ra_ap_ide_assists/handlers/
remove_dbg.rs

1use itertools::Itertools;
2use syntax::{
3    Edition, NodeOrToken, SyntaxNode, SyntaxToken, T,
4    ast::{self, AstNode, make},
5    match_ast,
6    syntax_editor::{Position, SyntaxEditor},
7};
8
9use crate::{AssistContext, AssistId, Assists};
10
11// Assist: remove_dbg
12//
13// Removes `dbg!()` macro call.
14//
15// ```
16// fn main() {
17//     let x = $0dbg!(42 * dbg!(4 + 2));$0
18// }
19// ```
20// ->
21// ```
22// fn main() {
23//     let x = 42 * (4 + 2);
24// }
25// ```
26pub(crate) fn remove_dbg(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
27    let macro_calls = if ctx.has_empty_selection() {
28        vec![ctx.find_node_at_offset::<ast::MacroExpr>()?]
29    } else {
30        ctx.covering_element()
31            .as_node()?
32            .descendants()
33            .filter(|node| ctx.selection_trimmed().contains_range(node.text_range()))
34            // When the selection exactly covers the macro call to be removed, `covering_element()`
35            // returns `ast::MacroCall` instead of its parent `ast::MacroExpr` that we want. So
36            // first try finding `ast::MacroCall`s and then retrieve their parent.
37            .filter_map(ast::MacroCall::cast)
38            .filter_map(|it| it.syntax().parent().and_then(ast::MacroExpr::cast))
39            .collect()
40    };
41
42    let replacements =
43        macro_calls.into_iter().filter_map(compute_dbg_replacement).collect::<Vec<_>>();
44    let target = replacements
45        .iter()
46        .flat_map(|(node_or_token, _)| node_or_token.iter())
47        .map(|t| t.text_range())
48        .reduce(|acc, range| acc.cover(range))?;
49    acc.add(AssistId::quick_fix("remove_dbg"), "Remove dbg!()", target, |builder| {
50        let mut editor = builder.make_editor(ctx.source_file().syntax());
51        for (range, expr) in replacements {
52            if let Some(expr) = expr {
53                editor.insert(Position::before(range[0].clone()), expr.syntax().clone_for_update());
54            }
55            for node_or_token in range {
56                editor.delete(node_or_token);
57            }
58        }
59        builder.add_file_edits(ctx.vfs_file_id(), editor);
60    })
61}
62
63/// Returns `None` when either
64/// - macro call is not `dbg!()`
65/// - any node inside `dbg!()` could not be parsed as an expression
66/// - (`macro_expr` has no parent - is that possible?)
67///
68/// Returns `Some(_, None)` when the macro call should just be removed.
69fn compute_dbg_replacement(
70    macro_expr: ast::MacroExpr,
71) -> Option<(Vec<NodeOrToken<SyntaxNode, SyntaxToken>>, Option<ast::Expr>)> {
72    let macro_call = macro_expr.macro_call()?;
73    let tt = macro_call.token_tree()?;
74    let r_delim = NodeOrToken::Token(tt.right_delimiter_token()?);
75    if macro_call.path()?.segment()?.name_ref()?.text() != "dbg"
76        || macro_call.excl_token().is_none()
77    {
78        return None;
79    }
80
81    let mac_input = tt.syntax().children_with_tokens().skip(1).take_while(|it| *it != r_delim);
82    let input_expressions = mac_input.chunk_by(|tok| tok.kind() == T![,]);
83    let input_expressions = input_expressions
84        .into_iter()
85        .filter_map(|(is_sep, group)| (!is_sep).then_some(group))
86        .map(|mut tokens| syntax::hacks::parse_expr_from_str(&tokens.join(""), Edition::CURRENT))
87        .collect::<Option<Vec<ast::Expr>>>()?;
88
89    let parent = macro_expr.syntax().parent()?;
90    Some(match &*input_expressions {
91        // dbg!()
92        [] => {
93            match_ast! {
94                match parent {
95                    ast::StmtList(_) => {
96                        let mut replace = vec![macro_expr.syntax().clone().into()];
97                        if let Some(prev_sibling) = macro_expr.syntax().prev_sibling_or_token()
98                            && prev_sibling.kind() == syntax::SyntaxKind::WHITESPACE {
99                                replace.push(prev_sibling);
100                        }
101                        (replace, None)
102                    },
103                    ast::ExprStmt(it) => {
104                        let mut replace = vec![it.syntax().clone().into()];
