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-rw-r--r--crates/ra_assists/src/flip_eq_operands.rs86
1 files changed, 86 insertions, 0 deletions
diff --git a/crates/ra_assists/src/flip_eq_operands.rs b/crates/ra_assists/src/flip_eq_operands.rs
new file mode 100644
index 000000000..df0bb689d
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+++ b/crates/ra_assists/src/flip_eq_operands.rs
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1use hir::db::HirDatabase;
2use ra_syntax::ast::{AstNode, BinExpr, BinOp};
3
4use crate::{AssistCtx, Assist, AssistId};
5
6pub(crate) fn flip_eq_operands(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
7 let expr = ctx.node_at_offset::<BinExpr>()?;
8 let lhs = expr.lhs()?.syntax();
9 let rhs = expr.rhs()?.syntax();
10 let op_range = expr.op()?.range();
11 let cursor_in_range = ctx.frange.range.is_subrange(&op_range);
12 let allowed_ops = [BinOp::EqualityTest, BinOp::NegatedEqualityTest];
13 let expr_op = expr.op_kind()?;
14 if !cursor_in_range || !allowed_ops.iter().any(|o| *o == expr_op) {
15 return None;
16 }
17 ctx.add_action(AssistId("flip_eq_operands"), "flip equality operands", |edit| {
18 edit.target(op_range);
19 edit.replace(lhs.range(), rhs.text());
20 edit.replace(rhs.range(), lhs.text());
21 });
22
23 ctx.build()
24}
25
26#[cfg(test)]
27mod tests {
28 use super::*;
29
30 use crate::helpers::{check_assist, check_assist_target};
31
32 #[test]
33 fn flip_eq_operands_for_simple_stmt() {
34 check_assist(
35 flip_eq_operands,
36 "fn f() { let res = 1 ==<|> 2; }",
37 "fn f() { let res = 2 ==<|> 1; }",
38 )
39 }
40
41 #[test]
42 fn flip_neq_operands_for_simple_stmt() {
43 check_assist(
44 flip_eq_operands,
45 "fn f() { let res = 1 !=<|> 2; }",
46 "fn f() { let res = 2 !=<|> 1; }",
47 )
48 }
49
50 #[test]
51 fn flip_eq_operands_for_complex_stmt() {
52 check_assist(
53 flip_eq_operands,
54 "fn f() { let res = (1 + 1) ==<|> (2 + 2); }",
55 "fn f() { let res = (2 + 2) ==<|> (1 + 1); }",
56 )
57 }
58
59 #[test]
60 fn flip_eq_operands_in_match_expr() {
61 check_assist(
62 flip_eq_operands,
63 r#"
64 fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
65 match other.downcast_ref::<Self>() {
66 None => false,
67 Some(it) => it ==<|> self,
68 }
69 }
70 "#,
71 r#"
72 fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
73 match other.downcast_ref::<Self>() {
74 None => false,
75 Some(it) => self ==<|> it,
76 }
77 }
78 "#,
79 )
80 }
81
82 #[test]
83 fn flip_eq_operands_target() {
84 check_assist_target(flip_eq_operands, "fn f() { let res = 1 ==<|> 2; }", "==")
85 }
86}