760 lines
26 KiB
Rust
760 lines
26 KiB
Rust
use clippy_utils::consts::{
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constant, constant_simple, Constant,
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Constant::{Int, F32, F64},
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};
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use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::higher;
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use clippy_utils::{eq_expr_value, get_parent_expr, in_constant, numeric_literal, peel_blocks, sugg};
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir::{BinOpKind, Expr, ExprKind, PathSegment, UnOp};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::ty;
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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use rustc_span::source_map::Spanned;
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use rustc_ast::ast;
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use std::f32::consts as f32_consts;
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use std::f64::consts as f64_consts;
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use sugg::Sugg;
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declare_clippy_lint! {
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/// ### What it does
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/// Looks for floating-point expressions that
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/// can be expressed using built-in methods to improve accuracy
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/// at the cost of performance.
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///
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/// ### Why is this bad?
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/// Negatively impacts accuracy.
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///
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/// ### Example
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/// ```rust
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/// let a = 3f32;
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/// let _ = a.powf(1.0 / 3.0);
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/// let _ = (1.0 + a).ln();
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/// let _ = a.exp() - 1.0;
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/// ```
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///
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/// Use instead:
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/// ```rust
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/// let a = 3f32;
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/// let _ = a.cbrt();
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/// let _ = a.ln_1p();
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/// let _ = a.exp_m1();
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/// ```
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#[clippy::version = "1.43.0"]
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pub IMPRECISE_FLOPS,
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nursery,
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"usage of imprecise floating point operations"
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}
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declare_clippy_lint! {
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/// ### What it does
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/// Looks for floating-point expressions that
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/// can be expressed using built-in methods to improve both
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/// accuracy and performance.
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///
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/// ### Why is this bad?
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/// Negatively impacts accuracy and performance.
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///
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/// ### Example
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/// ```rust
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/// use std::f32::consts::E;
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///
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/// let a = 3f32;
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/// let _ = (2f32).powf(a);
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/// let _ = E.powf(a);
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/// let _ = a.powf(1.0 / 2.0);
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/// let _ = a.log(2.0);
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/// let _ = a.log(10.0);
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/// let _ = a.log(E);
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/// let _ = a.powf(2.0);
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/// let _ = a * 2.0 + 4.0;
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/// let _ = if a < 0.0 {
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/// -a
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/// } else {
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/// a
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/// };
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/// let _ = if a < 0.0 {
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/// a
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/// } else {
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/// -a
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/// };
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/// ```
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///
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/// is better expressed as
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///
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/// ```rust
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/// use std::f32::consts::E;
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///
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/// let a = 3f32;
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/// let _ = a.exp2();
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/// let _ = a.exp();
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/// let _ = a.sqrt();
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/// let _ = a.log2();
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/// let _ = a.log10();
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/// let _ = a.ln();
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/// let _ = a.powi(2);
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/// let _ = a.mul_add(2.0, 4.0);
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/// let _ = a.abs();
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/// let _ = -a.abs();
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/// ```
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#[clippy::version = "1.43.0"]
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pub SUBOPTIMAL_FLOPS,
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nursery,
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"usage of sub-optimal floating point operations"
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}
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declare_lint_pass!(FloatingPointArithmetic => [
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IMPRECISE_FLOPS,
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SUBOPTIMAL_FLOPS
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]);
