mirror of
https://github.com/rust-lang/rust-clippy
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30 lines
1 KiB
Rust
30 lines
1 KiB
Rust
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use clippy_utils::diagnostics::span_lint_and_then;
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use clippy_utils::is_trait_method;
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use clippy_utils::source::snippet;
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use rustc_errors::Applicability;
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use rustc_hir::Expr;
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use rustc_lint::LateContext;
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use rustc_span::sym;
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use super::UNIT_HASH;
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pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, recv: &'tcx Expr<'_>, arg: &'tcx Expr<'_>) {
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if is_trait_method(cx, expr, sym::Hash) && cx.typeck_results().expr_ty(recv).is_unit() {
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span_lint_and_then(
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cx,
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UNIT_HASH,
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expr.span,
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"this call to `hash` on the unit type will do nothing",
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|diag| {
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diag.span_suggestion(
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expr.span,
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"remove the call to `hash` or consider using",
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format!("0_u8.hash({})", snippet(cx, arg.span, ".."),),
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Applicability::MaybeIncorrect,
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);
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diag.note("the implementation of `Hash` for `()` is a no-op");
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},
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);
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}
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}
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