6 BLOCK_EXPR, BREAK_EXPR, CLOSURE_EXPR, COMMENT, LOOP_EXPR, MATCH_ARM, MATCH_GUARD,
7 PATH_EXPR, RETURN_EXPR,
12 use crate::{utils::suggest_name, AssistContext, AssistId, AssistKind, Assists};
14 // Assist: extract_variable
16 // Extracts subexpression into a variable.
26 // let $0var_name = (1 + 2);
30 pub(crate) fn extract_variable(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
31 if ctx.has_empty_selection() {
35 let node = match ctx.covering_element() {
36 NodeOrToken::Node(it) => it,
37 NodeOrToken::Token(it) if it.kind() == COMMENT => {
38 cov_mark::hit!(extract_var_in_comment_is_not_applicable);
41 NodeOrToken::Token(it) => it.parent()?,
43 let node = node.ancestors().take_while(|anc| anc.text_range() == node.text_range()).last()?;
46 .take_while(|it| ctx.selection_trimmed().contains_range(it.text_range()))
47 .find_map(valid_target_expr)?;
49 if let Some(ty_info) = ctx.sema.type_of_expr(&to_extract) {
50 if ty_info.adjusted().is_unit() {
55 let reference_modifier = match get_receiver_type(&ctx, &to_extract) {
56 Some(receiver_type) if receiver_type.is_mutable_reference() => "&mut ",
57 Some(receiver_type) if receiver_type.is_reference() => "&",
61 let anchor = Anchor::from(&to_extract)?;
62 let indent = anchor.syntax().prev_sibling_or_token()?.as_token()?.clone();
63 let target = to_extract.syntax().text_range();
65 AssistId("extract_variable", AssistKind::RefactorExtract),
66 "Extract into variable",
70 match to_extract.syntax().parent().and_then(ast::RecordExprField::cast) {
71 Some(field) => field.name_ref(),
75 let mut buf = String::new();
77 let var_name = match &field_shorthand {
78 Some(it) => it.to_string(),
79 None => suggest_name::for_variable(&to_extract, &ctx.sema),
81 let expr_range = match &field_shorthand {
82 Some(it) => it.syntax().text_range().cover(to_extract.syntax().text_range()),
83 None => to_extract.syntax().text_range(),
87 Anchor::Before(_) | Anchor::Replace(_) => {
88 format_to!(buf, "let {} = {}", var_name, reference_modifier)
90 Anchor::WrapInBlock(_) => {
91 format_to!(buf, "{{ let {} = {}", var_name, reference_modifier)
94 format_to!(buf, "{}", to_extract.syntax());
96 if let Anchor::Replace(stmt) = anchor {
97 cov_mark::hit!(test_extract_var_expr_stmt);
98 if stmt.semicolon_token().is_none() {
101 match ctx.config.snippet_cap {
104 .replace(&format!("let {}", var_name), &format!("let $0{}", var_name));
105 edit.replace_snippet(cap, expr_range, snip)
107 None => edit.replace(expr_range, buf),
114 // We want to maintain the indent level,
115 // but we do not want to duplicate possible
116 // extra newlines in the indent block
117 let text = indent.text();
118 if text.starts_with('\n') {
120 buf.push_str(text.trim_start_matches('\n'));
125 edit.replace(expr_range, var_name.clone());
126 let offset = anchor.syntax().text_range().start();
127 match ctx.config.snippet_cap {
130 buf.replace(&format!("let {}", var_name), &format!("let $0{}", var_name));
131 edit.insert_snippet(cap, offset, snip)
133 None => edit.insert(offset, buf),
136 if let Anchor::WrapInBlock(_) = anchor {
137 edit.insert(anchor.syntax().text_range().end(), " }");
143 /// Check whether the node is a valid expression which can be extracted to a variable.
144 /// In general that's true for any expression, but in some cases that would produce invalid code.
