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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-19 09:25:53 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-19 09:25:53 +0000 |
commit | 73e0a5b7696ea019ba35b89f38fc8e7b285d99cb (patch) | |
tree | 0d2e175af6f114cb50a675bec0bc76e12e1bceb4 /library/core/src/any.rs | |
parent | Adding upstream version 1.75.0+dfsg1. (diff) | |
download | rustc-upstream.tar.xz rustc-upstream.zip |
Adding upstream version 1.76.0+dfsg1.upstream/1.76.0+dfsg1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/core/src/any.rs')
-rw-r--r-- | library/core/src/any.rs | 44 |
1 files changed, 23 insertions, 21 deletions
diff --git a/library/core/src/any.rs b/library/core/src/any.rs index 8f5404d97..e8f00e876 100644 --- a/library/core/src/any.rs +++ b/library/core/src/any.rs @@ -115,6 +115,11 @@ use crate::intrinsics; pub trait Any: 'static { /// Gets the `TypeId` of `self`. /// + /// If called on a `dyn Any` trait object + /// (or a trait object of a subtrait of `Any`), + /// this returns the `TypeId` of the underlying + /// concrete type, not that of `dyn Any` itself. + /// /// # Examples /// /// ``` @@ -690,44 +695,41 @@ pub const fn type_name<T: ?Sized>() -> &'static str { intrinsics::type_name::<T>() } -/// Returns the name of the type of the pointed-to value as a string slice. +/// Returns the type name of the pointed-to value as a string slice. +/// /// This is the same as `type_name::<T>()`, but can be used where the type of a /// variable is not easily available. /// /// # Note /// -/// This is intended for diagnostic use. The exact contents and format of the -/// string are not specified, other than being a best-effort description of the -/// type. For example, `type_name_of_val::<Option<String>>(None)` could return -/// `"Option<String>"` or `"std::option::Option<std::string::String>"`, but not -/// `"foobar"`. In addition, the output may change between versions of the -/// compiler. +/// Like [`type_name`], this is intended for diagnostic use and the exact output is not +/// guaranteed. It provides a best-effort description, but the output may change between +/// versions of the compiler. /// -/// This function does not resolve trait objects, -/// meaning that `type_name_of_val(&7u32 as &dyn Debug)` -/// may return `"dyn Debug"`, but not `"u32"`. +/// In short: use this for debugging, avoid using the output to affect program behavior. More +/// information is available at [`type_name`]. /// -/// The type name should not be considered a unique identifier of a type; -/// multiple types may share the same type name. -/// -/// The current implementation uses the same infrastructure as compiler -/// diagnostics and debuginfo, but this is not guaranteed. +/// Additionally, this function does not resolve trait objects. This means that +/// `type_name_of_val(&7u32 as &dyn Debug)` may return `"dyn Debug"`, but will not return `"u32"` +/// at this time. /// /// # Examples /// /// Prints the default integer and float types. /// /// ```rust -/// #![feature(type_name_of_val)] /// use std::any::type_name_of_val; /// -/// let x = 1; -/// println!("{}", type_name_of_val(&x)); -/// let y = 1.0; -/// println!("{}", type_name_of_val(&y)); +/// let s = "foo"; +/// let x: i32 = 1; +/// let y: f32 = 1.0; +/// +/// assert!(type_name_of_val(&s).contains("str")); +/// assert!(type_name_of_val(&x).contains("i32")); +/// assert!(type_name_of_val(&y).contains("f32")); /// ``` #[must_use] -#[unstable(feature = "type_name_of_val", issue = "66359")] +#[stable(feature = "type_name_of_val", since = "1.76.0")] #[rustc_const_unstable(feature = "const_type_name", issue = "63084")] pub const fn type_name_of_val<T: ?Sized>(_val: &T) -> &'static str { type_name::<T>() |