diff --git a/clippy_lints/src/consts.rs b/clippy_lints/src/consts.rs index b1d540c975158..b916071291581 100644 --- a/clippy_lints/src/consts.rs +++ b/clippy_lints/src/consts.rs @@ -268,6 +268,7 @@ impl<'c, 'cc> ConstEvalLateContext<'c, 'cc> { } } }, + ExprKind::Index(ref arr, ref index) => self.index(arr, index), // TODO: add other expressions. _ => None, } @@ -345,6 +346,31 @@ impl<'c, 'cc> ConstEvalLateContext<'c, 'cc> { } } + fn index(&mut self, lhs: &'_ Expr<'_>, index: &'_ Expr<'_>) -> Option { + let lhs = self.expr(lhs); + let index = self.expr(index); + + match (lhs, index) { + (Some(Constant::Vec(vec)), Some(Constant::Int(index))) => match vec[index as usize] { + Constant::F32(x) => Some(Constant::F32(x)), + Constant::F64(x) => Some(Constant::F64(x)), + _ => None, + }, + (Some(Constant::Vec(vec)), _) => { + if !vec.is_empty() && vec.iter().all(|x| *x == vec[0]) { + match vec[0] { + Constant::F32(x) => Some(Constant::F32(x)), + Constant::F64(x) => Some(Constant::F64(x)), + _ => None, + } + } else { + None + } + }, + _ => None, + } + } + /// A block can only yield a constant if it only has one constant expression. fn block(&mut self, block: &Block<'_>) -> Option { if block.stmts.is_empty() { @@ -492,6 +518,41 @@ pub fn miri_to_const(result: &ty::Const<'_>) -> Option { }, _ => None, }, + ty::ConstKind::Value(ConstValue::ByRef { alloc, offset: _ }) => match result.ty.kind { + ty::Array(sub_type, len) => match sub_type.kind { + ty::Float(FloatTy::F32) => match miri_to_const(len) { + Some(Constant::Int(len)) => alloc + .inspect_with_undef_and_ptr_outside_interpreter(0..(4 * len as usize)) + .to_owned() + .chunks(4) + .map(|chunk| { + Some(Constant::F32(f32::from_le_bytes( + chunk.try_into().expect("this shouldn't happen"), + ))) + }) + .collect::>>() + .map(Constant::Vec), + _ => None, + }, + ty::Float(FloatTy::F64) => match miri_to_const(len) { + Some(Constant::Int(len)) => alloc + .inspect_with_undef_and_ptr_outside_interpreter(0..(8 * len as usize)) + .to_owned() + .chunks(8) + .map(|chunk| { + Some(Constant::F64(f64::from_le_bytes( + chunk.try_into().expect("this shouldn't happen"), + ))) + }) + .collect::>>() + .map(Constant::Vec), + _ => None, + }, + // FIXME: implement other array type conversions. + _ => None, + }, + _ => None, + }, // FIXME: implement other conversions. _ => None, } diff --git a/clippy_lints/src/misc.rs b/clippy_lints/src/misc.rs index cedd15e8daf63..58a5a29eb16bc 100644 --- a/clippy_lints/src/misc.rs +++ b/clippy_lints/src/misc.rs @@ -369,26 +369,28 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MiscLints { return; } } - let (lint, msg) = if is_named_constant(cx, left) || is_named_constant(cx, right) { - (FLOAT_CMP_CONST, "strict comparison of `f32` or `f64` constant") - } else { - (FLOAT_CMP, "strict comparison of `f32` or `f64`") - }; + let is_comparing_arrays = is_array(cx, left) || is_array(cx, right); + let (lint, msg) = get_lint_and_message( + is_named_constant(cx, left) || is_named_constant(cx, right), + is_comparing_arrays, + ); span_lint_and_then(cx, lint, expr.span, msg, |db| { let lhs = Sugg::hir(cx, left, ".."); let rhs = Sugg::hir(cx, right, ".."); - db.span_suggestion( - expr.span, - "consider comparing them within some error", - format!