rustdoc: cross-crate re-exports: correctly render late-bound params in source order even if early-bound params are present

Author: fmease

src/librustdoc/clean/auto_trait.rs

@@ -334,7 +334,7 @@ where
                 match br {
                     // We only care about named late bound regions, as we need to add them
                     // to the 'for<>' section
-                    ty::BrNamed(_, name) => Some(GenericParamDef::lifetime(name)),
+                    ty::BrNamed(did, name) => Some(GenericParamDef::lifetime(did, name)),
                     _ => None,
                 }
             })

src/librustdoc/clean/inline.rs

@@ -281,8 +281,12 @@ fn build_external_function<'tcx>(cx: &mut DocContext<'tcx>, did: DefId) -> Box<c
     let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
         // NOTE: generics need to be cleaned before the decl!
         let mut generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
-        // FIXME: This does not place parameters in source order (late-bound ones come last)
         generics.params.extend(clean_bound_vars(sig.bound_vars()));
+        // FIXME(fmease): Does this work in the presence of synthetic params (impl-Trait, host effect)?
+        // FIXME(fmease): Optimization: Don't call def_ident_span on non-lifetime params!
+        if !sig.bound_vars().is_empty() {
+            generics.params.sort_by_key(|param| cx.tcx.def_ident_span(param.did).unwrap());
+        }
         let decl = clean_fn_decl_from_did_and_sig(cx, Some(did), sig);
         (generics, decl)
     });

src/librustdoc/clean/mod.rs

@@ -525,7 +525,6 @@ fn clean_generic_param_def<'tcx>(
             (
                 def.name,
                 GenericParamDefKind::Type {
-                    did: def.def_id,
                     bounds: ThinVec::new(), // These are filled in from the where-clauses.
                     default: default.map(Box::new),
                     synthetic,
@@ -557,7 +556,7 @@ fn clean_generic_param_def<'tcx>(
         ),
     };
 
-    GenericParamDef { name, kind }
+    GenericParamDef { name, did: def.def_id, kind }
 }
 
 fn clean_generic_param<'tcx>(
@@ -596,7 +595,6 @@ fn clean_generic_param<'tcx>(
             (
                 param.name.ident().name,
                 GenericParamDefKind::Type {
-                    did: param.def_id.to_def_id(),
                     bounds,
                     default: default.map(|t| clean_ty(t, cx)).map(Box::new),
                     synthetic,
@@ -614,7 +612,7 @@ fn clean_generic_param<'tcx>(
         ),
     };
 
-    GenericParamDef { name, kind }
+    GenericParamDef { name, did: param.def_id.to_def_id(), kind }
 }
 
 /// Synthetic type-parameters are inserted after normal ones.
@@ -646,8 +644,8 @@ pub(crate) fn clean_generics<'tcx>(
             let param = clean_generic_param(cx, Some(gens), param);
             match param.kind {
                 GenericParamDefKind::Lifetime { .. } => unreachable!(),
-                GenericParamDefKind::Type { did, ref bounds, .. } => {
-                    cx.impl_trait_bounds.insert(did.into(), bounds.to_vec());
+                GenericParamDefKind::Type { ref bounds, .. } => {
+                    cx.impl_trait_bounds.insert(param.did.into(), bounds.to_vec());
                 }
                 GenericParamDefKind::Const { .. } => unreachable!(),
             }
@@ -1064,8 +1062,11 @@ fn clean_fn_decl_legacy_const_generics(func: &mut Function, attrs: &[ast::Attrib
             match literal.kind {
                 ast::LitKind::Int(a, _) => {
                     let gen = func.generics.params.remove(0);
-                    if let GenericParamDef { name, kind: GenericParamDefKind::Const { ty, .. } } =
-                        gen
+                    if let GenericParamDef {
+                        name,
+                        kind: GenericParamDefKind::Const { ty, .. },
+                        ..
+                    } = gen
                     {
                         func.decl
                             .inputs
@@ -1365,8 +1366,12 @@ pub(crate) fn clean_middle_assoc_item<'tcx>(
                 tcx.generics_of(assoc_item.def_id),
                 tcx.explicit_predicates_of(assoc_item.def_id),
             );
-            // FIXME: This does not place parameters in source order (late-bound ones come last)
             generics.params.extend(clean_bound_vars(sig.bound_vars()));
+            // FIXME(fmease): Does this work in the presence of synthetic params (impl-Trait, host effect)?
+            // FIXME(fmease): Optimization: Don't call def_ident_span on non-lifetime params!
+            if !sig.bound_vars().is_empty() {
+                generics.params.sort_by_key(|param| tcx.def_ident_span(param.did).unwrap());
+            }
 
