From 9278b4c67284db95990673f26934b9d1d5af2e77 Mon Sep 17 00:00:00 2001 From: Jim Turner Date: Mon, 1 Mar 2021 16:09:41 -0500 Subject: [PATCH] Document panicking cases for integer division The panic on division by zero is expected, but the panic on overflow is somewhat surprising (since most arithmetic operations panic on overflow only when `debug_assertions` is enabled). As a result, it's helpful to document this behavior. --- library/core/src/ops/arith.rs | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/library/core/src/ops/arith.rs b/library/core/src/ops/arith.rs index 92090d8e6fca..da0f038e44e7 100644 --- a/library/core/src/ops/arith.rs +++ b/library/core/src/ops/arith.rs @@ -456,9 +456,13 @@ pub trait Div { } macro_rules! div_impl_integer { - ($($t:ty)*) => ($( + ($(($($t:ty)*) => $panic:expr),*) => ($($( /// This operation rounds towards zero, truncating any /// fractional part of the exact result. + /// + /// # Panics + /// + #[doc = $panic] #[stable(feature = "rust1", since = "1.0.0")] impl Div for $t { type Output = $t; @@ -468,10 +472,13 @@ macro_rules! div_impl_integer { } forward_ref_binop! { impl Div, div for $t, $t } - )*) + )*)*) } -div_impl_integer! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } +div_impl_integer! { + (usize u8 u16 u32 u64 u128) => "This operation will panic if `other == 0`.", + (isize i8 i16 i32 i64 i128) => "This operation will panic if `other == 0` or the division results in overflow." +} macro_rules! div_impl_float { ($($t:ty)*) => ($(