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// Returns the specialized log method for a given base if base is constant
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// and is one of 2, 10 and e
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fn get_specialized_log_method(cx: &LateContext<'_>, base: &Expr<'_>) -> Option<&'static str> {
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if let Some((value, _)) = constant(cx, cx.typeck_results(), base) {
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if F32(2.0) == value || F64(2.0) == value {
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return Some("log2");
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} else if F32(10.0) == value || F64(10.0) == value {
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return Some("log10");
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} else if F32(f32_consts::E) == value || F64(f64_consts::E) == value {
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return Some("ln");
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}
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}
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None
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}
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// Adds type suffixes and parenthesis to method receivers if necessary
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fn prepare_receiver_sugg<'a>(cx: &LateContext<'_>, mut expr: &'a Expr<'a>) -> Sugg<'a> {
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let mut suggestion = Sugg::hir(cx, expr, "..");
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if let ExprKind::Unary(UnOp::Neg, inner_expr) = &expr.kind {
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expr = inner_expr;
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}
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if_chain! {
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// if the expression is a float literal and it is unsuffixed then
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// add a suffix so the suggestion is valid and unambiguous
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if let ty::Float(float_ty) = cx.typeck_results().expr_ty(expr).kind();
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if let ExprKind::Lit(lit) = &expr.kind;
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if let ast::LitKind::Float(sym, ast::LitFloatType::Unsuffixed) = lit.node;
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then {
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let op = format!(
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"{suggestion}{}{}",
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// Check for float literals without numbers following the decimal
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// separator such as `2.` and adds a trailing zero
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if sym.as_str().ends_with('.') {
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"0"
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} else {
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""
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},
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float_ty.name_str()
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).into();
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suggestion = match suggestion {
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Sugg::MaybeParen(_) => Sugg::MaybeParen(op),
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_ => Sugg::NonParen(op)
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};
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}
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}
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suggestion.maybe_par()
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}
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fn check_log_base(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args: &[Expr<'_>]) {
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if let Some(method) = get_specialized_log_method(cx, &args[0]) {
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span_lint_and_sugg(
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cx,
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SUBOPTIMAL_FLOPS,
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expr.span,
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"logarithm for bases 2, 10 and e can be computed more accurately",
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"consider using",
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format!("{}.{method}()", Sugg::hir(cx, receiver, "..").maybe_par()),
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Applicability::MachineApplicable,
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);
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}
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}
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// TODO: Lint expressions of the form `(x + y).ln()` where y > 1 and
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// suggest usage of `(x + (y - 1)).ln_1p()` instead
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fn check_ln1p(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>) {
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if let ExprKind::Binary(
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Spanned {
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node: BinOpKind::Add, ..
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},
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lhs,
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rhs,
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) = receiver.kind
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{
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let recv = match (
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constant(cx, cx.typeck_results(), lhs),
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constant(cx, cx.typeck_results(), rhs),
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) {
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(Some((value, _)), _) if F32(1.0) == value || F64(1.0) == value => rhs,
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(_, Some((value, _))) if F32(1.0) == value || F64(1.0) == value => lhs,
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_ => return,
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};
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span_lint_and_sugg(
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cx,
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IMPRECISE_FLOPS,
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expr.span,
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"ln(1 + x) can be computed more accurately",
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"consider using",
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format!("{}.ln_1p()", prepare_receiver_sugg(cx, recv)),
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Applicability::MachineApplicable,
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);
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}
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}
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// Returns an integer if the float constant is a whole number and it can be
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// converted to an integer without loss of precision. For now we only check
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// ranges [-16777215, 16777216) for type f32 as whole number floats outside
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// this range are lossy and ambiguous.
