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

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;