use crate::consts::{
constant, constant_simple, Constant,
- Constant::{F32, F64},
+ Constant::{Int, F32, F64},
};
-use crate::utils::{higher, numeric_literal, span_lint_and_sugg, sugg, SpanlessEq};
+use crate::utils::{eq_expr_value, get_parent_expr, numeric_literal, span_lint_and_sugg, sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::{BinOpKind, Expr, ExprKind, UnOp};
+use rustc_hir::{BinOpKind, Expr, ExprKind, PathSegment, UnOp};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty;
use rustc_session::{declare_lint_pass, declare_tool_lint};
// Returns the specialized log method for a given base if base is constant
// and is one of 2, 10 and e
-fn get_specialized_log_method(cx: &LateContext<'_, '_>, base: &Expr<'_>) -> Option<&'static str> {
- if let Some((value, _)) = constant(cx, cx.tables, base) {
+fn get_specialized_log_method(cx: &LateContext<'_>, base: &Expr<'_>) -> Option<&'static str> {
+ if let Some((value, _)) = constant(cx, cx.typeck_results(), base) {
if F32(2.0) == value || F64(2.0) == value {
return Some("log2");
} else if F32(10.0) == value || F64(10.0) == value {
}
// Adds type suffixes and parenthesis to method receivers if necessary
-fn prepare_receiver_sugg<'a>(cx: &LateContext<'_, '_>, mut expr: &'a Expr<'a>) -> Sugg<'a> {
+fn prepare_receiver_sugg<'a>(cx: &LateContext<'_>, mut expr: &'a Expr<'a>) -> Sugg<'a> {
let mut suggestion = Sugg::hir(cx, expr, "..");
- if let ExprKind::Unary(UnOp::UnNeg, inner_expr) = &expr.kind {
+ if let ExprKind::Unary(UnOp::Neg, inner_expr) = &expr.kind {
expr = &inner_expr;
}
if_chain! {
// if the expression is a float literal and it is unsuffixed then
// add a suffix so the suggestion is valid and unambiguous
- if let ty::Float(float_ty) = cx.tables.expr_ty(expr).kind;
+ if let ty::Float(float_ty) = cx.typeck_results().expr_ty(expr).kind();
if let ExprKind::Lit(lit) = &expr.kind;
if let ast::LitKind::Float(sym, ast::LitFloatType::Unsuffixed) = lit.node;
then {
suggestion.maybe_par()
}
-fn check_log_base(cx: &LateContext<'_, '_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
+fn check_log_base(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
if let Some(method) = get_specialized_log_method(cx, &args[1]) {
span_lint_and_sugg(
cx,
// TODO: Lint expressions of the form `(x + y).ln()` where y > 1 and
// suggest usage of `(x + (y - 1)).ln_1p()` instead
-fn check_ln1p(cx: &LateContext<'_, '_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
+fn check_ln1p(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
if let ExprKind::Binary(
Spanned {
node: BinOpKind::Add, ..
rhs,
) = &args[0].kind
{
- let recv = match (constant(cx, cx.tables, lhs), constant(cx, cx.tables, rhs)) {
+ let recv = match (
+ constant(cx, cx.typeck_results(), lhs),
+ constant(cx, cx.typeck_results(), rhs),
+ ) {
(Some((value, _)), _) if F32(1.0) == value || F64(1.0) == value => rhs,
(_, Some((value, _))) if F32(1.0) == value || F64(1.0) == value => lhs,
_ => return,
}
}
-fn check_powf(cx: &LateContext<'_, '_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
+fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
// Check receiver
- if let Some((value, _)) = constant(cx, cx.tables, &args[0]) {
+ if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
let method = if F32(f32_consts::E) == value || F64(f64_consts::E) == value {
"exp"
} else if F32(2.0) == value || F64(2.0) == value {
}
// Check argument
- if let Some((value, _)) = constant(cx, cx.tables, &args[1]) {
+ if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[1]) {
let (lint, help, suggestion) = if F32(1.0 / 2.0) == value || F64(1.0 / 2.0) == value {
(
SUBOPTIMAL_FLOPS,
}
}
+fn check_powi(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
+ if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[1]) {
+ if value == Int(2) {
+ if let Some(parent) = get_parent_expr(cx, expr) {
+ if let Some(grandparent) = get_parent_expr(cx, parent) {
+ if let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, _, args, _) = grandparent.kind {
+ if method_name.as_str() == "sqrt" && detect_hypot(cx, args).is_some() {
+ return;
+ }
+ }
+ }
+
+ if let ExprKind::Binary(
+ Spanned {
+ node: BinOpKind::Add, ..
