53 lines
1.7 KiB
Rust
53 lines
1.7 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_sugg;
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use rustc_ast::ast::{Pat, PatKind};
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use rustc_errors::Applicability;
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use rustc_lint::EarlyContext;
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use rustc_span::source_map::Span;
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use super::UNNEEDED_WILDCARD_PATTERN;
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pub(super) fn check(cx: &EarlyContext<'_>, pat: &Pat) {
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if let PatKind::TupleStruct(_, _, ref patterns) | PatKind::Tuple(ref patterns) = pat.kind {
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if let Some(rest_index) = patterns.iter().position(|pat| pat.is_rest()) {
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if let Some((left_index, left_pat)) = patterns[..rest_index]
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.iter()
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.rev()
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.take_while(|pat| matches!(pat.kind, PatKind::Wild))
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.enumerate()
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.last()
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{
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span_lint(cx, left_pat.span.until(patterns[rest_index].span), left_index == 0);
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}
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if let Some((right_index, right_pat)) = patterns[rest_index + 1..]
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.iter()
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.take_while(|pat| matches!(pat.kind, PatKind::Wild))
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.enumerate()
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.last()
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{
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span_lint(
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cx,
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patterns[rest_index].span.shrink_to_hi().to(right_pat.span),
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right_index == 0,
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);
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}
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}
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}
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}
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fn span_lint(cx: &EarlyContext<'_>, span: Span, only_one: bool) {
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span_lint_and_sugg(
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cx,
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UNNEEDED_WILDCARD_PATTERN,
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span,
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if only_one {
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"this pattern is unneeded as the `..` pattern can match that element"
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} else {
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"these patterns are unneeded as the `..` pattern can match those elements"
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},
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if only_one { "remove it" } else { "remove them" },
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"".to_string(),
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Applicability::MachineApplicable,
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);
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}
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