1 use ide_db::{base_db::FileId, defs::Definition, search::FileReference};
3 algo::find_node_at_range,
4 ast::{self, HasArgList},
5 AstNode, SourceFile, SyntaxKind, SyntaxNode, TextRange, T,
8 use SyntaxKind::WHITESPACE;
11 assist_context::AssistBuilder, utils::next_prev, AssistContext, AssistId, AssistKind, Assists,
14 // Assist: remove_unused_param
16 // Removes unused function parameter.
19 // fn frobnicate(x: i32$0) {}
33 pub(crate) fn remove_unused_param(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
34 let param: ast::Param = ctx.find_node_at_offset()?;
35 let ident_pat = match param.pat()? {
36 ast::Pat::IdentPat(it) => it,
39 let func = param.syntax().ancestors().find_map(ast::Fn::cast)?;
41 param.syntax().parent()?.children().find_map(ast::SelfParam::cast).is_some();
43 // check if fn is in impl Trait for ..
46 .parent() // AssocItemList
47 .and_then(|x| x.parent())
48 .and_then(ast::Impl::cast)
49 .map_or(false, |imp| imp.trait_().is_some())
51 cov_mark::hit!(trait_impl);
55 let mut param_position = func.param_list()?.params().position(|it| it == param)?;
56 // param_list() does not take the self param into consideration, hence this additional check
57 // is required. For associated functions, param_position is incremented here. For inherent
58 // calls we revet the increment below, in process_usage, as those calls will not have an
59 // explicit self parameter.
64 let func = ctx.sema.to_def(&func)?;
65 Definition::Function(func)
69 let local = ctx.sema.to_def(&ident_pat)?;
70 Definition::Local(local)
72 if param_def.usages(&ctx.sema).at_least_one() {
73 cov_mark::hit!(keep_used);
77 AssistId("remove_unused_param", AssistKind::Refactor),
78 "Remove unused parameter",
79 param.syntax().text_range(),
81 builder.delete(range_to_remove(param.syntax()));
82 for (file_id, references) in fn_def.usages(&ctx.sema).all() {
83 process_usages(ctx, builder, file_id, references, param_position, is_self_present);
90 ctx: &AssistContext<'_>,
91 builder: &mut AssistBuilder,
93 references: Vec<FileReference>,
95 is_self_present: bool,
97 let source_file = ctx.sema.parse(file_id);
98 builder.edit_file(file_id);
99 let possible_ranges = references
101 .filter_map(|usage| process_usage(&source_file, usage, arg_to_remove, is_self_present));
103 let mut ranges_to_delete: Vec<TextRange> = vec![];
104 for range in possible_ranges {
105 if !ranges_to_delete.iter().any(|it| it.contains_range(range)) {
106 ranges_to_delete.push(range)
110 for range in ranges_to_delete {
111 builder.delete(range)
116 source_file: &SourceFile,
117 FileReference { range, .. }: FileReference,
118 mut arg_to_remove: usize,
119 is_self_present: bool,
120 ) -> Option<TextRange> {
121 let call_expr_opt: Option<ast::CallExpr> = find_node_at_range(source_file.syntax(), range);
122 if let Some(call_expr) = call_expr_opt {
123 let call_expr_range = call_expr.expr()?.syntax().text_range();
124 if !call_expr_range.contains_range(range) {
128 let arg = call_expr.arg_list()?.args().nth(arg_to_remove)?;
129 return Some(range_to_remove(arg.syntax()));
132 let method_call_expr_opt: Option<ast::MethodCallExpr> =
133 find_node_at_range(source_file.syntax(), range);
134 if let Some(method_call_expr) = method_call_expr_opt {
135 let method_call_expr_range = method_call_expr.name_ref()?.syntax().text_range();
136 if !method_call_expr_range.contains_range(range) {
144 let arg = method_call_expr.arg_list()?.args().nth(arg_to_remove)?;
145 return Some(range_to_remove(arg.syntax()));
151 pub(crate) fn range_to_remove(node: &SyntaxNode) -> TextRange {
152 let up_to_comma = next_prev().find_map(|dir| {
153 node.siblings_with_tokens(dir)
154 .filter_map(|it| it.into_token())
155 .find(|it| it.kind() == T![,])
158 if let Some((dir, token)) = up_to_comma {
159 if node.next_sibling().is_some() {
160 let up_to_space = token
161 .siblings_with_tokens(dir)
163 .take_while(|it| it.kind() == WHITESPACE)
165 .and_then(|it| it.into_token());
168 .cover(up_to_space.map_or(token.text_range(), |it| it.text_range()));
170 node.text_range().cover(token.text_range())
178 use crate::tests::{check_assist, check_assist_not_applicable};
188 fn foo(x: i32, $0y: i32) { x; }
189 fn b() { foo(9, 2,) }
193 fn foo(x: i32) { x; }
200 fn remove_unused_first_param() {
204 fn foo($0x: i32, y: i32) { y; }
206 fn b() { foo(1, 2,) }
209 fn foo(y: i32) { y; }
217 fn remove_unused_single_param() {
221 fn foo($0x: i32) { 0; }
234 fn remove_unused_surrounded_by_parms() {
238 fn foo(x: i32, $0y: i32, z: i32) { x; }
239 fn a() { foo(1, 2, 3) }
240 fn b() { foo(1, 2, 3,) }
243 fn foo(x: i32, z: i32) { x; }
245 fn b() { foo(1, 3,) }
251 fn remove_unused_qualified_call() {
255 mod bar { pub fn foo(x: i32, $0y: i32) { x; } }
256 fn b() { bar::foo(9, 2) }
259 mod bar { pub fn foo(x: i32) { x; } }
260 fn b() { bar::foo(9) }
266 fn remove_unused_turbofished_func() {
270 pub fn foo<T>(x: T, $0y: i32) { x; }
271 fn b() { foo::<i32>(9, 2) }
274 pub fn foo<T>(x: T) { x; }
275 fn b() { foo::<i32>(9) }
281 fn remove_unused_generic_unused_param_func() {
285 pub fn foo<T>(x: i32, $0y: T) { x; }
286 fn b() { foo::<i32>(9, 2) }
287 fn b2() { foo(9, 2) }
290 pub fn foo<T>(x: i32) { x; }
291 fn b() { foo::<i32>(9) }
299 cov_mark::check!(keep_used);
300 check_assist_not_applicable(
303 fn foo(x: i32, $0y: i32) { y; }
304 fn main() { foo(9, 2) }
311 cov_mark::check!(trait_impl);
312 check_assist_not_applicable(
326 fn remove_across_files() {
331 fn foo(x: i32, $0y: i32) { x; }
344 fn foo(x: i32) { x; }
359 fn test_remove_method_param() {
364 impl S { fn f(&self, $0_unused: i32) {} }
374 impl S { fn f(&self) {} }
390 fn foo(x: i32, $0y: i32) -> i32 {
399 fn foo(x: i32) -> i32 {