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1 use std::iter;
2 
3 use ast::make;
4 use either::Either;
5 use hir::{
6     HasSource, HirDisplay, InFile, Local, LocalSource, ModuleDef, PathResolution, Semantics,
7     TypeInfo, TypeParam,
8 };
9 use ide_db::{
10     defs::{Definition, NameRefClass},
11     famous_defs::FamousDefs,
12     helpers::mod_path_to_ast,
13     imports::insert_use::{insert_use, ImportScope},
14     search::{FileReference, ReferenceCategory, SearchScope},
15     syntax_helpers::node_ext::{
16         for_each_tail_expr, preorder_expr, walk_expr, walk_pat, walk_patterns_in_expr,
17     },
18     FxIndexSet, RootDatabase,
19 };
20 use itertools::Itertools;
21 use stdx::format_to;
22 use syntax::{
23     ast::{
24         self,
25         edit::{AstNodeEdit, IndentLevel},
26         AstNode, HasGenericParams,
27     },
28     match_ast, ted, SyntaxElement,
29     SyntaxKind::{self, COMMENT},
30     SyntaxNode, SyntaxToken, TextRange, TextSize, TokenAtOffset, WalkEvent, T,
31 };
32 
33 use crate::{
34     assist_context::{AssistContext, Assists, TreeMutator},
35     utils::generate_impl_text,
36     AssistId,
37 };
38 
39 // Assist: extract_function
40 //
41 // Extracts selected statements and comments into new function.
42 //
43 // ```
44 // fn main() {
45 //     let n = 1;
46 //     $0let m = n + 2;
47 //     // calculate
48 //     let k = m + n;$0
49 //     let g = 3;
50 // }
51 // ```
52 // ->
53 // ```
54 // fn main() {
55 //     let n = 1;
56 //     fun_name(n);
57 //     let g = 3;
58 // }
59 //
60 // fn $0fun_name(n: i32) {
61 //     let m = n + 2;
62 //     // calculate
63 //     let k = m + n;
64 // }
65 // ```
extract_function(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()>66 pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
67     let range = ctx.selection_trimmed();
68     if range.is_empty() {
69         return None;
70     }
71 
72     let node = ctx.covering_element();
73     if matches!(node.kind(), T!['{'] | T!['}'] | T!['('] | T![')'] | T!['['] | T![']']) {
74         cov_mark::hit!(extract_function_in_braces_is_not_applicable);
75         return None;
76     }
77 
78     if node.kind() == COMMENT {
79         cov_mark::hit!(extract_function_in_comment_is_not_applicable);
80         return None;
81     }
82 
83     let node = match node {
84         syntax::NodeOrToken::Node(n) => n,
85         syntax::NodeOrToken::Token(t) => t.parent()?,
86     };
87 
88     let body = extraction_target(&node, range)?;
89     let (container_info, contains_tail_expr) = body.analyze_container(&ctx.sema)?;
90 
91     let (locals_used, self_param) = body.analyze(&ctx.sema);
92 
93     let anchor = if self_param.is_some() { Anchor::Method } else { Anchor::Freestanding };
94     let insert_after = node_to_insert_after(&body, anchor)?;
95     let semantics_scope = ctx.sema.scope(&insert_after)?;
96     let module = semantics_scope.module();
97 
98     let ret_ty = body.return_ty(ctx)?;
99     let control_flow = body.external_control_flow(ctx, &container_info)?;
100     let ret_values = body.ret_values(ctx, node.parent().as_ref().unwrap_or(&node));
101 
102     let target_range = body.text_range();
103 
104     let scope = ImportScope::find_insert_use_container(&node, &ctx.sema)?;
105 
106     acc.add(
107         AssistId("extract_function", crate::AssistKind::RefactorExtract),
108         "Extract into function",
109         target_range,
110         move |builder| {
111             let outliving_locals: Vec<_> = ret_values.collect();
112             if stdx::never!(!outliving_locals.is_empty() && !ret_ty.is_unit()) {
113                 // We should not have variables that outlive body if we have expression block
114                 return;
115             }
116 
117             let params =
118                 body.extracted_function_params(ctx, &container_info, locals_used.iter().copied());
119 
120             let name = make_function_name(&semantics_scope);
121 
122             let fun = Function {
123                 name,
124                 self_param,
125                 params,
126                 control_flow,
127                 ret_ty,
128                 body,
129                 outliving_locals,
130                 contains_tail_expr,
131                 mods: container_info,
132             };
133 
134             let new_indent = IndentLevel::from_node(&insert_after);
135             let old_indent = fun.body.indent_level();
136 
137             builder.replace(target_range, make_call(ctx, &fun, old_indent));
138 
139             let has_impl_wrapper =
140                 insert_after.ancestors().any(|a| a.kind() == SyntaxKind::IMPL && a != insert_after);
141 
142             let fn_def = match fun.self_param_adt(ctx) {
143                 Some(adt) if anchor == Anchor::Method && !has_impl_wrapper => {
144                     let fn_def = format_function(ctx, module, &fun, old_indent, new_indent + 1);
145                     generate_impl_text(&adt, &fn_def).replace("{\n\n", "{")
146                 }
147                 _ => format_function(ctx, module, &fun, old_indent, new_indent),
148             };
149 
150             if fn_def.contains("ControlFlow") {
151                 let scope = match scope {
152                     ImportScope::File(it) => ImportScope::File(builder.make_mut(it)),
153                     ImportScope::Module(it) => ImportScope::Module(builder.make_mut(it)),
154                     ImportScope::Block(it) => ImportScope::Block(builder.make_mut(it)),
155                 };
156 
157                 let control_flow_enum =
158                     FamousDefs(&ctx.sema, module.krate()).core_ops_ControlFlow();
159 
160                 if let Some(control_flow_enum) = control_flow_enum {
161                     let mod_path = module.find_use_path_prefixed(
162                         ctx.sema.db,
163                         ModuleDef::from(control_flow_enum),
164                         ctx.config.insert_use.prefix_kind,
165                         ctx.config.prefer_no_std,
166                     );
167 
168                     if let Some(mod_path) = mod_path {
169                         insert_use(&scope, mod_path_to_ast(&mod_path), &ctx.config.insert_use);
170                     }
171                 }
172             }
173 
174             let insert_offset = insert_after.text_range().end();
175 
176             match ctx.config.snippet_cap {
177                 Some(cap) => builder.insert_snippet(cap, insert_offset, fn_def),
178                 None => builder.insert(insert_offset, fn_def),
179             };
180         },
181     )
182 }
183 
make_function_name(semantics_scope: &hir::SemanticsScope<'_>) -> ast::NameRef184 fn make_function_name(semantics_scope: &hir::SemanticsScope<'_>) -> ast::NameRef {
185     let mut names_in_scope = vec![];
186     semantics_scope.process_all_names(&mut |name, _| {
187         names_in_scope.push(name.display(semantics_scope.db.upcast()).to_string())
188     });
189 
190     let default_name = "fun_name";
191 
192     let mut name = default_name.to_string();
193     let mut counter = 0;
194     while names_in_scope.contains(&name) {
195         counter += 1;
196         name = format!("{default_name}{counter}")
197     }
198     make::name_ref(&name)
199 }
200 
201 /// Try to guess what user wants to extract
202 ///
203 /// We have basically have two cases:
204 /// * We want whole node, like `loop {}`, `2 + 2`, `{ let n = 1; }` exprs.
205 ///   Then we can use `ast::Expr`
206 /// * We want a few statements for a block. E.g.
207 ///   ```rust,no_run
208 ///   fn foo() -> i32 {
209 ///     let m = 1;
210 ///     $0
211 ///     let n = 2;
212 ///     let k = 3;
213 ///     k + n
214 ///     $0
215 ///   }
216 ///   ```
217 ///
extraction_target(node: &SyntaxNode, selection_range: TextRange) -> Option<FunctionBody>218 fn extraction_target(node: &SyntaxNode, selection_range: TextRange) -> Option<FunctionBody> {
219     if let Some(stmt) = ast::Stmt::cast(node.clone()) {
220         return match stmt {
221             ast::Stmt::Item(_) => None,
222             ast::Stmt::ExprStmt(_) | ast::Stmt::LetStmt(_) => Some(FunctionBody::from_range(
223                 node.parent().and_then(ast::StmtList::cast)?,
224                 node.text_range(),
225             )),
226         };
227     }
228 
229     // Covering element returned the parent block of one or multiple statements that have been selected
230     if let Some(stmt_list) = ast::StmtList::cast(node.clone()) {
231         if let Some(block_expr) = stmt_list.syntax().parent().and_then(ast::BlockExpr::cast) {
232             if block_expr.syntax().text_range() == selection_range {
233                 return FunctionBody::from_expr(block_expr.into());
234             }
235         }
236 
237         // Extract the full statements.
238         return Some(FunctionBody::from_range(stmt_list, selection_range));
239     }
240 
241     let expr = ast::Expr::cast(node.clone())?;
242     // A node got selected fully
243     if node.text_range() == selection_range {
244         return FunctionBody::from_expr(expr);
245     }
246 
247     node.ancestors().find_map(ast::Expr::cast).and_then(FunctionBody::from_expr)
248 }
249 
250 #[derive(Debug)]
251 struct Function {
252     name: ast::NameRef,
253     self_param: Option<ast::SelfParam>,
254     params: Vec<Param>,
255     control_flow: ControlFlow,
256     ret_ty: RetType,
257     body: FunctionBody,
258     outliving_locals: Vec<OutlivedLocal>,
259     /// Whether at least one of the container's tail expr is contained in the range we're extracting.
260     contains_tail_expr: bool,
261     mods: ContainerInfo,
262 }
263 
264 #[derive(Debug)]
265 struct Param {
266     var: Local,
267     ty: hir::Type,
268     move_local: bool,
269     requires_mut: bool,
270     is_copy: bool,
271 }
272 
273 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
274 enum ParamKind {
275     Value,
276     MutValue,
277     SharedRef,
278     MutRef,
279 }
280 
281 #[derive(Debug)]
282 enum FunType {
283     Unit,
284     Single(hir::Type),
285     Tuple(Vec<hir::Type>),
286 }
287 
288 /// Where to put extracted function definition
289 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
290 enum Anchor {
291     /// Extract free function and put right after current top-level function
292     Freestanding,
293     /// Extract method and put right after current function in the impl-block
294     Method,
295 }
296 
297 // FIXME: ControlFlow and ContainerInfo both track some function modifiers, feels like these two should
298 // probably be merged somehow.
299 #[derive(Debug)]
300 struct ControlFlow {
301     kind: Option<FlowKind>,
302     is_async: bool,
303     is_unsafe: bool,
304 }
305 
306 /// The thing whose expression we are extracting from. Can be a function, const, static, const arg, ...
307 #[derive(Clone, Debug)]
308 struct ContainerInfo {
309     is_const: bool,
310     parent_loop: Option<SyntaxNode>,
311     /// The function's return type, const's type etc.
312     ret_type: Option<hir::Type>,
313     generic_param_lists: Vec<ast::GenericParamList>,
314     where_clauses: Vec<ast::WhereClause>,
315 }
316 
317 /// Control flow that is exported from extracted function
318 ///
319 /// E.g.:
320 /// ```rust,no_run
321 /// loop {
322 ///     $0
323 ///     if 42 == 42 {
324 ///         break;
325 ///     }
326 ///     $0
327 /// }
328 /// ```
329 #[derive(Debug, Clone)]
330 enum FlowKind {
331     /// Return with value (`return $expr;`)
332     Return(Option<ast::Expr>),
333     Try {
334         kind: TryKind,
335     },
336     /// Break with label and value (`break 'label $expr;`)
337     Break(Option<ast::Lifetime>, Option<ast::Expr>),
338     /// Continue with label (`continue 'label;`)
339     Continue(Option<ast::Lifetime>),
340 }
341 
342 #[derive(Debug, Clone)]
343 enum TryKind {
344     Option,
345     Result { ty: hir::Type },
346 }
347 
348 #[derive(Debug)]
349 enum RetType {
350     Expr(hir::Type),
351     Stmt,
352 }
353 
354 impl RetType {
is_unit(&self) -> bool355     fn is_unit(&self) -> bool {
356         match self {
357             RetType::Expr(ty) => ty.is_unit(),
358             RetType::Stmt => true,
359         }
360     }
361 }
362 
363 /// Semantically same as `ast::Expr`, but preserves identity when using only part of the Block
364 /// This is the future function body, the part that is being extracted.
365 #[derive(Debug)]
366 enum FunctionBody {
367     Expr(ast::Expr),
368     Span { parent: ast::StmtList, text_range: TextRange },
369 }
370 
371 #[derive(Debug)]
372 struct OutlivedLocal {
373     local: Local,
374     mut_usage_outside_body: bool,
375 }
376 
377 /// Container of local variable usages
378 ///
379 /// Semantically same as `UsageSearchResult`, but provides more convenient interface
380 struct LocalUsages(ide_db::search::UsageSearchResult);
381 
382 impl LocalUsages {
find_local_usages(ctx: &AssistContext<'_>, var: Local) -> Self383     fn find_local_usages(ctx: &AssistContext<'_>, var: Local) -> Self {
384         Self(
385             Definition::Local(var)
386                 .usages(&ctx.sema)
387                 .in_scope(SearchScope::single_file(ctx.file_id()))
388                 .all(),
389         )
390     }
391 
iter(&self) -> impl Iterator<Item = &FileReference> + '_392     fn iter(&self) -> impl Iterator<Item = &FileReference> + '_ {
393         self.0.iter().flat_map(|(_, rs)| rs)
394     }
395 }
396 
397 impl Function {
return_type(&self, ctx: &AssistContext<'_>) -> FunType398     fn return_type(&self, ctx: &AssistContext<'_>) -> FunType {
399         match &self.ret_ty {
400             RetType::Expr(ty) if ty.is_unit() => FunType::Unit,
401             RetType::Expr(ty) => FunType::Single(ty.clone()),
402             RetType::Stmt => match self.outliving_locals.as_slice() {
403                 [] => FunType::Unit,
404                 [var] => FunType::Single(var.local.ty(ctx.db())),
405                 vars => {
406                     let types = vars.iter().map(|v| v.local.ty(ctx.db())).collect();
407                     FunType::Tuple(types)
408                 }
409             },
410         }
411     }
412 
self_param_adt(&self, ctx: &AssistContext<'_>) -> Option<ast::Adt>413     fn self_param_adt(&self, ctx: &AssistContext<'_>) -> Option<ast::Adt> {
414         let self_param = self.self_param.as_ref()?;
415         let def = ctx.sema.to_def(self_param)?;
416         let adt = def.ty(ctx.db()).strip_references().as_adt()?;
417         let InFile { file_id: _, value } = adt.source(ctx.db())?;
418         Some(value)
419     }
420 }
421 
422 impl ParamKind {
is_ref(&self) -> bool423     fn is_ref(&self) -> bool {
424         matches!(self, ParamKind::SharedRef | ParamKind::MutRef)
425     }
426 }
427 
428 impl Param {
kind(&self) -> ParamKind429     fn kind(&self) -> ParamKind {
430         match (self.move_local, self.requires_mut, self.is_copy) {
431             (false, true, _) => ParamKind::MutRef,
432             (false, false, false) => ParamKind::SharedRef,
433             (true, true, _) => ParamKind::MutValue,
434             (_, false, _) => ParamKind::Value,
435         }
436     }
437 
to_arg(&self, ctx: &AssistContext<'_>) -> ast::Expr438     fn to_arg(&self, ctx: &AssistContext<'_>) -> ast::Expr {
439         let var = path_expr_from_local(ctx, self.var);
440         match self.kind() {
441             ParamKind::Value | ParamKind::MutValue => var,
442             ParamKind::SharedRef => make::expr_ref(var, false),
443             ParamKind::MutRef => make::expr_ref(var, true),
444         }
445     }
446 
to_param(&self, ctx: &AssistContext<'_>, module: hir::Module) -> ast::Param447     fn to_param(&self, ctx: &AssistContext<'_>, module: hir::Module) -> ast::Param {
448         let var = self.var.name(ctx.db()).display(ctx.db()).to_string();
449         let var_name = make::name(&var);
450         let pat = match self.kind() {
451             ParamKind::MutValue => make::ident_pat(false, true, var_name),
452             ParamKind::Value | ParamKind::SharedRef | ParamKind::MutRef => {
453                 make::ext::simple_ident_pat(var_name)
454             }
455         };
456 
457         let ty = make_ty(&self.ty, ctx, module);
458         let ty = match self.kind() {
459             ParamKind::Value | ParamKind::MutValue => ty,
460             ParamKind::SharedRef => make::ty_ref(ty, false),
461             ParamKind::MutRef => make::ty_ref(ty, true),
462         };
463 
464         make::param(pat.into(), ty)
465     }
466 }
467 
468 impl TryKind {
of_ty(ty: hir::Type, ctx: &AssistContext<'_>) -> Option<TryKind>469     fn of_ty(ty: hir::Type, ctx: &AssistContext<'_>) -> Option<TryKind> {
470         if ty.is_unknown() {
471             // We favour Result for `expr?`
472             return Some(TryKind::Result { ty });
473         }
474         let adt = ty.as_adt()?;
475         let name = adt.name(ctx.db());
476         // FIXME: use lang items to determine if it is std type or user defined
477         //        E.g. if user happens to define type named `Option`, we would have false positive
478         let name = &name.display(ctx.db()).to_string();
479         match name.as_str() {
480             "Option" => Some(TryKind::Option),
481             "Result" => Some(TryKind::Result { ty }),
482             _ => None,
483         }
484     }
485 }
486 
487 impl FlowKind {
make_result_handler(&self, expr: Option<ast::Expr>) -> ast::Expr488     fn make_result_handler(&self, expr: Option<ast::Expr>) -> ast::Expr {
489         match self {
490             FlowKind::Return(_) => make::expr_return(expr),
491             FlowKind::Break(label, _) => make::expr_break(label.clone(), expr),
492             FlowKind::Try { .. } => {
493                 stdx::never!("cannot have result handler with try");
494                 expr.unwrap_or_else(|| make::expr_return(None))
495             }
496             FlowKind::Continue(label) => {
497                 stdx::always!(expr.is_none(), "continue with value is not possible");
498                 make::expr_continue(label.clone())
499             }
500         }
501     }
502 
expr_ty(&self, ctx: &AssistContext<'_>) -> Option<hir::Type>503     fn expr_ty(&self, ctx: &AssistContext<'_>) -> Option<hir::Type> {
504         match self {
505             FlowKind::Return(Some(expr)) | FlowKind::Break(_, Some(expr)) => {
506                 ctx.sema.type_of_expr(expr).map(TypeInfo::adjusted)
507             }
508             FlowKind::Try { .. } => {
509                 stdx::never!("try does not have defined expr_ty");
510                 None
511             }
512             _ => None,
513         }
514     }
515 }
516 
517 impl FunctionBody {
parent(&self) -> Option<SyntaxNode>518     fn parent(&self) -> Option<SyntaxNode> {
519         match self {
520             FunctionBody::Expr(expr) => expr.syntax().parent(),
521             FunctionBody::Span { parent, .. } => Some(parent.syntax().clone()),
522         }
523     }
524 
node(&self) -> &SyntaxNode525     fn node(&self) -> &SyntaxNode {
526         match self {
527             FunctionBody::Expr(e) => e.syntax(),
528             FunctionBody::Span { parent, .. } => parent.syntax(),
529         }
530     }
531 
extracted_from_trait_impl(&self) -> bool532     fn extracted_from_trait_impl(&self) -> bool {
533         match self.node().ancestors().find_map(ast::Impl::cast) {
534             Some(c) => return c.trait_().is_some(),
535             None => false,
536         }
537     }
538 
descendants(&self) -> impl Iterator<Item = SyntaxNode>539     fn descendants(&self) -> impl Iterator<Item = SyntaxNode> {
540         match self {
541             FunctionBody::Expr(expr) => expr.syntax().descendants(),
542             FunctionBody::Span { parent, .. } => parent.syntax().descendants(),
543         }
544     }
545 
descendant_paths(&self) -> impl Iterator<Item = ast::Path>546     fn descendant_paths(&self) -> impl Iterator<Item = ast::Path> {
547         self.descendants().filter_map(|node| {
548             match_ast! {
549                 match node {
550                     ast::Path(it) => Some(it),
551                     _ => None
552                 }
553             }
554         })
555     }
556 
from_expr(expr: ast::Expr) -> Option<Self>557     fn from_expr(expr: ast::Expr) -> Option<Self> {
558         match expr {
559             ast::Expr::BreakExpr(it) => it.expr().map(Self::Expr),
560             ast::Expr::ReturnExpr(it) => it.expr().map(Self::Expr),
561             ast::Expr::BlockExpr(it) if !it.is_standalone() => None,
562             expr => Some(Self::Expr(expr)),
563         }
564     }
565 
from_range(parent: ast::StmtList, selected: TextRange) -> FunctionBody566     fn from_range(parent: ast::StmtList, selected: TextRange) -> FunctionBody {
567         let full_body = parent.syntax().children_with_tokens();
568 
569         let mut text_range = full_body
570             .filter(|it| ast::Stmt::can_cast(it.kind()) || it.kind() == COMMENT)
571             .map(|element| element.text_range())
572             .filter(|&range| selected.intersect(range).filter(|it| !it.is_empty()).is_some())
573             .reduce(|acc, stmt| acc.cover(stmt));
574 
575         if let Some(tail_range) = parent
576             .tail_expr()
577             .map(|it| it.syntax().text_range())
578             .filter(|&it| selected.intersect(it).is_some())
579         {
580             text_range = Some(match text_range {
581                 Some(text_range) => text_range.cover(tail_range),
582                 None => tail_range,
583             });
584         }
585         Self::Span { parent, text_range: text_range.unwrap_or(selected) }
586     }
587 
indent_level(&self) -> IndentLevel588     fn indent_level(&self) -> IndentLevel {
589         match &self {
590             FunctionBody::Expr(expr) => IndentLevel::from_node(expr.syntax()),
591             FunctionBody::Span { parent, .. } => IndentLevel::from_node(parent.syntax()) + 1,
592         }
593     }
594 
tail_expr(&self) -> Option<ast::Expr>595     fn tail_expr(&self) -> Option<ast::Expr> {
596         match &self {
597             FunctionBody::Expr(expr) => Some(expr.clone()),
598             FunctionBody::Span { parent, text_range } => {
599                 let tail_expr = parent.tail_expr()?;
600                 text_range.contains_range(tail_expr.syntax().text_range()).then_some(tail_expr)
601             }
602         }
603     }
604 
walk_expr(&self, cb: &mut dyn FnMut(ast::Expr))605     fn walk_expr(&self, cb: &mut dyn FnMut(ast::Expr)) {
606         match self {
607             FunctionBody::Expr(expr) => walk_expr(expr, cb),
608             FunctionBody::Span { parent, text_range } => {
609                 parent
610                     .statements()
611                     .filter(|stmt| text_range.contains_range(stmt.syntax().text_range()))
612                     .filter_map(|stmt| match stmt {
613                         ast::Stmt::ExprStmt(expr_stmt) => expr_stmt.expr(),
614                         ast::Stmt::Item(_) => None,
615                         ast::Stmt::LetStmt(stmt) => stmt.initializer(),
616                     })
617                     .for_each(|expr| walk_expr(&expr, cb));
618                 if let Some(expr) = parent
619                     .tail_expr()
620                     .filter(|it| text_range.contains_range(it.syntax().text_range()))
621                 {
622                     walk_expr(&expr, cb);
623                 }
624             }
625         }
626     }
627 
preorder_expr(&self, cb: &mut dyn FnMut(WalkEvent<ast::Expr>) -> bool)628     fn preorder_expr(&self, cb: &mut dyn FnMut(WalkEvent<ast::Expr>) -> bool) {
629         match self {
630             FunctionBody::Expr(expr) => preorder_expr(expr, cb),
631             FunctionBody::Span { parent, text_range } => {
632                 parent
633                     .statements()
634                     .filter(|stmt| text_range.contains_range(stmt.syntax().text_range()))
635                     .filter_map(|stmt| match stmt {
636                         ast::Stmt::ExprStmt(expr_stmt) => expr_stmt.expr(),
637                         ast::Stmt::Item(_) => None,
638                         ast::Stmt::LetStmt(stmt) => stmt.initializer(),
639                     })
640                     .for_each(|expr| preorder_expr(&expr, cb));
641                 if let Some(expr) = parent
642                     .tail_expr()
643                     .filter(|it| text_range.contains_range(it.syntax().text_range()))
644                 {
645                     preorder_expr(&expr, cb);
646                 }
647             }
648         }
649     }
650 
walk_pat(&self, cb: &mut dyn FnMut(ast::Pat))651     fn walk_pat(&self, cb: &mut dyn FnMut(ast::Pat)) {
652         match self {
653             FunctionBody::Expr(expr) => walk_patterns_in_expr(expr, cb),
654             FunctionBody::Span { parent, text_range } => {
655                 parent
656                     .statements()
657                     .filter(|stmt| text_range.contains_range(stmt.syntax().text_range()))
658                     .for_each(|stmt| match stmt {
659                         ast::Stmt::ExprStmt(expr_stmt) => {
660                             if let Some(expr) = expr_stmt.expr() {
661                                 walk_patterns_in_expr(&expr, cb)
662                             }
663                         }
664                         ast::Stmt::Item(_) => (),
665                         ast::Stmt::LetStmt(stmt) => {
666                             if let Some(pat) = stmt.pat() {
667                                 walk_pat(&pat, cb);
668                             }
669                             if let Some(expr) = stmt.initializer() {
670                                 walk_patterns_in_expr(&expr, cb);
671                             }
672                         }
673                     });
674                 if let Some(expr) = parent
675                     .tail_expr()
676                     .filter(|it| text_range.contains_range(it.syntax().text_range()))
677                 {
678                     walk_patterns_in_expr(&expr, cb);
679                 }
680             }
681         }
682     }
683 
text_range(&self) -> TextRange684     fn text_range(&self) -> TextRange {
685         match self {
686             FunctionBody::Expr(expr) => expr.syntax().text_range(),
687             &FunctionBody::Span { text_range, .. } => text_range,
688         }
689     }
690 
contains_range(&self, range: TextRange) -> bool691     fn contains_range(&self, range: TextRange) -> bool {
692         self.text_range().contains_range(range)
693     }
694 
precedes_range(&self, range: TextRange) -> bool695     fn precedes_range(&self, range: TextRange) -> bool {
696         self.text_range().end() <= range.start()
697     }
698 
contains_node(&self, node: &SyntaxNode) -> bool699     fn contains_node(&self, node: &SyntaxNode) -> bool {
700         self.contains_range(node.text_range())
701     }
702 }
703 
704 impl FunctionBody {
705     /// Analyzes a function body, returning the used local variables that are referenced in it as well as
706     /// whether it contains an await expression.
