From a8ab02c4641de4e3ec634b3479fddb60e4ad7763 Mon Sep 17 00:00:00 2001 From: Samuel Tardieu Date: Thu, 3 Jul 2025 20:22:18 +0200 Subject: [PATCH] Fix several issues with `manual_is_multiple_of` - `&a % &b == 0` compiles, but requires dereferencing `b` when replacing with `a.is_multiple_of(b)`. - In `a % b == 0`, if type of `a` is not certain, `a.is_multiple_of(b)` might not be typable. - In `a % b == 0`, `a` and `b` must be unsigned integers, not any arbitrary types implementing `Rem` and outputing an integer. --- .../src/operators/manual_is_multiple_of.rs | 25 +++++- tests/ui/manual_is_multiple_of.fixed | 78 +++++++++++++++++++ tests/ui/manual_is_multiple_of.rs | 78 +++++++++++++++++++ tests/ui/manual_is_multiple_of.stderr | 32 +++++++- 4 files changed, 210 insertions(+), 3 deletions(-) diff --git a/clippy_lints/src/operators/manual_is_multiple_of.rs b/clippy_lints/src/operators/manual_is_multiple_of.rs index 821178a43158..55bb78cfce5f 100644 --- a/clippy_lints/src/operators/manual_is_multiple_of.rs +++ b/clippy_lints/src/operators/manual_is_multiple_of.rs @@ -2,11 +2,12 @@ use clippy_utils::consts::is_zero_integer_const; use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::msrvs::{self, Msrv}; use clippy_utils::sugg::Sugg; +use clippy_utils::ty::expr_type_is_certain; use rustc_ast::BinOpKind; use rustc_errors::Applicability; use rustc_hir::{Expr, ExprKind}; use rustc_lint::LateContext; -use rustc_middle::ty; +use rustc_middle::ty::{self, Ty}; use super::MANUAL_IS_MULTIPLE_OF; @@ -22,9 +23,21 @@ pub(super) fn check<'tcx>( && let Some(operand) = uint_compare_to_zero(cx, op, lhs, rhs) && let ExprKind::Binary(operand_op, operand_left, operand_right) = operand.kind && operand_op.node == BinOpKind::Rem + && matches!( + cx.typeck_results().expr_ty_adjusted(operand_left).peel_refs().kind(), + ty::Uint(_) + ) + && matches!( + cx.typeck_results().expr_ty_adjusted(operand_right).peel_refs().kind(), + ty::Uint(_) + ) + && expr_type_is_certain(cx, operand_left) { let mut app = Applicability::MachineApplicable; - let divisor = Sugg::hir_with_applicability(cx, operand_right, "_", &mut app); + let divisor = deref_sugg( + Sugg::hir_with_applicability(cx, operand_right, "_", &mut app), + cx.typeck_results().expr_ty_adjusted(operand_right), + ); span_lint_and_sugg( cx, MANUAL_IS_MULTIPLE_OF, @@ -64,3 +77,11 @@ fn uint_compare_to_zero<'tcx>( matches!(cx.typeck_results().expr_ty_adjusted(operand).kind(), ty::Uint(_)).then_some(operand) } + +fn deref_sugg<'a>(sugg: Sugg<'a>, ty: Ty<'_>) -> Sugg<'a> { + if let ty::Ref(_, target_ty, _) = ty.kind() { + deref_sugg(sugg.deref(), *target_ty) + } else { + sugg + } +} diff --git a/tests/ui/manual_is_multiple_of.fixed b/tests/ui/manual_is_multiple_of.fixed index 6735b99f298c..03f75e725ed5 100644 --- a/tests/ui/manual_is_multiple_of.fixed +++ b/tests/ui/manual_is_multiple_of.fixed @@ -23,3 +23,81 @@ fn f(a: u64, b: u64) { fn g(a: u64, b: u64) { let _ = a % b == 0; } + +fn needs_deref(a: &u64, b: &u64) { + let _ = a.is_multiple_of(*b); //~ manual_is_multiple_of +} + +fn closures(a: u64, b: u64) { + // Do not lint, types are ambiguous at this point + let cl = |a, b| a % b == 0; + let _ = cl(a, b); + + // Do not lint, types are ambiguous at this point + let cl = |a: _, b: _| a % b == 0; + let _ = cl(a, b); + + // Type of `a` is enough + let cl = |a: u64, b| a.is_multiple_of(b); //~ manual_is_multiple_of + let _ = cl(a, b); + + // Type of `a` is enough + let cl = |a: &u64, b| a.is_multiple_of(b); //~ manual_is_multiple_of + let _ = cl(&a, b); + + // Type of `b` is not enough + let cl = |a, b: u64| a % b == 0; + let _ = cl(&a, b); +} + +fn any_rem>(a: T, b: T) { + // An arbitrary `Rem` implementation should not lint + let _ = a % b == 0; +} + +mod issue15103 { + fn foo() -> Option { + let mut n: u64 = 150_000_000; + + (2..).find(|p| { + while n.is_multiple_of(*p) { + //~^ manual_is_multiple_of + n /= p; + } + n <= 1 + }) + } + + const fn generate_primes() -> [u64; N] { + let mut result = [0; N]; + if N == 0 { + return result; + } + result[0] = 2; + if N == 1 { + return result; + } + let mut idx = 1; + let mut p = 3; + while idx < N { + let mut j = 0; + while j < idx && p % result[j] != 0 { + j += 1; + } + if j == idx { + result[idx] = p; + idx += 1; + } + p += 1; + } + result + } + + fn bar() -> u32 { + let d = |n: u32| -> u32 { (1..