105                        if let Some(prev_sibling) = it.syntax().prev_sibling_or_token()
106                            && prev_sibling.kind() == syntax::SyntaxKind::WHITESPACE {
107                                replace.push(prev_sibling);
108                        }
109                        (replace, None)
110                    },
111                    _ => (vec![macro_call.syntax().clone().into()], Some(make::ext::expr_unit())),
112                }
113            }
114        }
115        // dbg!(2, 'x', &x, x, ...);
116        exprs if ast::ExprStmt::can_cast(parent.kind()) && exprs.iter().all(pure_expr) => {
117            let mut replace = vec![parent.clone().into()];
118            if let Some(prev_sibling) = parent.prev_sibling_or_token()
119                && prev_sibling.kind() == syntax::SyntaxKind::WHITESPACE
120            {
121                replace.push(prev_sibling);
122            }
123            (replace, None)
124        }
125        // dbg!(expr0)
126        [expr] => {
127            // dbg!(expr, &parent);
128            let wrap = match ast::Expr::cast(parent) {
129                Some(parent) => match (expr, parent) {
130                    (ast::Expr::CastExpr(_), ast::Expr::CastExpr(_)) => false,
131                    (
132                        ast::Expr::PrefixExpr(_) | ast::Expr::RefExpr(_) | ast::Expr::MacroExpr(_),
133                        ast::Expr::AwaitExpr(_)
134                        | ast::Expr::CallExpr(_)
135                        | ast::Expr::CastExpr(_)
136                        | ast::Expr::FieldExpr(_)
137                        | ast::Expr::IndexExpr(_)
138                        | ast::Expr::MethodCallExpr(_)
139                        | ast::Expr::RangeExpr(_)
140                        | ast::Expr::TryExpr(_),
141                    ) => true,
142                    (
143                        ast::Expr::BinExpr(_)
144                        | ast::Expr::CastExpr(_)
145                        | ast::Expr::RangeExpr(_)
146                        | ast::Expr::MacroExpr(_),
147                        ast::Expr::AwaitExpr(_)
148                        | ast::Expr::BinExpr(_)
149                        | ast::Expr::CallExpr(_)
150                        | ast::Expr::CastExpr(_)
151                        | ast::Expr::FieldExpr(_)
152                        | ast::Expr::IndexExpr(_)
153                        | ast::Expr::MethodCallExpr(_)
154                        | ast::Expr::PrefixExpr(_)
155                        | ast::Expr::RangeExpr(_)
156                        | ast::Expr::RefExpr(_)
157                        | ast::Expr::TryExpr(_),
158                    ) => true,
159                    _ => false,
160                },
161                None => false,
162            };
163            let expr = replace_nested_dbgs(expr.clone());
164            let expr = if wrap { make::expr_paren(expr).into() } else { expr.clone_subtree() };
165            (vec![macro_call.syntax().clone().into()], Some(expr))
166        }
167        // dbg!(expr0, expr1, ...)
168        exprs => {
169            let exprs = exprs.iter().cloned().map(replace_nested_dbgs);
170            let expr = make::expr_tuple(exprs);
171            (vec![macro_call.syntax().clone().into()], Some(expr.into()))
172        }
173    })
174}
175
176fn pure_expr(expr: &ast::Expr) -> bool {
177    match_ast! {
178        match (expr.syntax()) {
179            ast::Literal(_) => true,
180            ast::RefExpr(it) => {
181                matches!(it.expr(), Some(ast::Expr::PathExpr(p))
182                    if p.path().and_then(|p| p.as_single_name_ref()).is_some())
183            },
184            ast::PathExpr(it) => it.path().and_then(|it| it.as_single_name_ref()).is_some(),
185            _ => false,
186        }
187    }
188}
189
190fn replace_nested_dbgs(expanded: ast::Expr) -> ast::Expr {
191    if let ast::Expr::MacroExpr(mac) = &expanded {
192        // Special-case when `expanded` itself is `dbg!()` since we cannot replace the whole tree
193        // with `ted`. It should be fairly rare as it means the user wrote `dbg!(dbg!(..))` but you
194        // never know how code ends up being!