analyze( &self, sema: &Semantics<'_, RootDatabase>, ) -> (FxIndexSet<Local>, Option<ast::SelfParam>)707     fn analyze(
708         &self,
709         sema: &Semantics<'_, RootDatabase>,
710     ) -> (FxIndexSet<Local>, Option<ast::SelfParam>) {
711         let mut self_param = None;
712         let mut res = FxIndexSet::default();
713         let mut add_name_if_local = |name_ref: Option<_>| {
714             let local_ref =
715                 match name_ref.and_then(|name_ref| NameRefClass::classify(sema, &name_ref)) {
716                     Some(
717                         NameRefClass::Definition(Definition::Local(local_ref))
718                         | NameRefClass::FieldShorthand { local_ref, field_ref: _ },
719                     ) => local_ref,
720                     _ => return,
721                 };
722             let InFile { file_id, value } = local_ref.primary_source(sema.db).source;
723             // locals defined inside macros are not relevant to us
724             if !file_id.is_macro() {
725                 match value {
726                     Either::Right(it) => {
727                         self_param.replace(it);
728                     }
729                     Either::Left(_) => {
730                         res.insert(local_ref);
731                     }
732                 }
733             }
734         };
735         self.walk_expr(&mut |expr| match expr {
736             ast::Expr::PathExpr(path_expr) => {
737                 add_name_if_local(path_expr.path().and_then(|it| it.as_single_name_ref()))
738             }
739             ast::Expr::ClosureExpr(closure_expr) => {
740                 if let Some(body) = closure_expr.body() {
741                     body.syntax()
742                         .descendants()
743                         .map(ast::NameRef::cast)
744                         .for_each(&mut add_name_if_local);
745                 }
746             }
747             ast::Expr::MacroExpr(expr) => {
748                 if let Some(tt) = expr.macro_call().and_then(|call| call.token_tree()) {
749                     tt.syntax()
750                         .descendants_with_tokens()
751                         .filter_map(SyntaxElement::into_token)
752                         .filter(|it| matches!(it.kind(), SyntaxKind::IDENT | T![self]))
753                         .flat_map(|t| sema.descend_into_macros(t))
754                         .for_each(|t| add_name_if_local(t.parent().and_then(ast::NameRef::cast)));
755                 }
756             }
757             _ => (),
758         });
759         (res, self_param)
760     }
761 
analyze_container( &self, sema: &Semantics<'_, RootDatabase>, ) -> Option<(ContainerInfo, bool)>762     fn analyze_container(
763         &self,
764         sema: &Semantics<'_, RootDatabase>,
765     ) -> Option<(ContainerInfo, bool)> {
766         let mut ancestors = self.parent()?.ancestors();
767         let infer_expr_opt = |expr| sema.type_of_expr(&expr?).map(TypeInfo::adjusted);
768         let mut parent_loop = None;
769         let mut set_parent_loop = |loop_: &dyn ast::HasLoopBody| {
770             if loop_
771                 .loop_body()
772                 .map_or(false, |it| it.syntax().text_range().contains_range(self.text_range()))
773             {
774                 parent_loop.get_or_insert(loop_.syntax().clone());
775             }
776         };
777 
778         let (is_const, expr, ty) = loop {
779             let anc = ancestors.next()?;
780             break match_ast! {
781                 match anc {
782                     ast::ClosureExpr(closure) => (false, closure.body(), infer_expr_opt(closure.body())),
783                     ast::BlockExpr(block_expr) => {
784                         let (constness, block) = match block_expr.modifier() {
785                             Some(ast::BlockModifier::Const(_)) => (true, block_expr),
786                             Some(ast::BlockModifier::Try(_)) => (false, block_expr),
787                             Some(ast::BlockModifier::Label(label)) if label.lifetime().is_some() => (false, block_expr),
788                             _ => continue,
789                         };
790                         let expr = Some(ast::Expr::BlockExpr(block));
791                         (constness, expr.clone(), infer_expr_opt(expr))
792                     },
793                     ast::Fn(fn_) => {
794                         let func = sema.to_def(&fn_)?;
795                         let mut ret_ty = func.ret_type(sema.db);
796                         if func.is_async(sema.db) {
797                             if let Some(async_ret) = func.async_ret_type(sema.db) {
798                                 ret_ty = async_ret;
799                             }
800                         }
801                         (fn_.const_token().is_some(), fn_.body().map(ast::Expr::BlockExpr), Some(ret_ty))
802                     },
803                     ast::Static(statik) => {
804                         (true, statik.body(), Some(sema.to_def(&statik)?.ty(sema.db)))
805                     },
806                     ast::ConstArg(ca) => {
807                         (true, ca.expr(), infer_expr_opt(ca.expr()))
808                     },
809                     ast::Const(konst) => {
810                         (true, konst.body(), Some(sema.to_def(&konst)?.ty(sema.db)))
811                     },
812                     ast::ConstParam(cp) => {
813                         (true, cp.default_val(), Some(sema.to_def(&cp)?.ty(sema.db)))
814                     },
815                     ast::ConstBlockPat(cbp) => {
816                         let expr = cbp.block_expr().map(ast::Expr::BlockExpr);
817                         (true, expr.clone(), infer_expr_opt(expr))
818                     },
819                     ast::Variant(__) => return None,
820                     ast::Meta(__) => return None,
821                     ast::LoopExpr(it) => {
822                         set_parent_loop(&it);
823                         continue;
824                     },
825                     ast::ForExpr(it) => {
826                         set_parent_loop(&it);
827                         continue;
828                     },
829                     ast::WhileExpr(it) => {
830                         set_parent_loop(&it);
831                         continue;
832                     },
833                     _ => continue,
834                 }
835             };
836         };
837 
838         let expr = expr?;
839         let contains_tail_expr = if let Some(body_tail) = self.tail_expr() {
840             let mut contains_tail_expr = false;
841             let tail_expr_range = body_tail.syntax().text_range();
842             for_each_tail_expr(&expr, &mut |e| {
843                 if tail_expr_range.contains_range(e.syntax().text_range()) {
844                     contains_tail_expr = true;
845                 }
846             });
847             contains_tail_expr
848         } else {
849             false
850         };
851 
852         let parent = self.parent()?;
853         let parents = generic_parents(&parent);
854         let generic_param_lists = parents.iter().filter_map(|it| it.generic_param_list()).collect();
855         let where_clauses = parents.iter().filter_map(|it| it.where_clause()).collect();
856 
857         Some((
858             ContainerInfo {
859                 is_const,
860                 parent_loop,
861                 ret_type: ty,
862                 generic_param_lists,
863                 where_clauses,
864             },
865             contains_tail_expr,
866         ))
867     }
868 
return_ty(&self, ctx: &AssistContext<'_>) -> Option<RetType>869     fn return_ty(&self, ctx: &AssistContext<'_>) -> Option<RetType> {
870         match self.tail_expr() {
871             Some(expr) => ctx.sema.type_of_expr(&expr).map(TypeInfo::original).map(RetType::Expr),
872             None => Some(RetType::Stmt),
873         }
874     }
875 
876     /// Local variables defined inside `body` that are accessed outside of it
ret_values<'a>( &self, ctx: &'a AssistContext<'_>, parent: &SyntaxNode, ) -> impl Iterator<Item = OutlivedLocal> + 'a877     fn ret_values<'a>(
878         &self,
879         ctx: &'a AssistContext<'_>,
880         parent: &SyntaxNode,
881     ) -> impl Iterator<Item = OutlivedLocal> + 'a {
882         let parent = parent.clone();
883         let range = self.text_range();
884         locals_defined_in_body(&ctx.sema, self)
885             .into_iter()
886             .filter_map(move |local| local_outlives_body(ctx, range, local, &parent))
887     }
888 
889     /// Analyses the function body for external control flow.
external_control_flow( &self, ctx: &AssistContext<'_>, container_info: &ContainerInfo, ) -> Option<ControlFlow>890     fn external_control_flow(
891         &self,
892         ctx: &AssistContext<'_>,
893         container_info: &ContainerInfo,
894     ) -> Option<ControlFlow> {
895         let mut ret_expr = None;
896         let mut try_expr = None;
897         let mut break_expr = None;
898         let mut continue_expr = None;
899         let mut is_async = false;
900         let mut _is_unsafe = false;
901 
902         let mut unsafe_depth = 0;
903         let mut loop_depth = 0;
904 
905         self.preorder_expr(&mut |expr| {
906             let expr = match expr {
907                 WalkEvent::Enter(e) => e,
908                 WalkEvent::Leave(expr) => {
909                     match expr {
910                         ast::Expr::LoopExpr(_)
911                         | ast::Expr::ForExpr(_)
912                         | ast::Expr::WhileExpr(_) => loop_depth -= 1,
913                         ast::Expr::BlockExpr(block_expr) if block_expr.unsafe_token().is_some() => {
914                             unsafe_depth -= 1
915                         }
916                         _ => (),
917                     }
918                     return false;
919                 }
920             };
921             match expr {
922                 ast::Expr::LoopExpr(_) | ast::Expr::ForExpr(_) | ast::Expr::WhileExpr(_) => {
923                     loop_depth += 1;
924                 }
925                 ast::Expr::BlockExpr(block_expr) if block_expr.unsafe_token().is_some() => {
926                     unsafe_depth += 1
927                 }
928                 ast::Expr::ReturnExpr(it) => {
929                     ret_expr = Some(it);
930                 }
931                 ast::Expr::TryExpr(it) => {
932                     try_expr = Some(it);
933                 }
934                 ast::Expr::BreakExpr(it) if loop_depth == 0 => {
935                     break_expr = Some(it);
936                 }
937                 ast::Expr::ContinueExpr(it) if loop_depth == 0 => {
938                     continue_expr = Some(it);
939                 }
940                 ast::Expr::AwaitExpr(_) => is_async = true,
941                 // FIXME: Do unsafe analysis on expression, sem highlighting knows this so we should be able
942                 // to just lift that out of there
943                 // expr if unsafe_depth ==0 && expr.is_unsafe => is_unsafe = true,
944                 _ => {}
945             }
946             false
947         });
948 
949         let kind = match (try_expr, ret_expr, break_expr, continue_expr) {
950             (Some(_), _, None, None) => {
951                 let ret_ty = container_info.ret_type.clone()?;
952                 let kind = TryKind::of_ty(ret_ty, ctx)?;
953 
954                 Some(FlowKind::Try { kind })
955             }
956             (Some(_), _, _, _) => {
957                 cov_mark::hit!(external_control_flow_try_and_bc);
958                 return None;
959             }
960             (None, Some(r), None, None) => Some(FlowKind::Return(r.expr())),
961             (None, Some(_), _, _) => {
962                 cov_mark::hit!(external_control_flow_return_and_bc);
963                 return None;
964             }
965             (None, None, Some(_), Some(_)) => {
966                 cov_mark::hit!(external_control_flow_break_and_continue);
967                 return None;
968             }
969             (None, None, Some(b), None) => Some(FlowKind::Break(b.lifetime(), b.expr())),
970             (None, None, None, Some(c)) => Some(FlowKind::Continue(c.lifetime())),
971             (None, None, None, None) => None,
972         };
973 
974         Some(ControlFlow { kind, is_async, is_unsafe: _is_unsafe })
975     }
976 
977     /// find variables that should be extracted as params
978     ///
979     /// Computes additional info that affects param type and mutability
extracted_function_params( &self, ctx: &AssistContext<'_>, container_info: &ContainerInfo, locals: impl Iterator<Item = Local>, ) -> Vec<Param>980     fn extracted_function_params(
981         &self,
982         ctx: &AssistContext<'_>,
983         container_info: &ContainerInfo,
984         locals: impl Iterator<Item = Local>,
985     ) -> Vec<Param> {
986         locals
987             .map(|local| (local, local.primary_source(ctx.db())))
988             .filter(|(_, src)| is_defined_outside_of_body(ctx, self, src))
989             .filter_map(|(local, src)| match src.into_ident_pat() {
990                 Some(src) => Some((local, src)),
991                 None => {
992                     stdx::never!(false, "Local::is_self returned false, but source is SelfParam");
993                     None
994                 }
995             })
996             .map(|(var, src)| {
997                 let usages = LocalUsages::find_local_usages(ctx, var);
998                 let ty = var.ty(ctx.db());
999 
1000                 let defined_outside_parent_loop = container_info
1001                     .parent_loop
1002                     .as_ref()
1003                     .map_or(true, |it| it.text_range().contains_range(src.syntax().text_range()));
1004 
1005                 let is_copy = ty.is_copy(ctx.db());
1006                 let has_usages = self.has_usages_after_body(&usages);
1007                 let requires_mut =
1008                     !ty.is_mutable_reference() && has_exclusive_usages(ctx, &usages, self);
1009                 // We can move the value into the function call if it's not used after the call,
1010                 // if the var is not used but defined outside a loop we are extracting from we can't move it either
1011                 // as the function will reuse it in the next iteration.
1012                 let move_local = (!has_usages && defined_outside_parent_loop) || ty.is_reference();
1013                 Param { var, ty, move_local, requires_mut, is_copy }
1014             })
1015             .collect()
1016     }
1017 
has_usages_after_body(&self, usages: &LocalUsages) -> bool1018     fn has_usages_after_body(&self, usages: &LocalUsages) -> bool {
1019         usages.iter().any(|reference| self.precedes_range(reference.range))
1020     }
1021 }
1022 
1023 enum GenericParent {
1024     Fn(ast::Fn),
1025     Impl(ast::Impl),
1026     Trait(ast::Trait),
1027 }
1028 
1029 impl GenericParent {
generic_param_list(&self) -> Option<ast::GenericParamList>1030     fn generic_param_list(&self) -> Option<ast::GenericParamList> {
1031         match self {
1032             GenericParent::Fn(fn_) => fn_.generic_param_list(),
1033             GenericParent::Impl(impl_) => impl_.generic_param_list(),
1034             GenericParent::Trait(trait_) => trait_.generic_param_list(),
1035         }
1036     }
1037 
where_clause(&self) -> Option<ast::WhereClause>1038     fn where_clause(&self) -> Option<ast::WhereClause> {
1039         match self {
1040             GenericParent::Fn(fn_) => fn_.where_clause(),
1041             GenericParent::Impl(impl_) => impl_.where_clause(),
1042             GenericParent::Trait(trait_) => trait_.where_clause(),
1043         }
1044     }
1045 }
1046 
1047 /// Search `parent`'s ancestors for items with potentially applicable generic parameters
generic_parents(parent: &SyntaxNode) -> Vec<GenericParent>1048 fn generic_parents(parent: &SyntaxNode) -> Vec<GenericParent> {
1049     let mut list = Vec::new();
1050     if let Some(parent_item) = parent.ancestors().find_map(ast::Item::cast) {
1051         match parent_item {
1052             ast::Item::Fn(ref fn_) => {
1053                 if let Some(parent_parent) = parent_item
1054                     .syntax()
1055                     .parent()
1056                     .and_then(|it| it.parent())
1057                     .and_then(ast::Item::cast)
1058                 {
1059                     match parent_parent {
1060                         ast::Item::Impl(impl_) => list.push(GenericParent::Impl(impl_)),
1061                         ast::Item::Trait(trait_) => list.push(GenericParent::Trait(trait_)),
1062                         _ => (),
1063                     }
1064                 }
1065                 list.push(GenericParent::Fn(fn_.clone()));
1066             }
1067             _ => (),
1068         }
1069     }
1070     list
1071 }
1072 
1073 /// checks if relevant var is used with `&mut` access inside body
has_exclusive_usages( ctx: &AssistContext<'_>, usages: &LocalUsages, body: &FunctionBody, ) -> bool1074 fn has_exclusive_usages(
1075     ctx: &AssistContext<'_>,
1076     usages: &LocalUsages,
1077     body: &FunctionBody,
1078 ) -> bool {
1079     usages
1080         .iter()
1081         .filter(|reference| body.contains_range(reference.range))
1082         .any(|reference| reference_is_exclusive(reference, body, ctx))
1083 }
1084 
1085 /// checks if this reference requires `&mut` access inside node
reference_is_exclusive( reference: &FileReference, node: &dyn HasTokenAtOffset, ctx: &AssistContext<'_>, ) -> bool1086 fn reference_is_exclusive(
1087     reference: &FileReference,
1088     node: &dyn HasTokenAtOffset,
1089     ctx: &AssistContext<'_>,
1090 ) -> bool {
1091     // we directly modify variable with set: `n = 0`, `n += 1`
1092     if reference.category == Some(ReferenceCategory::Write) {
1093         return true;
1094     }
1095 
1096     // we take `&mut` reference to variable: `&mut v`
1097     let path = match path_element_of_reference(node, reference) {
1098         Some(path) => path,
1099         None => return false,
1100     };
1101 
1102     expr_require_exclusive_access(ctx, &path).unwrap_or(false)
1103 }
1104 
1105 /// checks if this expr requires `&mut` access, recurses on field access
expr_require_exclusive_access(ctx: &AssistContext<'_>, expr: &ast::Expr) -> Option<bool>1106 fn expr_require_exclusive_access(ctx: &AssistContext<'_>, expr: &ast::Expr) -> Option<bool> {
1107     if let ast::Expr::MacroExpr(_) = expr {
1108         // FIXME: expand macro and check output for mutable usages of the variable?