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#[expect(clippy::cast_possible_truncation)]
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fn get_integer_from_float_constant(value: &Constant) -> Option<i32> {
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match value {
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F32(num) if num.fract() == 0.0 => {
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if (-16_777_215.0..16_777_216.0).contains(num) {
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Some(num.round() as i32)
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} else {
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None
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}
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},
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F64(num) if num.fract() == 0.0 => {
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if (-2_147_483_648.0..2_147_483_648.0).contains(num) {
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Some(num.round() as i32)
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} else {
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None
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}
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},
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_ => None,
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}
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}
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fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args: &[Expr<'_>]) {
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// Check receiver
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if let Some((value, _)) = constant(cx, cx.typeck_results(), receiver) {
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if let Some(method) = if F32(f32_consts::E) == value || F64(f64_consts::E) == value {
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Some("exp")
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} else if F32(2.0) == value || F64(2.0) == value {
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Some("exp2")
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} else {
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None
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} {
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span_lint_and_sugg(
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cx,
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SUBOPTIMAL_FLOPS,
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expr.span,
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"exponent for bases 2 and e can be computed more accurately",
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"consider using",
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format!("{}.{method}()", prepare_receiver_sugg(cx, &args[0])),
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Applicability::MachineApplicable,
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);
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}
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}
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// Check argument
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if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
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let (lint, help, suggestion) = if F32(1.0 / 2.0) == value || F64(1.0 / 2.0) == value {
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(
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SUBOPTIMAL_FLOPS,
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"square-root of a number can be computed more efficiently and accurately",
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format!("{}.sqrt()", Sugg::hir(cx, receiver, "..").maybe_par()),
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)
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} else if F32(1.0 / 3.0) == value || F64(1.0 / 3.0) == value {
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(
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IMPRECISE_FLOPS,
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"cube-root of a number can be computed more accurately",
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format!("{}.cbrt()", Sugg::hir(cx, receiver, "..").maybe_par()),
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)
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} else if let Some(exponent) = get_integer_from_float_constant(&value) {
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(
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SUBOPTIMAL_FLOPS,
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"exponentiation with integer powers can be computed more efficiently",
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format!(
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"{}.powi({})",
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Sugg::hir(cx, receiver, "..").maybe_par(),
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numeric_literal::format(&exponent.to_string(), None, false)
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),
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)
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} else {
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return;
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};
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span_lint_and_sugg(
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cx,
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lint,
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expr.span,
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help,
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"consider using",
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suggestion,
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Applicability::MachineApplicable,
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);
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}
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}
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fn check_powi(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args: &[Expr<'_>]) {
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if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
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if value == Int(2) {
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if let Some(parent) = get_parent_expr(cx, expr) {
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if let Some(grandparent) = get_parent_expr(cx, parent) {
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if let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, receiver, ..) = grandparent.kind
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{
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if method_name.as_str() == "sqrt" && detect_hypot(cx, receiver).is_some() {
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return;
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}
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}
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}
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if let ExprKind::Binary(
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Spanned {
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node: op @ (BinOpKind::Add | BinOpKind::Sub),
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..
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},
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lhs,
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rhs,
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) = parent.kind
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{
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let other_addend = if lhs.hir_id == expr.hir_id { rhs } else { lhs };
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// Negate expr if original code has subtraction and expr is on the right side
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let maybe_neg_sugg = |expr, hir_id| {
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let sugg = Sugg::hir(cx, expr, "..");
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if matches!(op, BinOpKind::Sub) && hir_id == rhs.hir_id {
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format!("-{}", sugg.maybe_par())
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} else {
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sugg.to_string()
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}
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};
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span_lint_and_sugg(
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cx,
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SUBOPTIMAL_FLOPS,
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parent.span,
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"multiply and add expressions can be calculated more efficiently and accurately",
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"consider using",
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format!(
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"{}.mul_add({}, {})",
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Sugg::hir(cx, receiver, "..").maybe_par(),
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maybe_neg_sugg(receiver, expr.hir_id),
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maybe_neg_sugg(other_addend, other_addend.hir_id),
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),
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Applicability::MachineApplicable,
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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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fn detect_hypot(cx: &LateContext<'_>, receiver: &Expr<'_>) -> Option<String> {
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if let ExprKind::Binary(
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Spanned {
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node: BinOpKind::Add, ..