195        let replaced = if let Some((_, expr_opt)) = compute_dbg_replacement(mac.clone()) {
196            match expr_opt {
197                Some(expr) => expr,
198                None => {
199                    stdx::never!("dbg! inside dbg! should not be just removed");
200                    expanded
201                }
202            }
203        } else {
204            expanded
205        };
206
207        return replaced;
208    }
209
210    let expanded = expanded.clone_subtree();
211    let mut editor = SyntaxEditor::new(expanded.syntax().clone());
212    // We need to collect to avoid mutation during traversal.
213    let macro_exprs: Vec<_> =
214        expanded.syntax().descendants().filter_map(ast::MacroExpr::cast).collect();
215
216    for mac in macro_exprs {
217        let expr_opt = match compute_dbg_replacement(mac.clone()) {
218            Some((_, expr)) => expr,
219            None => continue,
220        };
221
222        if let Some(expr) = expr_opt {
223            editor.replace(mac.syntax(), expr.syntax().clone_for_update());
224        } else {
225            editor.delete(mac.syntax());
226        }
227    }
228    let expanded_syntax = editor.finish().new_root().clone();
229    ast::Expr::cast(expanded_syntax).unwrap()
230}
231
232#[cfg(test)]
233mod tests {
234    use crate::tests::{check_assist, check_assist_not_applicable};
235
236    use super::*;
237
238    fn check(
239        #[rust_analyzer::rust_fixture] ra_fixture_before: &str,
240        #[rust_analyzer::rust_fixture] ra_fixture_after: &str,
241    ) {
242        check_assist(
243            remove_dbg,
244            &format!("fn main() {{\n{ra_fixture_before}\n}}"),
245            &format!("fn main() {{\n{ra_fixture_after}\n}}"),
246        );
247    }
248
249    #[test]
250    fn test_remove_dbg() {
251        check("$0dbg!(1 + 1)", "1 + 1");
252        check("dbg!$0(1 + 1)", "1 + 1");
253        check("dbg!(1 $0+ 1)", "1 + 1");
254        check("dbg![$01 + 1]", "1 + 1");
255        check("dbg!{$01 + 1}", "1 + 1");
256    }
257
258    #[test]
259    fn test_remove_simple_dbg_statement() {
260        check_assist(
261            remove_dbg,
262            r#"
263fn foo() {
264    let n = 2;
265    $0dbg!(3);
266    dbg!(2.6);
267    dbg!(1, 2.5);
268    dbg!('x');
269    dbg!(&n);
270    dbg!(n);
271    // needless comment
272    dbg!("foo");$0
273}
274"#,
275            r#"
276fn foo() {
277    let n = 2;
278    // needless comment
279}
280"#,
281        );
282    }
283
284    #[test]
285    fn test_remove_dbg_not_applicable() {
286        check_assist_not_applicable(remove_dbg, "fn main() {$0vec![1, 2, 3]}");
287        check_assist_not_applicable(remove_dbg, "fn main() {$0dbg(5, 6, 7)}");
288        check_assist_not_applicable(remove_dbg, "fn main() {$0dbg!(5, 6, 7}");
289    }
290
291    #[test]
292    fn test_remove_dbg_keep_semicolon_in_let() {
293        // https://github.com/rust-lang/rust-analyzer/issues/5129#issuecomment-651399779
294        check(
295            r#"let res = $0dbg!(1 * 20); // needless comment"#,
296            r#"let res = 1 * 20; // needless comment"#,
297        );
298        check(r#"let res = $0dbg!(); // needless comment"#, r#"let res = (); // needless comment"#);
299        check(
300            r#"let res = $0dbg!(1, 2); // needless comment"#,
301            r#"let res = (1, 2); // needless comment"#,
302        );
303    }
304
305    #[test]