+ },
+ ref lhs,
+ ref rhs,
+ ) = parent.kind
+ {
+ let other_addend = if lhs.hir_id == expr.hir_id { rhs } else { lhs };
+
+ span_lint_and_sugg(
+ cx,
+ SUBOPTIMAL_FLOPS,
+ parent.span,
+ "square can be computed more efficiently",
+ "consider using",
+ format!(
+ "{}.mul_add({}, {})",
+ Sugg::hir(cx, &args[0], ".."),
+ Sugg::hir(cx, &args[0], ".."),
+ Sugg::hir(cx, &other_addend, ".."),
+ ),
+ Applicability::MachineApplicable,
+ );
+
+ return;
+ }
+ }
+
+ span_lint_and_sugg(
+ cx,
+ SUBOPTIMAL_FLOPS,
+ expr.span,
+ "square can be computed more efficiently",
+ "consider using",
+ format!("{} * {}", Sugg::hir(cx, &args[0], ".."), Sugg::hir(cx, &args[0], "..")),
+ Applicability::MachineApplicable,
+ );
+ }
+ }
+}
+
+fn detect_hypot(cx: &LateContext<'_>, args: &[Expr<'_>]) -> Option<String> {
+ if let ExprKind::Binary(
+ Spanned {
+ node: BinOpKind::Add, ..
+ },
+ ref add_lhs,
+ ref add_rhs,
+ ) = args[0].kind
+ {
+ // check if expression of the form x * x + y * y
+ if_chain! {
+ if let ExprKind::Binary(Spanned { node: BinOpKind::Mul, .. }, ref lmul_lhs, ref lmul_rhs) = add_lhs.kind;
+ if let ExprKind::Binary(Spanned { node: BinOpKind::Mul, .. }, ref rmul_lhs, ref rmul_rhs) = add_rhs.kind;
+ if eq_expr_value(cx, lmul_lhs, lmul_rhs);
+ if eq_expr_value(cx, rmul_lhs, rmul_rhs);
+ then {
+ return Some(format!("{}.hypot({})", Sugg::hir(cx, &lmul_lhs, ".."), Sugg::hir(cx, &rmul_lhs, "..")));
+ }
+ }
+
+ // check if expression of the form x.powi(2) + y.powi(2)
+ if_chain! {
+ if let ExprKind::MethodCall(
+ PathSegment { ident: lmethod_name, .. },
+ ref _lspan,
+ ref largs,
+ _
+ ) = add_lhs.kind;
+ if let ExprKind::MethodCall(
+ PathSegment { ident: rmethod_name, .. },
+ ref _rspan,
+ ref rargs,
+ _
+ ) = add_rhs.kind;
+ if lmethod_name.as_str() == "powi" && rmethod_name.as_str() == "powi";
+ if let Some((lvalue, _)) = constant(cx, cx.typeck_results(), &largs[1]);
+ if let Some((rvalue, _)) = constant(cx, cx.typeck_results(), &rargs[1]);
+ if Int(2) == lvalue && Int(2) == rvalue;
+ then {
+ return Some(format!("{}.hypot({})", Sugg::hir(cx, &largs[0], ".."), Sugg::hir(cx, &rargs[0], "..")));
+ }
+ }
+ }
+
+ None
+}
+
+fn check_hypot(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
+ if let Some(message) = detect_hypot(cx, args) {
+ span_lint_and_sugg(
+ cx,
+ IMPRECISE_FLOPS,
+ expr.span,
+ "hypotenuse can be computed more accurately",
+ "consider using",
+ message,
+ Applicability::MachineApplicable,
+ );
+ }
+}
+
// TODO: Lint expressions of the form `x.exp() - y` where y > 1
// and suggest usage of `x.exp_m1() - (y - 1)` instead
-fn check_expm1(cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
+fn check_expm1(cx: &LateContext<'_>, expr: &Expr<'_>) {
if_chain! {
if let ExprKind::Binary(Spanned { node: BinOpKind::Sub, .. }, ref lhs, ref rhs) = expr.kind;
- if cx.tables.expr_ty(lhs).is_floating_point();
- if let Some((value, _)) = constant(cx, cx.tables, rhs);
+ if cx.typeck_results().expr_ty(lhs).is_floating_point();
