Auto merge of #75815 - jyn514:ambiguous-primitives, r=guillaumegomez

Report an ambiguity if both modules and primitives are in scope for intra-doc links

Closes #75381

- Add a new `prim@` disambiguator, since both modules and primitives are in the same namespace
- Refactor `report_ambiguity` into a closure

Additionally, I noticed that rustdoc would previously allow `[struct@char]` if `char` resolved to a primitive (not if it had a DefId). I fixed that and added a test case.

I also need to update libstd to use `prim@char` instead of `type@char`. If possible I would also like to refactor `ambiguity_error` to use `Disambiguator` instead of its own hand-rolled match - that ran into issues with `prim@` (I updated one and not the other) and it would be better for them to be in sync.

library/alloc/src/string.rs

@@ -268,8 +268,8 @@ use crate::vec::Vec;
 ///
 /// Here, there's no need to allocate more memory inside the loop.
 ///
-/// [`str`]: type@str
-/// [`&str`]: type@str
+/// [`str`]: prim@str
+/// [`&str`]: prim@str
 /// [`Deref`]: core::ops::Deref
 /// [`as_str()`]: String::as_str
 #[derive(PartialOrd, Eq, Ord)]
@@ -296,7 +296,7 @@ pub struct String {
 ///
 /// [`Utf8Error`]: core::str::Utf8Error
 /// [`std::str`]: core::str
-/// [`&str`]: str
+/// [`&str`]: prim@str
 /// [`utf8_error`]: Self::utf8_error
 ///
 /// # Examples
@@ -472,7 +472,7 @@ impl String {
     ///
     /// [`from_utf8_unchecked`]: String::from_utf8_unchecked
     /// [`Vec<u8>`]: crate::vec::Vec
-    /// [`&str`]: str
+    /// [`&str`]: prim@str
     /// [`into_bytes`]: String::into_bytes
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -1576,6 +1576,8 @@ impl String {
     ///
     /// This will drop any excess capacity.
     ///
+    /// [`str`]: prim@str
+    ///
     /// # Examples
     ///
     /// Basic usage:
@@ -1644,7 +1646,7 @@ impl FromUtf8Error {
     /// on using it.
     ///
     /// [`std::str`]: core::str
-    /// [`&str`]: str
+    /// [`&str`]: prim@str
     ///
     /// # Examples
     ///

library/core/src/str/mod.rs

@@ -476,6 +476,7 @@ Section: Iterators
 /// This struct is created by the [`chars`] method on [`str`].
 /// See its documentation for more.
 ///
+/// [`char`]: prim@char
 /// [`chars`]: str::chars
 #[derive(Clone)]
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -673,6 +674,7 @@ impl<'a> Chars<'a> {
 /// This struct is created by the [`char_indices`] method on [`str`].
 /// See its documentation for more.
 ///
+/// [`char`]: prim@char
 /// [`char_indices`]: str::char_indices
 #[derive(Clone, Debug)]
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -2270,6 +2272,8 @@ impl str {
     /// This length is in bytes, not [`char`]s or graphemes. In other words,
     /// it may not be what a human considers the length of the string.
     ///
+    /// [`char`]: prim@char
+    ///
     /// # Examples
     ///
     /// Basic usage:
@@ -2791,7 +2795,9 @@ impl str {
     /// assert_eq!(None, chars.next());
     /// ```
     ///
-    /// Remember, [`char`]s may not match your human intuition about characters:
+    /// Remember, [`char`]s may not match your intuition about characters:
+    ///
+    /// [`char`]: prim@char
     ///
     /// ```
     /// let y = "y̆";
@@ -2842,7 +2848,9 @@ impl str {
     /// assert_eq!(None, char_indices.next());
     /// ```
     ///
-    /// Remember, [`char`]s may not match your human intuition about characters:
+    /// Remember, [`char`]s may not match your intuition about characters:
+    ///
+    /// [`char`]: prim@char
     ///
     /// ```
     /// let yes = "y̆es";
@@ -3053,6 +3061,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -3079,6 +3088,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -3104,6 +3114,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -3132,6 +3143,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -3179,6 +3191,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -3225,6 +3238,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Iterator behavior
@@ -3344,6 +3358,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -3383,6 +3398,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Iterator behavior
@@ -3434,6 +3450,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// Equivalent to [`split`], except that the trailing substring
@@ -3478,6 +3495,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// Equivalent to [`split`], except that the trailing substring is
@@ -3526,6 +3544,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Iterator behavior
@@ -3578,6 +3597,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Iterator behavior
@@ -3666,6 +3686,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Iterator behavior
@@ -3702,6 +3723,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Iterator behavior
@@ -3743,6 +3765,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Iterator behavior
@@ -3785,6 +3808,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Iterator behavior
@@ -4003,6 +4027,7 @@ impl str {
     /// The [pattern] can be a [`char`], a slice of [`char`]s, or a function
     /// or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -4050,6 +4075,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Text directionality
@@ -4094,6 +4120,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -4121,6 +4148,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Examples
@@ -4147,6 +4175,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Text directionality
@@ -4195,6 +4224,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Text directionality
@@ -4231,6 +4261,7 @@ impl str {
     /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
     /// function or closure that determines if a character matches.
     ///
+    /// [`char`]: prim@char
     /// [pattern]: self::pattern
     ///
     /// # Text directionality