1109         return None;
1110     }
1111 
1112     let parent = expr.syntax().parent()?;
1113 
1114     if let Some(bin_expr) = ast::BinExpr::cast(parent.clone()) {
1115         if matches!(bin_expr.op_kind()?, ast::BinaryOp::Assignment { .. }) {
1116             return Some(bin_expr.lhs()?.syntax() == expr.syntax());
1117         }
1118         return Some(false);
1119     }
1120 
1121     if let Some(ref_expr) = ast::RefExpr::cast(parent.clone()) {
1122         return Some(ref_expr.mut_token().is_some());
1123     }
1124 
1125     if let Some(method_call) = ast::MethodCallExpr::cast(parent.clone()) {
1126         let func = ctx.sema.resolve_method_call(&method_call)?;
1127         let self_param = func.self_param(ctx.db())?;
1128         let access = self_param.access(ctx.db());
1129 
1130         return Some(matches!(access, hir::Access::Exclusive));
1131     }
1132 
1133     if let Some(field) = ast::FieldExpr::cast(parent) {
1134         return expr_require_exclusive_access(ctx, &field.into());
1135     }
1136 
1137     Some(false)
1138 }
1139 
1140 trait HasTokenAtOffset {
token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken>1141     fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken>;
1142 }
1143 
1144 impl HasTokenAtOffset for SyntaxNode {
token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken>1145     fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken> {
1146         SyntaxNode::token_at_offset(self, offset)
1147     }
1148 }
1149 
1150 impl HasTokenAtOffset for FunctionBody {
token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken>1151     fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken> {
1152         match self {
1153             FunctionBody::Expr(expr) => expr.syntax().token_at_offset(offset),
1154             FunctionBody::Span { parent, text_range } => {
1155                 match parent.syntax().token_at_offset(offset) {
1156                     TokenAtOffset::None => TokenAtOffset::None,
1157                     TokenAtOffset::Single(t) => {
1158                         if text_range.contains_range(t.text_range()) {
1159                             TokenAtOffset::Single(t)
1160                         } else {
1161                             TokenAtOffset::None
1162                         }
1163                     }
1164                     TokenAtOffset::Between(a, b) => {
1165                         match (
1166                             text_range.contains_range(a.text_range()),
1167                             text_range.contains_range(b.text_range()),
1168                         ) {
1169                             (true, true) => TokenAtOffset::Between(a, b),
1170                             (true, false) => TokenAtOffset::Single(a),
1171                             (false, true) => TokenAtOffset::Single(b),
1172                             (false, false) => TokenAtOffset::None,
1173                         }
1174                     }
1175                 }
1176             }
1177         }
1178     }
1179 }
1180 
1181 /// find relevant `ast::Expr` for reference
1182 ///
1183 /// # Preconditions
1184 ///
1185 /// `node` must cover `reference`, that is `node.text_range().contains_range(reference.range)`
path_element_of_reference( node: &dyn HasTokenAtOffset, reference: &FileReference, ) -> Option<ast::Expr>1186 fn path_element_of_reference(
1187     node: &dyn HasTokenAtOffset,
1188     reference: &FileReference,
1189 ) -> Option<ast::Expr> {
1190     let token = node.token_at_offset(reference.range.start()).right_biased().or_else(|| {
1191         stdx::never!(false, "cannot find token at variable usage: {:?}", reference);
1192         None
1193     })?;
1194     let path = token.parent_ancestors().find_map(ast::Expr::cast).or_else(|| {
1195         stdx::never!(false, "cannot find path parent of variable usage: {:?}", token);
1196         None
1197     })?;
1198     stdx::always!(
1199         matches!(path, ast::Expr::PathExpr(_) | ast::Expr::MacroExpr(_)),
1200         "unexpected expression type for variable usage: {:?}",
1201         path
1202     );
1203     Some(path)
1204 }
1205 
1206 /// list local variables defined inside `body`
locals_defined_in_body( sema: &Semantics<'_, RootDatabase>, body: &FunctionBody, ) -> FxIndexSet<Local>1207 fn locals_defined_in_body(
1208     sema: &Semantics<'_, RootDatabase>,
1209     body: &FunctionBody,
1210 ) -> FxIndexSet<Local> {
1211     // FIXME: this doesn't work well with macros
1212     //        see https://github.com/rust-lang/rust-analyzer/pull/7535#discussion_r570048550
1213     let mut res = FxIndexSet::default();
1214     body.walk_pat(&mut |pat| {
1215         if let ast::Pat::IdentPat(pat) = pat {
1216             if let Some(local) = sema.to_def(&pat) {
1217                 res.insert(local);
1218             }
1219         }
1220     });
1221     res
1222 }
1223 
1224 /// Returns usage details if local variable is used after(outside of) body
local_outlives_body( ctx: &AssistContext<'_>, body_range: TextRange, local: Local, parent: &SyntaxNode, ) -> Option<OutlivedLocal>1225 fn local_outlives_body(
1226     ctx: &AssistContext<'_>,
1227     body_range: TextRange,
1228     local: Local,
1229     parent: &SyntaxNode,
1230 ) -> Option<OutlivedLocal> {
1231     let usages = LocalUsages::find_local_usages(ctx, local);
1232     let mut has_mut_usages = false;
1233     let mut any_outlives = false;
1234     for usage in usages.iter() {
1235         if body_range.end() <= usage.range.start() {
1236             has_mut_usages |= reference_is_exclusive(usage, parent, ctx);
1237             any_outlives |= true;
1238             if has_mut_usages {
1239                 break; // no need to check more elements we have all the info we wanted
1240             }
1241         }
1242     }
1243     if !any_outlives {
1244         return None;
1245     }
1246     Some(OutlivedLocal { local, mut_usage_outside_body: has_mut_usages })
1247 }
1248 
1249 /// checks if the relevant local was defined before(outside of) body
is_defined_outside_of_body( ctx: &AssistContext<'_>, body: &FunctionBody, src: &LocalSource, ) -> bool1250 fn is_defined_outside_of_body(
1251     ctx: &AssistContext<'_>,
1252     body: &FunctionBody,
1253     src: &LocalSource,
1254 ) -> bool {
1255     src.original_file(ctx.db()) == ctx.file_id() && !body.contains_node(src.syntax())
1256 }
1257 
1258 /// find where to put extracted function definition
1259 ///
1260 /// Function should be put right after returned node
node_to_insert_after(body: &FunctionBody, anchor: Anchor) -> Option<SyntaxNode>1261 fn node_to_insert_after(body: &FunctionBody, anchor: Anchor) -> Option<SyntaxNode> {
1262     let node = body.node();
1263     let mut ancestors = node.ancestors().peekable();
1264     let mut last_ancestor = None;
1265     while let Some(next_ancestor) = ancestors.next() {
1266         match next_ancestor.kind() {
1267             SyntaxKind::SOURCE_FILE => break,
1268             SyntaxKind::IMPL => {
1269                 if body.extracted_from_trait_impl() && matches!(anchor, Anchor::Method) {
1270                     let impl_node = find_non_trait_impl(&next_ancestor);
1271                     if let target_node @ Some(_) = impl_node.as_ref().and_then(last_impl_member) {
1272                         return target_node;
1273                     }
1274                 }
1275             }
1276             SyntaxKind::ITEM_LIST if !matches!(anchor, Anchor::Freestanding) => continue,
1277             SyntaxKind::ITEM_LIST => {
1278                 if ancestors.peek().map(SyntaxNode::kind) == Some(SyntaxKind::MODULE) {
1279                     break;
1280                 }
1281             }
1282             SyntaxKind::ASSOC_ITEM_LIST if !matches!(anchor, Anchor::Method) => continue,
1283             SyntaxKind::ASSOC_ITEM_LIST if body.extracted_from_trait_impl() => continue,
1284             SyntaxKind::ASSOC_ITEM_LIST => {
1285                 if ancestors.peek().map(SyntaxNode::kind) == Some(SyntaxKind::IMPL) {
1286                     break;
1287                 }
1288             }
1289             _ => (),
1290         }
1291         last_ancestor = Some(next_ancestor);
1292     }
1293     last_ancestor
1294 }
1295 
find_non_trait_impl(trait_impl: &SyntaxNode) -> Option<ast::Impl>1296 fn find_non_trait_impl(trait_impl: &SyntaxNode) -> Option<ast::Impl> {
1297     let as_impl = ast::Impl::cast(trait_impl.clone())?;
1298     let impl_type = Some(impl_type_name(&as_impl)?);
1299 
1300     let siblings = trait_impl.parent()?.children();
1301     siblings
1302         .filter_map(ast::Impl::cast)
1303         .find(|s| impl_type_name(s) == impl_type && !is_trait_impl(s))
1304 }
1305 
last_impl_member(impl_node: &ast::Impl) -> Option<SyntaxNode>1306 fn last_impl_member(impl_node: &ast::Impl) -> Option<SyntaxNode> {
1307     let last_child = impl_node.assoc_item_list()?.assoc_items().last()?;
1308     Some(last_child.syntax().clone())
1309 }
1310 
is_trait_impl(node: &ast::Impl) -> bool1311 fn is_trait_impl(node: &ast::Impl) -> bool {
1312     node.trait_().is_some()
1313 }
1314 
impl_type_name(impl_node: &ast::Impl) -> Option<String>1315 fn impl_type_name(impl_node: &ast::Impl) -> Option<String> {
1316     Some(impl_node.self_ty()?.to_string())
1317 }
1318 
make_call(ctx: &AssistContext<'_>, fun: &Function, indent: IndentLevel) -> String1319 fn make_call(ctx: &AssistContext<'_>, fun: &Function, indent: IndentLevel) -> String {
1320     let ret_ty = fun.return_type(ctx);
1321 
1322     let args = make::arg_list(fun.params.iter().map(|param| param.to_arg(ctx)));
1323     let name = fun.name.clone();
1324     let mut call_expr = if fun.self_param.is_some() {
1325         let self_arg = make::expr_path(make::ext::ident_path("self"));
1326         make::expr_method_call(self_arg, name, args)
1327     } else {
1328         let func = make::expr_path(make::path_unqualified(make::path_segment(name)));
1329         make::expr_call(func, args)
1330     };
1331 
1332     let handler = FlowHandler::from_ret_ty(fun, &ret_ty);
1333 
1334     if fun.control_flow.is_async {
1335         call_expr = make::expr_await(call_expr);
1336     }
1337     let expr = handler.make_call_expr(call_expr).indent(indent);
1338 
1339     let mut_modifier = |var: &OutlivedLocal| if var.mut_usage_outside_body { "mut " } else { "" };
1340 
1341     let mut buf = String::new();
1342     match fun.outliving_locals.as_slice() {
1343         [] => {}
1344         [var] => {
1345             let modifier = mut_modifier(var);
1346             let name = var.local.name(ctx.db());
1347             format_to!(buf, "let {modifier}{} = ", name.display(ctx.db()))
1348         }
1349         vars => {
1350             buf.push_str("let (");
1351             let bindings = vars.iter().format_with(", ", |local, f| {
1352                 let modifier = mut_modifier(local);
1353                 let name = local.local.name(ctx.db());
1354                 f(&format_args!("{modifier}{}", name.display(ctx.db())))?;
1355                 Ok(())
1356             });
1357             format_to!(buf, "{bindings}");
1358             buf.push_str(") = ");
1359         }
1360     }
1361 
1362     format_to!(buf, "{expr}");
1363     let insert_comma = fun
1364         .body
1365         .parent()
1366         .and_then(ast::MatchArm::cast)
1367         .map_or(false, |it| it.comma_token().is_none());
1368     if insert_comma {
1369         buf.push(',');
1370     } else if fun.ret_ty.is_unit() && (!fun.outliving_locals.is_empty() || !expr.is_block_like()) {
1371         buf.push(';');
1372     }
1373     buf
1374 }
1375 
1376 enum FlowHandler {
1377     None,
1378     Try { kind: TryKind },
1379     If { action: FlowKind },
1380     IfOption { action: FlowKind },
1381     MatchOption { none: FlowKind },
1382     MatchResult { err: FlowKind },
1383 }
1384 
1385 impl FlowHandler {
from_ret_ty(fun: &Function, ret_ty: &FunType) -> FlowHandler1386     fn from_ret_ty(fun: &Function, ret_ty: &FunType) -> FlowHandler {
1387         match &fun.control_flow.kind {
1388             None => FlowHandler::None,
1389             Some(flow_kind) => {
1390                 let action = flow_kind.clone();
1391                 if let FunType::Unit = ret_ty {
1392                     match flow_kind {
1393                         FlowKind::Return(None)
1394                         | FlowKind::Break(_, None)
1395                         | FlowKind::Continue(_) => FlowHandler::If { action },
1396                         FlowKind::Return(_) | FlowKind::Break(_, _) => {
1397                             FlowHandler::IfOption { action }
1398                         }
1399                         FlowKind::Try { kind } => FlowHandler::Try { kind: kind.clone() },
1400                     }
1401                 } else {
1402                     match flow_kind {
1403                         FlowKind::Return(None)
1404                         | FlowKind::Break(_, None)
1405                         | FlowKind::Continue(_) => FlowHandler::MatchOption { none: action },
1406                         FlowKind::Return(_) | FlowKind::Break(_, _) => {
1407                             FlowHandler::MatchResult { err: action }
1408                         }
1409                         FlowKind::Try { kind } => FlowHandler::Try { kind: kind.clone() },
1410                     }
1411                 }
1412             }
1413         }
1414     }
1415 
make_call_expr(&self, call_expr: ast::Expr) -> ast::Expr1416     fn make_call_expr(&self, call_expr: ast::Expr) -> ast::Expr {
1417         match self {
1418             FlowHandler::None => call_expr,
1419             FlowHandler::Try { kind: _ } => make::expr_try(call_expr),
1420             FlowHandler::If { action } => {
1421                 let action = action.make_result_handler(None);
1422                 let stmt = make::expr_stmt(action);
1423                 let block = make::block_expr(iter::once(stmt.into()), None);
1424                 let controlflow_break_path = make::path_from_text("ControlFlow::Break");
1425                 let condition = make::expr_let(
1426                     make::tuple_struct_pat(
1427                         controlflow_break_path,
1428                         iter::once(make::wildcard_pat().into()),
1429                     )
1430                     .into(),
1431                     call_expr,
1432                 );
1433                 make::expr_if(condition.into(), block, None)
1434             }
1435             FlowHandler::IfOption { action } => {
1436                 let path = make::ext::ident_path("Some");
1437                 let value_pat = make::ext::simple_ident_pat(make::name("value"));
1438                 let pattern = make::tuple_struct_pat(path, iter::once(value_pat.into()));
1439                 let cond = make::expr_let(pattern.into(), call_expr);
1440                 let value = make::expr_path(make::ext::ident_path("value"));
1441                 let action_expr = action.make_result_handler(Some(value));
1442                 let action_stmt = make::expr_stmt(action_expr);
1443                 let then = make::block_expr(iter::once(action_stmt.into()), None);
1444                 make::expr_if(cond.into(), then, None)
1445             }
1446             FlowHandler::MatchOption { none } => {
1447                 let some_name = "value";
1448 
1449                 let some_arm = {
1450                     let path = make::ext::ident_path("Some");
1451                     let value_pat = make::ext::simple_ident_pat(make::name(some_name));
1452                     let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
1453                     let value = make::expr_path(make::ext::ident_path(some_name));
1454                     make::match_arm(iter::once(pat.into()), None, value)
1455                 };
1456                 let none_arm = {
1457                     let path = make::ext::ident_path("None");
1458                     let pat = make::path_pat(path);
1459                     make::match_arm(iter::once(pat), None, none.make_result_handler(None))
1460                 };
1461                 let arms = make::match_arm_list(vec![some_arm, none_arm]);
1462                 make::expr_match(call_expr, arms)
1463             }
1464             FlowHandler::MatchResult { err } => {
1465                 let ok_name = "value";
1466                 let err_name = "value";
1467 
1468                 let ok_arm = {
1469                     let path = make::ext::ident_path("Ok");
1470                     let value_pat = make::ext::simple_ident_pat(make::name(ok_name));
1471                     let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
1472                     let value = make::expr_path(make::ext::ident_path(ok_name));
1473                     make::match_arm(iter::once(pat.into()), None, value)
1474                 };
1475                 let err_arm = {
1476                     let path = make::ext::ident_path("Err");
1477                     let value_pat = make::ext::simple_ident_pat(make::name(err_name));
1478                     let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
1479                     let value = make::expr_path(make::ext::ident_path(err_name));
1480                     make::match_arm(
1481                         iter::once(pat.into()),
1482                         None,
1483                         err.make_result_handler(Some(value)),
1484                     )
1485                 };
1486                 let arms = make::match_arm_list(vec![ok_arm, err_arm]);
1487                 make::expr_match(call_expr, arms)
1488             }
1489         }
1490     }
1491 }
1492 
path_expr_from_local(ctx: &AssistContext<'_>, var: Local) -> ast::Expr1493 fn path_expr_from_local(ctx: &AssistContext<'_>, var: Local) -> ast::Expr {
1494     let name = var.name(ctx.db()).display(ctx.db()).to_string();
1495     make::expr_path(make::ext::ident_path(&name))
1496 }
1497 
format_function( ctx: &AssistContext<'_>, module: hir::Module, fun: &Function, old_indent: IndentLevel, new_indent: IndentLevel, ) -> String1498 fn format_function(
1499     ctx: &AssistContext<'_>,
1500     module: hir::Module,
1501     fun: &Function,
1502     old_indent: IndentLevel,
1503     new_indent: IndentLevel,
1504 ) -> String {
1505     let mut fn_def = String::new();
1506 
1507     let fun_name = &fun.name;
1508     let params = fun.make_param_list(ctx, module);
1509     let ret_ty = fun.make_ret_ty(ctx, module);
1510     let body = make_body(ctx, old_indent, new_indent, fun);
1511     let const_kw = if fun.mods.is_const { "const " } else { "" };
1512     let async_kw = if fun.control_flow.is_async { "async " } else { "" };
1513     let unsafe_kw = if fun.control_flow.is_unsafe { "unsafe " } else { "" };
1514     let (generic_params, where_clause) = make_generic_params_and_where_clause(ctx, fun);
1515 
1516     format_to!(fn_def, "\n\n{new_indent}{const_kw}{async_kw}{unsafe_kw}");
1517     match ctx.config.snippet_cap {
1518         Some(_) => format_to!(fn_def, "fn $0{fun_name}"),
1519         None => format_to!(fn_def, "fn {fun_name}"),
1520     }
1521 
1522     if let Some(generic_params) = generic_params {
1523         format_to!(fn_def, "{generic_params}");
1524     }
1525 
1526     format_to!(fn_def, "{params}");
1527 
1528     if let Some(ret_ty) = ret_ty {
1529         format_to!(fn_def, " {ret_ty}");
1530     }
1531 
1532     if let Some(where_clause) = where_clause {
1533         format_to!(fn_def, " {where_clause}");
1534     }
1535 
1536     format_to!(fn_def, " {body}");
1537 
1538     fn_def
1539 }
1540 
make_generic_params_and_where_clause( ctx: &AssistContext<'_>, fun: &Function, ) -> (Option<ast::GenericParamList>, Option<ast::WhereClause>)1541 fn make_generic_params_and_where_clause(
1542     ctx: &AssistContext<'_>,
1543     fun: &Function,
1544 ) -> (Option<ast::GenericParamList>, Option<ast::WhereClause>) {
1545     let used_type_params = fun.type_params(ctx);
1546 
1547     let generic_param_list = make_generic_param_list(ctx, fun, &used_type_params);
1548     let where_clause = make_where_clause(ctx, fun, &used_type_params);
1549 
1550     (generic_param_list, where_clause)
1551 }
1552 
make_generic_param_list( ctx: &AssistContext<'_>, fun: &Function, used_type_params: &[TypeParam], ) -> Option<ast::GenericParamList>1553 fn make_generic_param_list(
1554     ctx: &AssistContext<'_>,
1555     fun: &Function,
1556     used_type_params: &[TypeParam],
1557 ) -> Option<ast::GenericParamList> {
1558     let mut generic_params = fun
1559         .mods
1560         .generic_param_lists
1561         .iter()
1562         .flat_map(|parent_params| {
1563             parent_params
1564                 .generic_params()
1565                 .filter(|param| param_is_required(ctx, param, used_type_params))
1566         })
1567         .peekable();
1568 
1569     if generic_params.peek().is_some() {
1570         Some(make::generic_param_list(generic_params))
1571     } else {
1572         None
1573     }
1574 }
1575 
param_is_required( ctx: &AssistContext<'_>, param: &ast::GenericParam, used_type_params: &[TypeParam], ) -> bool1576 fn param_is_required(
1577     ctx: &AssistContext<'_>,
1578     param: &ast::GenericParam,
1579     used_type_params: &[TypeParam],
1580 ) -> bool {
1581     match param {
1582         ast::GenericParam::ConstParam(_) | ast::GenericParam::LifetimeParam(_) => false,
1583         ast::GenericParam::TypeParam(type_param) => match &ctx.sema.to_def(type_param) {
1584             Some(def) => used_type_params.contains(def),
1585             _ => false,
1586         },
1587     }
1588 }
1589 
make_where_clause( ctx: &AssistContext<'_>, fun: &Function, used_type_params: &[TypeParam], ) -> Option<ast::WhereClause>1590 fn make_where_clause(
1591     ctx: &AssistContext<'_>,
1592     fun: &Function,
1593     used_type_params: &[TypeParam],
1594 ) -> Option<ast::WhereClause> {
1595     let mut predicates = fun
1596         .mods
1597         .where_clauses
1598         .iter()
1599         .flat_map(|parent_where_clause| {
1600             parent_where_clause
1601                 .predicates()
1602                 .filter(|pred| pred_is_required(ctx, pred, used_type_params))
1603         })
1604         .peekable();
1605 
1606     if predicates.peek().is_some() {
1607         Some(make::where_clause(predicates))
1608     } else {
1609         None
1610     }
1611 }
1612 
pred_is_required( ctx: &AssistContext<'_>, pred: &ast::WherePred, used_type_params: &[TypeParam], ) -> bool1613 fn pred_is_required(
1614     ctx: &AssistContext<'_>,
1615     pred: &ast::WherePred,
1616     used_type_params: &[TypeParam],
1617 ) -> bool {
1618     match resolved_type_param(ctx, pred) {
1619         Some(it) => used_type_params.contains(&it),
1620         None => false,
1621     }
1622 }
1623 
resolved_type_param(ctx: &AssistContext<'_>, pred: &ast::WherePred) -> Option<TypeParam>1624 fn resolved_type_param(ctx: &AssistContext<'_>, pred: &ast::WherePred) -> Option<TypeParam> {
1625     let path = match pred.ty()? {
1626         ast::Type::PathType(path_type) => path_type.path(),
1627         _ => None,
1628     }?;
1629 
1630     match ctx.sema.resolve_path(&path)? {
1631         PathResolution::TypeParam(type_param) => Some(type_param),
1632         _ => None,
1633     }
1634 }
1635 
1636 impl Function {
1637     /// Collect all the `TypeParam`s used in the `body` and `params`.