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},
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add_lhs,
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add_rhs,
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) = receiver.kind
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{
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// check if expression of the form x * x + y * y
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if_chain! {
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if let ExprKind::Binary(Spanned { node: BinOpKind::Mul, .. }, lmul_lhs, lmul_rhs) = add_lhs.kind;
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if let ExprKind::Binary(Spanned { node: BinOpKind::Mul, .. }, rmul_lhs, rmul_rhs) = add_rhs.kind;
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if eq_expr_value(cx, lmul_lhs, lmul_rhs);
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if eq_expr_value(cx, rmul_lhs, rmul_rhs);
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then {
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return Some(format!("{}.hypot({})", Sugg::hir(cx, lmul_lhs, "..").maybe_par(), Sugg::hir(cx, rmul_lhs, "..")));
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}
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}
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// check if expression of the form x.powi(2) + y.powi(2)
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if_chain! {
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if let ExprKind::MethodCall(
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PathSegment { ident: lmethod_name, .. },
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largs_0, [largs_1, ..],
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_
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) = &add_lhs.kind;
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if let ExprKind::MethodCall(
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PathSegment { ident: rmethod_name, .. },
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rargs_0, [rargs_1, ..],
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_
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) = &add_rhs.kind;
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if lmethod_name.as_str() == "powi" && rmethod_name.as_str() == "powi";
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if let Some((lvalue, _)) = constant(cx, cx.typeck_results(), largs_1);
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if let Some((rvalue, _)) = constant(cx, cx.typeck_results(), rargs_1);
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if Int(2) == lvalue && Int(2) == rvalue;
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then {
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return Some(format!("{}.hypot({})", Sugg::hir(cx, largs_0, "..").maybe_par(), Sugg::hir(cx, rargs_0, "..")));
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}
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}
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}
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None
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}
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fn check_hypot(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>) {
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if let Some(message) = detect_hypot(cx, receiver) {
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span_lint_and_sugg(
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cx,
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IMPRECISE_FLOPS,
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expr.span,
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"hypotenuse can be computed more accurately",
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"consider using",
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message,
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Applicability::MachineApplicable,
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);
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}
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}
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// TODO: Lint expressions of the form `x.exp() - y` where y > 1
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// and suggest usage of `x.exp_m1() - (y - 1)` instead
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fn check_expm1(cx: &LateContext<'_>, expr: &Expr<'_>) {
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if_chain! {
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if let ExprKind::Binary(Spanned { node: BinOpKind::Sub, .. }, lhs, rhs) = expr.kind;
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if cx.typeck_results().expr_ty(lhs).is_floating_point();
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if let Some((value, _)) = constant(cx, cx.typeck_results(), rhs);
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if F32(1.0) == value || F64(1.0) == value;
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if let ExprKind::MethodCall(path, self_arg, ..) = &lhs.kind;
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if cx.typeck_results().expr_ty(self_arg).is_floating_point();
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if path.ident.name.as_str() == "exp";
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then {
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span_lint_and_sugg(
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cx,
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IMPRECISE_FLOPS,
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expr.span,
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"(e.pow(x) - 1) can be computed more accurately",
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"consider using",
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format!(
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"{}.exp_m1()",
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Sugg::hir(cx, self_arg, "..").maybe_par()
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),
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Applicability::MachineApplicable,
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);
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}
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}
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}
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fn is_float_mul_expr<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<(&'a Expr<'a>, &'a Expr<'a>)> {
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if_chain! {
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if let ExprKind::Binary(Spanned { node: BinOpKind::Mul, .. }, lhs, rhs) = &expr.kind;
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if cx.typeck_results().expr_ty(lhs).is_floating_point();
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if cx.typeck_results().expr_ty(rhs).is_floating_point();
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then {
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return Some((lhs, rhs));
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}
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}
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None
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}
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// TODO: Fix rust-lang/rust-clippy#4735
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fn check_mul_add(cx: &LateContext<'_>, expr: &Expr<'_>) {
|
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if let ExprKind::Binary(
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Spanned {
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node: op @ (BinOpKind::Add | BinOpKind::Sub),
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..