( - "({}).abs() {} error", - lhs - rhs, - if op == BinOpKind::Eq { '<' } else { '>' } - ), - Applicability::HasPlaceholders, // snippet - ); - db.span_note(expr.span, "`f32::EPSILON` and `f64::EPSILON` are available."); + if !is_comparing_arrays { + db.span_suggestion( + expr.span, + "consider comparing them within some error", + format!( + "({}).abs() {} error", + lhs - rhs, + if op == BinOpKind::Eq { '<' } else { '>' } + ), + Applicability::HasPlaceholders, // snippet + ); + } + db.note("`f32::EPSILON` and `f64::EPSILON` are available for the `error`"); }); } else if op == BinOpKind::Rem && is_integer_const(cx, right, 1) { span_lint(cx, MODULO_ONE, expr.span, "any number modulo 1 will be 0"); @@ -440,6 +442,31 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MiscLints { } } +fn get_lint_and_message( + is_comparing_constants: bool, + is_comparing_arrays: bool, +) -> (&'static rustc_lint::Lint, &'static str) { + if is_comparing_constants { + ( + FLOAT_CMP_CONST, + if is_comparing_arrays { + "strict comparison of `f32` or `f64` constant arrays" + } else { + "strict comparison of `f32` or `f64` constant" + }, + ) + } else { + ( + FLOAT_CMP, + if is_comparing_arrays { + "strict comparison of `f32` or `f64` arrays" + } else { + "strict comparison of `f32` or `f64`" + }, + ) + } +} + fn check_nan(cx: &LateContext<'_, '_>, expr: &Expr<'_>, cmp_expr: &Expr<'_>) { if_chain! { if !in_constant(cx, cmp_expr.hir_id); @@ -475,6 +502,11 @@ fn is_allowed<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> boo match constant(cx, cx.tables, expr) { Some((Constant::F32(f), _)) => f == 0.0 || f.is_infinite(), Some((Constant::F64(f), _)) => f == 0.0 || f.is_infinite(), + Some((Constant::Vec(vec), _)) => vec.iter().all(|f| match f { + Constant::F32(f) => *f == 0.0 || (*f).is_infinite(), + Constant::F64(f) => *f == 0.0 || (*f).is_infinite(), + _ => false, + }), _ => false, } } @@ -499,7 +531,17 @@ fn is_signum(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool { } fn is_float(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool { - matches!(walk_ptrs_ty(cx.tables.expr_ty(expr)).kind, ty::Float(_)) + let value = &walk_ptrs_ty(cx.tables.expr_ty(expr)).kind; + + if let ty::Array(arr_ty, _) = value { + return matches!(arr_ty.kind, ty::Float(_)); + }; + + matches!(value, ty::Float(_)) +} + +fn is_array(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool { + matches!(&walk_ptrs_ty(cx.tables.expr_ty(expr)).kind, ty::Array(_, _)) } fn check_to_owned(cx: &LateContext<'_, '_>, expr: &Expr<'_>, other: &Expr<'_>) { diff --git a/tests/ui/float_cmp.rs b/tests/ui/float_cmp.rs index c8248723bc9d6..9fa0e5f5c079b 100644 --- a/tests/ui/float_cmp.rs +++ b/tests/ui/float_cmp.rs @@ -1,5 +1,11 @@ #![warn(clippy::float_cmp)] -#![allow(unused, clippy::no_effect, clippy::unnecessary_operation, clippy::cast_lossless)] +#![allow( + unused, + clippy::no_effect, + clippy::unnecessary_operation, + clippy::cast_lossless, + clippy::many_single_char_names +)] use std::ops::Add; @@ -77,6 +83,21 @@ fn main() { assert_eq!