Go into more detail about panicking in drop.

This commit is contained in:
Kevin Reid 2023-08-18 07:12:09 -07:00
parent b9177c0adb
commit 2bccf1e296

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@ -217,8 +217,13 @@ pub trait Drop {
///
/// # Panics
///
/// Given that a [`panic!`] will call `drop` as it unwinds, any [`panic!`]
/// in a `drop` implementation will likely abort.
/// Implementations should generally avoid [`panic!`]ing, because `drop()` may itself be called
/// during unwinding due to a panic, and if the `drop()` panics in that situation (a “double
/// panic”), this will likely abort the program. It is possible to check [`panicking()`] first,
/// which may be desirable for a `Drop` implementation that is reporting a bug of the kind
/// “you didn't finish using this before it was dropped”; but most types should simply clean up
/// their owned allocations or other resources and return normally from `drop()`, regardless of
/// what state they are in.
///
/// Note that even if this panics, the value is considered to be dropped;
/// you must not cause `drop` to be called again. This is normally automatically
@ -227,6 +232,7 @@ pub trait Drop {
///
/// [E0040]: ../../error_codes/E0040.html
/// [`panic!`]: crate::panic!
/// [`panicking()`]: ../../std/thread/fn.panicking.html
/// [`mem::drop`]: drop
/// [`ptr::drop_in_place`]: crate::ptr::drop_in_place
#[stable(feature = "rust1", since = "1.0.0")]