=n / 2).filter(|i| n.is_multiple_of(*i)).sum() }; + //~^ manual_is_multiple_of + + let d = |n| (1..=n / 2).filter(|i| n % i == 0).sum(); + (1..1_000).filter(|&i| i == d(d(i)) && i != d(i)).sum() + } +} diff --git a/tests/ui/manual_is_multiple_of.rs b/tests/ui/manual_is_multiple_of.rs index 00b638e4fd9f..7b6fa64c843d 100644 --- a/tests/ui/manual_is_multiple_of.rs +++ b/tests/ui/manual_is_multiple_of.rs @@ -23,3 +23,81 @@ fn f(a: u64, b: u64) { fn g(a: u64, b: u64) { let _ = a % b == 0; } + +fn needs_deref(a: &u64, b: &u64) { + let _ = a % b == 0; //~ manual_is_multiple_of +} + +fn closures(a: u64, b: u64) { + // Do not lint, types are ambiguous at this point + let cl = |a, b| a % b == 0; + let _ = cl(a, b); + + // Do not lint, types are ambiguous at this point + let cl = |a: _, b: _| a % b == 0; + let _ = cl(a, b); + + // Type of `a` is enough + let cl = |a: u64, b| a % b == 0; //~ manual_is_multiple_of + let _ = cl(a, b); + + // Type of `a` is enough + let cl = |a: &u64, b| a % b == 0; //~ manual_is_multiple_of + let _ = cl(&a, b); + + // Type of `b` is not enough + let cl = |a, b: u64| a % b == 0; + let _ = cl(&a, b); +} + +fn any_rem>(a: T, b: T) { + // An arbitrary `Rem` implementation should not lint + let _ = a % b == 0; +} + +mod issue15103 { + fn foo() -> Option { + let mut n: u64 = 150_000_000; + + (2..).find(|p| { + while n % p == 0 { + //~^ manual_is_multiple_of + n /= p; + } + n <= 1 + }) + } + + const fn generate_primes() -> [u64; N] { + let mut result = [0; N]; + if N == 0 { + return result; + } + result[0] = 2; + if N == 1 { + return result; + } + let mut idx = 1; + let mut p = 3; + while idx < N { + let mut j = 0; + while j < idx && p % result[j] != 0 { + j += 1; + } + if j == idx { + result[idx] = p; + idx += 1; + } + p += 1; + } + result + } + + fn bar() -> u32 { + let d = |n: u32| -> u32 { (1..=n / 2).filter(|i| n % i == 0).sum() }; + //~^ manual_is_multiple_of + + let d = |n| (1..=n / 2).filter(|i| n % i == 0).sum(); + (1..1_000).filter(|&i| i == d(d(i)) && i != d(i)).sum() + } +} diff --git a/tests/ui/manual_is_multiple_of.stderr b/tests/ui/manual_is_multiple_of.stderr index 0b1ae70c2a70..8523599ec402 100644 --- a/tests/ui/manual_is_multiple_of.stderr +++ b/tests/ui/manual_is_multiple_of.stderr @@ -37,5 +37,35 @@ error: manual implementation of `.is_multiple_of()` LL | let _ = 0 < a % b; | ^^^^^^^^^ help: replace with: `!a.is_multiple_of(b)` -error: aborting due to 6 previous errors +error: manual implementation of `.is_multiple_of()` + --> tests/ui/manual_is_multiple_of.rs:28:13 + | +LL | let _ = a % b == 0; + | ^^^^^^^^^^ help: replace with: `a.is_multiple_of(*b)` + +error: manual implementation of `.is_multiple_of()` + --> tests/ui/manual_is_multiple_of.rs:41:26 + | +LL | let cl = |a: u64, b| a % b == 0; + | ^^^^^^^^^^ help: replace with: `a.is_multiple_of(b)` + +error: manual implementation of `.is_multiple_of()` + --> tests/ui/manual_is_multiple_of.rs:45:27 + | +LL | let cl = |a: &u64, b| a % b == 0; + | ^^^^^^^^^^ help: replace with: `a.is_multiple_of(b)` + +error: manual implementation of `.is_multiple_of()` + --> tests/ui/manual_is_multiple_of.rs:63:19 + | +LL | while n % p == 0 { + | ^^^^^^^^^^ help: replace with: `n.is_multiple_of(*p)` + +error: manual implementation of `.is_multiple_of()` + --> tests/ui/manual_is_multiple_of.rs:97:58 + | +LL | let d = |n: u32| -> u32 { (1..=n / 2).filter(|i| n % i == 0).sum() }; + | ^^^^^^^^^^ help: replace with: `n.is_multiple_of(*i)` + +error: aborting due to 11 previous errors