_counters_start_at_1_per_name() {
1153 fn baz() -> Baz { Baz }
1155 $0bar(baz(), baz(), "foo", "bar")
1160 fn baz() -> Baz { Baz }
1162 bar(baz(), baz(), "foo", "bar")
1165 fn bar(baz_1: Baz, baz_2: Baz, arg_1: &str, arg_2: &str) {
1173 fn add_function_in_module() {
1185 pub(crate) fn my_fn() {
1198 fn qualified_path_uses_correct_scope() {
1221 fn baz(foo: foo::Foo) {
1229 fn add_function_in_module_containing_other_items() {
1234 fn something_else() {}
1243 fn something_else() {}
1245 pub(crate) fn my_fn() {
1258 fn add_function_in_nested_module() {
1273 pub(crate) fn my_fn() {
1287 fn add_function_in_another_file() {
1302 pub(crate) fn bar() {
1309 fn add_function_with_return_type() {
1314 let x: u32 = foo$0();
1330 fn add_function_not_applicable_if_function_already_exists() {
1331 check_assist_not_applicable(
1344 fn add_function_not_applicable_if_unresolved_variable_in_call_is_selected() {
1345 check_assist_not_applicable(
1346 // bar is resolved, but baz isn't.
1347 // The assist is only active if the cursor is on an unresolved path,
1348 // but the assist should only be offered if the path is a function call.
1361 fn create_method_with_no_args() {
1379 fn bar(&self) ${0:-> _} {
1388 fn create_function_with_async() {
1401 async fn bar(arg: i32) ${0:-> _} {
1409 fn create_method() {
1414 fn foo() {S.bar$0();}
1422 fn bar(&self) ${0:-> _} {
1431 fn create_method_within_an_impl() {
1436 fn foo() {S.bar$0();}
1444 fn bar(&self) ${0:-> _} {
1454 fn create_method_from_different_module() {
1461 fn foo() {s::S.bar$0();}
1469 pub(crate) fn bar(&self) ${0:-> _} {
1474 fn foo() {s::S.bar();}
1480 fn create_method_from_descendant_module() {
1502 fn bar(&self) ${0:-> _} {
1512 fn create_method_with_cursor_anywhere_on_call_expresion() {
1517 fn foo() {$0S.bar();}
1525 fn bar(&self) ${0:-> _} {
1534 fn create_static_method() {
1539 fn foo() {S::bar$0();}
1543 fn foo() {S::bar();}
1547 fn bar() ${0:-> _} {
1556 fn create_static_method_within_an_impl() {
1561 fn foo() {S::bar$0();}
1567 fn foo() {S::bar();}
1569 fn bar() ${0:-> _} {
1579 fn create_static_method_from_different_module() {
1586 fn foo() {s::S::bar$0();}
1594 pub(crate) fn bar() ${0:-> _} {
1599 fn foo() {s::S::bar();}
1605 fn create_static_method_with_cursor_anywhere_on_call_expresion() {
1610 fn foo() {$0S::bar();}
1614 fn foo() {S::bar();}
1618 fn bar() ${0:-> _} {
1627 fn no_panic_on_invalid_global_path() {
1640 fn foo() ${0:-> _} {
1648 fn handle_tuple_indexing() {
1663 fn foo(arg0: ()) ${0:-> _} {
1671 fn add_function_with_const_arg() {
1675 const VALUE: usize = 0;
1681 const VALUE: usize = 0;
1686 fn foo(value: usize) ${0:-> _} {
1694 fn add_function_with_static_arg() {
1698 static VALUE: usize = 0;
1704 static VALUE: usize = 0;
1709 fn foo(value: usize) ${0:-> _} {
1717 fn add_function_with_static_mut_arg() {
1721 static mut VALUE: usize = 0;
1727 static mut VALUE: usize = 0;
1732 fn foo(value: usize) ${0:-> _} {