Lints and suggestions for the Nix programming language
refactor(empty_list_concat): let-else and try-expression
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-16
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lib/src/lints/empty_list_concat.rs
+17
-16
lib/src/lints/empty_list_concat.rs
···
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impl Rule for EmptyListConcat {
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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(bin_expr) = BinOp::cast(node.clone())
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&& let Some(lhs) = bin_expr.lhs()
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&& let Some(rhs) = bin_expr.rhs()
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&& let Some(op) = bin_expr.operator()
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&& let BinOpKind::Concat = op
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{
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let at = node.text_range();
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let message = "Concatenation with the empty list, `[]`, is a no-op";
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if is_empty_array(&lhs) {
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Some(self.report().suggest(at, message, Suggestion::new(at, rhs)))
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} else if is_empty_array(&rhs) {
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Some(self.report().suggest(at, message, Suggestion::new(at, lhs)))
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} else {
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None
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}
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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 bin_expr = BinOp::cast(node.clone())?;
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let lhs = bin_expr.lhs()?;
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let rhs = bin_expr.rhs()?;
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let Some(BinOpKind::Concat) = bin_expr.operator() else {
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return None;
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};
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+
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let at = node.text_range();
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let message = "Concatenation with the empty list, `[]`, is a no-op";
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if is_empty_array(&lhs) {
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Some(self.report().suggest(at, message, Suggestion::new(at, rhs)))
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} else if is_empty_array(&rhs) {
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Some(self.report().suggest(at, message, Suggestion::new(at, lhs)))
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} else {
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None
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}