type_params(&self, ctx: &AssistContext<'_>) -> Vec<TypeParam>1638     fn type_params(&self, ctx: &AssistContext<'_>) -> Vec<TypeParam> {
1639         let type_params_in_descendant_paths =
1640             self.body.descendant_paths().filter_map(|it| match ctx.sema.resolve_path(&it) {
1641                 Some(PathResolution::TypeParam(type_param)) => Some(type_param),
1642                 _ => None,
1643             });
1644         let type_params_in_params = self.params.iter().filter_map(|p| p.ty.as_type_param(ctx.db()));
1645         type_params_in_descendant_paths.chain(type_params_in_params).collect()
1646     }
1647 
make_param_list(&self, ctx: &AssistContext<'_>, module: hir::Module) -> ast::ParamList1648     fn make_param_list(&self, ctx: &AssistContext<'_>, module: hir::Module) -> ast::ParamList {
1649         let self_param = self.self_param.clone();
1650         let params = self.params.iter().map(|param| param.to_param(ctx, module));
1651         make::param_list(self_param, params)
1652     }
1653 
make_ret_ty(&self, ctx: &AssistContext<'_>, module: hir::Module) -> Option<ast::RetType>1654     fn make_ret_ty(&self, ctx: &AssistContext<'_>, module: hir::Module) -> Option<ast::RetType> {
1655         let fun_ty = self.return_type(ctx);
1656         let handler = if self.contains_tail_expr {
1657             FlowHandler::None
1658         } else {
1659             FlowHandler::from_ret_ty(self, &fun_ty)
1660         };
1661         let ret_ty = match &handler {
1662             FlowHandler::None => {
1663                 if matches!(fun_ty, FunType::Unit) {
1664                     return None;
1665                 }
1666                 fun_ty.make_ty(ctx, module)
1667             }
1668             FlowHandler::Try { kind: TryKind::Option } => {
1669                 make::ext::ty_option(fun_ty.make_ty(ctx, module))
1670             }
1671             FlowHandler::Try { kind: TryKind::Result { ty: parent_ret_ty } } => {
1672                 let handler_ty = parent_ret_ty
1673                     .type_arguments()
1674                     .nth(1)
1675                     .map(|ty| make_ty(&ty, ctx, module))
1676                     .unwrap_or_else(make::ty_placeholder);
1677                 make::ext::ty_result(fun_ty.make_ty(ctx, module), handler_ty)
1678             }
1679             FlowHandler::If { .. } => make::ty("ControlFlow<()>"),
1680             FlowHandler::IfOption { action } => {
1681                 let handler_ty = action
1682                     .expr_ty(ctx)
1683                     .map(|ty| make_ty(&ty, ctx, module))
1684                     .unwrap_or_else(make::ty_placeholder);
1685                 make::ext::ty_option(handler_ty)
1686             }
1687             FlowHandler::MatchOption { .. } => make::ext::ty_option(fun_ty.make_ty(ctx, module)),
1688             FlowHandler::MatchResult { err } => {
1689                 let handler_ty = err
1690                     .expr_ty(ctx)
1691                     .map(|ty| make_ty(&ty, ctx, module))
1692                     .unwrap_or_else(make::ty_placeholder);
1693                 make::ext::ty_result(fun_ty.make_ty(ctx, module), handler_ty)
1694             }
1695         };
1696         Some(make::ret_type(ret_ty))
1697     }
1698 }
1699 
1700 impl FunType {
make_ty(&self, ctx: &AssistContext<'_>, module: hir::Module) -> ast::Type1701     fn make_ty(&self, ctx: &AssistContext<'_>, module: hir::Module) -> ast::Type {
1702         match self {
1703             FunType::Unit => make::ty_unit(),
1704             FunType::Single(ty) => make_ty(ty, ctx, module),
1705             FunType::Tuple(types) => match types.as_slice() {
1706                 [] => {
1707                     stdx::never!("tuple type with 0 elements");
1708                     make::ty_unit()
1709                 }
1710                 [ty] => {
1711                     stdx::never!("tuple type with 1 element");
1712                     make_ty(ty, ctx, module)
1713                 }
1714                 types => {
1715                     let types = types.iter().map(|ty| make_ty(ty, ctx, module));
1716                     make::ty_tuple(types)
1717                 }
1718             },
1719         }
1720     }
1721 }
1722 
make_body( ctx: &AssistContext<'_>, old_indent: IndentLevel, new_indent: IndentLevel, fun: &Function, ) -> ast::BlockExpr1723 fn make_body(
1724     ctx: &AssistContext<'_>,
1725     old_indent: IndentLevel,
1726     new_indent: IndentLevel,
1727     fun: &Function,
1728 ) -> ast::BlockExpr {
1729     let ret_ty = fun.return_type(ctx);
1730     let handler = if fun.contains_tail_expr {
1731         FlowHandler::None
1732     } else {
1733         FlowHandler::from_ret_ty(fun, &ret_ty)
1734     };
1735 
1736     let block = match &fun.body {
1737         FunctionBody::Expr(expr) => {
1738             let expr = rewrite_body_segment(ctx, &fun.params, &handler, expr.syntax());
1739             let expr = ast::Expr::cast(expr).unwrap();
1740             match expr {
1741                 ast::Expr::BlockExpr(block) => {
1742                     // If the extracted expression is itself a block, there is no need to wrap it inside another block.
1743                     let block = block.dedent(old_indent);
1744                     // Recreate the block for formatting consistency with other extracted functions.
1745                     make::block_expr(block.statements(), block.tail_expr())
1746                 }
1747                 _ => {
1748                     let expr = expr.dedent(old_indent).indent(IndentLevel(1));
1749 
1750                     make::block_expr(Vec::new(), Some(expr))
1751                 }
1752             }
1753         }
1754         FunctionBody::Span { parent, text_range } => {
1755             let mut elements: Vec<_> = parent
1756                 .syntax()
1757                 .children_with_tokens()
1758                 .filter(|it| text_range.contains_range(it.text_range()))
1759                 .map(|it| match &it {
1760                     syntax::NodeOrToken::Node(n) => syntax::NodeOrToken::Node(
1761                         rewrite_body_segment(ctx, &fun.params, &handler, n),
1762                     ),
1763                     _ => it,
1764                 })
1765                 .collect();
1766 
1767             let mut tail_expr = match &elements.last() {
1768                 Some(syntax::NodeOrToken::Node(node)) if ast::Expr::can_cast(node.kind()) => {
1769                     ast::Expr::cast(node.clone())
1770                 }
1771                 _ => None,
1772             };
1773 
1774             match tail_expr {
1775                 Some(_) => {
1776                     elements.pop();
1777                 }
1778                 None => match fun.outliving_locals.as_slice() {
1779                     [] => {}
1780                     [var] => {
1781                         tail_expr = Some(path_expr_from_local(ctx, var.local));
1782                     }
1783                     vars => {
1784                         let exprs = vars.iter().map(|var| path_expr_from_local(ctx, var.local));
1785                         let expr = make::expr_tuple(exprs);
1786                         tail_expr = Some(expr);
1787                     }
1788                 },
1789             };
1790 
1791             let body_indent = IndentLevel(1);
1792             let elements = elements
1793                 .into_iter()
1794                 .map(|node_or_token| match &node_or_token {
1795                     syntax::NodeOrToken::Node(node) => match ast::Stmt::cast(node.clone()) {
1796                         Some(stmt) => {
1797                             let indented = stmt.dedent(old_indent).indent(body_indent);
1798                             let ast_node = indented.syntax().clone_subtree();
1799                             syntax::NodeOrToken::Node(ast_node)
1800                         }
1801                         _ => node_or_token,
1802                     },
1803                     _ => node_or_token,
1804                 })
1805                 .collect::<Vec<SyntaxElement>>();
1806             let tail_expr = tail_expr.map(|expr| expr.dedent(old_indent).indent(body_indent));
1807 
1808             make::hacky_block_expr(elements, tail_expr)
1809         }
1810     };
1811 
1812     let block = match &handler {
1813         FlowHandler::None => block,
1814         FlowHandler::Try { kind } => {
1815             let block = with_default_tail_expr(block, make::expr_unit());
1816             map_tail_expr(block, |tail_expr| {
1817                 let constructor = match kind {
1818                     TryKind::Option => "Some",
1819                     TryKind::Result { .. } => "Ok",
1820                 };
1821                 let func = make::expr_path(make::ext::ident_path(constructor));
1822                 let args = make::arg_list(iter::once(tail_expr));
1823                 make::expr_call(func, args)
1824             })
1825         }
1826         FlowHandler::If { .. } => {
1827             let controlflow_continue = make::expr_call(
1828                 make::expr_path(make::path_from_text("ControlFlow::Continue")),
1829                 make::arg_list(iter::once(make::expr_unit())),
1830             );
1831             with_tail_expr(block, controlflow_continue)
1832         }
1833         FlowHandler::IfOption { .. } => {
1834             let none = make::expr_path(make::ext::ident_path("None"));
1835             with_tail_expr(block, none)
1836         }
1837         FlowHandler::MatchOption { .. } => map_tail_expr(block, |tail_expr| {
1838             let some = make::expr_path(make::ext::ident_path("Some"));
1839             let args = make::arg_list(iter::once(tail_expr));
1840             make::expr_call(some, args)
1841         }),
1842         FlowHandler::MatchResult { .. } => map_tail_expr(block, |tail_expr| {
1843             let ok = make::expr_path(make::ext::ident_path("Ok"));
1844             let args = make::arg_list(iter::once(tail_expr));
1845             make::expr_call(ok, args)
1846         }),
1847     };
1848 
1849     block.indent(new_indent)
1850 }
1851 
map_tail_expr(block: ast::BlockExpr, f: impl FnOnce(ast::Expr) -> ast::Expr) -> ast::BlockExpr1852 fn map_tail_expr(block: ast::BlockExpr, f: impl FnOnce(ast::Expr) -> ast::Expr) -> ast::BlockExpr {
1853     let tail_expr = match block.tail_expr() {
1854         Some(tail_expr) => tail_expr,
1855         None => return block,
1856     };
1857     make::block_expr(block.statements(), Some(f(tail_expr)))
1858 }
1859 
with_default_tail_expr(block: ast::BlockExpr, tail_expr: ast::Expr) -> ast::BlockExpr1860 fn with_default_tail_expr(block: ast::BlockExpr, tail_expr: ast::Expr) -> ast::BlockExpr {
1861     match block.tail_expr() {
1862         Some(_) => block,
1863         None => make::block_expr(block.statements(), Some(tail_expr)),
1864     }
1865 }
1866 
with_tail_expr(block: ast::BlockExpr, tail_expr: ast::Expr) -> ast::BlockExpr1867 fn with_tail_expr(block: ast::BlockExpr, tail_expr: ast::Expr) -> ast::BlockExpr {
1868     let stmt_tail_opt: Option<ast::Stmt> =
1869         block.tail_expr().map(|expr| make::expr_stmt(expr).into());
1870 
1871     let mut elements: Vec<SyntaxElement> = vec![];
1872 
1873     block.statements().for_each(|stmt| {
1874         elements.push(syntax::NodeOrToken::Node(stmt.syntax().clone()));
1875     });
1876 
1877     if let Some(stmt_list) = block.stmt_list() {
1878         stmt_list.syntax().children_with_tokens().for_each(|node_or_token| {
1879             match &node_or_token {
1880                 syntax::NodeOrToken::Token(_) => elements.push(node_or_token),
1881                 _ => (),
1882             };
1883         });
1884     }
1885 
1886     if let Some(stmt_tail) = stmt_tail_opt {
1887         elements.push(syntax::NodeOrToken::Node(stmt_tail.syntax().clone()));
1888     }
1889 
1890     make::hacky_block_expr(elements, Some(tail_expr))
1891 }
1892 
format_type(ty: &hir::Type, ctx: &AssistContext<'_>, module: hir::Module) -> String1893 fn format_type(ty: &hir::Type, ctx: &AssistContext<'_>, module: hir::Module) -> String {
1894     ty.display_source_code(ctx.db(), module.into(), true).ok().unwrap_or_else(|| "_".to_string())
1895 }
1896 
make_ty(ty: &hir::Type, ctx: &AssistContext<'_>, module: hir::Module) -> ast::Type1897 fn make_ty(ty: &hir::Type, ctx: &AssistContext<'_>, module: hir::Module) -> ast::Type {
1898     let ty_str = format_type(ty, ctx, module);
1899     make::ty(&ty_str)
1900 }
1901 
rewrite_body_segment( ctx: &AssistContext<'_>, params: &[Param], handler: &FlowHandler, syntax: &SyntaxNode, ) -> SyntaxNode1902 fn rewrite_body_segment(
1903     ctx: &AssistContext<'_>,
1904     params: &[Param],
1905     handler: &FlowHandler,
1906     syntax: &SyntaxNode,
1907 ) -> SyntaxNode {
1908     let syntax = fix_param_usages(ctx, params, syntax);
1909     update_external_control_flow(handler, &syntax);
1910     syntax
1911 }
1912 
1913 /// change all usages to account for added `&`/`&mut` for some params
fix_param_usages(ctx: &AssistContext<'_>, params: &[Param], syntax: &SyntaxNode) -> SyntaxNode1914 fn fix_param_usages(ctx: &AssistContext<'_>, params: &[Param], syntax: &SyntaxNode) -> SyntaxNode {
1915     let mut usages_for_param: Vec<(&Param, Vec<ast::Expr>)> = Vec::new();
1916 
1917     let tm = TreeMutator::new(syntax);
1918 
1919     for param in params {
1920         if !param.kind().is_ref() {
1921             continue;
1922         }
1923 
1924         let usages = LocalUsages::find_local_usages(ctx, param.var);
1925         let usages = usages
1926             .iter()
1927             .filter(|reference| syntax.text_range().contains_range(reference.range))
1928             .filter_map(|reference| path_element_of_reference(syntax, reference))
1929             .map(|expr| tm.make_mut(&expr));
1930 
1931         usages_for_param.push((param, usages.collect()));
1932     }
1933 
1934     let res = tm.make_syntax_mut(syntax);
1935 
1936     for (param, usages) in usages_for_param {
1937         for usage in usages {
1938             match usage.syntax().ancestors().skip(1).find_map(ast::Expr::cast) {
1939                 Some(ast::Expr::MethodCallExpr(_) | ast::Expr::FieldExpr(_)) => {
1940                     // do nothing
1941                 }
1942                 Some(ast::Expr::RefExpr(node))
1943                     if param.kind() == ParamKind::MutRef && node.mut_token().is_some() =>
1944                 {
1945                     ted::replace(node.syntax(), node.expr().unwrap().syntax());
1946                 }
1947                 Some(ast::Expr::RefExpr(node))
1948                     if param.kind() == ParamKind::SharedRef && node.mut_token().is_none() =>
1949                 {
1950                     ted::replace(node.syntax(), node.expr().unwrap().syntax());
1951                 }
1952                 Some(_) | None => {
1953                     let p = &make::expr_prefix(T![*], usage.clone()).clone_for_update();
1954                     ted::replace(usage.syntax(), p.syntax())
1955                 }
1956             }
1957         }
1958     }
1959 
1960     res
1961 }
1962 
update_external_control_flow(handler: &FlowHandler, syntax: &SyntaxNode)1963 fn update_external_control_flow(handler: &FlowHandler, syntax: &SyntaxNode) {
1964     let mut nested_loop = None;
1965     let mut nested_scope = None;
1966     for event in syntax.preorder() {
1967         match event {
1968             WalkEvent::Enter(e) => match e.kind() {
1969                 SyntaxKind::LOOP_EXPR | SyntaxKind::WHILE_EXPR | SyntaxKind::FOR_EXPR => {
1970                     if nested_loop.is_none() {
1971                         nested_loop = Some(e.clone());
1972                     }
1973                 }
1974                 SyntaxKind::FN
1975                 | SyntaxKind::CONST
1976                 | SyntaxKind::STATIC
1977                 | SyntaxKind::IMPL
1978                 | SyntaxKind::MODULE => {
1979                     if nested_scope.is_none() {
1980                         nested_scope = Some(e.clone());
1981                     }
1982                 }
1983                 _ => {}
1984             },
1985             WalkEvent::Leave(e) => {
1986                 if nested_scope.is_none() {
1987                     if let Some(expr) = ast::Expr::cast(e.clone()) {
1988                         match expr {
1989                             ast::Expr::ReturnExpr(return_expr) => {
1990                                 let expr = return_expr.expr();
1991                                 if let Some(replacement) = make_rewritten_flow(handler, expr) {
1992                                     ted::replace(return_expr.syntax(), replacement.syntax())
1993                                 }
1994                             }
1995                             ast::Expr::BreakExpr(break_expr) if nested_loop.is_none() => {
1996                                 let expr = break_expr.expr();
1997                                 if let Some(replacement) = make_rewritten_flow(handler, expr) {
1998                                     ted::replace(break_expr.syntax(), replacement.syntax())
1999                                 }
2000                             }
2001                             ast::Expr::ContinueExpr(continue_expr) if nested_loop.is_none() => {
2002                                 if let Some(replacement) = make_rewritten_flow(handler, None) {
2003                                     ted::replace(continue_expr.syntax(), replacement.syntax())
2004                                 }
2005                             }
2006                             _ => {
2007                                 // do nothing
2008                             }
2009                         }
2010                     }
2011                 }
2012 
2013                 if nested_loop.as_ref() == Some(&e) {
2014                     nested_loop = None;
2015                 }
2016                 if nested_scope.as_ref() == Some(&e) {
2017                     nested_scope = None;
2018                 }
2019             }
2020         };
2021     }
2022 }
2023 
make_rewritten_flow(handler: &FlowHandler, arg_expr: Option<ast::Expr>) -> Option<ast::Expr>2024 fn make_rewritten_flow(handler: &FlowHandler, arg_expr: Option<ast::Expr>) -> Option<ast::Expr> {
2025     let value = match handler {
2026         FlowHandler::None | FlowHandler::Try { .. } => return None,
2027         FlowHandler::If { .. } => make::expr_call(
2028             make::expr_path(make::path_from_text("ControlFlow::Break")),
2029             make::arg_list(iter::once(make::expr_unit())),
2030         ),
2031         FlowHandler::IfOption { .. } => {
2032             let expr = arg_expr.unwrap_or_else(|| make::expr_tuple(Vec::new()));
2033             let args = make::arg_list(iter::once(expr));
2034             make::expr_call(make::expr_path(make::ext::ident_path("Some")), args)
2035         }
2036         FlowHandler::MatchOption { .. } => make::expr_path(make::ext::ident_path("None")),
2037         FlowHandler::MatchResult { .. } => {
2038             let expr = arg_expr.unwrap_or_else(|| make::expr_tuple(Vec::new()));
2039             let args = make::arg_list(iter::once(expr));
2040             make::expr_call(make::expr_path(make::ext::ident_path("Err")), args)
2041         }
2042     };
2043     Some(make::expr_return(Some(value)).clone_for_update())
2044 }
2045 
2046 #[cfg(test)]
2047 mod tests {
2048     use crate::tests::{check_assist, check_assist_not_applicable};
2049 
2050     use super::*;
2051 
2052     #[test]
no_args_from_binary_expr()2053     fn no_args_from_binary_expr() {
2054         check_assist(
2055             extract_function,
2056             r#"
2057 fn foo() {
2058     foo($01 + 1$0);
2059 }
2060 "#,
2061             r#"
2062 fn foo() {
2063     foo(fun_name());
2064 }
2065 
2066 fn $0fun_name() -> i32 {
2067     1 + 1
2068 }
2069 "#,
2070         );
2071     }
2072 
2073     #[test]
no_args_from_binary_expr_in_module()2074     fn no_args_from_binary_expr_in_module() {
2075         check_assist(
2076             extract_function,
2077             r#"
2078 mod bar {
2079     fn foo() {
2080         foo($01 + 1$0);
2081     }
2082 }
2083 "#,
2084             r#"
2085 mod bar {
2086     fn foo() {
2087         foo(fun_name());
2088     }
2089 
2090     fn $0fun_name() -> i32 {
