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 https://github.com/rust-lang/rust/issues/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.

3 files changed, 91 insertions, 8 deletions

diff --git a/src/test/rustdoc-ui/intra-link-prim-conflict.rs b/src/test/rustdoc-ui/intra-link-prim-conflict.rs
new file mode 100644
index 00000000000..34276fbcf20
--- /dev/null
+++ b/src/test/rustdoc-ui/intra-link-prim-conflict.rs
@@ -0,0 +1,30 @@
+#![deny(broken_intra_doc_links)]
+//~^ NOTE lint level is defined
+
+/// [char]
+//~^ ERROR both a module and a builtin type
+//~| NOTE ambiguous link
+//~| HELP to link to the module
+//~| HELP to link to the builtin type
+
+/// [type@char]
+//~^ ERROR both a module and a builtin type
+//~| NOTE ambiguous link
+//~| HELP to link to the module
+//~| HELP to link to the builtin type
+
+/// [mod@char] // ok
+/// [prim@char] // ok
+
+/// [struct@char]
+//~^ ERROR incompatible link
+//~| HELP use its disambiguator
+//~| NOTE resolved to a module
+pub mod char {}
+
+pub mod inner {
+    //! [struct@char]
+    //~^ ERROR incompatible link
+    //~| HELP use its disambiguator
+    //~| NOTE resolved to a builtin type
+}
diff --git a/src/test/rustdoc-ui/intra-link-prim-conflict.stderr b/src/test/rustdoc-ui/intra-link-prim-conflict.stderr
new file mode 100644
index 00000000000..b28a4426666
--- /dev/null
+++ b/src/test/rustdoc-ui/intra-link-prim-conflict.stderr
@@ -0,0 +1,53 @@
+error: `char` is both a module and a builtin type
+  --> $DIR/intra-link-prim-conflict.rs:4:6
+   |
+LL | /// [char]
+   |      ^^^^ ambiguous link
+   |
+note: the lint level is defined here
+  --> $DIR/intra-link-prim-conflict.rs:1:9
+   |
+LL | #![deny(broken_intra_doc_links)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^
+help: to link to the module, prefix with the item type
+   |
+LL | /// [module@char]
+   |      ^^^^^^^^^^^
+help: to link to the builtin type, prefix with the item type
+   |
+LL | /// [prim@char]
+   |      ^^^^^^^^^
+
+error: `char` is both a module and a builtin type
+  --> $DIR/intra-link-prim-conflict.rs:10:6
+   |
+LL | /// [type@char]
+   |      ^^^^^^^^^ ambiguous link
+   |
+help: to link to the module, prefix with the item type
+   |
+LL | /// [module@char]
+   |      ^^^^^^^^^^^
+help: to link to the builtin type, prefix with the item type
+   |
+LL | /// [prim@char]
+   |      ^^^^^^^^^
+
+error: incompatible link kind for `char`
+  --> $DIR/intra-link-prim-conflict.rs:19:6
+   |
+LL | /// [struct@char]
+   |      ^^^^^^^^^^^ help: to link to the module, use its disambiguator: `mod@char`
+   |
+   = note: this link resolved to a module, which is not a struct
+
+error: incompatible link kind for `char`
+  --> $DIR/intra-link-prim-conflict.rs:26:10
+   |
+LL |     //! [struct@char]
+   |          ^^^^^^^^^^^ help: to link to the builtin type, use its disambiguator: `prim@char`
+   |
+   = note: this link resolved to a builtin type, which is not a struct
+
+error: aborting due to 4 previous errors
+
diff --git a/src/test/rustdoc/intra-link-prim-precedence.rs b/src/test/rustdoc/intra-link-prim-precedence.rs
index 15ea1232fd6..0a4e57ef643 100644
--- a/src/test/rustdoc/intra-link-prim-precedence.rs
+++ b/src/test/rustdoc/intra-link-prim-precedence.rs
@@ -1,17 +1,17 @@
 // ignore-tidy-linelength
 #![deny(broken_intra_doc_links)]
 
-pub mod char {}
+pub mod char {
+    /// [char]
+    // @has intra_link_prim_precedence/char/struct.Inner.html '//a/@href' 'https://doc.rust-lang.org/nightly/std/primitive.char.html'
+    pub struct Inner;
+}
 
-/// See also [type@char]
+/// See [prim@char]
 // @has intra_link_prim_precedence/struct.MyString.html '//a/@href' 'https://doc.rust-lang.org/nightly/std/primitive.char.html'
 pub struct MyString;
 
-/// See also [char]
-// @has intra_link_prim_precedence/struct.MyString2.html '//a/@href' 'https://doc.rust-lang.org/nightly/std/primitive.char.html'
-pub struct MyString2;
-
 /// See also [crate::char] and [mod@char]
-// @has intra_link_prim_precedence/struct.MyString3.html '//*[@href="../intra_link_prim_precedence/char/index.html"]' 'crate::char'
+// @has intra_link_prim_precedence/struct.MyString2.html '//*[@href="../intra_link_prim_precedence/char/index.html"]' 'crate::char'
 // @has - '//*[@href="../intra_link_prim_precedence/char/index.html"]' 'mod@char'
-pub struct MyString3;
+pub struct MyString2;