diff options
| -rw-r--r-- | library/core/src/any.rs | 39 | ||||
| -rw-r--r-- | tests/ui/hygiene/cross-crate-define-and-use.rs | 1 |
2 files changed, 18 insertions, 22 deletions
diff --git a/library/core/src/any.rs b/library/core/src/any.rs index 8f5404d9713..8c18788e591 100644 --- a/library/core/src/any.rs +++ b/library/core/src/any.rs @@ -690,44 +690,41 @@ 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. -/// -/// This function does not resolve trait objects, -/// meaning that `type_name_of_val(&7u32 as &dyn Debug)` -/// may return `"dyn Debug"`, but not `"u32"`. +/// 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. /// -/// The type name should not be considered a unique identifier of a type; -/// multiple types may share the same type name. +/// In short: use this for debugging, avoid using the output to affect program behavior. More +/// information is available at [`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 = "CURRENT_RUSTC_VERSION")] #[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>() diff --git a/tests/ui/hygiene/cross-crate-define-and-use.rs b/tests/ui/hygiene/cross-crate-define-and-use.rs index 94f1adff626..62b1820235c 100644 --- a/tests/ui/hygiene/cross-crate-define-and-use.rs +++ b/tests/ui/hygiene/cross-crate-define-and-use.rs @@ -6,7 +6,6 @@ // check-pass // aux-build:use_by_macro.rs -#![feature(type_name_of_val)] extern crate use_by_macro; use use_by_macro::*; |