2091         1 + 1
2092     }
2093 }
2094 "#,
2095         );
2096     }
2097 
2098     #[test]
no_args_from_binary_expr_indented()2099     fn no_args_from_binary_expr_indented() {
2100         check_assist(
2101             extract_function,
2102             r#"
2103 fn foo() {
2104     $0{ 1 + 1 }$0;
2105 }
2106 "#,
2107             r#"
2108 fn foo() {
2109     fun_name();
2110 }
2111 
2112 fn $0fun_name() -> i32 {
2113     1 + 1
2114 }
2115 "#,
2116         );
2117     }
2118 
2119     #[test]
no_args_from_stmt_with_last_expr()2120     fn no_args_from_stmt_with_last_expr() {
2121         check_assist(
2122             extract_function,
2123             r#"
2124 fn foo() -> i32 {
2125     let k = 1;
2126     $0let m = 1;
2127     m + 1$0
2128 }
2129 "#,
2130             r#"
2131 fn foo() -> i32 {
2132     let k = 1;
2133     fun_name()
2134 }
2135 
2136 fn $0fun_name() -> i32 {
2137     let m = 1;
2138     m + 1
2139 }
2140 "#,
2141         );
2142     }
2143 
2144     #[test]
no_args_from_stmt_unit()2145     fn no_args_from_stmt_unit() {
2146         check_assist(
2147             extract_function,
2148             r#"
2149 fn foo() {
2150     let k = 3;
2151     $0let m = 1;
2152     let n = m + 1;$0
2153     let g = 5;
2154 }
2155 "#,
2156             r#"
2157 fn foo() {
2158     let k = 3;
2159     fun_name();
2160     let g = 5;
2161 }
2162 
2163 fn $0fun_name() {
2164     let m = 1;
2165     let n = m + 1;
2166 }
2167 "#,
2168         );
2169     }
2170 
2171     #[test]
no_args_if()2172     fn no_args_if() {
2173         check_assist(
2174             extract_function,
2175             r#"
2176 fn foo() {
2177     $0if true { }$0
2178 }
2179 "#,
2180             r#"
2181 fn foo() {
2182     fun_name();
2183 }
2184 
2185 fn $0fun_name() {
2186     if true { }
2187 }
2188 "#,
2189         );
2190     }
2191 
2192     #[test]
no_args_if_else()2193     fn no_args_if_else() {
2194         check_assist(
2195             extract_function,
2196             r#"
2197 fn foo() -> i32 {
2198     $0if true { 1 } else { 2 }$0
2199 }
2200 "#,
2201             r#"
2202 fn foo() -> i32 {
2203     fun_name()
2204 }
2205 
2206 fn $0fun_name() -> i32 {
2207     if true { 1 } else { 2 }
2208 }
2209 "#,
2210         );
2211     }
2212 
2213     #[test]
no_args_if_let_else()2214     fn no_args_if_let_else() {
2215         check_assist(
2216             extract_function,
2217             r#"
2218 fn foo() -> i32 {
2219     $0if let true = false { 1 } else { 2 }$0
2220 }
2221 "#,
2222             r#"
2223 fn foo() -> i32 {
2224     fun_name()
2225 }
2226 
2227 fn $0fun_name() -> i32 {
2228     if let true = false { 1 } else { 2 }
2229 }
2230 "#,
2231         );
2232     }
2233 
2234     #[test]
no_args_match()2235     fn no_args_match() {
2236         check_assist(
2237             extract_function,
2238             r#"
2239 fn foo() -> i32 {
2240     $0match true {
2241         true => 1,
2242         false => 2,
2243     }$0
2244 }
2245 "#,
2246             r#"
2247 fn foo() -> i32 {
2248     fun_name()
2249 }
2250 
2251 fn $0fun_name() -> i32 {
2252     match true {
2253         true => 1,
2254         false => 2,
2255     }
2256 }
2257 "#,
2258         );
2259     }
2260 
2261     #[test]
no_args_while()2262     fn no_args_while() {
2263         check_assist(
2264             extract_function,
2265             r#"
2266 fn foo() {
2267     $0while true { }$0
2268 }
2269 "#,
2270             r#"
2271 fn foo() {
2272     fun_name();
2273 }
2274 
2275 fn $0fun_name() {
2276     while true { }
2277 }
2278 "#,
2279         );
2280     }
2281 
2282     #[test]
no_args_for()2283     fn no_args_for() {
2284         check_assist(
2285             extract_function,
2286             r#"
2287 fn foo() {
2288     $0for v in &[0, 1] { }$0
2289 }
2290 "#,
2291             r#"
2292 fn foo() {
2293     fun_name();
2294 }
2295 
2296 fn $0fun_name() {
2297     for v in &[0, 1] { }
2298 }
2299 "#,
2300         );
2301     }
2302 
2303     #[test]
no_args_from_loop_unit()2304     fn no_args_from_loop_unit() {
2305         check_assist(
2306             extract_function,
2307             r#"
2308 fn foo() {
2309     $0loop {
2310         let m = 1;
2311     }$0
2312 }
2313 "#,
2314             r#"
2315 fn foo() {
2316     fun_name()
2317 }
2318 
2319 fn $0fun_name() -> ! {
2320     loop {
2321         let m = 1;
2322     }
2323 }
2324 "#,
2325         );
2326     }
2327 
2328     #[test]
no_args_from_loop_with_return()2329     fn no_args_from_loop_with_return() {
2330         check_assist(
2331             extract_function,
2332             r#"
2333 fn foo() {
2334     let v = $0loop {
2335         let m = 1;
2336         break m;
2337     }$0;
2338 }
2339 "#,
2340             r#"
2341 fn foo() {
2342     let v = fun_name();
2343 }
2344 
2345 fn $0fun_name() -> i32 {
2346     loop {
2347         let m = 1;
2348         break m;
2349     }
2350 }
2351 "#,
2352         );
2353     }
2354 
2355     #[test]
no_args_from_match()2356     fn no_args_from_match() {
2357         check_assist(
2358             extract_function,
2359             r#"
2360 fn foo() {
2361     let v: i32 = $0match Some(1) {
2362         Some(x) => x,
2363         None => 0,
2364     }$0;
2365 }
2366 "#,
2367             r#"
2368 fn foo() {
2369     let v: i32 = fun_name();
2370 }
2371 
2372 fn $0fun_name() -> i32 {
2373     match Some(1) {
2374         Some(x) => x,
2375         None => 0,
2376     }
2377 }
2378 "#,
2379         );
2380     }
2381 
2382     #[test]
extract_partial_block_single_line()2383     fn extract_partial_block_single_line() {
2384         check_assist(
2385             extract_function,
2386             r#"
2387 fn foo() {
2388     let n = 1;
2389     let mut v = $0n * n;$0
2390     v += 1;
2391 }
2392 "#,
2393             r#"
2394 fn foo() {
2395     let n = 1;
2396     let mut v = fun_name(n);
2397     v += 1;
2398 }
2399 
2400 fn $0fun_name(n: i32) -> i32 {
2401     let mut v = n * n;
2402     v
2403 }
2404 "#,
2405         );
2406     }
2407 
2408     #[test]
extract_partial_block()2409     fn extract_partial_block() {
2410         check_assist(
2411             extract_function,
2412             r#"
2413 fn foo() {
2414     let m = 2;
2415     let n = 1;
2416     let mut v = m $0* n;
2417     let mut w = 3;$0
2418     v += 1;
2419     w += 1;
2420 }
2421 "#,
2422             r#"
2423 fn foo() {
2424     let m = 2;
2425     let n = 1;
2426     let (mut v, mut w) = fun_name(m, n);
2427     v += 1;
2428     w += 1;
2429 }
2430 
2431 fn $0fun_name(m: i32, n: i32) -> (i32, i32) {
2432     let mut v = m * n;
2433     let mut w = 3;
2434     (v, w)
2435 }
2436 "#,
2437         );
2438     }
2439 
2440     #[test]
argument_form_expr()2441     fn argument_form_expr() {
2442         check_assist(
2443             extract_function,
2444             r#"
2445 fn foo() -> u32 {
2446     let n = 2;
2447     $0n+2$0
2448 }
2449 "#,
2450             r#"
2451 fn foo() -> u32 {
2452     let n = 2;
2453     fun_name(n)
2454 }
2455 
2456 fn $0fun_name(n: u32) -> u32 {
2457     n+2
2458 }
2459 "#,
2460         )
2461     }
2462 
2463     #[test]
argument_used_twice_form_expr()2464     fn argument_used_twice_form_expr() {
2465         check_assist(
2466             extract_function,
2467             r#"
2468 fn foo() -> u32 {
2469     let n = 2;
2470     $0n+n$0
2471 }
2472 "#,
2473             r#"
2474 fn foo() -> u32 {
2475     let n = 2;
2476     fun_name(n)
2477 }
2478 
2479 fn $0fun_name(n: u32) -> u32 {
2480     n+n
2481 }
2482 "#,
2483         )
2484     }
2485 
2486     #[test]
two_arguments_form_expr()2487     fn two_arguments_form_expr() {
2488         check_assist(
2489             extract_function,
2490             r#"
2491 fn foo() -> u32 {
2492     let n = 2;
2493     let m = 3;
2494     $0n+n*m$0
2495 }
2496 "#,
2497             r#"
2498 fn foo() -> u32 {
2499     let n = 2;
2500     let m = 3;
2501     fun_name(n, m)
2502 }
2503 
2504 fn $0fun_name(n: u32, m: u32) -> u32 {
2505     n+n*m
2506 }
2507 "#,
2508         )
2509     }
2510 
2511     #[test]
argument_and_locals()2512     fn argument_and_locals() {
2513         check_assist(
2514             extract_function,
2515             r#"
2516 fn foo() -> u32 {
2517     let n = 2;
2518     $0let m = 1;
2519     n + m$0
2520 }
2521 "#,
2522             r#"
2523 fn foo() -> u32 {
2524     let n = 2;
2525     fun_name(n)
2526 }
2527 
2528 fn $0fun_name(n: u32) -> u32 {
2529     let m = 1;
2530     n + m
2531 }
2532 "#,
2533         )
2534     }
2535 
2536     #[test]
in_comment_is_not_applicable()2537     fn in_comment_is_not_applicable() {
2538         cov_mark::check!(extract_function_in_comment_is_not_applicable);
2539         check_assist_not_applicable(extract_function, r"fn main() { 1 + /* $0comment$0 */ 1; }");
2540     }
2541 
2542     #[test]
part_of_expr_stmt()2543     fn part_of_expr_stmt() {
2544         check_assist(
2545             extract_function,
2546             r#"
2547 fn foo() {
2548     $01$0 + 1;
2549 }
2550 "#,
2551             r#"
2552 fn foo() {
2553     fun_name() + 1;
2554 }
2555 
2556 fn $0fun_name() -> i32 {
2557     1
2558 }
2559 "#,
2560         );
2561     }
2562 
2563     #[test]
function_expr()2564     fn function_expr() {
2565         check_assist(
2566             extract_function,
2567             r#"
2568 fn foo() {
2569     $0bar(1 + 1)$0
2570 }
2571 "#,
2572             r#"
2573 fn foo() {
2574     fun_name();
2575 }
2576 
2577 fn $0fun_name() {
2578     bar(1 + 1)
2579 }
2580 "#,
2581         )
2582     }
2583 
2584     #[test]
extract_from_nested()2585     fn extract_from_nested() {
2586         check_assist(
2587             extract_function,
2588             r#"
2589 fn main() {
2590     let x = true;
2591     let tuple = match x {
2592         true => ($02 + 2$0, true)
2593         _ => (0, false)
2594     };
2595 }
2596 "#,
2597             r#"
2598 fn main() {
2599     let x = true;
2600     let tuple = match x {
2601         true => (fun_name(), true)
2602         _ => (0, false)
2603     };
2604 }
2605 
2606 fn $0fun_name() -> i32 {
2607     2 + 2
2608 }
2609 "#,
2610         );
2611     }
2612 
2613     #[test]
param_from_closure()2614     fn param_from_closure() {
2615         check_assist(
2616             extract_function,
2617             r#"
2618 fn main() {
2619     let lambda = |x: u32| $0x * 2$0;
2620 }
2621 "#,
2622             r#"
2623 fn main() {
2624     let lambda = |x: u32| fun_name(x);
2625 }
2626 
2627 fn $0fun_name(x: u32) -> u32 {
2628     x * 2
2629 }
2630 "#,
2631         );
2632     }
2633 
2634     #[test]
extract_return_stmt()2635     fn extract_return_stmt() {
2636         check_assist(
2637             extract_function,
2638             r#"
2639 fn foo() -> u32 {
2640     $0return 2 + 2$0;
2641 }
2642 "#,
2643             r#"
2644 fn foo() -> u32 {
2645     return fun_name();
2646 }
2647 
2648 fn $0fun_name() -> u32 {
2649     2 + 2
2650 }
2651 "#,
2652         );
2653     }
2654 
2655     #[test]
does_not_add_extra_whitespace()2656     fn does_not_add_extra_whitespace() {
2657         check_assist(
2658             extract_function,
2659             r#"
2660 fn foo() -> u32 {
2661 
2662 
2663     $0return 2 + 2$0;
2664 }
2665 "#,
2666             r#"
2667 fn foo() -> u32 {
2668 
2669 
2670     return fun_name();
2671 }
2672 
2673 fn $0fun_name() -> u32 {
2674     2 + 2
2675 }
2676 "#,
2677         );
2678     }
2679 
2680     #[test]
break_stmt()2681     fn break_stmt() {
2682         check_assist(
2683             extract_function,
2684             r#"
2685 fn main() {
2686     let result = loop {
2687         $0break 2 + 2$0;
2688     };
2689 }
2690 "#,
2691             r#"
2692 fn main() {
2693     let result = loop {
2694         break fun_name();
2695     };
2696 }
2697 
2698 fn $0fun_name() -> i32 {
2699     2 + 2
2700 }
2701 "#,
2702         );
2703     }
2704 
2705     #[test]
extract_cast()2706     fn extract_cast() {
2707         check_assist(
2708             extract_function,
2709             r#"
2710 fn main() {
2711     let v = $00f32 as u32$0;
2712 }
2713 "#,
2714             r#"
2715 fn main() {
2716     let v = fun_name();
2717 }
2718 
2719 fn $0fun_name() -> u32 {
2720     0f32 as u32
2721 }
2722 "#,
2723         );
2724     }
2725 
2726     #[test]
return_not_applicable()2727     fn return_not_applicable() {
2728         check_assist_not_applicable(extract_function, r"fn foo() { $0return$0; } ");
2729     }
2730 
2731     #[test]
method_to_freestanding()2732     fn method_to_freestanding() {
2733         check_assist(
2734             extract_function,
2735             r#"
2736 struct S;
2737 
2738 impl S {
2739     fn foo(&self) -> i32 {
2740         $01+1$0
2741     }
2742 }
2743 "#,
2744             r#"
2745 struct S;
2746 
2747 impl S {
2748     fn foo(&self) -> i32 {
2749         fun_name()
2750     }
2751 }
2752 
2753 fn $0fun_name() -> i32 {
2754     1+1
2755 }
2756 "#,
2757         );
2758     }
2759 
2760     #[test]
method_with_reference()2761     fn method_with_reference() {
2762         check_assist(
2763             extract_function,
2764             r#"
2765 struct S { f: i32 };
2766 
2767 impl S {
2768     fn foo(&self) -> i32 {
2769         $0self.f+self.f$0
2770     }
2771 }
2772 "#,
2773             r#"
2774 struct S { f: i32 };
2775 
2776 impl S {
2777     fn foo(&self) -> i32 {
2778         self.fun_name()
2779     }
2780 
2781     fn $0fun_name(&self) -> i32 {
2782         self.f+self.f
2783     }
2784 }
2785 "#,
2786         );
2787     }
2788 
2789     #[test]
method_with_mut()2790     fn method_with_mut() {
2791         check_assist(
2792             extract_function,
2793             r#"
2794 struct S { f: i32 };
2795 
2796 impl S {
2797     fn foo(&mut self) {
2798         $0self.f += 1;$0
2799     }
2800 }
2801 "#,
2802             r#"
2803 struct S { f: i32 };
2804 
2805 impl S {
2806     fn foo(&mut self) {
2807         self.fun_name();
2808     }
2809 
2810     fn $0fun_name(&mut self) {
2811         self.f += 1;
2812     }
2813 }
2814 "#,
2815         );
2816     }
2817 
2818     #[test]
variable_defined_inside_and_used_after_no_ret()2819     fn variable_defined_inside_and_used_after_no_ret() {
2820         check_assist(
2821             extract_function,
2822             r#"
2823 fn foo() {
2824     let n = 1;
2825     $0let k = n * n;$0
2826     let m = k + 1;
2827 }
2828 "#,
2829             r#"
2830 fn foo() {
2831     let n = 1;
2832     let k = fun_name(n);
2833     let m = k + 1;
2834 }
2835 
2836 fn $0fun_name(n: i32) -> i32 {
2837     let k = n * n;
2838     k
2839 }
2840 "#,
2841         );
2842     }
2843 
2844     #[test]
variable_defined_inside_and_used_after_mutably_no_ret()2845     fn variable_defined_inside_and_used_after_mutably_no_ret() {
2846         check_assist(
2847             extract_function,
2848             r#"
2849 fn foo() {
2850     let n = 1;
2851     $0let mut k = n * n;$0
2852     k += 1;
2853 }
2854 "#,
2855             r#"
2856 fn foo() {
2857     let n = 1;
2858     let mut k = fun_name(n);
2859     k += 1;
2860 }
2861 
2862 fn $0fun_name(n: i32) -> i32 {
2863     let mut k = n * n;
2864     k
2865 }
2866 "#,
2867         );
2868     }
2869 
2870     #[test]
two_variables_defined_inside_and_used_after_no_ret()2871     fn two_variables_defined_inside_and_used_after_no_ret() {
2872         check_assist(
2873             extract_function,
2874             r#"
2875 fn foo() {
2876     let n = 1;
2877     $0let k = n * n;
2878     let m = k + 2;$0
2879     let h = k + m;
2880 }
2881 "#,
2882             r#"
2883 fn foo() {
2884     let n = 1;
2885     let (k, m) = fun_name(n);
2886     let h = k + m;
2887 }
2888 
2889 fn $0fun_name(n: i32) -> (i32, i32) {
2890     let k = n * n;
2891     let m = k + 2;
2892     (k, m)
2893 }
2894 "#,
2895         );
2896     }
2897 
2898     #[test]
multi_variables_defined_inside_and_used_after_mutably_no_ret()2899     fn multi_variables_defined_inside_and_used_after_mutably_no_ret() {
2900         check_assist(
2901             extract_function,
2902             r#"
2903 fn foo() {
2904     let n = 1;
2905     $0let mut k = n * n;
2906     let mut m = k + 2;
2907     let mut o = m + 3;
2908     o += 1;$0
2909     k += o;
2910     m = 1;
2911 }
2912 "#,
2913             r#"
2914 fn foo() {
2915     let n = 1;
2916     let (mut k, mut m, o) = fun_name(n);
2917     k += o;
2918     m = 1;
2919 }
2920 
2921 fn $0fun_name(n: i32) -> (i32, i32, i32) {
2922     let mut k = n * n;
2923     let mut m = k + 2;
2924     let mut o = m + 3;
2925     o += 1;
2926     (k, m, o)
2927 }
2928 "#,
2929         );
2930     }
2931 
2932     #[test]
nontrivial_patterns_define_variables()2933     fn nontrivial_patterns_define_variables() {
2934         check_assist(
2935             extract_function,
2936             r#"
2937 struct Counter(i32);
2938 fn foo() {
2939     $0let Counter(n) = Counter(0);$0
2940     let m = n;
2941 }
2942 "#,
2943             r#"
2944 struct Counter(i32);
2945 fn foo() {
2946     let n = fun_name();
2947     let m = n;
2948 }
2949 
2950 fn $0fun_name() -> i32 {
2951     let Counter(n) = Counter(0);
2952     n
2953 }
2954 "#,
2955         );
2956     }
2957 
2958     #[test]
struct_with_two_fields_pattern_define_variables()2959     fn struct_with_two_fields_pattern_define_variables() {
2960         check_assist(
2961             extract_function,
2962             r#"
2963 struct Counter { n: i32, m: i32 };
2964 fn foo() {
2965     $0let Counter { n, m: k } = Counter { n: 1, m: 2 };$0
2966     let h = n + k;
2967 }
2968 "#,
2969             r#"
2970 struct Counter { n: i32, m: i32 };
2971 fn foo() {
2972     let (n, k) = fun_name();
2973     let h = n + k;
2974 }
2975 
2976 fn $0fun_name() -> (i32, i32) {
2977     let Counter { n, m: k } = Counter { n: 1, m: 2 };
2978     (n, k)
2979 }
2980 "#,
2981         );
2982     }
2983 
2984     #[test]
mut_var_from_outer_scope()2985     fn mut_var_from_outer_scope() {
2986         check_assist(
2987             extract_function,
2988             r#"
2989 fn foo() {
2990     let mut n = 1;
2991     $0n += 1;$0
2992     let m = n + 1;
2993 }
2994 "#,
2995             r#"
2996 fn foo() {
2997     let mut n = 1;
2998     fun_name(&mut n);
2999     let m = n + 1;
3000 }
3001 
3002 fn $0fun_name(n: &mut i32) {
3003     *n += 1;
3004 }
3005 "#,
3006         );
3007     }
3008 
3009     #[test]
mut_field_from_outer_scope()3010     fn mut_field_from_outer_scope() {
3011         check_assist(
3012             extract_function,
3013             r#"
3014 struct C { n: i32 }
3015 fn foo() {
3016     let mut c = C { n: 0 };
3017     $0c.n += 1;$0
3018     let m = c.n + 1;
3019 }
3020 "#,
3021             r#"
3022 struct C { n: i32 }
3023 fn foo() {
3024     let mut c = C { n: 0 };
3025     fun_name(&mut c);
3026     let m = c.n + 1;
3027 }
3028 
3029 fn $0fun_name(c: &mut C) {
3030     c.n += 1;
3031 }
3032 "#,
3033         );
3034     }
3035 
3036     #[test]
mut_nested_field_from_outer_scope()3037     fn mut_nested_field_from_outer_scope() {
3038         check_assist(
3039             extract_function,
3040             r#"
3041 struct P { n: i32}
3042 struct C { p: P }
3043 fn foo() {
3044     let mut c = C { p: P { n: 0 } };
3045     let mut v = C { p: P { n: 0 } };
3046     let u = C { p: P { n: 0 } };
3047     $0c.p.n += u.p.n;
3048     let r = &mut v.p.n;$0
3049     let m = c.p.n + v.p.n + u.p.n;
3050 }
3051 "#,
3052             r#"
3053 struct P { n: i32}
3054 struct C { p: P }
3055 fn foo() {
3056     let mut c = C { p: P { n: 0 } };
3057     let mut v = C { p: P { n: 0 } };
3058     let u = C { p: P { n: 0 } };
3059     fun_name(&mut c, &u, &mut v);
3060     let m = c.p.n + v.p.n + u.p.n;
3061 }
3062 
3063 fn $0fun_name(c: &mut C, u: &C, v: &mut C) {
3064     c.p.n += u.p.n;
3065     let r = &mut v.p.n;
3066 }
3067 "#,
3068         );
3069     }
3070 
3071     #[test]
mut_param_many_usages_stmt()3072     fn mut_param_many_usages_stmt() {
3073         check_assist(
3074             extract_function,
3075             r#"
3076 fn bar(k: i32) {}
3077 trait I: Copy {
3078     fn succ(&self) -> Self;
3079     fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
3080 }
3081 impl I for i32 {
3082     fn succ(&self) -> Self { *self + 1 }
3083 }
3084 fn foo() {
3085     let mut n = 1;
3086     $0n += n;
3087     bar(n);
3088     bar(n+1);
3089     bar(n*n);
3090     bar(&n);
3091     n.inc();
3092     let v = &mut n;
3093     *v = v.succ();
