rustdoc: get unnormalized link destination for suggestions

Fixes #110111

This bug, and the workaround in this commit, is closely linked to
[raphlinus/pulldown-cmark#441], getting offsets of link
components. In particular, pulldown-cmark doesn't provide the
offsets of the contents of a link.

To work around this, rustdoc parser parts of a link definition
itself.

[raphlinus/pulldown-cmark#441]: https://github.com/raphlinus/pulldown-cmark/issues/441

3 files changed, 416 insertions, 3 deletions

diff --git a/tests/rustdoc-ui/intra-doc/issue-110495-suffix-with-space.stderr b/tests/rustdoc-ui/intra-doc/issue-110495-suffix-with-space.stderr
index 8669b0c2086..6c834fd0a1b 100644
--- a/tests/rustdoc-ui/intra-doc/issue-110495-suffix-with-space.stderr
+++ b/tests/rustdoc-ui/intra-doc/issue-110495-suffix-with-space.stderr
@@ -36,7 +36,7 @@ LL | //! [`Clone ()`].
 help: to link to the trait, prefix with `trait@`
    |
 LL - //! [`Clone ()`].
-LL + //! [`trait@Clone (`].
+LL + //! [`trait@Clone `].
    |
 
 error: incompatible link kind for `Clone`
@@ -47,8 +47,9 @@ LL | //! [`Clone !`].
    |
 help: to link to the derive macro, prefix with `derive@`
    |
-LL | //! [`derive@Clone !`].
-   |       +++++++
+LL - //! [`Clone !`].
+LL + //! [`derive@Clone `].
+   |
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/rustdoc-ui/intra-doc/weird-syntax.rs b/tests/rustdoc-ui/intra-doc/weird-syntax.rs
new file mode 100644
index 00000000000..ca18842fb21
--- /dev/null
+++ b/tests/rustdoc-ui/intra-doc/weird-syntax.rs
@@ -0,0 +1,140 @@
+// Many examples are from
+// https://github.com/rust-lang/rust/issues/110111#issuecomment-1517800781
+#![deny(rustdoc::broken_intra_doc_links)]
+
+//! This test case is closely linked to [raphlinus/pulldown-cmark#441], getting offsets of
+//! link components. In particular, pulldown-cmark doesn't provide the offsets of the contents
+//! of a link.
+//!
+//! To work around this, rustdoc parses parts of a link definition itself. This is basically a
+//! test suite for that link syntax parser.
+//!
+//! [raphlinus/pulldown-cmark#441]: https://github.com/raphlinus/pulldown-cmark/issues/441
+
+use std::clone::Clone;
+
+// Basic version //
+
+/// [`struct@Clone`] //~ERROR link
+pub struct LinkToCloneWithBackquotes;
+
+/// [```struct@Clone```] //~ERROR link
+pub struct LinkToCloneWithMultipleBackquotes;
+
+/// [  `  struct@Clone  `  ] //~ERROR link
+pub struct LinkToCloneWithSpacesAndBackquotes;
+
+/// [  `Clone ()`  ] //~ERROR link
+pub struct LinkToCloneWithSpacesBackquotesAndParens;
+
+/// [`Clone ()`  ] //~ERROR link
+pub struct LinkToCloneWithSpacesEndBackquotesAndParens;
+
+/// [  `Clone ()`] //~ERROR link
+pub struct LinkToCloneWithSpacesStartBackquotesAndParens;
+
+/// [```Clone ()```] //~ERROR link
+pub struct LinkToCloneWithMultipleBackquotesAndParens;
+
+/// [```Clone \(\)```] // not URL-shaped enough
+pub struct LinkToCloneWithMultipleBackquotesAndEscapedParens;
+
+/// [  ```  Clone ()  ```  ] //~ERROR link
+pub struct LinkToCloneWithSpacesMultipleBackquotesAndParens;
+
+/// [ x \] ] // not URL-shaped enough
+pub struct LinkWithEscapedCloseBrace;
+
+/// [ x \[ ] // not URL-shaped enough
+pub struct LinkWithEscapedOpenBrace;
+
+/// [ x \( ] // not URL-shaped enough
+pub struct LinkWithEscapedCloseParen;
+
+/// [ x \) ] // not URL-shaped enough
+pub struct LinkWithEscapedOpenParen;
+
+/// [ Clone \(\) ] // not URL-shaped enough
+pub struct LinkWithEscapedParens;
+
+// [][] version //
+
+/// [x][ struct@Clone] //~ERROR link
+pub struct XLinkToCloneWithStartSpace;
+
+/// [x][struct@Clone ] //~ERROR link
+pub struct XLinkToCloneWithEndSpace;
+
+/// [x][Clone\(\)] not URL-shaped enough
+pub struct XLinkToCloneWithEscapedParens;
+
+/// [x][`Clone`] not URL-shaped enough
+pub struct XLinkToCloneWithBackquotes;
+
+/// [x][Clone()] //~ERROR link
+pub struct XLinkToCloneWithUnescapedParens;
+
+/// [x][Clone  ()] //~ERROR link
+pub struct XLinkToCloneWithUnescapedParensAndDoubleSpace;
+
+/// [x][Clone  [] //~ERROR unresolved link to `x`
+pub struct XLinkToCloneWithUnmatchedOpenParenAndDoubleSpace;
+
+/// [x][Clone  \[] // not URL-shaped enough
+pub struct XLinkToCloneWithUnmatchedEscapedOpenParenAndDoubleSpace;
+
+/// [x][Clone  \]] // not URL-shaped enough
+pub struct XLinkToCloneWithUnmatchedEscapedCloseParenAndDoubleSpace;
