Rollup merge of #96647 - Enselic:fix-hrtb-for-wherepredicate, r=CraftSpider

rustdoc-json: Fix HRTBs for WherePredicate::BoundPredicate

Information about HRTBs are already present for `GenericBound:: TraitBound` and `FunctionPointer`. This PR adds HRTB info also to `WherePredicate::BoundPredicate`.

Use the same field name and type as for the other ones (`generic_params: Vec<GenericParamDef>`). I have verified that this gives rustdoc JSON clients the data they need and in a format that is easy to work with (see https://github.com/Enselic/public-api/pull/92).

I will be happy to add tests for this change (and bump `FORMAT_VERSION` which I just realized I forgot), but it is always nice to get one round of feedback first, so that I don't put a lot of effort into tests that then have to be discarded.

`@rustbot` modify labels: +T-rustdoc +A-rustdoc-json

4 files changed, 73 insertions, 8 deletions

diff --git a/src/librustdoc/json/conversions.rs b/src/librustdoc/json/conversions.rs
index 56b02cd8480..412387313dc 100644
--- a/src/librustdoc/json/conversions.rs
+++ b/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(),
diff --git a/src/rustdoc-json-types/lib.rs b/src/rustdoc-json-types/lib.rs
index 17b3859a77b..eb2c8e5bae1 100644
--- a/src/rustdoc-json-types/lib.rs
+++ b/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,
@@ -408,7 +416,13 @@ pub enum GenericBound {
     TraitBound {
         #[serde(rename = "trait")]
         trait_: Type,
-        /// Used for HRTBs
+        /// Used for Higher-Rank Trait Bounds (HRTBs)
+        /// ```plain
+        /// where F: for<'a, 'b> Fn(&'a u8, &'b u8)
+        ///          ^^^^^^^^^^^
+        ///          |
+        ///          this part
+        /// ```
         generic_params: Vec<GenericParamDef>,
         modifier: TraitBoundModifier,
     },
@@ -487,6 +501,13 @@ pub enum Type {
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 pub struct FunctionPointer {
     pub decl: FnDecl,
+    /// Used for Higher-Rank Trait Bounds (HRTBs)
+    /// ```plain
+    /// for<'c> fn(val: &'c i32) -> i32
+    /// ^^^^^^^
+    ///       |
+    ///       this part
+    /// ```
     pub generic_params: Vec<GenericParamDef>,
     pub header: Header,
 }
diff --git a/src/test/rustdoc-json/fn_pointer/generics.rs b/src/test/rustdoc-json/fn_pointer/generics.rs
new file mode 100644
index 00000000000..646f720e663
--- /dev/null
+++ b/src/test/rustdoc-json/fn_pointer/generics.rs
@@ -0,0 +1,14 @@
+// ignore-tidy-linelength
+
+#![feature(no_core)]
+#![no_core]
+
+// @count generics.json "$.index[*][?(@.name=='WithHigherRankTraitBounds')].inner.type.inner.decl.inputs[*]" 1
+// @is - "$.index[*][?(@.name=='WithHigherRankTraitBounds')].inner.type.inner.decl.inputs[0][0]" '"val"'
+// @is - "$.index[*][?(@.name=='WithHigherRankTraitBounds')].inner.type.inner.decl.inputs[0][1].kind" '"borrowed_ref"'
+// @is - "$.index[*][?(@.name=='WithHigherRankTraitBounds')].inner.type.inner.decl.inputs[0][1].inner.lifetime" \"\'c\"
+// @is - "$.index[*][?(@.name=='WithHigherRankTraitBounds')].inner.type.inner.decl.output" '{ "kind": "primitive", "inner": "i32" }'
+// @count - "$.index[*][?(@.name=='WithHigherRankTraitBounds')].inner.type.inner.generic_params[*]" 1
+// @is - "$.index[*][?(@.name=='WithHigherRankTraitBounds')].inner.type.inner.generic_params[0].name" \"\'c\"
+// @is - "$.index[*][?(@.name=='WithHigherRankTraitBounds')].inner.type.inner.generic_params[0].kind" '{ "lifetime": { "outlives": [] } }'
+pub type WithHigherRankTraitBounds = for<'c> fn(val: &'c i32) -> i32;
diff --git a/src/test/rustdoc-json/fns/generic_args.rs b/src/test/rustdoc-json/fns/generic_args.rs
index 3b03724b040..69150443c29 100644
--- a/src/test/rustdoc-json/fns/generic_args.rs
+++ b/src/test/rustdoc-json/fns/generic_args.rs
@@ -6,6 +6,9 @@
 // @set foo = generic_args.json "$.index[*][?(@.name=='Foo')].id"
 pub trait Foo {}
 
