diff options
author | Akshay <[email protected]> | 2021-09-13 17:50:25 +0100 |
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committer | Akshay <[email protected]> | 2021-09-13 17:50:25 +0100 |
commit | 4152367f5dee2a70ff49f4aff4040d5d433b8e44 (patch) | |
tree | fea606b3121702ae2f714f51697135e3c7b9a9ee /lib/src/lints | |
parent | 7a3c3822ba4a368b0475bc5de89ced78fa8b3cb5 (diff) |
add demo lint: bool_comparison
Diffstat (limited to 'lib/src/lints')
-rw-r--r-- | lib/src/lints/bool_comparison.rs | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/lib/src/lints/bool_comparison.rs b/lib/src/lints/bool_comparison.rs new file mode 100644 index 0000000..4476b31 --- /dev/null +++ b/lib/src/lints/bool_comparison.rs | |||
@@ -0,0 +1,78 @@ | |||
1 | use crate::{Diagnostic, Lint, Metadata, Rule}; | ||
2 | |||
3 | use if_chain::if_chain; | ||
4 | use macros::lint; | ||
5 | use rnix::{ | ||
6 | types::{BinOp, BinOpKind, Ident, TokenWrapper, TypedNode}, | ||
7 | NodeOrToken, SyntaxElement, SyntaxKind, SyntaxNode, | ||
8 | }; | ||
9 | |||
10 | #[lint( | ||
11 | name = "bool_comparison", | ||
12 | note = "Unnecessary comparison with boolean", | ||
13 | match_with = "SyntaxKind::NODE_BIN_OP" | ||
14 | )] | ||
15 | struct BoolComparison; | ||
16 | |||
17 | impl Rule for BoolComparison { | ||
18 | fn validate(&self, node: &SyntaxElement) -> Option<Diagnostic> { | ||
19 | if_chain! { | ||
20 | if let NodeOrToken::Node(bin_op_node) = node; | ||
21 | if let Some(bin_expr) = BinOp::cast(bin_op_node.clone()); | ||
22 | if let Some(lhs) = bin_expr.lhs(); | ||
23 | if let Some(rhs) = bin_expr.rhs(); | ||
24 | |||
25 | if let BinOpKind::Equal | BinOpKind::NotEqual = bin_expr.operator(); | ||
26 | let (non_bool_side, bool_side) = if is_boolean_ident(&lhs) { | ||
27 | (rhs, lhs) | ||
28 | } else if is_boolean_ident(&rhs) { | ||
29 | (lhs, rhs) | ||
30 | } else { | ||
31 | return None | ||
32 | }; | ||
33 | then { | ||
34 | let at = node.text_range(); | ||
35 | let message = format!( | ||
36 | "Comparing `{}` with boolean literal `{}`", | ||
37 | non_bool_side, | ||
38 | bool_side | ||
39 | ); | ||
40 | dbg!(Some(Diagnostic::new(at, message))) | ||
41 | } else { | ||
42 | None | ||
43 | } | ||
44 | } | ||
45 | } | ||
46 | } | ||
47 | |||
48 | // not entirely accurate, underhanded nix programmers might write `true = false` | ||
49 | fn is_boolean_ident(node: &SyntaxNode) -> bool { | ||
50 | if let Some(ident_expr) = Ident::cast(node.clone()) { | ||
51 | ident_expr.as_str() == "true" || ident_expr.as_str() == "false" | ||
52 | } else { | ||
53 | false | ||
54 | } | ||
55 | } | ||
56 | |||
57 | // #[cfg(test)] | ||
58 | // mod tests { | ||
59 | // use super::*; | ||
60 | // use rnix::{parser, WalkEvent}; | ||
61 | // | ||
62 | // #[test] | ||
63 | // fn trivial() { | ||
64 | // let src = r#" | ||
65 | // a == true | ||
66 | // "#; | ||
67 | // let parsed = rnix::parse(src).as_result().ok().unwrap(); | ||
68 | // let _ = parsed | ||
69 | // .node() | ||
70 | // .preorder_with_tokens() | ||
71 | // .filter_map(|event| match event { | ||
72 | // WalkEvent::Enter(t) => Some(t), | ||
73 | // _ => None, | ||
74 | // }) | ||
75 | // .map(|node| BoolComparison.validate(&node)) | ||
76 | // .collect::<Vec<_>>(); | ||
77 | // } | ||
78 | // } | ||