rustdoc-json: Fix HRTBs for WherePredicate::BoundPredicate

src/librustdoc/json/conversions.rs

@@ -350,10 +350,16 @@ impl FromWithTcx<clean::WherePredicate> for WherePredicate {
     fn from_tcx(predicate: clean::WherePredicate, tcx: TyCtxt<'_>) -> Self {
         use clean::WherePredicate::*;
         match predicate {
-            BoundPredicate { ty, bounds, .. } => WherePredicate::BoundPredicate {
+            BoundPredicate { ty, bounds, bound_params } => WherePredicate::BoundPredicate {
                 type_: ty.into_tcx(tcx),
                 bounds: bounds.into_iter().map(|x| x.into_tcx(tcx)).collect(),
-                // FIXME: add `bound_params` to rustdoc-json-params?
+                generic_params: bound_params
+                    .into_iter()
+                    .map(|x| GenericParamDef {
+                        name: x.0.to_string(),
+                        kind: GenericParamDefKind::Lifetime { outlives: vec![] },
+                    })
+                    .collect(),
             },
             RegionPredicate { lifetime, bounds } => WherePredicate::RegionPredicate {
                 lifetime: lifetime.0.to_string(),

src/rustdoc-json-types/lib.rs

@@ -9,7 +9,7 @@ use std::path::PathBuf;
 use serde::{Deserialize, Serialize};
 
 /// rustdoc format-version.
-pub const FORMAT_VERSION: u32 = 14;
+pub const FORMAT_VERSION: u32 = 15;
 
 /// 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
@@ -391,6 +391,14 @@ pub enum WherePredicate {
         #[serde(rename = "type")]
         type_: Type,
         bounds: Vec<GenericBound>,
+        /// Used for Higher-Rank Trait Bounds (HRTBs)
+        /// ```plain
+        /// where for<'a> &'a T: Iterator,"
+        ///       ^^^^^^^
+        ///       |
+        ///       this part
+        /// ```
+        generic_params: Vec<GenericParamDef>,
     },
     RegionPredicate {
         lifetime: String,