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},
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lhs,
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rhs,
|
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) = &expr.kind
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{
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if let Some(parent) = get_parent_expr(cx, expr) {
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if let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, receiver, ..) = parent.kind {
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if method_name.as_str() == "sqrt" && detect_hypot(cx, receiver).is_some() {
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return;
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}
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}
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}
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let maybe_neg_sugg = |expr| {
|
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let sugg = Sugg::hir(cx, expr, "..");
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if let BinOpKind::Sub = op {
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format!("-{sugg}")
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} else {
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sugg.to_string()
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}
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|
};
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|
|
let (recv, arg1, arg2) = if let Some((inner_lhs, inner_rhs)) = is_float_mul_expr(cx, lhs) {
|
|
(
|
|
inner_lhs,
|
|
Sugg::hir(cx, inner_rhs, "..").to_string(),
|
|
maybe_neg_sugg(rhs),
|
|
)
|
|
} else if let Some((inner_lhs, inner_rhs)) = is_float_mul_expr(cx, rhs) {
|
|
(
|
|
inner_lhs,
|
|
maybe_neg_sugg(inner_rhs),
|
|
Sugg::hir(cx, lhs, "..").to_string(),
|
|
)
|
|
} else {
|
|
return;
|
|
};
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
SUBOPTIMAL_FLOPS,
|
|
expr.span,
|
|
"multiply and add expressions can be calculated more efficiently and accurately",
|
|
"consider using",
|
|
format!("{}.mul_add({arg1}, {arg2})", prepare_receiver_sugg(cx, recv)),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
|
|
/// Returns true iff expr is an expression which tests whether or not
|
|
/// test is positive or an expression which tests whether or not test
|
|
/// is nonnegative.
|
|
/// Used for check-custom-abs function below
|
|
fn is_testing_positive(cx: &LateContext<'_>, expr: &Expr<'_>, test: &Expr<'_>) -> bool {
|
|
if let ExprKind::Binary(Spanned { node: op, .. }, left, right) = expr.kind {
|
|
match op {
|
|
BinOpKind::Gt | BinOpKind::Ge => is_zero(cx, right) && eq_expr_value(cx, left, test),
|
|
BinOpKind::Lt | BinOpKind::Le => is_zero(cx, left) && eq_expr_value(cx, right, test),
|
|
_ => false,
|
|
}
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
/// See [`is_testing_positive`]
|
|
fn is_testing_negative(cx: &LateContext<'_>, expr: &Expr<'_>, test: &Expr<'_>) -> bool {
|
|
if let ExprKind::Binary(Spanned { node: op, .. }, left, right) = expr.kind {
|
|
match op {
|
|
BinOpKind::Gt | BinOpKind::Ge => is_zero(cx, left) && eq_expr_value(cx, right, test),
|
|
BinOpKind::Lt | BinOpKind::Le => is_zero(cx, right) && eq_expr_value(cx, left, test),
|
|
_ => false,
|
|
}
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
/// Returns true iff expr is some zero literal
|
|
fn is_zero(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
|
|
match constant_simple(cx, cx.typeck_results(), expr) {
|
|
Some(Constant::Int(i)) => i == 0,
|
|
Some(Constant::F32(f)) => f == 0.0,
|
|
Some(Constant::F64(f)) => f == 0.0,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
/// If the two expressions are negations of each other, then it returns
|
|
/// a tuple, in which the first element is true iff expr1 is the
|
|
/// positive expressions, and the second element is the positive
|
|
/// one of the two expressions
|
|
/// If the two expressions are not negations of each other, then it
|
|
/// returns None.
