Auto merge of #109802 - notriddle:notriddle/rustdoc-search-generics-nested, r=GuillaumeGomez

rustdoc-search: add support for nested generics

This change allows `search.js` to parse nested generics (which look `Like<This<Example>>`) and match them. It maintains the existing "bag semantics", so that the order of type parameters is ignored but the number is required to be greater than or equal to what's in the query.

For example, a function with the signature `fn read_all(&mut self: impl Read) -> Result<Vec<u8>, Error>` will match these queries:

* `Read -> Result<Vec<u8>, Error>`
* `Read -> Result<Error, Vec>`
* `Read -> Result<Vec<u8>>`

But it *does not* match `Result<Vec, u8>` or `Result<u8<Vec>>`.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/doc/rustdoc/src/how-to-read-rustdoc.md b/src/doc/rustdoc/src/how-to-read-rustdoc.md
index 2957916d56c..56342f65d99 100644
--- a/src/doc/rustdoc/src/how-to-read-rustdoc.md
+++ b/src/doc/rustdoc/src/how-to-read-rustdoc.md
@@ -94,6 +94,17 @@ can be matched with the following queries:
 * `trait:Iterator<primitive:u32> -> primitive:usize`
 * `Iterator -> usize`
 
+Generics and function parameters are order-agnostic, but sensitive to nesting
+and number of matches. For example, a function with the signature
+`fn read_all(&mut self: impl Read) -> Result<Vec<u8>, Error>`
+will match these queries:
+
+* `Read -> Result<Vec<u8>, Error>`
+* `Read -> Result<Error, Vec>`
+* `Read -> Result<Vec<u8>>`
+
+But it *does not* match `Result<Vec, u8>` or `Result<u8<Vec>>`.
+
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