+ if let Some((value, _)) = constant(cx, cx.typeck_results(), rhs);
if F32(1.0) == value || F64(1.0) == value;
- if let ExprKind::MethodCall(ref path, _, ref method_args) = lhs.kind;
- if cx.tables.expr_ty(&method_args[0]).is_floating_point();
+ if let ExprKind::MethodCall(ref path, _, ref method_args, _) = lhs.kind;
+ if cx.typeck_results().expr_ty(&method_args[0]).is_floating_point();
if path.ident.name.as_str() == "exp";
then {
span_lint_and_sugg(
}
}
-fn is_float_mul_expr<'a>(cx: &LateContext<'_, '_>, expr: &'a Expr<'a>) -> Option<(&'a Expr<'a>, &'a Expr<'a>)> {
+fn is_float_mul_expr<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<(&'a Expr<'a>, &'a Expr<'a>)> {
if_chain! {
if let ExprKind::Binary(Spanned { node: BinOpKind::Mul, .. }, ref lhs, ref rhs) = &expr.kind;
- if cx.tables.expr_ty(lhs).is_floating_point();
- if cx.tables.expr_ty(rhs).is_floating_point();
+ if cx.typeck_results().expr_ty(lhs).is_floating_point();
+ if cx.typeck_results().expr_ty(rhs).is_floating_point();
then {
return Some((lhs, rhs));
}
}
// TODO: Fix rust-lang/rust-clippy#4735
-fn check_mul_add(cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
+fn check_mul_add(cx: &LateContext<'_>, expr: &Expr<'_>) {
if let ExprKind::Binary(
Spanned {
node: BinOpKind::Add, ..
rhs,
) = &expr.kind
{
+ if let Some(parent) = get_parent_expr(cx, expr) {
+ if let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, _, args, _) = parent.kind {
+ if method_name.as_str() == "sqrt" && detect_hypot(cx, args).is_some() {
+ return;
+ }
+ }
+ }
+
let (recv, arg1, arg2) = if let Some((inner_lhs, inner_rhs)) = is_float_mul_expr(cx, lhs) {
(inner_lhs, inner_rhs, rhs)
} else if let Some((inner_lhs, inner_rhs)) = is_float_mul_expr(cx, rhs) {
/// 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 {
+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) && are_exprs_equal(cx, left, test),
- BinOpKind::Lt | BinOpKind::Le => is_zero(cx, left) && are_exprs_equal(cx, right, test),
+ 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 {
}
/// See [`is_testing_positive`]
-fn is_testing_negative(cx: &LateContext<'_, '_>, expr: &Expr<'_>, test: &Expr<'_>) -> bool {
+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) && are_exprs_equal(cx, right, test),
- BinOpKind::Lt | BinOpKind::Le => is_zero(cx, right) && are_exprs_equal(cx, left, test),
+ 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 {
}
}
-fn are_exprs_equal(cx: &LateContext<'_, '_>, expr1: &Expr<'_>, expr2: &Expr<'_>) -> bool {
- SpanlessEq::new(cx).ignore_fn().eq_expr(expr1, expr2)
-}
-
/// Returns true iff expr is some zero literal
-fn is_zero(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
- match constant_simple(cx, cx.tables, expr) {
+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,
/// 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::UnNeg, expr1_negated) = &expr1.kind {
- if are_exprs_equal(cx, expr1_negated, expr2) {