|
|
fn are_negated<'a>(cx: &LateContext<'_>, expr1: &'a Expr<'a>, expr2: &'a Expr<'a>) -> Option<(bool, &'a Expr<'a>)> {
|
|
if let ExprKind::Unary(UnOp::Neg, expr1_negated) = &expr1.kind {
|
|
if eq_expr_value(cx, expr1_negated, expr2) {
|
|
return Some((false, expr2));
|
|
}
|
|
}
|
|
if let ExprKind::Unary(UnOp::Neg, expr2_negated) = &expr2.kind {
|
|
if eq_expr_value(cx, expr1, expr2_negated) {
|
|
return Some((true, expr1));
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
fn check_custom_abs(cx: &LateContext<'_>, expr: &Expr<'_>) {
|
|
if_chain! {
|
|
if let Some(higher::If { cond, then, r#else: Some(r#else) }) = higher::If::hir(expr);
|
|
let if_body_expr = peel_blocks(then);
|
|
let else_body_expr = peel_blocks(r#else);
|
|
if let Some((if_expr_positive, body)) = are_negated(cx, if_body_expr, else_body_expr);
|
|
then {
|
|
let positive_abs_sugg = (
|
|
"manual implementation of `abs` method",
|
|
format!("{}.abs()", Sugg::hir(cx, body, "..").maybe_par()),
|
|
);
|
|
let negative_abs_sugg = (
|
|
"manual implementation of negation of `abs` method",
|
|
format!("-{}.abs()", Sugg::hir(cx, body, "..").maybe_par()),
|
|
);
|
|
let sugg = if is_testing_positive(cx, cond, body) {
|
|
if if_expr_positive {
|
|
positive_abs_sugg
|
|
} else {
|
|
negative_abs_sugg
|
|
}
|
|
} else if is_testing_negative(cx, cond, body) {
|
|
if if_expr_positive {
|
|
negative_abs_sugg
|
|
} else {
|
|
positive_abs_sugg
|
|
}
|
|
} else {
|
|
return;
|
|
};
|
|
span_lint_and_sugg(
|
|
cx,
|
|
SUBOPTIMAL_FLOPS,
|
|
expr.span,
|
|
sugg.0,
|
|
"try",
|
|
sugg.1,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn are_same_base_logs(cx: &LateContext<'_>, expr_a: &Expr<'_>, expr_b: &Expr<'_>) -> bool {
|
|
if_chain! {
|
|
if let ExprKind::MethodCall(PathSegment { ident: method_name_a, .. }, _, args_a, _) = expr_a.kind;
|
|
if let ExprKind::MethodCall(PathSegment { ident: method_name_b, .. }, _, args_b, _) = expr_b.kind;
|
|
then {
|
|
return method_name_a.as_str() == method_name_b.as_str() &&
|
|
args_a.len() == args_b.len() &&
|
|
(
|
|
["ln", "log2", "log10"].contains(&method_name_a.as_str()) ||
|
|
method_name_a.as_str() == "log" && args_a.len() == 1 && eq_expr_value(cx, &args_a[0], &args_b[0])
|
|
);
|
|
}
|
|
}
|
|
|
|
false
|
|
}
|
|
|
|
fn check_log_division(cx: &LateContext<'_>, expr: &Expr<'_>) {
|
|
// check if expression of the form x.logN() / y.logN()
|
|
if_chain! {
|
|
if let ExprKind::Binary(
|
|
Spanned {
|
|
node: BinOpKind::Div, ..
|
|
},
|
|
lhs,
|
|
rhs,
|
|
) = &expr.kind;
|
|
if are_same_base_logs(cx, lhs, rhs);
|
|
if let ExprKind::MethodCall(_, largs_self, ..) = &lhs.kind;
|
|
if let ExprKind::MethodCall(_, rargs_self, ..) = &rhs.kind;
|
|
then {
|
|
span_lint_and_sugg(
|
|
cx,
|
|
SUBOPTIMAL_FLOPS,
|
|
expr.span,
|
|
"log base can be expressed more clearly",
|
|
"consider using",
|
|
format!("{}.log({})", Sugg::hir(cx, largs_self, "..").maybe_par(), Sugg::hir(cx, rargs_self, ".."),),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_radians(cx: &LateContext<'_>, expr: &Expr<'_>) {
|
|
if_chain! {
|
|
if let ExprKind::Binary(
|
|
Spanned {
|
|
node: BinOpKind::Div, ..
|
|
},
|
|
div_lhs,
|
|
div_rhs,
|
|
) = &expr.kind;
|
|
if let ExprKind::Binary(
|
|
Spanned {
|
|
node: BinOpKind::Mul, ..