306    fn test_remove_dbg_cast_cast() {
307        check(r#"let res = $0dbg!(x as u32) as u32;"#, r#"let res = x as u32 as u32;"#);
308    }
309
310    #[test]
311    fn test_remove_dbg_prefix() {
312        check(r#"let res = $0dbg!(&result).foo();"#, r#"let res = (&result).foo();"#);
313        check(r#"let res = &$0dbg!(&result);"#, r#"let res = &&result;"#);
314        check(r#"let res = $0dbg!(!result) && true;"#, r#"let res = !result && true;"#);
315    }
316
317    #[test]
318    fn test_remove_dbg_post_expr() {
319        check(r#"let res = $0dbg!(fut.await).foo();"#, r#"let res = fut.await.foo();"#);
320        check(r#"let res = $0dbg!(result?).foo();"#, r#"let res = result?.foo();"#);
321        check(r#"let res = $0dbg!(foo as u32).foo();"#, r#"let res = (foo as u32).foo();"#);
322        check(r#"let res = $0dbg!(array[3]).foo();"#, r#"let res = array[3].foo();"#);
323        check(r#"let res = $0dbg!(tuple.3).foo();"#, r#"let res = tuple.3.foo();"#);
324    }
325
326    #[test]
327    fn test_remove_dbg_range_expr() {
328        check(r#"let res = $0dbg!(foo..bar).foo();"#, r#"let res = (foo..bar).foo();"#);
329        check(r#"let res = $0dbg!(foo..=bar).foo();"#, r#"let res = (foo..=bar).foo();"#);
330    }
331
332    #[test]
333    fn test_remove_empty_dbg() {
334        check_assist(remove_dbg, r#"fn foo() { $0dbg!(); }"#, r#"fn foo() { }"#);
335        check_assist(
336            remove_dbg,
337            r#"
338fn foo() {
339    $0dbg!();
340}
341"#,
342            r#"
343fn foo() {
344}
345"#,
346        );
347        check_assist(
348            remove_dbg,
349            r#"
350fn foo() {
351    let test = $0dbg!();
352}"#,
353            r#"
354fn foo() {
355    let test = ();
356}"#,
357        );
358        check_assist(
359            remove_dbg,
360            r#"
361fn foo() {
362    let t = {
363        println!("Hello, world");
364        $0dbg!()
365    };
366}"#,
367            r#"
368fn foo() {
369    let t = {
370        println!("Hello, world");
371    };
372}"#,
373        );
374    }
375
376    #[test]
377    fn test_remove_multi_dbg() {
378        check(r#"$0dbg!(0, 1)"#, r#"(0, 1)"#);
379        check(r#"$0dbg!(0, (1, 2))"#, r#"(0, (1, 2))"#);
380    }
381
382    #[test]
383    fn test_range() {
384        check(
385            r#"
386fn f() {
387    dbg!(0) + $0dbg!(1);
388    dbg!(())$0
389}
390"#,
391            r#"
392fn f() {
393    dbg!(0) + 1;
394    ()
395}
396"#,
397        );
398    }
399
400    #[test]
401    fn test_range_partial() {
402        check_assist_not_applicable(remove_dbg, r#"$0dbg$0!(0)"#);
403        check_assist_not_applicable(remove_dbg, r#"$0dbg!(0$0)"#);
404    }
405
406    #[test]
407    fn test_nested_dbg() {
408        check(
409            r#"$0let x = dbg!(dbg!(dbg!(dbg!(0 + 1)) * 2) + dbg!(3));$0"#,
410            r#"let x = ((0 + 1) * 2) + 3;"#,
411        );
412        check(r#"$0dbg!(10, dbg!(), dbg!(20, 30))$0"#, r#"(10, (), (20, 30))"#);
413    }
414
415    #[test]
416    fn test_multiple_nested_dbg() {
417        check(
418            r#"
419fn f() {
420    $0dbg!();
421    let x = dbg!(dbg!(dbg!(0 + 1)) + 2) + dbg!(3);
422    dbg!(10, dbg!(), dbg!(20, 30));$0
423}
424"#,
425            r#"
426fn f() {
427    let x = ((0 + 1) + 2) + 3;
428    (10, (), (20, 30));
429}
430"#,
431        );
432    }
433}
ra_ap_ide_assists/handlers/remove_dbg.rs

ra_ap_ide_assists/handlers/
remove_dbg.rs