+
+// []() version //
+
+/// [w]( struct@Clone) //~ERROR link
+pub struct WLinkToCloneWithStartSpace;
+
+/// [w](struct@Clone ) //~ERROR link
+pub struct WLinkToCloneWithEndSpace;
+
+/// [w](Clone\(\)) //~ERROR link
+pub struct WLinkToCloneWithEscapedParens;
+
+/// [w](`Clone`) not URL-shaped enough
+pub struct WLinkToCloneWithBackquotes;
+
+/// [w](Clone()) //~ERROR link
+pub struct WLinkToCloneWithUnescapedParens;
+
+/// [w](Clone  ()) not URL-shaped enough
+pub struct WLinkToCloneWithUnescapedParensAndDoubleSpace;
+
+/// [w](Clone  () //~ERROR unresolved link to `w`
+pub struct WLinkToCloneWithUnmatchedOpenParenAndDoubleSpace;
+
+/// [w](Clone  \() //~ERROR unresolved link to `w`
+pub struct WLinkToCloneWithUnmatchedEscapedOpenParenAndDoubleSpace;
+
+/// [w](Clone  \)) //~ERROR unresolved link to `w`
+pub struct WLinkToCloneWithUnmatchedEscapedCloseParenAndDoubleSpace;
+
+// References
+
+/// The [cln][] link here is going to be unresolved, because `Clone()` gets rejected //~ERROR link
+/// in Markdown for not being URL-shaped enough.
+///
+/// [cln]: Clone() //~ERROR link
+pub struct LinkToCloneWithParensInReference;
+
+/// The [cln][] link here is going to be unresolved, because `struct@Clone` gets //~ERROR link
+/// rejected in Markdown for not being URL-shaped enough.
+///
+/// [cln]: struct@Clone //~ERROR link
+pub struct LinkToCloneWithWrongPrefix;
+
+/// The [cln][] link here will produce a plain text suggestion //~ERROR link
+///
+/// [cln]: Clone\(\)
+pub struct LinkToCloneWithEscapedParensInReference;
+
+/// The [cln][] link here will produce a plain text suggestion //~ERROR link
+///
+/// [cln]: struct\@Clone
+pub struct LinkToCloneWithEscapedAtsInReference;
diff --git a/tests/rustdoc-ui/intra-doc/weird-syntax.stderr b/tests/rustdoc-ui/intra-doc/weird-syntax.stderr
new file mode 100644
index 00000000000..f50feb57fcc
--- /dev/null
+++ b/tests/rustdoc-ui/intra-doc/weird-syntax.stderr
@@ -0,0 +1,272 @@
+error: incompatible link kind for `Clone`
+  --> $DIR/weird-syntax.rs:18:7
+   |
+LL | /// [`struct@Clone`]
+   |       ^^^^^^^^^^^^ this link resolved to a trait, which is not a struct
+   |
+note: the lint level is defined here
+  --> $DIR/weird-syntax.rs:3:9
+   |
+LL | #![deny(rustdoc::broken_intra_doc_links)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: to link to the trait, prefix with `trait@`
+   |
+LL | /// [`trait@Clone`]
+   |       ~~~~~~
+
+error: incompatible link kind for `Clone`
+  --> $DIR/weird-syntax.rs:21:9
+   |
+LL | /// [```struct@Clone```]
+   |         ^^^^^^^^^^^^ this link resolved to a trait, which is not a struct
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL | /// [```trait@Clone```]
+   |         ~~~~~~
+
+error: incompatible link kind for `Clone`
+  --> $DIR/weird-syntax.rs:24:11
+   |
+LL | /// [  `  struct@Clone  `  ]
+   |           ^^^^^^^^^^^^ this link resolved to a trait, which is not a struct
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL | /// [  `  trait@Clone  `  ]
+   |           ~~~~~~
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:27:9
+   |
+LL | /// [  `Clone ()`  ]
+   |         ^^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [  `Clone ()`  ]
+LL + /// [  `trait@Clone `  ]
+   |
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:30:7
+   |
+LL | /// [`Clone ()`  ]
+   |       ^^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [`Clone ()`  ]
+LL + /// [`trait@Clone `  ]
+   |
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:33:9
+   |
+LL | /// [  `Clone ()`]
+   |         ^^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [  `Clone ()`]
+LL + /// [  `trait@Clone `]
+   |
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:36:9
+   |
+LL | /// [```Clone ()```]
+   |         ^^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [```Clone ()```]
+LL + /// [```trait@Clone ```]
+   |
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:42:13
+   |
+LL | /// [  ```  Clone ()  ```  ]
+   |             ^^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [  ```  Clone ()  ```  ]
+LL + /// [  ```  trait@Clone   ```  ]
+   |
+
+error: incompatible link kind for `Clone`
+  --> $DIR/weird-syntax.rs:62:10
+   |
+LL | /// [x][ struct@Clone]
+   |          ^^^^^^^^^^^^ this link resolved to a trait, which is not a struct