(a, b); // no errors + const ZERO_ARRAY: [f32; 2] = [0.0, 0.0]; + const NON_ZERO_ARRAY: [f32; 2] = [0.0, 0.1]; + + let i = 0; + let j = 1; + + ZERO_ARRAY[i] == NON_ZERO_ARRAY[j]; // ok, because lhs is zero regardless of i + NON_ZERO_ARRAY[i] == NON_ZERO_ARRAY[j]; + + let a1: [f32; 1] = [0.0]; + let a2: [f32; 1] = [1.1]; + + a1 == a2; + a1[0] == a2[0]; + // no errors - comparing signums is ok let x32 = 3.21f32; 1.23f32.signum() == x32.signum(); diff --git a/tests/ui/float_cmp.stderr b/tests/ui/float_cmp.stderr index 90c25a6db37d2..2d454e8e70de5 100644 --- a/tests/ui/float_cmp.stderr +++ b/tests/ui/float_cmp.stderr @@ -1,39 +1,51 @@ error: strict comparison of `f32` or `f64` - --> $DIR/float_cmp.rs:59:5 + --> $DIR/float_cmp.rs:65:5 | LL | ONE as f64 != 2.0; | ^^^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(ONE as f64 - 2.0).abs() > error` | = note: `-D clippy::float-cmp` implied by `-D warnings` -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp.rs:59:5 - | -LL | ONE as f64 != 2.0; - | ^^^^^^^^^^^^^^^^^ + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` error: strict comparison of `f32` or `f64` - --> $DIR/float_cmp.rs:64:5 + --> $DIR/float_cmp.rs:70:5 | LL | x == 1.0; | ^^^^^^^^ help: consider comparing them within some error: `(x - 1.0).abs() < error` | -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp.rs:64:5 - | -LL | x == 1.0; - | ^^^^^^^^ + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` error: strict comparison of `f32` or `f64` - --> $DIR/float_cmp.rs:67:5 + --> $DIR/float_cmp.rs:73:5 | LL | twice(x) != twice(ONE as f64); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(twice(x) - twice(ONE as f64)).abs() > error` | -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp.rs:67:5 + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` + +error: strict comparison of `f32` or `f64` + --> $DIR/float_cmp.rs:93:5 | -LL | twice(x) != twice(ONE as f64); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | NON_ZERO_ARRAY[i] == NON_ZERO_ARRAY[j]; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(NON_ZERO_ARRAY[i] - NON_ZERO_ARRAY[j]).abs() < error` + | + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` + +error: strict comparison of `f32` or `f64` arrays + --> $DIR/float_cmp.rs:98:5 + | +LL | a1 == a2; + | ^^^^^^^^ + | + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` + +error: strict comparison of `f32` or `f64` + --> $DIR/float_cmp.rs:99:5 + | +LL | a1[0] == a2[0]; + | ^^^^^^^^^^^^^^ help: consider comparing them within some error: `(a1[0] - a2[0]).abs() < error` + | + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` -error: aborting due to 3 previous errors +error: aborting due to 6 previous errors diff --git a/tests/ui/float_cmp_const.rs b/tests/ui/float_cmp_const.rs index a338040e19be6..dfc025558a2f4 100644 --- a/tests/ui/float_cmp_const.rs +++ b/tests/ui/float_cmp_const.rs @@ -46,4 +46,17 @@ fn main() { v != w; v == 1.0; v != 1.0; + + const ZERO_ARRAY: [f32; 3] = [0.0, 0.0, 0.0]; + const ZERO_INF_ARRAY: [f32; 3] = [0.0, ::std::f32::INFINITY, ::std::f32::NEG_INFINITY]; + const NON_ZERO_ARRAY: [f32; 3] = [0.0, 0.1, 0.2]; + const NON_ZERO_ARRAY2: [f32; 3] = [0.2, 0.1, 0.0]; + + // no errors, zero and infinity values + NON_ZERO_ARRAY[0] == NON_ZERO_ARRAY2[1]; // lhs is 0.0 + ZERO_ARRAY == NON_ZERO_ARRAY; // lhs is all zeros + ZERO_INF_ARRAY == NON_ZERO_ARRAY; // lhs is all zeros or infinities + + // has errors + NON_ZERO_ARRAY == NON_ZERO_ARRAY2; } diff --git a/tests/ui/float_cmp_const.stderr b/tests/ui/float_cmp_const.stderr index 2dc43cf4e5fba..19dc4a284b726 100644 --- a/tests/ui/float_cmp_const.stderr +++ b/tests/ui/float_cmp_const.stderr @@ -5,11 +5,7 @@ LL | 1f32 == ONE; | ^^^^^^^^^^^ help: consider comparing them within some error: `(1f32 - ONE).abs() < error` | = note: `-D clippy::float-cmp-const` implied by `-D warnings` -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp_const.rs:20:5 - | -LL | 1f32 == ONE; - | ^^^^^^^^^^^ + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` error: strict comparison of `f32` or `f64` constant --> $DIR/float_cmp_const.rs:21:5 @@ -17,11 +13,7 @@ error: strict comparison of `f32` or `f64` constant LL | TWO == ONE; | ^^^^^^^^^^ help: consider comparing them within some error: `(TWO - ONE).abs() < error` | -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp_const.rs:21:5 - | -LL | TWO == ONE; - | ^^^^^^^^^^ + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` error: strict comparison of `f32` or `f64` constant --> $DIR/float_cmp_const.rs:22:5 @@ -29,11 +21,7 @@ error: strict comparison of `f32` or `f64` constant LL | TWO != ONE; | ^^^^^^^^^^ help: consider comparing them within some error: `(TWO - ONE).abs() > error` | -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp_const.rs:22:5 - | -LL | TWO != ONE; - | ^^^^^^^^^^ + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` error: strict comparison of `f32` or `f64` constant --> $DIR/float_cmp_const.rs:23:5 @@ -41,11 +29,7 @@ error: strict comparison of `f32` or `f64` constant LL | ONE + ONE == TWO; | ^^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(ONE + ONE - TWO).abs() < error` | -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp_const.rs:23:5 - | -LL | ONE + ONE == TWO; - | ^^^^^^^^^^^^^^^^ + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` error: strict comparison of `f32` or `f64` constant --> $DIR/float_cmp_const.rs:25:5 @@ -53,11 +37,7 @@ error: strict comparison of `f32` or `f64` constant LL | x as f32 == ONE; | ^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(x as f32 - ONE).abs() < error` | -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp_const.rs:25:5 - | -LL | x as f32 == ONE; - | ^^^^^^^^^^^^^^^ + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` error: strict comparison of `f32` or `f64` constant --> $DIR/float_cmp_const.rs:28:5 @@ -65,11 +45,7 @@ error: strict comparison of `f32` or `f64` constant LL | v == ONE; | ^^^^^^^^ help: consider comparing them within some error: `(v - ONE).abs() < error` | -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp_const.rs:28:5 - | -LL | v == ONE; - | ^^^^^^^^ + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` error: strict comparison of `f32` or `f64` constant --> $DIR/float_cmp_const.rs:29:5 @@ -77,11 +53,15 @@ error: strict comparison of `f32` or `f64` constant LL | v != ONE; | ^^^^^^^^ help: consider comparing them within some error: `(v - ONE).abs() > error` | -note: `f32::EPSILON` and `f64::EPSILON` are available. - --> $DIR/float_cmp_const.rs:29:5 + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` + +error: strict comparison of `f32` or `f64` constant arrays + --> $DIR/float_cmp_const.rs:61:5 | -LL | v != ONE; - | ^^^^^^^^ +LL | NON_ZERO_ARRAY == NON_ZERO_ARRAY2; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error` -error: aborting due to 7 previous errors +error: aborting due to 8 previous errors