145 fn valid_target_expr(node: SyntaxNode) -> Option<ast::Expr> {
147 PATH_EXPR | LOOP_EXPR => None,
148 BREAK_EXPR => ast::BreakExpr::cast(node).and_then(|e| e.expr()),
149 RETURN_EXPR => ast::ReturnExpr::cast(node).and_then(|e| e.expr()),
151 ast::BlockExpr::cast(node).filter(|it| it.is_standalone()).map(ast::Expr::from)
153 _ => ast::Expr::cast(node),
157 fn get_receiver_type(ctx: &AssistContext, expression: &ast::Expr) -> Option<hir::Type> {
158 let receiver = get_receiver(expression.clone())?;
159 Some(ctx.sema.type_of_expr(&receiver)?.original())
162 /// In the expression `a.b.c.x()`, find `a`
163 fn get_receiver(expression: ast::Expr) -> Option<ast::Expr> {
165 ast::Expr::FieldExpr(field) if field.expr().is_some() => {
166 let nested_expression = &field.expr()?;
167 get_receiver(nested_expression.to_owned())
169 _ => Some(expression),
176 Replace(ast::ExprStmt),
177 WrapInBlock(SyntaxNode),
181 fn from(to_extract: &ast::Expr) -> Option<Anchor> {
185 .take_while(|it| !ast::Item::can_cast(it.kind()) || ast::MacroCall::can_cast(it.kind()))
187 if ast::MacroCall::can_cast(node.kind()) {
191 node.parent().and_then(ast::StmtList::cast).and_then(|it| it.tail_expr())
193 if expr.syntax() == &node {
194 cov_mark::hit!(test_extract_var_last_expr);
195 return Some(Anchor::Before(node));
199 if let Some(parent) = node.parent() {
200 if parent.kind() == CLOSURE_EXPR {
201 cov_mark::hit!(test_extract_var_in_closure_no_block);
202 return Some(Anchor::WrapInBlock(node));
204 if parent.kind() == MATCH_ARM {
205 if node.kind() == MATCH_GUARD {
206 cov_mark::hit!(test_extract_var_in_match_guard);
208 cov_mark::hit!(test_extract_var_in_match_arm_no_block);
209 return Some(Anchor::WrapInBlock(node));
214 if let Some(stmt) = ast::Stmt::cast(node.clone()) {
215 if let ast::Stmt::ExprStmt(stmt) = stmt {
216 if stmt.expr().as_ref() == Some(to_extract) {
217 return Some(Anchor::Replace(stmt));
220 return Some(Anchor::Before(node));
226 fn syntax(&self) -> &SyntaxNode {
228 Anchor::Before(it) | Anchor::WrapInBlock(it) => it,
229 Anchor::Replace(stmt) => stmt.syntax(),
236 use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
241 fn test_extract_var_simple() {
250 let $0var_name = 1 + 1;
257 fn extract_var_in_comment_is_not_applicable() {
258 cov_mark::check!(extract_var_in_comment_is_not_applicable);
259 check_assist_not_applicable(extract_variable, "fn main() { 1 + /* $0comment$0 */ 1; }");
263 fn test_extract_var_expr_stmt() {
264 cov_mark::check!(test_extract_var_expr_stmt);
273 let $0var_name = 1 + 1;
285 let $0var_name = { let x = 0; x };
292 fn test_extract_var_part_of_expr_stmt() {
308 fn test_extract_var_last_expr() {
309 cov_mark::check!(test_extract_var_last_expr);
319 let $0var_name = 1 + 1;
331 fn bar(i: i32) -> i32 {
337 let $0bar = bar(1 + 1);
341 fn bar(i: i32) -> i32 {
349 fn test_extract_var_in_match_arm_no_block() {
350 cov_mark::check!(test_extract_var_in_match_arm_no_block);
356 let tuple = match x {
357 true => ($02 + 2$0, true)
365 let tuple = match x {
366 true => { let $0var_name = 2 + 2; (var_name, true) }
375 fn test_extract_var_in_match_arm_with_block() {
381 let tuple = match x {
393 let tuple = match x {
396 let $0var_name = 2 + y;
407 fn test_extract_var_in_match_guard() {
408 cov_mark::check!(test_extract_var_in_match_guard);
414 () if $010 > 0$0 => 1
421 let $0var_name = 10 > 0;
432 fn test_extract_var_in_closure_no_block() {
433 cov_mark::check!(test_extract_var_in_closure_no_block);
438 let lambda = |x: u32| $0x * 2$0;
443 let lambda = |x: u32| { let $0var_name = x * 2; var_name };
450 fn test_extract_var_in_closure_with_block() {
455 let lambda = |x: u32| { $0x * 2$0 };
460 let lambda = |x: u32| { let $0var_name = x * 2; var_name };