3094     n.succ();$0
3095     let m = n + 1;
3096 }
3097 "#,
3098             r#"
3099 fn bar(k: i32) {}
3100 trait I: Copy {
3101     fn succ(&self) -> Self;
3102     fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
3103 }
3104 impl I for i32 {
3105     fn succ(&self) -> Self { *self + 1 }
3106 }
3107 fn foo() {
3108     let mut n = 1;
3109     fun_name(&mut n);
3110     let m = n + 1;
3111 }
3112 
3113 fn $0fun_name(n: &mut i32) {
3114     *n += *n;
3115     bar(*n);
3116     bar(*n+1);
3117     bar(*n**n);
3118     bar(&*n);
3119     n.inc();
3120     let v = n;
3121     *v = v.succ();
3122     n.succ();
3123 }
3124 "#,
3125         );
3126     }
3127 
3128     #[test]
mut_param_many_usages_expr()3129     fn mut_param_many_usages_expr() {
3130         check_assist(
3131             extract_function,
3132             r#"
3133 fn bar(k: i32) {}
3134 trait I: Copy {
3135     fn succ(&self) -> Self;
3136     fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
3137 }
3138 impl I for i32 {
3139     fn succ(&self) -> Self { *self + 1 }
3140 }
3141 fn foo() {
3142     let mut n = 1;
3143     $0{
3144         n += n;
3145         bar(n);
3146         bar(n+1);
3147         bar(n*n);
3148         bar(&n);
3149         n.inc();
3150         let v = &mut n;
3151         *v = v.succ();
3152         n.succ();
3153     }$0
3154     let m = n + 1;
3155 }
3156 "#,
3157             r#"
3158 fn bar(k: i32) {}
3159 trait I: Copy {
3160     fn succ(&self) -> Self;
3161     fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
3162 }
3163 impl I for i32 {
3164     fn succ(&self) -> Self { *self + 1 }
3165 }
3166 fn foo() {
3167     let mut n = 1;
3168     fun_name(&mut n);
3169     let m = n + 1;
3170 }
3171 
3172 fn $0fun_name(n: &mut i32) {
3173     *n += *n;
3174     bar(*n);
3175     bar(*n+1);
3176     bar(*n**n);
3177     bar(&*n);
3178     n.inc();
3179     let v = n;
3180     *v = v.succ();
3181     n.succ();
3182 }
3183 "#,
3184         );
3185     }
3186 
3187     #[test]
mut_param_by_value()3188     fn mut_param_by_value() {
3189         check_assist(
3190             extract_function,
3191             r#"
3192 fn foo() {
3193     let mut n = 1;
3194     $0n += 1;$0
3195 }
3196 "#,
3197             r"
3198 fn foo() {
3199     let mut n = 1;
3200     fun_name(n);
3201 }
3202 
3203 fn $0fun_name(mut n: i32) {
3204     n += 1;
3205 }
3206 ",
3207         );
3208     }
3209 
3210     #[test]
mut_param_because_of_mut_ref()3211     fn mut_param_because_of_mut_ref() {
3212         check_assist(
3213             extract_function,
3214             r#"
3215 fn foo() {
3216     let mut n = 1;
3217     $0let v = &mut n;
3218     *v += 1;$0
3219     let k = n;
3220 }
3221 "#,
3222             r#"
3223 fn foo() {
3224     let mut n = 1;
3225     fun_name(&mut n);
3226     let k = n;
3227 }
3228 
3229 fn $0fun_name(n: &mut i32) {
3230     let v = n;
3231     *v += 1;
3232 }
3233 "#,
3234         );
3235     }
3236 
3237     #[test]
mut_param_by_value_because_of_mut_ref()3238     fn mut_param_by_value_because_of_mut_ref() {
3239         check_assist(
3240             extract_function,
3241             r"
3242 fn foo() {
3243     let mut n = 1;
3244     $0let v = &mut n;
3245     *v += 1;$0
3246 }
3247 ",
3248             r#"
3249 fn foo() {
3250     let mut n = 1;
3251     fun_name(n);
3252 }
3253 
3254 fn $0fun_name(mut n: i32) {
3255     let v = &mut n;
3256     *v += 1;
3257 }
3258 "#,
3259         );
3260     }
3261 
3262     #[test]
mut_method_call()3263     fn mut_method_call() {
3264         check_assist(
3265             extract_function,
3266             r#"
3267 trait I {
3268     fn inc(&mut self);
3269 }
3270 impl I for i32 {
3271     fn inc(&mut self) { *self += 1 }
3272 }
3273 fn foo() {
3274     let mut n = 1;
3275     $0n.inc();$0
3276 }
3277 "#,
3278             r#"
3279 trait I {
3280     fn inc(&mut self);
3281 }
3282 impl I for i32 {
3283     fn inc(&mut self) { *self += 1 }
3284 }
3285 fn foo() {
3286     let mut n = 1;
3287     fun_name(n);
3288 }
3289 
3290 fn $0fun_name(mut n: i32) {
3291     n.inc();
3292 }
3293 "#,
3294         );
3295     }
3296 
3297     #[test]
shared_method_call()3298     fn shared_method_call() {
3299         check_assist(
3300             extract_function,
3301             r#"
3302 trait I {
3303     fn succ(&self);
3304 }
3305 impl I for i32 {
3306     fn succ(&self) { *self + 1 }
3307 }
3308 fn foo() {
3309     let mut n = 1;
3310     $0n.succ();$0
3311 }
3312 "#,
3313             r"
3314 trait I {
3315     fn succ(&self);
3316 }
3317 impl I for i32 {
3318     fn succ(&self) { *self + 1 }
3319 }
3320 fn foo() {
3321     let mut n = 1;
3322     fun_name(n);
3323 }
3324 
3325 fn $0fun_name(n: i32) {
3326     n.succ();
3327 }
3328 ",
3329         );
3330     }
3331 
3332     #[test]
mut_method_call_with_other_receiver()3333     fn mut_method_call_with_other_receiver() {
3334         check_assist(
3335             extract_function,
3336             r#"
3337 trait I {
3338     fn inc(&mut self, n: i32);
3339 }
3340 impl I for i32 {
3341     fn inc(&mut self, n: i32) { *self += n }
3342 }
3343 fn foo() {
3344     let mut n = 1;
3345     $0let mut m = 2;
3346     m.inc(n);$0
3347 }
3348 "#,
3349             r"
3350 trait I {
3351     fn inc(&mut self, n: i32);
3352 }
3353 impl I for i32 {
3354     fn inc(&mut self, n: i32) { *self += n }
3355 }
3356 fn foo() {
3357     let mut n = 1;
3358     fun_name(n);
3359 }
3360 
3361 fn $0fun_name(n: i32) {
3362     let mut m = 2;
3363     m.inc(n);
3364 }
3365 ",
3366         );
3367     }
3368 
3369     #[test]
non_copy_without_usages_after()3370     fn non_copy_without_usages_after() {
3371         check_assist(
3372             extract_function,
3373             r#"
3374 struct Counter(i32);
3375 fn foo() {
3376     let c = Counter(0);
3377     $0let n = c.0;$0
3378 }
3379 "#,
3380             r"
3381 struct Counter(i32);
3382 fn foo() {
3383     let c = Counter(0);
3384     fun_name(c);
3385 }
3386 
3387 fn $0fun_name(c: Counter) {
3388     let n = c.0;
3389 }
3390 ",
3391         );
3392     }
3393 
3394     #[test]
non_copy_used_after()3395     fn non_copy_used_after() {
3396         check_assist(
3397             extract_function,
3398             r"
3399 struct Counter(i32);
3400 fn foo() {
3401     let c = Counter(0);
3402     $0let n = c.0;$0
3403     let m = c.0;
3404 }
3405 ",
3406             r#"
3407 struct Counter(i32);
3408 fn foo() {
3409     let c = Counter(0);
3410     fun_name(&c);
3411     let m = c.0;
3412 }
3413 
3414 fn $0fun_name(c: &Counter) {
3415     let n = c.0;
3416 }
3417 "#,
3418         );
3419     }
3420 
3421     #[test]
copy_used_after()3422     fn copy_used_after() {
3423         check_assist(
3424             extract_function,
3425             r#"
3426 //- minicore: copy
3427 fn foo() {
3428     let n = 0;
3429     $0let m = n;$0
3430     let k = n;
3431 }
3432 "#,
3433             r#"
3434 fn foo() {
3435     let n = 0;
3436     fun_name(n);
3437     let k = n;
3438 }
3439 
3440 fn $0fun_name(n: i32) {
3441     let m = n;
3442 }
3443 "#,
3444         )
3445     }
3446 
3447     #[test]
copy_custom_used_after()3448     fn copy_custom_used_after() {
3449         check_assist(
3450             extract_function,
3451             r#"
3452 //- minicore: copy, derive
3453 #[derive(Clone, Copy)]
3454 struct Counter(i32);
3455 fn foo() {
3456     let c = Counter(0);
3457     $0let n = c.0;$0
3458     let m = c.0;
3459 }
3460 "#,
3461             r#"
3462 #[derive(Clone, Copy)]
3463 struct Counter(i32);
3464 fn foo() {
3465     let c = Counter(0);
3466     fun_name(c);
3467     let m = c.0;
3468 }
3469 
3470 fn $0fun_name(c: Counter) {
3471     let n = c.0;
3472 }
3473 "#,
3474         );
3475     }
3476 
3477     #[test]
indented_stmts()3478     fn indented_stmts() {
3479         check_assist(
3480             extract_function,
3481             r#"
3482 fn foo() {
3483     if true {
3484         loop {
3485             $0let n = 1;
3486             let m = 2;$0
3487         }
3488     }
3489 }
3490 "#,
3491             r#"
3492 fn foo() {
3493     if true {
3494         loop {
3495             fun_name();
3496         }
3497     }
3498 }
3499 
3500 fn $0fun_name() {
3501     let n = 1;
3502     let m = 2;
3503 }
3504 "#,
3505         );
3506     }
3507 
3508     #[test]
indented_stmts_inside_mod()3509     fn indented_stmts_inside_mod() {
3510         check_assist(
3511             extract_function,
3512             r#"
3513 mod bar {
3514     fn foo() {
3515         if true {
3516             loop {
3517                 $0let n = 1;
3518                 let m = 2;$0
3519             }
3520         }
3521     }
3522 }
3523 "#,
3524             r#"
3525 mod bar {
3526     fn foo() {
3527         if true {
3528             loop {
3529                 fun_name();
3530             }
3531         }
3532     }
3533 
3534     fn $0fun_name() {
3535         let n = 1;
3536         let m = 2;
3537     }
3538 }
3539 "#,
3540         );
3541     }
3542 
3543     #[test]
break_loop()3544     fn break_loop() {
3545         check_assist(
3546             extract_function,
3547             r#"
3548 //- minicore: option
3549 fn foo() {
3550     loop {
3551         let n = 1;
3552         $0let m = n + 1;
3553         break;
3554         let k = 2;$0
3555         let h = 1 + k;
3556     }
3557 }
3558 "#,
3559             r#"
3560 fn foo() {
3561     loop {
3562         let n = 1;
3563         let k = match fun_name(n) {
3564             Some(value) => value,
3565             None => break,
3566         };
3567         let h = 1 + k;
3568     }
3569 }
3570 
3571 fn $0fun_name(n: i32) -> Option<i32> {
3572     let m = n + 1;
3573     return None;
3574     let k = 2;
3575     Some(k)
3576 }
3577 "#,
3578         );
3579     }
3580 
3581     #[test]
return_to_parent()3582     fn return_to_parent() {
3583         check_assist(
3584             extract_function,
3585             r#"
3586 //- minicore: copy, result
3587 fn foo() -> i64 {
3588     let n = 1;
3589     $0let m = n + 1;
3590     return 1;
3591     let k = 2;$0
3592     (n + k) as i64
3593 }
3594 "#,
3595             r#"
3596 fn foo() -> i64 {
3597     let n = 1;
3598     let k = match fun_name(n) {
3599         Ok(value) => value,
3600         Err(value) => return value,
3601     };
3602     (n + k) as i64
3603 }
3604 
3605 fn $0fun_name(n: i32) -> Result<i32, i64> {
3606     let m = n + 1;
3607     return Err(1);
3608     let k = 2;
3609     Ok(k)
3610 }
3611 "#,
3612         );
3613     }
3614 
3615     #[test]
break_and_continue()3616     fn break_and_continue() {
3617         cov_mark::check!(external_control_flow_break_and_continue);
3618         check_assist_not_applicable(
3619             extract_function,
3620             r#"
3621 fn foo() {
3622     loop {
3623         let n = 1;
3624         $0let m = n + 1;
3625         break;
3626         let k = 2;
3627         continue;
3628         let k = k + 1;$0
3629         let r = n + k;
3630     }
3631 }
3632 "#,
3633         );
3634     }
3635 
3636     #[test]
return_and_break()3637     fn return_and_break() {
3638         cov_mark::check!(external_control_flow_return_and_bc);
3639         check_assist_not_applicable(
3640             extract_function,
3641             r#"
3642 fn foo() {
3643     loop {
3644         let n = 1;
3645         $0let m = n + 1;
3646         break;
3647         let k = 2;
3648         return;
3649         let k = k + 1;$0
3650         let r = n + k;
3651     }
3652 }
3653 "#,
3654         );
3655     }
3656 
3657     #[test]
break_loop_with_if()3658     fn break_loop_with_if() {
3659         check_assist(
3660             extract_function,
3661             r#"
3662 //- minicore: try
3663 fn foo() {
3664     loop {
3665         let mut n = 1;
3666         $0let m = n + 1;
3667         break;
3668         n += m;$0
3669         let h = 1 + n;
3670     }
3671 }
3672 "#,
3673             r#"
3674 use core::ops::ControlFlow;
3675 
3676 fn foo() {
3677     loop {
3678         let mut n = 1;
3679         if let ControlFlow::Break(_) = fun_name(&mut n) {
3680             break;
3681         }
3682         let h = 1 + n;
3683     }
3684 }
3685 
3686 fn $0fun_name(n: &mut i32) -> ControlFlow<()> {
3687     let m = *n + 1;
3688     return ControlFlow::Break(());
3689     *n += m;
3690     ControlFlow::Continue(())
3691 }
3692 "#,
3693         );
3694     }
3695 
3696     #[test]
break_loop_nested()3697     fn break_loop_nested() {
3698         check_assist(
3699             extract_function,
3700             r#"
3701 //- minicore: try
3702 fn foo() {
3703     loop {
3704         let mut n = 1;
3705         $0let m = n + 1;
3706         if m == 42 {
3707             break;
3708         }$0
3709         let h = 1;
3710     }
3711 }
3712 "#,
3713             r#"
3714 use core::ops::ControlFlow;
3715 
3716 fn foo() {
3717     loop {
3718         let mut n = 1;
3719         if let ControlFlow::Break(_) = fun_name(n) {
3720             break;
3721         }
3722         let h = 1;
3723     }
3724 }
3725 
3726 fn $0fun_name(n: i32) -> ControlFlow<()> {
3727     let m = n + 1;
3728     if m == 42 {
3729         return ControlFlow::Break(());
3730     }
3731     ControlFlow::Continue(())
3732 }
3733 "#,
3734         );
3735     }
3736 
3737     #[test]
break_loop_nested_labeled()3738     fn break_loop_nested_labeled() {
3739         check_assist(
3740             extract_function,
3741             r#"
3742 //- minicore: try
3743 fn foo() {
3744     'bar: loop {
3745         loop {
3746             $0break 'bar;$0
3747         }
3748     }
3749 }
3750 "#,
3751             r#"
3752 use core::ops::ControlFlow;
3753 
3754 fn foo() {
3755     'bar: loop {
3756         loop {
3757             if let ControlFlow::Break(_) = fun_name() {
3758                 break 'bar;
3759             }
3760         }
3761     }
3762 }
3763 
3764 fn $0fun_name() -> ControlFlow<()> {
3765     return ControlFlow::Break(());
3766     ControlFlow::Continue(())
3767 }
3768 "#,
3769         );
3770     }
3771 
3772     #[test]
continue_loop_nested_labeled()3773     fn continue_loop_nested_labeled() {
3774         check_assist(
3775             extract_function,
3776             r#"
3777 //- minicore: try
3778 fn foo() {
3779     'bar: loop {
3780         loop {
3781             $0continue 'bar;$0
3782         }
3783     }
3784 }
3785 "#,
3786             r#"
3787 use core::ops::ControlFlow;
3788 
3789 fn foo() {
3790     'bar: loop {
3791         loop {
3792             if let ControlFlow::Break(_) = fun_name() {
3793                 continue 'bar;
3794             }
3795         }
3796     }
3797 }
3798 
3799 fn $0fun_name() -> ControlFlow<()> {
3800     return ControlFlow::Break(());
3801     ControlFlow::Continue(())
3802 }
3803 "#,
3804         );
3805     }
3806 
3807     #[test]
return_from_nested_loop()3808     fn return_from_nested_loop() {
3809         check_assist(
3810             extract_function,
3811             r#"
3812 fn foo() {
3813     loop {
3814         let n = 1;$0
3815         let k = 1;
3816         loop {
3817             return;
3818         }
3819         let m = k + 1;$0
3820         let h = 1 + m;
3821     }
3822 }
3823 "#,
3824             r#"
3825 fn foo() {
3826     loop {
3827         let n = 1;
3828         let m = match fun_name() {
3829             Some(value) => value,
3830             None => return,
3831         };
3832         let h = 1 + m;
3833     }
3834 }
3835 
3836 fn $0fun_name() -> Option<i32> {
3837     let k = 1;
3838     loop {
3839         return None;
3840     }
3841     let m = k + 1;
3842     Some(m)
3843 }
3844 "#,
3845         );
3846     }
3847 
3848     #[test]
break_from_nested_loop()3849     fn break_from_nested_loop() {
3850         check_assist(
3851             extract_function,
3852             r#"
3853 fn foo() {
3854     loop {
3855         let n = 1;
3856         $0let k = 1;
3857         loop {
3858             break;
3859         }
3860         let m = k + 1;$0
3861         let h = 1 + m;
3862     }
3863 }
3864 "#,
3865             r#"
3866 fn foo() {
3867     loop {
3868         let n = 1;
3869         let m = fun_name();
3870         let h = 1 + m;
3871     }
3872 }
3873 
3874 fn $0fun_name() -> i32 {
3875     let k = 1;
3876     loop {
3877         break;
3878     }
3879     let m = k + 1;
3880     m
3881 }
3882 "#,
3883         );
3884     }
3885 
3886     #[test]
break_from_nested_and_outer_loops()3887     fn break_from_nested_and_outer_loops() {
3888         check_assist(
3889             extract_function,
3890             r#"
3891 fn foo() {
3892     loop {
3893         let n = 1;
3894         $0let k = 1;
3895         loop {
3896             break;
3897         }
3898         if k == 42 {
3899             break;
3900         }
3901         let m = k + 1;$0
3902         let h = 1 + m;
3903     }
3904 }
3905 "#,
3906             r#"
3907 fn foo() {
3908     loop {
3909         let n = 1;
3910         let m = match fun_name() {
3911             Some(value) => value,
3912             None => break,
3913         };
3914         let h = 1 + m;
3915     }
3916 }
3917 
3918 fn $0fun_name() -> Option<i32> {
3919     let k = 1;
3920     loop {
3921         break;
3922     }
3923     if k == 42 {
3924         return None;
3925     }
3926     let m = k + 1;
3927     Some(m)
3928 }
3929 "#,
3930         );
3931     }
3932 
3933     #[test]
return_from_nested_fn()3934     fn return_from_nested_fn() {
3935         check_assist(
3936             extract_function,
3937             r#"
3938 fn foo() {
3939     loop {
3940         let n = 1;
3941         $0let k = 1;
3942         fn test() {
3943             return;
3944         }
3945         let m = k + 1;$0
3946         let h = 1 + m;
3947     }
3948 }
3949 "#,
3950             r#"
3951 fn foo() {
3952     loop {
3953         let n = 1;
3954         let m = fun_name();
3955         let h = 1 + m;
3956     }
3957 }
3958 
3959 fn $0fun_name() -> i32 {
3960     let k = 1;
3961     fn test() {
3962         return;
3963     }
3964     let m = k + 1;
3965     m
3966 }
3967 "#,
3968         );
3969     }
3970 
3971     #[test]
break_with_value()3972     fn break_with_value() {
3973         check_assist(
3974             extract_function,
3975             r#"
3976 fn foo() -> i32 {
3977     loop {
3978         let n = 1;
3979         $0let k = 1;
3980         if k == 42 {
3981             break 3;
3982         }
3983         let m = k + 1;$0
3984         let h = 1;
3985     }
3986 }
3987 "#,
3988             r#"
3989 fn foo() -> i32 {
3990     loop {
3991         let n = 1;
3992         if let Some(value) = fun_name() {
3993             break value;
3994         }
3995         let h = 1;
3996     }
3997 }
3998 
3999 fn $0fun_name() -> Option<i32> {
4000     let k = 1;
4001     if k == 42 {
4002         return Some(3);
4003     }
4004     let m = k + 1;
4005     None
4006 }
4007 "#,
4008         );
4009     }
4010 
4011     #[test]
break_with_value_and_label()4012     fn break_with_value_and_label() {
4013         check_assist(
4014             extract_function,
4015             r#"
4016 fn foo() -> i32 {
4017     'bar: loop {
4018         let n = 1;
4019         $0let k = 1;
4020         if k == 42 {
4021             break 'bar 4;
4022         }
4023         let m = k + 1;$0
4024         let h = 1;
4025     }
4026 }
4027 "#,
4028             r#"
4029 fn foo() -> i32 {
4030     'bar: loop {
4031         let n = 1;
4032         if let Some(value) = fun_name() {
4033             break 'bar value;
4034         }
4035         let h = 1;
4036     }
4037 }
4038 
4039 fn $0fun_name() -> Option<i32> {
4040     let k = 1;
4041     if k == 42 {
4042         return Some(4);
4043     }
4044     let m = k + 1;
4045     None
4046 }
4047 "#,
4048         );
4049     }
4050 
4051     #[test]
break_with_value_and_return()4052     fn break_with_value_and_return() {
4053         check_assist(
4054             extract_function,
4055             r#"
4056 fn foo() -> i64 {
4057     loop {
4058         let n = 1;$0
4059         let k = 1;
4060         if k == 42 {
4061             break 3;
4062         }
4063         let m = k + 1;$0
4064         let h = 1 + m;
4065     }
4066 }
4067 "#,
4068             r#"
4069 fn foo() -> i64 {
4070     loop {
4071         let n = 1;
4072         let m = match fun_name() {
4073             Ok(value) => value,
4074             Err(value) => break value,
4075         };
4076         let h = 1 + m;