+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::UnNeg, expr2_negated) = &expr2.kind {
- if are_exprs_equal(cx, expr1, expr2_negated) {
+ 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<'_>) {
+fn check_custom_abs(cx: &LateContext<'_>, expr: &Expr<'_>) {
if_chain! {
- if let Some((cond, body, Some(else_body))) = higher::if_block(&expr);
+ if let ExprKind::If(cond, body, else_body) = expr.kind;
if let ExprKind::Block(block, _) = body.kind;
if block.stmts.is_empty();
if let Some(if_body_expr) = block.expr;
- if let ExprKind::Block(else_block, _) = else_body.kind;
+ if let Some(ExprKind::Block(else_block, _)) = else_body.map(|el| &el.kind);
if else_block.stmts.is_empty();
if let Some(else_body_expr) = else_block.expr;
if let Some((if_expr_positive, body)) = are_negated(cx, if_body_expr, else_body_expr);
}
}
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for FloatingPointArithmetic {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
- if let ExprKind::MethodCall(ref path, _, args) = &expr.kind {
- let recv_ty = cx.tables.expr_ty(&args[0]);
+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, .. }, _, ref args_a, _) = expr_a.kind;
+ if let ExprKind::MethodCall(PathSegment { ident: method_name_b, .. }, _, ref 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() == 2 && eq_expr_value(cx, &args_a[1], &args_b[1])
+ );
+ }
+ }
+
+ 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(_, _, ref largs, _) = lhs.kind;
+ if let ExprKind::MethodCall(_, _, ref rargs, _) = 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[0], ".."), Sugg::hir(cx, &rargs[0], ".."),),
+ 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)
+ {
+ span_lint_and_sugg(
+ cx,
+ SUBOPTIMAL_FLOPS,
+ expr.span,
+ "conversion to degrees can be done more accurately",
+ "consider using",
+ format!("{}.to_degrees()", Sugg::hir(cx, &mul_lhs, "..")),
+ Applicability::MachineApplicable,
+ );
+ } else if
+ (F32(180_f32) == rvalue || F64(180_f64) == rvalue) &&
+ (F32(f32_consts::PI) == lvalue || F64(f64_consts::PI) == lvalue)
+ {
+ span_lint_and_sugg(
+ cx,
+ SUBOPTIMAL_FLOPS,
+ expr.span,
+ "conversion to radians can be done more accurately",
+ "consider using",
+ format!("{}.to_radians()", Sugg::hir(cx, &mul_lhs, "..")),
+ Applicability::MachineApplicable,
+ );
+ }
+ }
+ }
+}
+
+impl<'tcx> LateLintPass<'tcx> for FloatingPointArithmetic {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+ if let ExprKind::MethodCall(ref path, _, args, _) = &expr.kind {
+ let recv_ty = cx.typeck_results().expr_ty(&args[0]);
if recv_ty.is_floating_point() {
match &*path.ident.name.as_str() {
"ln" => check_ln1p(cx, expr, args),
"log" => check_log_base(cx, expr, args),
"powf" => check_powf(cx, expr, args),
+ "powi" => check_powi(cx, expr, args),
+ "sqrt" => check_hypot(cx, expr, args),
_ => {},
}
}
check_expm1(cx, expr);
check_mul_add(cx, expr);
check_custom_abs(cx, expr);
+ check_log_division(cx, expr);
+ check_radians(cx, expr);
}
}
}
projects / rust.git / blobdiff