Add rustdoc-json support for use<>

rustfmt.toml

@@ -22,6 +22,7 @@ ignore = [
     "/tests/rustdoc-ui/",             # Some have syntax errors, some are whitespace-sensitive.
     "/tests/ui/",                     # Some have syntax errors, some are whitespace-sensitive.
     "/tests/ui-fulldeps/",            # Some are whitespace-sensitive (e.g. `// ~ERROR` comments).
+    "/tests/rustdoc-json/impl-trait-precise-capturing.rs",
 
     # Do not format submodules.
     # FIXME: sync submodule list with tidy/bootstrap/etc

src/librustdoc/json/conversions.rs

@@ -542,6 +542,7 @@ impl FromWithTcx<clean::GenericBound> for GenericBound {
                 }
             }
             Outlives(lifetime) => GenericBound::Outlives(convert_lifetime(lifetime)),
+            Use(args) => GenericBound::Use(args.into_iter().map(|arg| arg.to_string()).collect()),
         }
     }
 }

src/rustdoc-json-types/lib.rs

@@ -8,7 +8,7 @@ use serde::{Deserialize, Serialize};
 use std::path::PathBuf;
 
 /// rustdoc format-version.
-pub const FORMAT_VERSION: u32 = 31;
+pub const FORMAT_VERSION: u32 = 32;
 
 /// A `Crate` is the root of the emitted JSON blob. It contains all type/documentation information
 /// about the language items in the local crate, as well as info about external items to allow
@@ -538,6 +538,8 @@ pub enum GenericBound {
         modifier: TraitBoundModifier,
     },
     Outlives(String),
+    /// `use<'a, T>` precise-capturing bound syntax
+    Use(Vec<String>),
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]

src/tools/jsondoclint/src/validator.rs

@@ -298,6 +298,7 @@ impl<'a> Validator<'a> {
                 generic_params.iter().for_each(|gpd| self.check_generic_param_def(gpd));
             }
             GenericBound::Outlives(_) => {}
+            GenericBound::Use(_) => {}
         }
     }
 

tests/rustdoc-json/impl-trait-precise-capturing.rs

@@ -0,0 +1,6 @@
+#![feature(precise_capturing)]
+
+// @is "$.index[*][?(@.name=='hello')].inner.function.decl.output.impl_trait[1].use[0]" \"\'a\"
+// @is "$.index[*][?(@.name=='hello')].inner.function.decl.output.impl_trait[1].use[1]" \"T\"
+// @is "$.index[*][?(@.name=='hello')].inner.function.decl.output.impl_trait[1].use[2]" \"N\"
+pub fn hello<'a, T, const N: usize>() -> impl Sized + use<'a, T, N> {}