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 ref_kind = match get_receiver_type(&ctx, &to_extract) {
56 Some(receiver_type) if receiver_type.is_mutable_reference() => RefKind::MutRef,
57 Some(receiver_type) if receiver_type.is_reference() => RefKind::Ref,
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(),
86 let reference_modifier = match ref_kind {
87 RefKind::MutRef => "&mut ",
93 Anchor::Before(_) | Anchor::Replace(_) => {
94 format_to!(buf, "let {} = {}", var_name, reference_modifier)
96 Anchor::WrapInBlock(_) => {
97 format_to!(buf, "{{ let {} = {}", var_name, reference_modifier)
100 format_to!(buf, "{}", to_extract.syntax());
102 if let Anchor::Replace(stmt) = anchor {
103 cov_mark::hit!(test_extract_var_expr_stmt);
104 if stmt.semicolon_token().is_none() {
107 match ctx.config.snippet_cap {
110 .replace(&format!("let {}", var_name), &format!("let $0{}", var_name));
111 edit.replace_snippet(cap, expr_range, snip)
113 None => edit.replace(expr_range, buf),
120 // We want to maintain the indent level,
121 // but we do not want to duplicate possible
122 // extra newlines in the indent block
123 let text = indent.text();
124 if text.starts_with('\n') {
126 buf.push_str(text.trim_start_matches('\n'));
131 edit.replace(expr_range, var_name.clone());
132 let offset = anchor.syntax().text_range().start();
133 match ctx.config.snippet_cap {
136 buf.replace(&format!("let {}", var_name), &format!("let $0{}", var_name));
137 edit.insert_snippet(cap, offset, snip)
139 None => edit.insert(offset, buf),
142 if let Anchor::WrapInBlock(_) = anchor {
143 edit.insert(anchor.syntax().text_range().end(), " }");
149 /// Check whether the node is a valid expression which can be extracted to a variable.
150 /// In general that's true for any expression, but in some cases that would produce invalid code.
151 fn valid_target_expr(node: SyntaxNode) -> Option<ast::Expr> {
153 PATH_EXPR | LOOP_EXPR => None,
154 BREAK_EXPR => ast::BreakExpr::cast(node).and_then(|e| e.expr()),
155 RETURN_EXPR => ast::ReturnExpr::cast(node).and_then(|e| e.expr()),
157 ast::BlockExpr::cast(node).filter(|it| it.is_standalone()).map(ast::Expr::from)
159 _ => ast::Expr::cast(node),
163 fn get_receiver_type(ctx: &AssistContext, expression: &ast::Expr) -> Option<hir::Type> {
164 let receiver = get_receiver(expression.clone())?;
165 Some(ctx.sema.type_of_expr(&receiver)?.original())
168 /// In the expression `a.b.c.x()`, find `a`
169 fn get_receiver(expression: ast::Expr) -> Option<ast::Expr> {
171 ast::Expr::FieldExpr(field) if field.expr().is_some() => {
172 let nested_expression = &field.expr()?;
173 get_receiver(nested_expression.to_owned())
175 ast::Expr::PathExpr(_) => Some(expression),
190 Replace(ast::ExprStmt),
191 WrapInBlock(SyntaxNode),
195 fn from(to_extract: &ast::Expr) -> Option<Anchor> {
199 .take_while(|it| !ast::Item::can_cast(it.kind()) || ast::MacroCall::can_cast(it.kind()))
201 if ast::MacroCall::can_cast(node.kind()) {
205 node.parent().and_then(ast::StmtList::cast).and_then(|it| it.tail_expr())
207 if expr.syntax() == &node {
208 cov_mark::hit!(test_extract_var_last_expr);
209 return Some(Anchor::Before(node));
213 if let Some(parent) = node.parent() {
214 if parent.kind() == CLOSURE_EXPR {
215 cov_mark::hit!(test_extract_var_in_closure_no_block);
216 return Some(Anchor::WrapInBlock(node));
218 if parent.kind() == MATCH_ARM {
219 if node.kind() == MATCH_GUARD {
220 cov_mark::hit!(test_extract_var_in_match_guard);
222 cov_mark::hit!(test_extract_var_in_match_arm_no_block);
223 return Some(Anchor::WrapInBlock(node));
228 if let Some(stmt) = ast::Stmt::cast(node.clone()) {
229 if let ast::Stmt::ExprStmt(stmt) = stmt {
230 if stmt.expr().as_ref() == Some(to_extract) {
231 return Some(Anchor::Replace(stmt));
234 return Some(Anchor::Before(node));
240 fn syntax(&self) -> &SyntaxNode {
242 Anchor::Before(it) | Anchor::WrapInBlock(it) => it,
243 Anchor::Replace(stmt) => stmt.syntax(),
250 use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
255 fn test_extract_var_simple() {
264 let $0var_name = 1 + 1;
271 fn extract_var_in_comment_is_not_applicable() {
272 cov_mark::check!(extract_var_in_comment_is_not_applicable);
273 check_assist_not_applicable(extract_variable, "fn main() { 1 + /* $0comment$0 */ 1; }");
277 fn test_extract_var_expr_stmt() {
278 cov_mark::check!(test_extract_var_expr_stmt);
287 let $0var_name = 1 + 1;
299 let $0var_name = { let x = 0; x };
306 fn test_extract_var_part_of_expr_stmt() {
322 fn test_extract_var_last_expr() {
323 cov_mark::check!(test_extract_var_last_expr);
333 let $0var_name = 1 + 1;
345 fn bar(i: i32) -> i32 {
351 let $0bar = bar(1 + 1);
355 fn bar(i: i32) -> i32 {