+// @set generic_foo = generic_args.json "$.index[*][?(@.name=='GenericFoo')].id"
+pub trait GenericFoo<'a> {}
+
 // @is - "$.index[*][?(@.name=='generics')].inner.generics.where_predicates" "[]"
 // @count - "$.index[*][?(@.name=='generics')].inner.generics.params[*]" 1
 // @is - "$.index[*][?(@.name=='generics')].inner.generics.params[0].name" '"F"'
@@ -29,19 +32,40 @@ pub fn generics<F: Foo>(f: F) {}
 // @is - "$.index[*][?(@.name=='impl_trait')].inner.decl.inputs[0][1].inner[0].trait_bound.trait.inner.id" $foo
 pub fn impl_trait(f: impl Foo) {}
 
-// @count - "$.index[*][?(@.name=='where_clase')].inner.generics.params[*]" 1
+// @count - "$.index[*][?(@.name=='where_clase')].inner.generics.params[*]" 3
 // @is - "$.index[*][?(@.name=='where_clase')].inner.generics.params[0].name" '"F"'
 // @is - "$.index[*][?(@.name=='where_clase')].inner.generics.params[0].kind" '{"type": {"bounds": [], "default": null, "synthetic": false}}'
-// @count - "$.index[*][?(@.name=='where_clase')].inner.decl.inputs[*]" 1
+// @count - "$.index[*][?(@.name=='where_clase')].inner.decl.inputs[*]" 3
 // @is - "$.index[*][?(@.name=='where_clase')].inner.decl.inputs[0][0]" '"f"'
 // @is - "$.index[*][?(@.name=='where_clase')].inner.decl.inputs[0][1].kind" '"generic"'
 // @is - "$.index[*][?(@.name=='where_clase')].inner.decl.inputs[0][1].inner" '"F"'
-// @count - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[*]" 1
+// @count - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[*]" 3
+
 // @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[0].bound_predicate.type" '{"inner": "F", "kind": "generic"}'
 // @count - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[0].bound_predicate.bounds[*]" 1
 // @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[0].bound_predicate.bounds[0].trait_bound.trait.inner.id" $foo
-pub fn where_clase<F>(f: F)
+
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[1].bound_predicate.type" '{"inner": "G", "kind": "generic"}'
+// @count - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[1].bound_predicate.bounds[*]" 1
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[1].bound_predicate.bounds[0].trait_bound.trait.inner.id" $generic_foo
+// @count - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[1].bound_predicate.bounds[0].trait_bound.generic_params[*]" 1
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[1].bound_predicate.bounds[0].trait_bound.generic_params[0].name" \"\'a\"
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[1].bound_predicate.bounds[0].trait_bound.generic_params[0].kind" '{ "lifetime": { "outlives": [] } }'
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[1].bound_predicate.generic_params" "[]"
+
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.type.kind" '"borrowed_ref"'
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.type.inner.lifetime" \"\'b\"
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.type.inner.type" '{"inner": "H", "kind": "generic"}'
+// @count - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.bounds[*]" 1
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.bounds[0].trait_bound.trait.inner.id" $foo
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.bounds[0].trait_bound.generic_params" "[]"
+// @count - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.generic_params[*]" 1
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.generic_params[0].name" \"\'b\"
+// @is - "$.index[*][?(@.name=='where_clase')].inner.generics.where_predicates[2].bound_predicate.generic_params[0].kind" '{ "lifetime": { "outlives": [] } }'
+pub fn where_clase<F, G, H>(f: F, g: G, h: H)
 where
     F: Foo,
+    G: for<'a> GenericFoo<'a>,
+    for<'b> &'b H: Foo,
 {
 }