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL | /// [x][ trait@Clone]
+   |          ~~~~~~
+
+error: incompatible link kind for `Clone`
+  --> $DIR/weird-syntax.rs:65:9
+   |
+LL | /// [x][struct@Clone ]
+   |         ^^^^^^^^^^^^ this link resolved to a trait, which is not a struct
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL | /// [x][trait@Clone ]
+   |         ~~~~~~
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:74:9
+   |
+LL | /// [x][Clone()]
+   |         ^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [x][Clone()]
+LL + /// [x][trait@Clone]
+   |
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:77:9
+   |
+LL | /// [x][Clone  ()]
+   |         ^^^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [x][Clone  ()]
+LL + /// [x][trait@Clone  ]
+   |
+
+error: unresolved link to `x`
+  --> $DIR/weird-syntax.rs:80:6
+   |
+LL | /// [x][Clone  []
+   |      ^ no item named `x` in scope
+   |
+   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+
+error: incompatible link kind for `Clone`
+  --> $DIR/weird-syntax.rs:91:10
+   |
+LL | /// [w]( struct@Clone)
+   |          ^^^^^^^^^^^^ this link resolved to a trait, which is not a struct
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL | /// [w]( trait@Clone)
+   |          ~~~~~~
+
+error: incompatible link kind for `Clone`
+  --> $DIR/weird-syntax.rs:94:9
+   |
+LL | /// [w](struct@Clone )
+   |         ^^^^^^^^^^^^ this link resolved to a trait, which is not a struct
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL | /// [w](trait@Clone )
+   |         ~~~~~~
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:97:9
+   |
+LL | /// [w](Clone\(\))
+   |         ^^^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [w](Clone\(\))
+LL + /// [w](trait@Clone)
+   |
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:103:9
+   |
+LL | /// [w](Clone())
+   |         ^^^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+help: to link to the trait, prefix with `trait@`
+   |
+LL - /// [w](Clone())
+LL + /// [w](trait@Clone)
+   |
+
+error: unresolved link to `w`
+  --> $DIR/weird-syntax.rs:109:6
+   |
+LL | /// [w](Clone  ()
+   |      ^ no item named `w` in scope
+   |
+   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+
+error: unresolved link to `w`
+  --> $DIR/weird-syntax.rs:112:6
+   |
+LL | /// [w](Clone  \()
+   |      ^ no item named `w` in scope
+   |
+   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+
+error: unresolved link to `w`
+  --> $DIR/weird-syntax.rs:115:6
+   |
+LL | /// [w](Clone  \))
+   |      ^ no item named `w` in scope
+   |
+   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+
+error: unresolved link to `cln`
+  --> $DIR/weird-syntax.rs:120:10
+   |
+LL | /// The [cln][] link here is going to be unresolved, because `Clone()` gets rejected
+   |          ^^^ no item named `cln` in scope
+   |
+   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+
+error: unresolved link to `cln`
+  --> $DIR/weird-syntax.rs:123:6
+   |
+LL | /// [cln]: Clone()
+   |      ^^^ no item named `cln` in scope
+   |
+   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+
+error: unresolved link to `cln`
+  --> $DIR/weird-syntax.rs:126:10
+   |
+LL | /// The [cln][] link here is going to be unresolved, because `struct@Clone` gets
+   |          ^^^ no item named `cln` in scope
+   |
+   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+
+error: unresolved link to `cln`
+  --> $DIR/weird-syntax.rs:129:6
+   |
+LL | /// [cln]: struct@Clone
+   |      ^^^ no item named `cln` in scope
+   |
+   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+
+error: unresolved link to `Clone`
+  --> $DIR/weird-syntax.rs:132:9
+   |
+LL | /// The [cln][] link here will produce a plain text suggestion
+   |         ^^^^^ this link resolves to the trait `Clone`, which is not in the value namespace
+   |
+   = help: to link to the trait, prefix with `trait@`: trait@Clone
+
+error: incompatible link kind for `Clone`
+  --> $DIR/weird-syntax.rs:137:9
+   |
+LL | /// The [cln][] link here will produce a plain text suggestion
+   |         ^^^^^ this link resolved to a trait, which is not a struct
+   |
+   = help: to link to the trait, prefix with `trait@`: trait@Clone
+
+error: aborting due to 26 previous errors
+