|
|
},
|
|
mul_lhs,
|
|
mul_rhs,
|
|
) = &div_lhs.kind;
|
|
if let Some((rvalue, _)) = constant(cx, cx.typeck_results(), div_rhs);
|
|
if let Some((lvalue, _)) = constant(cx, cx.typeck_results(), mul_rhs);
|
|
then {
|
|
// TODO: also check for constant values near PI/180 or 180/PI
|
|
if (F32(f32_consts::PI) == rvalue || F64(f64_consts::PI) == rvalue) &&
|
|
(F32(180_f32) == lvalue || F64(180_f64) == lvalue)
|
|
{
|
|
let mut proposal = format!("{}.to_degrees()", Sugg::hir(cx, mul_lhs, "..").maybe_par());
|
|
if_chain! {
|
|
if let ExprKind::Lit(ref literal) = mul_lhs.kind;
|
|
if let ast::LitKind::Float(ref value, float_type) = literal.node;
|
|
if float_type == ast::LitFloatType::Unsuffixed;
|
|
then {
|
|
if value.as_str().ends_with('.') {
|
|
proposal = format!("{}0_f64.to_degrees()", Sugg::hir(cx, mul_lhs, ".."));
|
|
} else {
|
|
proposal = format!("{}_f64.to_degrees()", Sugg::hir(cx, mul_lhs, ".."));
|
|
}
|
|
}
|
|
}
|
|
span_lint_and_sugg(
|
|
cx,
|
|
SUBOPTIMAL_FLOPS,
|
|
expr.span,
|
|
"conversion to degrees can be done more accurately",
|
|
"consider using",
|
|
proposal,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
} else if
|
|
(F32(180_f32) == rvalue || F64(180_f64) == rvalue) &&
|
|
(F32(f32_consts::PI) == lvalue || F64(f64_consts::PI) == lvalue)
|
|
{
|
|
let mut proposal = format!("{}.to_radians()", Sugg::hir(cx, mul_lhs, "..").maybe_par());
|
|
if_chain! {
|
|
if let ExprKind::Lit(ref literal) = mul_lhs.kind;
|
|
if let ast::LitKind::Float(ref value, float_type) = literal.node;
|
|
if float_type == ast::LitFloatType::Unsuffixed;
|
|
then {
|
|
if value.as_str().ends_with('.') {
|
|
proposal = format!("{}0_f64.to_radians()", Sugg::hir(cx, mul_lhs, ".."));
|
|
} else {
|
|
proposal = format!("{}_f64.to_radians()", Sugg::hir(cx, mul_lhs, ".."));
|
|
}
|
|
}
|
|
}
|
|
span_lint_and_sugg(
|
|
cx,
|
|
SUBOPTIMAL_FLOPS,
|
|
expr.span,
|
|
"conversion to radians can be done more accurately",
|
|
"consider using",
|
|
proposal,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> LateLintPass<'tcx> for FloatingPointArithmetic {
|
|
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
|
|
// All of these operations are currently not const.
|
|
if in_constant(cx, expr.hir_id) {
|
|
return;
|
|
}
|
|
|
|
if let ExprKind::MethodCall(path, receiver, args, _) = &expr.kind {
|
|
let recv_ty = cx.typeck_results().expr_ty(receiver);
|
|
|
|
if recv_ty.is_floating_point() {
|
|
match path.ident.name.as_str() {
|
|
"ln" => check_ln1p(cx, expr, receiver),
|
|
"log" => check_log_base(cx, expr, receiver, args),
|
|
"powf" => check_powf(cx, expr, receiver, args),
|
|
"powi" => check_powi(cx, expr, receiver, args),
|
|
"sqrt" => check_hypot(cx, expr, receiver),
|
|
_ => {},
|
|
}
|
|
}
|
|
} else {
|
|
check_expm1(cx, expr);
|
|
check_mul_add(cx, expr);
|
|
check_custom_abs(cx, expr);
|
|
check_log_division(cx, expr);
|
|
check_radians(cx, expr);
|
|
}
|
|
}
|
|
}
|