64 lines
2.1 KiB
Rust
64 lines
2.1 KiB
Rust
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use crate::utils::{in_macro, span_help_and_lint, SpanlessHash};
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use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
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use rustc::{declare_tool_lint, lint_array};
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use rustc_data_structures::fx::FxHashMap;
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use rustc::hir::*;
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declare_clippy_lint! {
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pub TYPE_REPETITION_IN_BOUNDS,
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complexity,
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"Types are repeated unnecessary in trait bounds use `+` instead of using `T: _, T: _`"
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}
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#[derive(Copy, Clone)]
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pub struct TraitBounds;
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impl LintPass for TraitBounds {
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fn get_lints(&self) -> LintArray {
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lint_array!(TYPE_REPETITION_IN_BOUNDS)
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}
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fn name(&self) -> &'static str {
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"TypeRepetitionInBounds"
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TraitBounds {
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fn check_generics(&mut self, cx: &LateContext<'a, 'tcx>, gen: &'tcx Generics) {
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if in_macro(gen.span) {
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return;
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}
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let hash = | ty | -> u64 {
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let mut hasher = SpanlessHash::new(cx, cx.tables);
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hasher.hash_ty(ty);
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hasher.finish()
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};
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let mut map = FxHashMap::default();
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for bound in &gen.where_clause.predicates {
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if let WherePredicate::BoundPredicate(ref p) = bound {
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let h = hash(&p.bounded_ty);
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if let Some(ref v) = map.insert(h, p.bounds) {
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let mut hint_string = format!("consider combining the bounds: `{:?}: ", p.bounded_ty);
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for &b in v.iter() {
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hint_string.push_str(&format!("{:?}, ", b));
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}
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for &b in p.bounds.iter() {
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hint_string.push_str(&format!("{:?}, ", b));
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}
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hint_string.truncate(hint_string.len() - 2);
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hint_string.push('`');
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span_help_and_lint(
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cx,
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TYPE_REPETITION_IN_BOUNDS,
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p.span,
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"this type has already been used as a bound predicate",
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&hint_string,
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);
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}
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}
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}
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}
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}
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