From a60429891fe9eb5290f95a52dd5e56f62d25d344 Mon Sep 17 00:00:00 2001 From: Akshay Date: Sat, 2 Oct 2021 10:50:47 +0530 Subject: new lint: empty-let-in --- lib/src/lints/empty_let_in.rs | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 lib/src/lints/empty_let_in.rs (limited to 'lib/src/lints') diff --git a/lib/src/lints/empty_let_in.rs b/lib/src/lints/empty_let_in.rs new file mode 100644 index 0000000..4b074e7 --- /dev/null +++ b/lib/src/lints/empty_let_in.rs @@ -0,0 +1,42 @@ +use crate::{Lint, Metadata, Report, Rule, Suggestion}; + +use if_chain::if_chain; +use macros::lint; +use rnix::{ + types::{LetIn, TypedNode, + EntryHolder}, + NodeOrToken, SyntaxElement, SyntaxKind, +}; + +#[lint( + name = "empty let-in", + note = "Useless let-in expression", + code = 2, + match_with = SyntaxKind::NODE_LET_IN +)] +struct EmptyLetIn; + +impl Rule for EmptyLetIn { + fn validate(&self, node: &SyntaxElement) -> Option { + if_chain! { + if let NodeOrToken::Node(let_in_node) = node; + if let Some(let_in_expr) = LetIn::cast(let_in_node.clone()); + let entries = let_in_expr.entries(); + let inherits = let_in_expr.inherits(); + + if entries.count() == 0; + if inherits.count() == 0; + + if let Some(body) = let_in_expr.body(); + then { + let at = node.text_range(); + let replacement = body; + let message = "This let-in expression has no entries"; + Some(Self::report().suggest(at, message, Suggestion::new(at, replacement))) + } else { + None + } + } + } +} + -- cgit v1.2.3