library/std/src/error.rs

@@ -296,6 +296,8 @@ impl From<String> for Box<dyn Error> {
 impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
     /// Converts a [`str`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
     ///
+    /// [`str`]: prim@str
+    ///
     /// # Examples
     ///
     /// ```
@@ -317,6 +319,8 @@ impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
 impl From<&str> for Box<dyn Error> {
     /// Converts a [`str`] into a box of dyn [`Error`].
     ///
+    /// [`str`]: prim@str
+    ///
     /// # Examples
     ///
     /// ```

library/std/src/ffi/c_str.rs

@@ -69,7 +69,7 @@ use crate::sys;
 /// extern functions. See the documentation for that function for a
 /// discussion on ensuring the lifetime of the raw pointer.
 ///
-/// [`&str`]: str
+/// [`&str`]: prim@str
 /// [slice.as_ptr]: ../primitive.slice.html#method.as_ptr
 /// [slice.len]: ../primitive.slice.html#method.len
 /// [`Deref`]: ops::Deref
@@ -180,7 +180,7 @@ pub struct CString {
 /// println!("string: {}", my_string_safe());
 /// ```
 ///
-/// [`&str`]: str
+/// [`&str`]: prim@str
 #[derive(Hash)]
 #[stable(feature = "rust1", since = "1.0.0")]
 // FIXME:
@@ -1351,7 +1351,7 @@ impl CStr {
     /// function will return the corresponding [`&str`] slice. Otherwise,
     /// it will return an error with details of where UTF-8 validation failed.
     ///
-    /// [`&str`]: str
+    /// [`&str`]: prim@str
     ///
     /// # Examples
     ///
@@ -1379,6 +1379,7 @@ impl CStr {
     /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD] and return a
     /// [`Cow`]`::`[`Owned`]`(`[`String`]`)` with the result.
     ///
+    /// [`str`]: prim@str
     /// [`Borrowed`]: Cow::Borrowed
     /// [`Owned`]: Cow::Owned
     /// [U+FFFD]: crate::char::REPLACEMENT_CHARACTER

library/std/src/io/mod.rs

@@ -480,7 +480,7 @@ where
 /// ```
 ///
 /// [`read()`]: Read::read
-/// [`&str`]: str
+/// [`&str`]: prim@str
 /// [`std::io`]: self
 /// [`File`]: crate::fs::File
 /// [slice]: ../../std/primitive.slice.html

library/std/src/lib.rs

@@ -172,6 +172,7 @@
 //! [`Vec<T>`]: vec::Vec
 //! [`atomic`]: sync::atomic
 //! [`for`]: ../book/ch03-05-control-flow.html#looping-through-a-collection-with-for
+//! [`str`]: prim@str
 //! [`mpsc`]: sync::mpsc
 //! [`std::cmp`]: cmp
 //! [`std::slice`]: slice

src/doc/rustdoc/src/unstable-features.md

@@ -81,7 +81,7 @@ impl<T> AsyncReceiver<T> {
 }
 ```
 
-Paths in Rust have three namespaces: type, value, and macro. Items from these namespaces are allowed to overlap. In case of ambiguity, rustdoc will warn about the ambiguity and ask you to disambiguate, which can be done by using a prefix like `struct@`, `enum@`, `type@`, `trait@`, `union@`, `const@`, `static@`, `value@`, `function@`, `mod@`, `fn@`, `module@`, `method@` , `macro@`, or `derive@`:
+Paths in Rust have three namespaces: type, value, and macro. Items from these namespaces are allowed to overlap. In case of ambiguity, rustdoc will warn about the ambiguity and ask you to disambiguate, which can be done by using a prefix like `struct@`, `enum@`, `type@`, `trait@`, `union@`, `const@`, `static@`, `value@`, `function@`, `mod@`, `fn@`, `module@`, `method@`, `prim@`, `primitive@`, `macro@`, or `derive@`:
 
 ```rust
 /// See also: [`Foo`](struct@Foo)