71 lines
2.3 KiB
Rust
71 lines
2.3 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_then;
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use clippy_utils::{match_def_path, paths, sugg};
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use if_chain::if_chain;
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use rustc_ast::util::parser::AssocOp;
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use rustc_errors::Applicability;
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use rustc_hir::def::{DefKind, Res};
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use rustc_hir::{BinOpKind, Expr, ExprKind};
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use rustc_lint::LateContext;
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use rustc_middle::ty;
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use rustc_span::source_map::Spanned;
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use super::FLOAT_EQUALITY_WITHOUT_ABS;
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pub(crate) fn check<'tcx>(
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cx: &LateContext<'tcx>,
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expr: &'tcx Expr<'_>,
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op: BinOpKind,
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lhs: &'tcx Expr<'_>,
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rhs: &'tcx Expr<'_>,
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) {
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let (lhs, rhs) = match op {
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BinOpKind::Lt => (lhs, rhs),
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BinOpKind::Gt => (rhs, lhs),
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_ => return,
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};
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if_chain! {
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// left hand side is a subtraction
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if let ExprKind::Binary(
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Spanned {
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node: BinOpKind::Sub,
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..
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},
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val_l,
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val_r,
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) = lhs.kind;
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// right hand side matches either f32::EPSILON or f64::EPSILON
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if let ExprKind::Path(ref epsilon_path) = rhs.kind;
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if let Res::Def(DefKind::AssocConst, def_id) = cx.qpath_res(epsilon_path, rhs.hir_id);
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if match_def_path(cx, def_id, &paths::F32_EPSILON) || match_def_path(cx, def_id, &paths::F64_EPSILON);
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// values of the subtractions on the left hand side are of the type float
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let t_val_l = cx.typeck_results().expr_ty(val_l);
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let t_val_r = cx.typeck_results().expr_ty(val_r);
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if let ty::Float(_) = t_val_l.kind();
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if let ty::Float(_) = t_val_r.kind();
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then {
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let sug_l = sugg::Sugg::hir(cx, val_l, "..");
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let sug_r = sugg::Sugg::hir(cx, val_r, "..");
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// format the suggestion
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let suggestion = format!("{}.abs()", sugg::make_assoc(AssocOp::Subtract, &sug_l, &sug_r).maybe_par());
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// spans the lint
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span_lint_and_then(
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cx,
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FLOAT_EQUALITY_WITHOUT_ABS,
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expr.span,
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"float equality check without `.abs()`",
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| diag | {
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diag.span_suggestion(
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lhs.span,
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"add `.abs()`",
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suggestion,
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Applicability::MaybeIncorrect,
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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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