4077     }
4078 }
4079 
4080 fn $0fun_name() -> Result<i32, i64> {
4081     let k = 1;
4082     if k == 42 {
4083         return Err(3);
4084     }
4085     let m = k + 1;
4086     Ok(m)
4087 }
4088 "#,
4089         );
4090     }
4091 
4092     #[test]
try_option()4093     fn try_option() {
4094         check_assist(
4095             extract_function,
4096             r#"
4097 //- minicore: option
4098 fn bar() -> Option<i32> { None }
4099 fn foo() -> Option<()> {
4100     let n = bar()?;
4101     $0let k = foo()?;
4102     let m = k + 1;$0
4103     let h = 1 + m;
4104     Some(())
4105 }
4106 "#,
4107             r#"
4108 fn bar() -> Option<i32> { None }
4109 fn foo() -> Option<()> {
4110     let n = bar()?;
4111     let m = fun_name()?;
4112     let h = 1 + m;
4113     Some(())
4114 }
4115 
4116 fn $0fun_name() -> Option<i32> {
4117     let k = foo()?;
4118     let m = k + 1;
4119     Some(m)
4120 }
4121 "#,
4122         );
4123     }
4124 
4125     #[test]
try_option_unit()4126     fn try_option_unit() {
4127         check_assist(
4128             extract_function,
4129             r#"
4130 //- minicore: option
4131 fn foo() -> Option<()> {
4132     let n = 1;
4133     $0let k = foo()?;
4134     let m = k + 1;$0
4135     let h = 1 + n;
4136     Some(())
4137 }
4138 "#,
4139             r#"
4140 fn foo() -> Option<()> {
4141     let n = 1;
4142     fun_name()?;
4143     let h = 1 + n;
4144     Some(())
4145 }
4146 
4147 fn $0fun_name() -> Option<()> {
4148     let k = foo()?;
4149     let m = k + 1;
4150     Some(())
4151 }
4152 "#,
4153         );
4154     }
4155 
4156     #[test]
try_result()4157     fn try_result() {
4158         check_assist(
4159             extract_function,
4160             r#"
4161 //- minicore: result
4162 fn foo() -> Result<(), i64> {
4163     let n = 1;
4164     $0let k = foo()?;
4165     let m = k + 1;$0
4166     let h = 1 + m;
4167     Ok(())
4168 }
4169 "#,
4170             r#"
4171 fn foo() -> Result<(), i64> {
4172     let n = 1;
4173     let m = fun_name()?;
4174     let h = 1 + m;
4175     Ok(())
4176 }
4177 
4178 fn $0fun_name() -> Result<i32, i64> {
4179     let k = foo()?;
4180     let m = k + 1;
4181     Ok(m)
4182 }
4183 "#,
4184         );
4185     }
4186 
4187     #[test]
try_option_with_return()4188     fn try_option_with_return() {
4189         check_assist(
4190             extract_function,
4191             r#"
4192 //- minicore: option
4193 fn foo() -> Option<()> {
4194     let n = 1;
4195     $0let k = foo()?;
4196     if k == 42 {
4197         return None;
4198     }
4199     let m = k + 1;$0
4200     let h = 1 + m;
4201     Some(())
4202 }
4203 "#,
4204             r#"
4205 fn foo() -> Option<()> {
4206     let n = 1;
4207     let m = fun_name()?;
4208     let h = 1 + m;
4209     Some(())
4210 }
4211 
4212 fn $0fun_name() -> Option<i32> {
4213     let k = foo()?;
4214     if k == 42 {
4215         return None;
4216     }
4217     let m = k + 1;
4218     Some(m)
4219 }
4220 "#,
4221         );
4222     }
4223 
4224     #[test]
try_result_with_return()4225     fn try_result_with_return() {
4226         check_assist(
4227             extract_function,
4228             r#"
4229 //- minicore: result
4230 fn foo() -> Result<(), i64> {
4231     let n = 1;
4232     $0let k = foo()?;
4233     if k == 42 {
4234         return Err(1);
4235     }
4236     let m = k + 1;$0
4237     let h = 1 + m;
4238     Ok(())
4239 }
4240 "#,
4241             r#"
4242 fn foo() -> Result<(), i64> {
4243     let n = 1;
4244     let m = fun_name()?;
4245     let h = 1 + m;
4246     Ok(())
4247 }
4248 
4249 fn $0fun_name() -> Result<i32, i64> {
4250     let k = foo()?;
4251     if k == 42 {
4252         return Err(1);
4253     }
4254     let m = k + 1;
4255     Ok(m)
4256 }
4257 "#,
4258         );
4259     }
4260 
4261     #[test]
try_and_break()4262     fn try_and_break() {
4263         cov_mark::check!(external_control_flow_try_and_bc);
4264         check_assist_not_applicable(
4265             extract_function,
4266             r#"
4267 //- minicore: option
4268 fn foo() -> Option<()> {
4269     loop {
4270         let n = Some(1);
4271         $0let m = n? + 1;
4272         break;
4273         let k = 2;
4274         let k = k + 1;$0
4275         let r = n + k;
4276     }
4277     Some(())
4278 }
4279 "#,
4280         );
4281     }
4282 
4283     #[test]
try_and_return_ok()4284     fn try_and_return_ok() {
4285         check_assist(
4286             extract_function,
4287             r#"
4288 //- minicore: result
4289 fn foo() -> Result<(), i64> {
4290     let n = 1;
4291     $0let k = foo()?;
4292     if k == 42 {
4293         return Ok(1);
4294     }
4295     let m = k + 1;$0
4296     let h = 1 + m;
4297     Ok(())
4298 }
4299 "#,
4300             r#"
4301 fn foo() -> Result<(), i64> {
4302     let n = 1;
4303     let m = fun_name()?;
4304     let h = 1 + m;
4305     Ok(())
4306 }
4307 
4308 fn $0fun_name() -> Result<i32, i64> {
4309     let k = foo()?;
4310     if k == 42 {
4311         return Ok(1);
4312     }
4313     let m = k + 1;
4314     Ok(m)
4315 }
4316 "#,
4317         );
4318     }
4319 
4320     #[test]
param_usage_in_macro()4321     fn param_usage_in_macro() {
4322         check_assist(
4323             extract_function,
4324             r#"
4325 macro_rules! m {
4326     ($val:expr) => { $val };
4327 }
4328 
4329 fn foo() {
4330     let n = 1;
4331     $0let k = n * m!(n);$0
4332     let m = k + 1;
4333 }
4334 "#,
4335             r#"
4336 macro_rules! m {
4337     ($val:expr) => { $val };
4338 }
4339 
4340 fn foo() {
4341     let n = 1;
4342     let k = fun_name(n);
4343     let m = k + 1;
4344 }
4345 
4346 fn $0fun_name(n: i32) -> i32 {
4347     let k = n * m!(n);
4348     k
4349 }
4350 "#,
4351         );
4352     }
4353 
4354     #[test]
param_usage_in_macro_with_nested_tt()4355     fn param_usage_in_macro_with_nested_tt() {
4356         check_assist(
4357             extract_function,
4358             r#"
4359 macro_rules! m {
4360     ($val:expr) => { $val };
4361 }
4362 
4363 fn foo() {
4364     let n = 1;
4365     let t = 1;
4366     $0let k = n * m!((n) + { t });$0
4367     let m = k + 1;
4368 }
4369 "#,
4370             r#"
4371 macro_rules! m {
4372     ($val:expr) => { $val };
4373 }
4374 
4375 fn foo() {
4376     let n = 1;
4377     let t = 1;
4378     let k = fun_name(n, t);
4379     let m = k + 1;
4380 }
4381 
4382 fn $0fun_name(n: i32, t: i32) -> i32 {
4383     let k = n * m!((n) + { t });
4384     k
4385 }
4386 "#,
4387         )
4388     }
4389 
4390     #[test]
param_usage_in_macro_with_nested_tt_2()4391     fn param_usage_in_macro_with_nested_tt_2() {
4392         check_assist(
4393             extract_function,
4394             r#"
4395 macro_rules! m {
4396     ($val:expr) => { $val };
4397 }
4398 
4399 struct S(i32);
4400 impl S {
4401     fn foo(&self) {
4402         let n = 1;
4403         $0let k = n * m!((n) + { self.0 });$0
4404         let m = k + 1;
4405     }
4406 }
4407 "#,
4408             r#"
4409 macro_rules! m {
4410     ($val:expr) => { $val };
4411 }
4412 
4413 struct S(i32);
4414 impl S {
4415     fn foo(&self) {
4416         let n = 1;
4417         let k = self.fun_name(n);
4418         let m = k + 1;
4419     }
4420 
4421     fn $0fun_name(&self, n: i32) -> i32 {
4422         let k = n * m!((n) + { self.0 });
4423         k
4424     }
4425 }
4426 "#,
4427         )
4428     }
4429 
4430     #[test]
extract_with_await()4431     fn extract_with_await() {
4432         check_assist(
4433             extract_function,
4434             r#"
4435 //- minicore: future
4436 fn main() {
4437     $0some_function().await;$0
4438 }
4439 
4440 async fn some_function() {
4441 
4442 }
4443 "#,
4444             r#"
4445 fn main() {
4446     fun_name().await;
4447 }
4448 
4449 async fn $0fun_name() {
4450     some_function().await;
4451 }
4452 
4453 async fn some_function() {
4454 
4455 }
4456 "#,
4457         );
4458     }
4459 
4460     #[test]
extract_with_await_and_result_not_producing_match_expr()4461     fn extract_with_await_and_result_not_producing_match_expr() {
4462         check_assist(
4463             extract_function,
4464             r#"
4465 //- minicore: future, result
4466 async fn foo() -> Result<(), ()> {
4467     $0async {}.await;
4468     Err(())?$0
4469 }
4470 "#,
4471             r#"
4472 async fn foo() -> Result<(), ()> {
4473     fun_name().await?
4474 }
4475 
4476 async fn $0fun_name() -> Result<(), ()> {
4477     async {}.await;
4478     Err(())?
4479 }
4480 "#,
4481         );
4482     }
4483 
4484     #[test]
extract_with_await_and_result_producing_match_expr()4485     fn extract_with_await_and_result_producing_match_expr() {
4486         check_assist(
4487             extract_function,
4488             r#"
4489 //- minicore: future
4490 async fn foo() -> i32 {
4491     loop {
4492         let n = 1;$0
4493         let k = async { 1 }.await;
4494         if k == 42 {
4495             break 3;
4496         }
4497         let m = k + 1;$0
4498         let h = 1 + m;
4499     }
4500 }
4501 "#,
4502             r#"
4503 async fn foo() -> i32 {
4504     loop {
4505         let n = 1;
4506         let m = match fun_name().await {
4507             Ok(value) => value,
4508             Err(value) => break value,
4509         };
4510         let h = 1 + m;
4511     }
4512 }
4513 
4514 async fn $0fun_name() -> Result<i32, i32> {
4515     let k = async { 1 }.await;
4516     if k == 42 {
4517         return Err(3);
4518     }
4519     let m = k + 1;
4520     Ok(m)
4521 }
4522 "#,
4523         );
4524     }
4525 
4526     #[test]
extract_with_await_in_args()4527     fn extract_with_await_in_args() {
4528         check_assist(
4529             extract_function,
4530             r#"
4531 //- minicore: future
4532 fn main() {
4533     $0function_call("a", some_function().await);$0
4534 }
4535 
4536 async fn some_function() {
4537 
4538 }
4539 "#,
4540             r#"
4541 fn main() {
4542     fun_name().await;
4543 }
4544 
4545 async fn $0fun_name() {
4546     function_call("a", some_function().await);
4547 }
4548 
4549 async fn some_function() {
4550 
4551 }
4552 "#,
4553         );
4554     }
4555 
4556     #[test]
extract_does_not_extract_standalone_blocks()4557     fn extract_does_not_extract_standalone_blocks() {
4558         check_assist_not_applicable(
4559             extract_function,
4560             r#"
4561 fn main() $0{}$0
4562 "#,
4563         );
4564     }
4565 
4566     #[test]
extract_adds_comma_for_match_arm()4567     fn extract_adds_comma_for_match_arm() {
4568         check_assist(
4569             extract_function,
4570             r#"
4571 fn main() {
4572     match 6 {
4573         100 => $0{ 100 }$0
4574         _ => 0,
4575     };
4576 }
4577 "#,
4578             r#"
4579 fn main() {
4580     match 6 {
4581         100 => fun_name(),
4582         _ => 0,
4583     };
4584 }
4585 
4586 fn $0fun_name() -> i32 {
4587     100
4588 }
4589 "#,
4590         );
4591         check_assist(
4592             extract_function,
4593             r#"
4594 fn main() {
4595     match 6 {
4596         100 => $0{ 100 }$0,
4597         _ => 0,
4598     };
4599 }
4600 "#,
4601             r#"
4602 fn main() {
4603     match 6 {
4604         100 => fun_name(),
4605         _ => 0,
4606     };
4607 }
4608 
4609 fn $0fun_name() -> i32 {
4610     100
4611 }
4612 "#,
4613         );
4614     }
4615 
4616     #[test]
extract_does_not_tear_comments_apart()4617     fn extract_does_not_tear_comments_apart() {
4618         check_assist(
4619             extract_function,
4620             r#"
4621 fn foo() {
4622     /*$0*/
4623     foo();
4624     foo();
4625     /*$0*/
4626 }
4627 "#,
4628             r#"
4629 fn foo() {
4630     fun_name();
4631 }
4632 
4633 fn $0fun_name() {
4634     /**/
4635     foo();
4636     foo();
4637     /**/
4638 }
4639 "#,
4640         );
4641     }
4642 
4643     #[test]
extract_does_not_tear_body_apart()4644     fn extract_does_not_tear_body_apart() {
4645         check_assist(
4646             extract_function,
4647             r#"
4648 fn foo() {
4649     $0foo();
4650 }$0
4651 "#,
4652             r#"
4653 fn foo() {
4654     fun_name();
4655 }
4656 
4657 fn $0fun_name() {
4658     foo();
4659 }
4660 "#,
4661         );
4662     }
4663 
4664     #[test]
extract_does_not_wrap_res_in_res()4665     fn extract_does_not_wrap_res_in_res() {
4666         check_assist(
4667             extract_function,
4668             r#"
4669 //- minicore: result
4670 fn foo() -> Result<(), i64> {
4671     $0Result::<i32, i64>::Ok(0)?;
4672     Ok(())$0
4673 }
4674 "#,
4675             r#"
4676 fn foo() -> Result<(), i64> {
4677     fun_name()?
4678 }
4679 
4680 fn $0fun_name() -> Result<(), i64> {
4681     Result::<i32, i64>::Ok(0)?;
4682     Ok(())
4683 }
4684 "#,
4685         );
4686     }
4687 
4688     #[test]
extract_knows_const()4689     fn extract_knows_const() {
4690         check_assist(
4691             extract_function,
4692             r#"
4693 const fn foo() {
4694     $0()$0
4695 }
4696 "#,
4697             r#"
4698 const fn foo() {
4699     fun_name();
4700 }
4701 
4702 const fn $0fun_name() {
4703     ()
4704 }
4705 "#,
4706         );
4707         check_assist(
4708             extract_function,
4709             r#"
4710 const FOO: () = {
4711     $0()$0
4712 };
4713 "#,
4714             r#"
4715 const FOO: () = {
4716     fun_name();
4717 };
4718 
4719 const fn $0fun_name() {
4720     ()
4721 }
4722 "#,
4723         );
4724     }
4725 
4726     #[test]
extract_does_not_move_outer_loop_vars()4727     fn extract_does_not_move_outer_loop_vars() {
4728         check_assist(
4729             extract_function,
4730             r#"
4731 //- minicore: iterator
4732 fn foo() {
4733     let mut x = 5;
4734     for _ in 0..10 {
4735         $0x += 1;$0
4736     }
4737 }
4738 "#,
4739             r#"
4740 fn foo() {
4741     let mut x = 5;
4742     for _ in 0..10 {
4743         fun_name(&mut x);
4744     }
4745 }
4746 
4747 fn $0fun_name(x: &mut i32) {
4748     *x += 1;
4749 }
4750 "#,
4751         );
4752         check_assist(
4753             extract_function,
4754             r#"
4755 //- minicore: iterator
4756 fn foo() {
4757     for _ in 0..10 {
4758         let mut x = 5;
4759         $0x += 1;$0
4760     }
4761 }
4762 "#,
4763             r#"
4764 fn foo() {
4765     for _ in 0..10 {
4766         let mut x = 5;
4767         fun_name(x);
4768     }
4769 }
4770 
4771 fn $0fun_name(mut x: i32) {
4772     x += 1;
4773 }
4774 "#,
4775         );
4776         check_assist(
4777             extract_function,
4778             r#"
4779 //- minicore: iterator
4780 fn foo() {
4781     loop {
4782         let mut x = 5;
4783         for _ in 0..10 {
4784             $0x += 1;$0
4785         }
4786     }
4787 }
4788 "#,
4789             r#"
4790 fn foo() {
4791     loop {
4792         let mut x = 5;
4793         for _ in 0..10 {
4794             fun_name(&mut x);
4795         }
4796     }
4797 }
4798 
4799 fn $0fun_name(x: &mut i32) {
4800     *x += 1;
4801 }
4802 "#,
4803         );
4804     }
4805 
4806     // regression test for #9822
4807     #[test]
extract_mut_ref_param_has_no_mut_binding_in_loop()4808     fn extract_mut_ref_param_has_no_mut_binding_in_loop() {
4809         check_assist(
4810             extract_function,
4811             r#"
4812 struct Foo;
4813 impl Foo {
4814     fn foo(&mut self) {}
4815 }
4816 fn foo() {
4817     let mut x = Foo;
4818     while false {
4819         let y = &mut x;
4820         $0y.foo();$0
4821     }
4822     let z = x;
4823 }
4824 "#,
4825             r#"
4826 struct Foo;
4827 impl Foo {
4828     fn foo(&mut self) {}
4829 }
4830 fn foo() {
4831     let mut x = Foo;
4832     while false {
4833         let y = &mut x;
4834         fun_name(y);
4835     }
4836     let z = x;
4837 }
4838 
4839 fn $0fun_name(y: &mut Foo) {
4840     y.foo();
4841 }
4842 "#,
4843         );
4844     }
4845 
4846     #[test]
extract_with_macro_arg()4847     fn extract_with_macro_arg() {
4848         check_assist(
4849             extract_function,
4850             r#"
4851 macro_rules! m {
4852     ($val:expr) => { $val };
4853 }
4854 fn main() {
4855     let bar = "bar";
4856     $0m!(bar);$0
4857 }
4858 "#,
4859             r#"
4860 macro_rules! m {
4861     ($val:expr) => { $val };
4862 }
4863 fn main() {
4864     let bar = "bar";
4865     fun_name(bar);
4866 }
4867 
4868 fn $0fun_name(bar: &str) {
4869     m!(bar);
4870 }
4871 "#,
4872         );
4873     }
4874 
4875     #[test]
unresolveable_types_default_to_placeholder()4876     fn unresolveable_types_default_to_placeholder() {
4877         check_assist(
4878             extract_function,
4879             r#"
4880 fn foo() {
4881     let a = __unresolved;
4882     let _ = $0{a}$0;
4883 }
4884 "#,
4885             r#"
4886 fn foo() {
4887     let a = __unresolved;
4888     let _ = fun_name(a);
4889 }
4890 
4891 fn $0fun_name(a: _) -> _ {
4892     a
4893 }
4894 "#,
4895         );
4896     }
4897 
4898     #[test]
reference_mutable_param_with_further_usages()4899     fn reference_mutable_param_with_further_usages() {
4900         check_assist(
4901             extract_function,
4902             r#"
4903 pub struct Foo {
4904     field: u32,
4905 }
4906 
4907 pub fn testfn(arg: &mut Foo) {
4908     $0arg.field = 8;$0
4909     // Simulating access after the extracted portion
4910     arg.field = 16;
4911 }
4912 "#,
4913             r#"
4914 pub struct Foo {
4915     field: u32,
4916 }
4917 
4918 pub fn testfn(arg: &mut Foo) {
4919     fun_name(arg);
4920     // Simulating access after the extracted portion
4921     arg.field = 16;
4922 }
4923 
4924 fn $0fun_name(arg: &mut Foo) {
4925     arg.field = 8;
4926 }
4927 "#,
4928         );
4929     }
4930 
4931     #[test]
reference_mutable_param_without_further_usages()4932     fn reference_mutable_param_without_further_usages() {
4933         check_assist(
4934             extract_function,
4935             r#"
4936 pub struct Foo {
4937     field: u32,
4938 }
4939 
4940 pub fn testfn(arg: &mut Foo) {
4941     $0arg.field = 8;$0
4942 }
4943 "#,
4944             r#"
4945 pub struct Foo {
4946     field: u32,
4947 }
4948 
4949 pub fn testfn(arg: &mut Foo) {
4950     fun_name(arg);
4951 }
4952 
4953 fn $0fun_name(arg: &mut Foo) {
4954     arg.field = 8;
4955 }
4956 "#,
4957         );
4958     }
4959 
4960     #[test]
extract_function_copies_comment_at_start()4961     fn extract_function_copies_comment_at_start() {
4962         check_assist(
4963             extract_function,
4964             r#"
4965 fn func() {
4966     let i = 0;
4967     $0// comment here!
4968     let x = 0;$0
4969 }
4970 "#,
4971             r#"
4972 fn func() {
4973     let i = 0;
4974     fun_name();
4975 }
4976 
4977 fn $0fun_name() {
4978     // comment here!
4979     let x = 0;
4980 }
4981 "#,
4982         );
4983     }
4984 
4985     #[test]
extract_function_copies_comment_in_between()4986     fn extract_function_copies_comment_in_between() {
4987         check_assist(
4988             extract_function,
4989             r#"
4990 fn func() {
4991     let i = 0;$0
4992     let a = 0;
4993     // comment here!
4994     let x = 0;$0
4995 }
4996 "#,
4997             r#"
4998 fn func() {
4999     let i = 0;
5000     fun_name();
5001 }
5002 
5003 fn $0fun_name() {
5004     let a = 0;
5005     // comment here!
5006     let x = 0;
5007 }
5008 "#,
5009         );
5010     }
5011 
5012     #[test]
extract_function_copies_comment_at_end()5013     fn extract_function_copies_comment_at_end() {
5014         check_assist(
5015             extract_function,
5016             r#"
5017 fn func() {
5018     let i = 0;
5019     $0let x = 0;
5020     // comment here!$0
5021 }
5022 "#,
5023             r#"
5024 fn func() {
5025     let i = 0;
5026     fun_name();
5027 }
5028 
5029 fn $0fun_name() {
5030     let x = 0;
5031     // comment here!
5032 }
5033 "#,
5034         );
5035     }
5036 
5037     #[test]
extract_function_copies_comment_indented()5038     fn extract_function_copies_comment_indented() {
5039         check_assist(
5040             extract_function,
5041             r#"
5042 fn func() {
5043     let i = 0;
5044     $0let x = 0;
5045     while(true) {
5046         // comment here!
5047     }$0
5048 }
5049 "#,
5050             r#"
5051 fn func() {
5052     let i = 0;
5053     fun_name();
5054 }
5055 
5056 fn $0fun_name() {
5057     let x = 0;
5058     while(true) {
5059         // comment here!