467 fn test_extract_var_path_simple() {
472 let o = $0Some(true)$0;
477 let $0var_name = Some(true);
485 fn test_extract_var_path_method() {
490 let v = $0bar.foo()$0;
495 let $0foo = bar.foo();
503 fn test_extract_var_return() {
513 let $0var_name = 2 + 2;
521 fn test_extract_var_does_not_add_extra_whitespace() {
535 let $0var_name = 2 + 2;
552 let $0var_name = 2 + 2;
577 let $0var_name = 2 + 2;
585 fn test_extract_var_break() {
598 let $0var_name = 2 + 2;
607 fn test_extract_var_for_cast() {
612 let v = $00f32 as u32$0;
617 let $0var_name = 0f32 as u32;
625 fn extract_var_field_shorthand() {
651 fn extract_var_name_from_type() {
665 let $0test = { Test(10) };
673 fn extract_var_name_from_parameter() {
677 fn bar(test: u32, size: u32)
684 fn bar(test: u32, size: u32)
695 fn extract_var_parameter_name_has_precedence_over_type() {
699 struct TextSize(u32);
700 fn bar(test: u32, size: TextSize)
703 bar(1, $0{ TextSize(1+1) }$0);
707 struct TextSize(u32);
708 fn bar(test: u32, size: TextSize)
711 let $0size = { TextSize(1+1) };
719 fn extract_var_name_from_function() {
723 fn is_required(test: u32, size: u32) -> bool
726 $0is_required(1, 2)$0
730 fn is_required(test: u32, size: u32) -> bool
733 let $0is_required = is_required(1, 2);
741 fn extract_var_name_from_method() {
747 fn bar(&self, n: u32) -> u32 { n }
757 fn bar(&self, n: u32) -> u32 { n }
761 let $0bar = S.bar(1);
769 fn extract_var_name_from_method_param() {
775 fn bar(&self, n: u32, size: u32) { n }
785 fn bar(&self, n: u32, size: u32) { n }
797 fn extract_var_name_from_ufcs_method_param() {
803 fn bar(&self, n: u32, size: u32) { n }
807 S::bar(&S, $01 + 1$0, 2)
813 fn bar(&self, n: u32, size: u32) { n }
825 fn extract_var_parameter_name_has_precedence_over_function() {
829 fn bar(test: u32, size: u32)
832 bar(1, $0symbol_size(1, 2)$0);
836 fn bar(test: u32, size: u32)
839 let $0size = symbol_size(1, 2);
847 fn extract_macro_call() {
873 fn test_extract_var_for_return_not_applicable() {
874 check_assist_not_applicable(extract_variable, "fn foo() { $0return$0; } ");
878 fn test_extract_var_for_break_not_applicable() {
879 check_assist_not_applicable(extract_variable, "fn main() { loop { $0break$0; }; }");
883 fn test_extract_var_unit_expr_not_applicable() {
884 check_assist_not_applicable(
898 // FIXME: This is not quite correct, but good enough(tm) for the sorting heuristic
900 fn extract_var_target() {
901 check_assist_target(extract_variable, "fn foo() -> u32 { $0return 2 + 2$0; }", "2 + 2");
908 let tuple = match x {
909 true => ($02 + 2$0, true)
919 fn extract_var_no_block_body() {
920 check_assist_not_applicable(
923 const X: usize = $0100$0;
929 fn test_extract_var_mutable_reference_parameter() {
946 let $0var_name = &mut s.vec;
953 fn test_extract_var_mutable_reference_parameter_deep_nesting() {
968 $0f.field.field.vec$0.push(0);
982 let $0var_name = &mut f.field.field.vec;
989 fn test_extract_var_reference_parameter() {
1006 $0s.sub$0.do_thing();
1012 fn do_thing(&self) {
1029 fn test_extract_var_reference_parameter_deep_nesting() {
1035 fn do_thing(&self) {
1053 $0s.sub.field.field$0.do_thing();
1058 fn do_thing(&self) {
1076 let $0z = &s.sub.field.field;
1083 fn test_extract_var_regular_parameter() {
1090 fn do_thing(&self) {
1100 $0s.sub$0.do_thing();
1106 fn do_thing(&self) {
1123 fn test_extract_var_mutable_reference_local() {
1145 fn do_thing(&self) {
1152 let local = &mut S::new();
1153 $0local.sub$0.do_thing();
1174 fn do_thing(&self) {
1181 let local = &mut S::new();
1182 let $0x = &mut local.sub;
1189 fn test_extract_var_reference_local() {
1211 fn do_thing(&self) {
1218 let local = &S::new();
1219 $0local.sub$0.do_thing();
1240 fn do_thing(&self) {
1247 let local = &S::new();
1248 let $0x = &local.sub;