363 fn test_extract_var_in_match_arm_no_block() {
364 cov_mark::check!(test_extract_var_in_match_arm_no_block);
370 let tuple = match x {
371 true => ($02 + 2$0, true)
379 let tuple = match x {
380 true => { let $0var_name = 2 + 2; (var_name, true) }
389 fn test_extract_var_in_match_arm_with_block() {
395 let tuple = match x {
407 let tuple = match x {
410 let $0var_name = 2 + y;
421 fn test_extract_var_in_match_guard() {
422 cov_mark::check!(test_extract_var_in_match_guard);
428 () if $010 > 0$0 => 1
435 let $0var_name = 10 > 0;
446 fn test_extract_var_in_closure_no_block() {
447 cov_mark::check!(test_extract_var_in_closure_no_block);
452 let lambda = |x: u32| $0x * 2$0;
457 let lambda = |x: u32| { let $0var_name = x * 2; var_name };
464 fn test_extract_var_in_closure_with_block() {
469 let lambda = |x: u32| { $0x * 2$0 };
474 let lambda = |x: u32| { let $0var_name = x * 2; var_name };
481 fn test_extract_var_path_simple() {
486 let o = $0Some(true)$0;
491 let $0var_name = Some(true);
499 fn test_extract_var_path_method() {
504 let v = $0bar.foo()$0;
509 let $0foo = bar.foo();
517 fn test_extract_var_return() {
527 let $0var_name = 2 + 2;
535 fn test_extract_var_does_not_add_extra_whitespace() {
549 let $0var_name = 2 + 2;
566 let $0var_name = 2 + 2;
591 let $0var_name = 2 + 2;
599 fn test_extract_var_break() {
612 let $0var_name = 2 + 2;
621 fn test_extract_var_for_cast() {
626 let v = $00f32 as u32$0;
631 let $0var_name = 0f32 as u32;
639 fn extract_var_field_shorthand() {
665 fn extract_var_name_from_type() {
679 let $0test = { Test(10) };
687 fn extract_var_name_from_parameter() {
691 fn bar(test: u32, size: u32)
698 fn bar(test: u32, size: u32)
709 fn extract_var_parameter_name_has_precedence_over_type() {
713 struct TextSize(u32);
714 fn bar(test: u32, size: TextSize)
717 bar(1, $0{ TextSize(1+1) }$0);
721 struct TextSize(u32);
722 fn bar(test: u32, size: TextSize)
725 let $0size = { TextSize(1+1) };
733 fn extract_var_name_from_function() {
737 fn is_required(test: u32, size: u32) -> bool
740 $0is_required(1, 2)$0
744 fn is_required(test: u32, size: u32) -> bool
747 let $0is_required = is_required(1, 2);
755 fn extract_var_name_from_method() {
761 fn bar(&self, n: u32) -> u32 { n }
771 fn bar(&self, n: u32) -> u32 { n }
775 let $0bar = S.bar(1);
783 fn extract_var_name_from_method_param() {
789 fn bar(&self, n: u32, size: u32) { n }
799 fn bar(&self, n: u32, size: u32) { n }
811 fn extract_var_name_from_ufcs_method_param() {
817 fn bar(&self, n: u32, size: u32) { n }
821 S::bar(&S, $01 + 1$0, 2)
827 fn bar(&self, n: u32, size: u32) { n }
839 fn extract_var_parameter_name_has_precedence_over_function() {
843 fn bar(test: u32, size: u32)
846 bar(1, $0symbol_size(1, 2)$0);
850 fn bar(test: u32, size: u32)
853 let $0size = symbol_size(1, 2);
861 fn extract_macro_call() {
887 fn test_extract_var_for_return_not_applicable() {
888 check_assist_not_applicable(extract_variable, "fn foo() { $0return$0; } ");
892 fn test_extract_var_for_break_not_applicable() {
893 check_assist_not_applicable(extract_variable, "fn main() { loop { $0break$0; }; }");
897 fn test_extract_var_unit_expr_not_applicable() {
898 check_assist_not_applicable(
912 // FIXME: This is not quite correct, but good enough(tm) for the sorting heuristic
914 fn extract_var_target() {
915 check_assist_target(extract_variable, "fn foo() -> u32 { $0return 2 + 2$0; }", "2 + 2");
922 let tuple = match x {
923 true => ($02 + 2$0, true)
933 fn extract_var_no_block_body() {
934 check_assist_not_applicable(
937 const X: usize = $0100$0;
943 fn test_extract_var_mutable_reference_parameter() {
960 let $0var_name = &mut s.vec;
967 fn test_extract_var_mutable_reference_parameter_deep_nesting() {
982 $0f.field.field.vec$0.push(0);
996 let $0var_name = &mut f.field.field.vec;
1003 fn test_extract_var_reference_parameter() {
1010 fn do_thing(&self) {
1020 $0s.sub$0.do_thing();
1026 fn do_thing(&self) {
1043 fn test_extract_var_reference_parameter_deep_nesting() {
1049 fn do_thing(&self) {
1067 $0s.sub.field.field$0.do_thing();
1072 fn do_thing(&self) {
1090 let $0z = &s.sub.field.field;
1097 fn test_extract_var_regular_parameter() {
1104 fn do_thing(&self) {
1114 $0s.sub$0.do_thing();
1120 fn do_thing(&self) {
1137 fn test_extract_var_mutable_reference_local() {
1159 fn do_thing(&self) {
1166 let local = &mut S::new();
1167 $0local.sub$0.do_thing();
1188 fn do_thing(&self) {
1195 let local = &mut S::new();
1196 let $0x = &mut local.sub;
1203 fn test_extract_var_reference_local() {
1225 fn do_thing(&self) {
1232 let local = &S::new();
1233 $0local.sub$0.do_thing();
1254 fn do_thing(&self) {
1261 let local = &S::new();
1262 let $0x = &local.sub;