5060     }
5061 }
5062 "#,
5063         );
5064     }
5065 
5066     #[test]
extract_function_does_preserve_whitespace()5067     fn extract_function_does_preserve_whitespace() {
5068         check_assist(
5069             extract_function,
5070             r#"
5071 fn func() {
5072     let i = 0;
5073     $0let a = 0;
5074 
5075     let x = 0;$0
5076 }
5077 "#,
5078             r#"
5079 fn func() {
5080     let i = 0;
5081     fun_name();
5082 }
5083 
5084 fn $0fun_name() {
5085     let a = 0;
5086 
5087     let x = 0;
5088 }
5089 "#,
5090         );
5091     }
5092 
5093     #[test]
extract_function_long_form_comment()5094     fn extract_function_long_form_comment() {
5095         check_assist(
5096             extract_function,
5097             r#"
5098 fn func() {
5099     let i = 0;
5100     $0/* a comment */
5101     let x = 0;$0
5102 }
5103 "#,
5104             r#"
5105 fn func() {
5106     let i = 0;
5107     fun_name();
5108 }
5109 
5110 fn $0fun_name() {
5111     /* a comment */
5112     let x = 0;
5113 }
5114 "#,
5115         );
5116     }
5117 
5118     #[test]
it_should_not_generate_duplicate_function_names()5119     fn it_should_not_generate_duplicate_function_names() {
5120         check_assist(
5121             extract_function,
5122             r#"
5123 fn fun_name() {
5124     $0let x = 0;$0
5125 }
5126 "#,
5127             r#"
5128 fn fun_name() {
5129     fun_name1();
5130 }
5131 
5132 fn $0fun_name1() {
5133     let x = 0;
5134 }
5135 "#,
5136         );
5137     }
5138 
5139     #[test]
should_increment_suffix_until_it_finds_space()5140     fn should_increment_suffix_until_it_finds_space() {
5141         check_assist(
5142             extract_function,
5143             r#"
5144 fn fun_name1() {
5145     let y = 0;
5146 }
5147 
5148 fn fun_name() {
5149     $0let x = 0;$0
5150 }
5151 "#,
5152             r#"
5153 fn fun_name1() {
5154     let y = 0;
5155 }
5156 
5157 fn fun_name() {
5158     fun_name2();
5159 }
5160 
5161 fn $0fun_name2() {
5162     let x = 0;
5163 }
5164 "#,
5165         );
5166     }
5167 
5168     #[test]
extract_method_from_trait_impl()5169     fn extract_method_from_trait_impl() {
5170         check_assist(
5171             extract_function,
5172             r#"
5173 struct Struct(i32);
5174 trait Trait {
5175     fn bar(&self) -> i32;
5176 }
5177 
5178 impl Trait for Struct {
5179     fn bar(&self) -> i32 {
5180         $0self.0 + 2$0
5181     }
5182 }
5183 "#,
5184             r#"
5185 struct Struct(i32);
5186 trait Trait {
5187     fn bar(&self) -> i32;
5188 }
5189 
5190 impl Trait for Struct {
5191     fn bar(&self) -> i32 {
5192         self.fun_name()
5193     }
5194 }
5195 
5196 impl Struct {
5197     fn $0fun_name(&self) -> i32 {
5198         self.0 + 2
5199     }
5200 }
5201 "#,
5202         );
5203     }
5204 
5205     #[test]
extract_method_from_trait_with_existing_non_empty_impl_block()5206     fn extract_method_from_trait_with_existing_non_empty_impl_block() {
5207         check_assist(
5208             extract_function,
5209             r#"
5210 struct Struct(i32);
5211 trait Trait {
5212     fn bar(&self) -> i32;
5213 }
5214 
5215 impl Struct {
5216     fn foo() {}
5217 }
5218 
5219 impl Trait for Struct {
5220     fn bar(&self) -> i32 {
5221         $0self.0 + 2$0
5222     }
5223 }
5224 "#,
5225             r#"
5226 struct Struct(i32);
5227 trait Trait {
5228     fn bar(&self) -> i32;
5229 }
5230 
5231 impl Struct {
5232     fn foo() {}
5233 
5234     fn $0fun_name(&self) -> i32 {
5235         self.0 + 2
5236     }
5237 }
5238 
5239 impl Trait for Struct {
5240     fn bar(&self) -> i32 {
5241         self.fun_name()
5242     }
5243 }
5244 "#,
5245         )
5246     }
5247 
5248     #[test]
extract_function_from_trait_with_existing_non_empty_impl_block()5249     fn extract_function_from_trait_with_existing_non_empty_impl_block() {
5250         check_assist(
5251             extract_function,
5252             r#"
5253 struct Struct(i32);
5254 trait Trait {
5255     fn bar(&self) -> i32;
5256 }
5257 
5258 impl Struct {
5259     fn foo() {}
5260 }
5261 
5262 impl Trait for Struct {
5263     fn bar(&self) -> i32 {
5264         let three_squared = $03 * 3$0;
5265         self.0 + three_squared
5266     }
5267 }
5268 "#,
5269             r#"
5270 struct Struct(i32);
5271 trait Trait {
5272     fn bar(&self) -> i32;
5273 }
5274 
5275 impl Struct {
5276     fn foo() {}
5277 }
5278 
5279 impl Trait for Struct {
5280     fn bar(&self) -> i32 {
5281         let three_squared = fun_name();
5282         self.0 + three_squared
5283     }
5284 }
5285 
5286 fn $0fun_name() -> i32 {
5287     3 * 3
5288 }
5289 "#,
5290         )
5291     }
5292 
5293     #[test]
extract_method_from_trait_with_multiple_existing_impl_blocks()5294     fn extract_method_from_trait_with_multiple_existing_impl_blocks() {
5295         check_assist(
5296             extract_function,
5297             r#"
5298 struct Struct(i32);
5299 struct StructBefore(i32);
5300 struct StructAfter(i32);
5301 trait Trait {
5302     fn bar(&self) -> i32;
5303 }
5304 
5305 impl StructBefore {
5306     fn foo(){}
5307 }
5308 
5309 impl Struct {
5310     fn foo(){}
5311 }
5312 
5313 impl StructAfter {
5314     fn foo(){}
5315 }
5316 
5317 impl Trait for Struct {
5318     fn bar(&self) -> i32 {
5319         $0self.0 + 2$0
5320     }
5321 }
5322 "#,
5323             r#"
5324 struct Struct(i32);
5325 struct StructBefore(i32);
5326 struct StructAfter(i32);
5327 trait Trait {
5328     fn bar(&self) -> i32;
5329 }
5330 
5331 impl StructBefore {
5332     fn foo(){}
5333 }
5334 
5335 impl Struct {
5336     fn foo(){}
5337 
5338     fn $0fun_name(&self) -> i32 {
5339         self.0 + 2
5340     }
5341 }
5342 
5343 impl StructAfter {
5344     fn foo(){}
5345 }
5346 
5347 impl Trait for Struct {
5348     fn bar(&self) -> i32 {
5349         self.fun_name()
5350     }
5351 }
5352 "#,
5353         )
5354     }
5355 
5356     #[test]
extract_method_from_trait_with_multiple_existing_trait_impl_blocks()5357     fn extract_method_from_trait_with_multiple_existing_trait_impl_blocks() {
5358         check_assist(
5359             extract_function,
5360             r#"
5361 struct Struct(i32);
5362 trait Trait {
5363     fn bar(&self) -> i32;
5364 }
5365 trait TraitBefore {
5366     fn before(&self) -> i32;
5367 }
5368 trait TraitAfter {
5369     fn after(&self) -> i32;
5370 }
5371 
5372 impl TraitBefore for Struct {
5373     fn before(&self) -> i32 {
5374         42
5375     }
5376 }
5377 
5378 impl Struct {
5379     fn foo(){}
5380 }
5381 
5382 impl TraitAfter for Struct {
5383     fn after(&self) -> i32 {
5384         42
5385     }
5386 }
5387 
5388 impl Trait for Struct {
5389     fn bar(&self) -> i32 {
5390         $0self.0 + 2$0
5391     }
5392 }
5393 "#,
5394             r#"
5395 struct Struct(i32);
5396 trait Trait {
5397     fn bar(&self) -> i32;
5398 }
5399 trait TraitBefore {
5400     fn before(&self) -> i32;
5401 }
5402 trait TraitAfter {
5403     fn after(&self) -> i32;
5404 }
5405 
5406 impl TraitBefore for Struct {
5407     fn before(&self) -> i32 {
5408         42
5409     }
5410 }
5411 
5412 impl Struct {
5413     fn foo(){}
5414 
5415     fn $0fun_name(&self) -> i32 {
5416         self.0 + 2
5417     }
5418 }
5419 
5420 impl TraitAfter for Struct {
5421     fn after(&self) -> i32 {
5422         42
5423     }
5424 }
5425 
5426 impl Trait for Struct {
5427     fn bar(&self) -> i32 {
5428         self.fun_name()
5429     }
5430 }
5431 "#,
5432         )
5433     }
5434 
5435     #[test]
closure_arguments()5436     fn closure_arguments() {
5437         check_assist(
5438             extract_function,
5439             r#"
5440 fn parent(factor: i32) {
5441     let v = &[1, 2, 3];
5442 
5443     $0v.iter().map(|it| it * factor);$0
5444 }
5445 "#,
5446             r#"
5447 fn parent(factor: i32) {
5448     let v = &[1, 2, 3];
5449 
5450     fun_name(v, factor);
5451 }
5452 
5453 fn $0fun_name(v: &[i32; 3], factor: i32) {
5454     v.iter().map(|it| it * factor);
5455 }
5456 "#,
5457         );
5458     }
5459 
5460     #[test]
preserve_generics()5461     fn preserve_generics() {
5462         check_assist(
5463             extract_function,
5464             r#"
5465 fn func<T: Debug>(i: T) {
5466     $0foo(i);$0
5467 }
5468 "#,
5469             r#"
5470 fn func<T: Debug>(i: T) {
5471     fun_name(i);
5472 }
5473 
5474 fn $0fun_name<T: Debug>(i: T) {
5475     foo(i);
5476 }
5477 "#,
5478         );
5479     }
5480 
5481     #[test]
dont_emit_type_with_hidden_lifetime_parameter()5482     fn dont_emit_type_with_hidden_lifetime_parameter() {
5483         // FIXME: We should emit a `<T: Debug>` generic argument for the generated function
5484         check_assist(
5485             extract_function,
5486             r#"
5487 struct Struct<'a, T>(&'a T);
5488 fn func<T: Debug>(i: Struct<'_, T>) {
5489     $0foo(i);$0
5490 }
5491 "#,
5492             r#"
5493 struct Struct<'a, T>(&'a T);
5494 fn func<T: Debug>(i: Struct<'_, T>) {
5495     fun_name(i);
5496 }
5497 
5498 fn $0fun_name(i: Struct<'_, T>) {
5499     foo(i);
5500 }
5501 "#,
5502         );
5503     }
5504 
5505     #[test]
preserve_generics_from_body()5506     fn preserve_generics_from_body() {
5507         check_assist(
5508             extract_function,
5509             r#"
5510 fn func<T: Default>() -> T {
5511     $0T::default()$0
5512 }
5513 "#,
5514             r#"
5515 fn func<T: Default>() -> T {
5516     fun_name()
5517 }
5518 
5519 fn $0fun_name<T: Default>() -> T {
5520     T::default()
5521 }
5522 "#,
5523         );
5524     }
5525 
5526     #[test]
filter_unused_generics()5527     fn filter_unused_generics() {
5528         check_assist(
5529             extract_function,
5530             r#"
5531 fn func<T: Debug, U: Copy>(i: T, u: U) {
5532     bar(u);
5533     $0foo(i);$0
5534 }
5535 "#,
5536             r#"
5537 fn func<T: Debug, U: Copy>(i: T, u: U) {
5538     bar(u);
5539     fun_name(i);
5540 }
5541 
5542 fn $0fun_name<T: Debug>(i: T) {
5543     foo(i);
5544 }
5545 "#,
5546         );
5547     }
5548 
5549     #[test]
empty_generic_param_list()5550     fn empty_generic_param_list() {
5551         check_assist(
5552             extract_function,
5553             r#"
5554 fn func<T: Debug>(t: T, i: u32) {
5555     bar(t);
5556     $0foo(i);$0
5557 }
5558 "#,
5559             r#"
5560 fn func<T: Debug>(t: T, i: u32) {
5561     bar(t);
5562     fun_name(i);
5563 }
5564 
5565 fn $0fun_name(i: u32) {
5566     foo(i);
5567 }
5568 "#,
5569         );
5570     }
5571 
5572     #[test]
preserve_where_clause()5573     fn preserve_where_clause() {
5574         check_assist(
5575             extract_function,
5576             r#"
5577 fn func<T>(i: T) where T: Debug {
5578     $0foo(i);$0
5579 }
5580 "#,
5581             r#"
5582 fn func<T>(i: T) where T: Debug {
5583     fun_name(i);
5584 }
5585 
5586 fn $0fun_name<T>(i: T) where T: Debug {
5587     foo(i);
5588 }
5589 "#,
5590         );
5591     }
5592 
5593     #[test]
filter_unused_where_clause()5594     fn filter_unused_where_clause() {
5595         check_assist(
5596             extract_function,
5597             r#"
5598 fn func<T, U>(i: T, u: U) where T: Debug, U: Copy {
5599     bar(u);
5600     $0foo(i);$0
5601 }
5602 "#,
5603             r#"
5604 fn func<T, U>(i: T, u: U) where T: Debug, U: Copy {
5605     bar(u);
5606     fun_name(i);
5607 }
5608 
5609 fn $0fun_name<T>(i: T) where T: Debug {
5610     foo(i);
5611 }
5612 "#,
5613         );
5614     }
5615 
5616     #[test]
nested_generics()5617     fn nested_generics() {
5618         check_assist(
5619             extract_function,
5620             r#"
5621 struct Struct<T: Into<i32>>(T);
5622 impl <T: Into<i32> + Copy> Struct<T> {
5623     fn func<V: Into<i32>>(&self, v: V) -> i32 {
5624         let t = self.0;
5625         $0t.into() + v.into()$0
5626     }
5627 }
5628 "#,
5629             r#"
5630 struct Struct<T: Into<i32>>(T);
5631 impl <T: Into<i32> + Copy> Struct<T> {
5632     fn func<V: Into<i32>>(&self, v: V) -> i32 {
5633         let t = self.0;
5634         fun_name(t, v)
5635     }
5636 }
5637 
5638 fn $0fun_name<T: Into<i32> + Copy, V: Into<i32>>(t: T, v: V) -> i32 {
5639     t.into() + v.into()
5640 }
5641 "#,
5642         );
5643     }
5644 
5645     #[test]
filters_unused_nested_generics()5646     fn filters_unused_nested_generics() {
5647         check_assist(
5648             extract_function,
5649             r#"
5650 struct Struct<T: Into<i32>, U: Debug>(T, U);
5651 impl <T: Into<i32> + Copy, U: Debug> Struct<T, U> {
5652     fn func<V: Into<i32>>(&self, v: V) -> i32 {
5653         let t = self.0;
5654         $0t.into() + v.into()$0
5655     }
5656 }
5657 "#,
5658             r#"
5659 struct Struct<T: Into<i32>, U: Debug>(T, U);
5660 impl <T: Into<i32> + Copy, U: Debug> Struct<T, U> {
5661     fn func<V: Into<i32>>(&self, v: V) -> i32 {
5662         let t = self.0;
5663         fun_name(t, v)
5664     }
5665 }
5666 
5667 fn $0fun_name<T: Into<i32> + Copy, V: Into<i32>>(t: T, v: V) -> i32 {
5668     t.into() + v.into()
5669 }
5670 "#,
5671         );
5672     }
5673 
5674     #[test]
nested_where_clauses()5675     fn nested_where_clauses() {
5676         check_assist(
5677             extract_function,
5678             r#"
5679 struct Struct<T>(T) where T: Into<i32>;
5680 impl <T> Struct<T> where T: Into<i32> + Copy {
5681     fn func<V>(&self, v: V) -> i32 where V: Into<i32> {
5682         let t = self.0;
5683         $0t.into() + v.into()$0
5684     }
5685 }
5686 "#,
5687             r#"
5688 struct Struct<T>(T) where T: Into<i32>;
5689 impl <T> Struct<T> where T: Into<i32> + Copy {
5690     fn func<V>(&self, v: V) -> i32 where V: Into<i32> {
5691         let t = self.0;
5692         fun_name(t, v)
5693     }
5694 }
5695 
5696 fn $0fun_name<T, V>(t: T, v: V) -> i32 where T: Into<i32> + Copy, V: Into<i32> {
5697     t.into() + v.into()
5698 }
5699 "#,
5700         );
5701     }
5702 
5703     #[test]
filters_unused_nested_where_clauses()5704     fn filters_unused_nested_where_clauses() {
5705         check_assist(
5706             extract_function,
5707             r#"
5708 struct Struct<T, U>(T, U) where T: Into<i32>, U: Debug;
5709 impl <T, U> Struct<T, U> where T: Into<i32> + Copy, U: Debug {
5710     fn func<V>(&self, v: V) -> i32 where V: Into<i32> {
5711         let t = self.0;
5712         $0t.into() + v.into()$0
5713     }
5714 }
5715 "#,
5716             r#"
5717 struct Struct<T, U>(T, U) where T: Into<i32>, U: Debug;
5718 impl <T, U> Struct<T, U> where T: Into<i32> + Copy, U: Debug {
5719     fn func<V>(&self, v: V) -> i32 where V: Into<i32> {
5720         let t = self.0;
5721         fun_name(t, v)
5722     }
5723 }
5724 
5725 fn $0fun_name<T, V>(t: T, v: V) -> i32 where T: Into<i32> + Copy, V: Into<i32> {
5726     t.into() + v.into()
5727 }
5728 "#,
5729         );
5730     }
5731 
5732     #[test]
non_tail_expr_of_tail_expr_loop()5733     fn non_tail_expr_of_tail_expr_loop() {
5734         check_assist(
5735             extract_function,
5736             r#"
5737 pub fn f() {
5738     loop {
5739         $0if true {
5740             continue;
5741         }$0
5742 
5743         if false {
5744             break;
5745         }
5746     }
5747 }
5748 "#,
5749             r#"
5750 pub fn f() {
5751     loop {
5752         if let ControlFlow::Break(_) = fun_name() {
5753             continue;
5754         }
5755 
5756         if false {
5757             break;
5758         }
5759     }
5760 }
5761 
5762 fn $0fun_name() -> ControlFlow<()> {
5763     if true {
5764         return ControlFlow::Break(());
5765     }
5766     ControlFlow::Continue(())
5767 }
5768 "#,
5769         );
5770     }
5771 
5772     #[test]
non_tail_expr_of_tail_if_block()5773     fn non_tail_expr_of_tail_if_block() {
5774         // FIXME: double semicolon
5775         check_assist(
5776             extract_function,
5777             r#"
5778 //- minicore: option, try
5779 impl<T> core::ops::Try for Option<T> {
5780     type Output = T;
5781     type Residual = Option<!>;
5782 }
5783 impl<T> core::ops::FromResidual for Option<T> {}
5784 
5785 fn f() -> Option<()> {
5786     if true {
5787         let a = $0if true {
5788             Some(())?
5789         } else {
5790             ()
5791         }$0;
5792         Some(a)
5793     } else {
5794         None
5795     }
5796 }
5797 "#,
5798             r#"
5799 impl<T> core::ops::Try for Option<T> {
5800     type Output = T;
5801     type Residual = Option<!>;
5802 }
5803 impl<T> core::ops::FromResidual for Option<T> {}
5804 
5805 fn f() -> Option<()> {
5806     if true {
5807         let a = fun_name()?;;
5808         Some(a)
5809     } else {
5810         None
5811     }
5812 }
5813 
5814 fn $0fun_name() -> Option<()> {
5815     Some(if true {
5816         Some(())?
5817     } else {
5818         ()
5819     })
5820 }
5821 "#,
5822         );
5823     }
5824 
5825     #[test]
tail_expr_of_tail_block_nested()5826     fn tail_expr_of_tail_block_nested() {
5827         check_assist(
5828             extract_function,
5829             r#"
5830 //- minicore: option, try
5831 impl<T> core::ops::Try for Option<T> {
5832     type Output = T;
5833     type Residual = Option<!>;
5834 }
5835 impl<T> core::ops::FromResidual for Option<T> {}
5836 
5837 fn f() -> Option<()> {
5838     if true {
5839         $0{
5840             let a = if true {
5841                 Some(())?
5842             } else {
5843                 ()
5844             };
5845             Some(a)
5846         }$0
5847     } else {
5848         None
5849     }
5850 }
5851 "#,
5852             r#"
5853 impl<T> core::ops::Try for Option<T> {
5854     type Output = T;
5855     type Residual = Option<!>;
5856 }
5857 impl<T> core::ops::FromResidual for Option<T> {}
5858 
5859 fn f() -> Option<()> {
5860     if true {
5861         fun_name()?
5862     } else {
5863         None
5864     }
5865 }
5866 
5867 fn $0fun_name() -> Option<()> {
5868     let a = if true {
5869         Some(())?
5870     } else {
5871         ()
5872     };
5873     Some(a)
5874 }
5875 "#,
5876         );
5877     }
5878 
5879     #[test]
non_tail_expr_with_comment_of_tail_expr_loop()5880     fn non_tail_expr_with_comment_of_tail_expr_loop() {
5881         check_assist(
5882             extract_function,
5883             r#"
5884 pub fn f() {
5885     loop {
5886         $0// A comment
5887         if true {
5888             continue;
5889         }$0
5890         if false {
5891             break;
5892         }
5893     }
5894 }
5895 "#,
5896             r#"
5897 pub fn f() {
5898     loop {
5899         if let ControlFlow::Break(_) = fun_name() {
5900             continue;
5901         }
5902         if false {
5903             break;
5904         }
5905     }
5906 }
5907 
5908 fn $0fun_name() -> ControlFlow<()> {
5909     // A comment
5910     if true {
5911         return ControlFlow::Break(());
5912     }
5913     ControlFlow::Continue(())
5914 }
5915 "#,
5916         );
5917     }
5918 
5919     #[test]
in_left_curly_is_not_applicable()5920     fn in_left_curly_is_not_applicable() {
5921         cov_mark::check!(extract_function_in_braces_is_not_applicable);
5922         check_assist_not_applicable(extract_function, r"fn foo() { $0}$0");
5923     }
5924 
5925     #[test]
in_right_curly_is_not_applicable()5926     fn in_right_curly_is_not_applicable() {
5927         cov_mark::check!(extract_function_in_braces_is_not_applicable);
5928         check_assist_not_applicable(extract_function, r"fn foo() $0{$0 }");
5929     }
5930 
5931     #[test]
in_left_paren_is_not_applicable()5932     fn in_left_paren_is_not_applicable() {
5933         cov_mark::check!(extract_function_in_braces_is_not_applicable);
5934         check_assist_not_applicable(extract_function, r"fn foo( $0)$0 { }");
5935     }
5936 
5937     #[test]
in_right_paren_is_not_applicable()5938     fn in_right_paren_is_not_applicable() {
5939         cov_mark::check!(extract_function_in_braces_is_not_applicable);
5940         check_assist_not_applicable(extract_function, r"fn foo $0($0 ) { }");
5941     }
5942 
5943     #[test]
in_left_brack_is_not_applicable()5944     fn in_left_brack_is_not_applicable() {
5945         cov_mark::check!(extract_function_in_braces_is_not_applicable);
5946         check_assist_not_applicable(extract_function, r"fn foo(arr: &mut [i32$0]$0) {}");
5947     }
5948 
5949     #[test]
in_right_brack_is_not_applicable()5950     fn in_right_brack_is_not_applicable() {
5951         cov_mark::check!(extract_function_in_braces_is_not_applicable);
5952         check_assist_not_applicable(extract_function, r"fn foo(arr: &mut $0[$0i32]) {}");
5953     }
5954 }
5955