Lints and suggestions for the Nix programming language
refactor(empty_pattern): let-else and try-expression
+27
-21
+27
-21
lib/src/lints/empty_pattern.rs
+27
-21
lib/src/lints/empty_pattern.rs
···
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impl Rule for EmptyPattern {
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fn validate(&self, node: &SyntaxElement, _sess: &SessionInfo) -> Option<Report> {
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if let NodeOrToken::Node(node) = node
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&& let Some(lambda_expr) = Lambda::cast(node.clone())
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&& let Some(arg) = lambda_expr.arg()
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&& let Some(body) = lambda_expr.body()
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&& let Some(pattern) = Pattern::cast(arg)
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// no patterns within `{ }`
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&& pattern.entries().count() == 0
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// pattern is not bound
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&& pattern.at().is_none()
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// not a nixos module
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&& !is_module(&body)
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{
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let at = pattern.node().text_range();
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let message = "This pattern is empty, use `_` instead";
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let replacement = make::ident("_").node().clone();
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Some(
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self.report()
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.suggest(at, message, Suggestion::new(at, replacement)),
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)
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} else {
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None
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let NodeOrToken::Node(node) = node else {
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return None;
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};
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+
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let lambda_expr = Lambda::cast(node.clone())?;
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let pattern = Pattern::cast(lambda_expr.arg()?)?;
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+
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// no patterns within `{ }`
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if pattern.entries().count() != 0 {
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return None;
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}
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+
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// pattern is not bound
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if pattern.at().is_some() {
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return None;
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}
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+
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if is_module(&lambda_expr.body()?) {
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return None;
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}
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+
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let at = pattern.node().text_range();
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let message = "This pattern is empty, use `_` instead";
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let replacement = make::ident("_").node().clone();
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Some(
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self.report()
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.suggest(at, message, Suggestion::new(at, replacement)),
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)
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}
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}
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