             let mut decl = clean_fn_decl_from_did_and_sig(cx, Some(assoc_item.def_id), sig);
 
@@ -2192,10 +2197,10 @@ pub(crate) fn clean_middle_ty<'tcx>(
                 .iter()
                 .flat_map(|pred| pred.bound_vars())
                 .filter_map(|var| match var {
-                    ty::BoundVariableKind::Region(ty::BrNamed(_, name))
+                    ty::BoundVariableKind::Region(ty::BrNamed(did, name))
                         if name != kw::UnderscoreLifetime =>
                     {
-                        Some(GenericParamDef::lifetime(name))
+                        Some(GenericParamDef::lifetime(did, name))
                     }
                     _ => None,
                 })
@@ -3167,15 +3172,15 @@ fn clean_bound_vars<'tcx>(
     bound_vars
         .into_iter()
         .filter_map(|var| match var {
-            ty::BoundVariableKind::Region(ty::BrNamed(_, name))
+            ty::BoundVariableKind::Region(ty::BrNamed(did, name))
                 if name != kw::UnderscoreLifetime =>
             {
-                Some(GenericParamDef::lifetime(name))
+                Some(GenericParamDef::lifetime(did, name))
             }
             ty::BoundVariableKind::Ty(ty::BoundTyKind::Param(did, name)) => Some(GenericParamDef {
                 name,
+                did,
                 kind: GenericParamDefKind::Type {
-                    did,
                     bounds: ThinVec::new(),
                     default: None,
                     synthetic: false,

src/librustdoc/clean/simplify.rs

@@ -149,7 +149,7 @@ pub(crate) fn move_bounds_to_generic_parameters(generics: &mut clean::Generics)
         } else if let WherePredicate::RegionPredicate { lifetime: Lifetime(arg), bounds } =
             &mut pred
             && let Some(GenericParamDef {
-                kind: GenericParamDefKind::Lifetime { outlives: param_bounds },
+                kind: GenericParamDefKind::Lifetime { outlives: param_bounds, .. },
                 ..
             }) = generics.params.iter_mut().find(|param| &param.name == arg)
         {

src/librustdoc/clean/types.rs

@@ -1326,7 +1326,7 @@ impl WherePredicate {
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub(crate) enum GenericParamDefKind {
     Lifetime { outlives: ThinVec<Lifetime> },
-    Type { did: DefId, bounds: ThinVec<GenericBound>, default: Option<Box<Type>>, synthetic: bool },
+    Type { bounds: ThinVec<GenericBound>, default: Option<Box<Type>>, synthetic: bool },
     // Option<Box<String>> makes this type smaller than `Option<String>` would.
     Const { ty: Box<Type>, default: Option<Box<String>>, is_host_effect: bool },
 }
@@ -1339,13 +1339,14 @@ impl GenericParamDefKind {
 
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub(crate) struct GenericParamDef {
+    pub(crate) did: DefId,
     pub(crate) name: Symbol,
     pub(crate) kind: GenericParamDefKind,
 }
 
 impl GenericParamDef {
-    pub(crate) fn lifetime(name: Symbol) -> Self {
-        Self { name, kind: GenericParamDefKind::Lifetime { outlives: ThinVec::new() } }
+    pub(crate) fn lifetime(did: DefId, name: Symbol) -> Self {
+        Self { name, did, kind: GenericParamDefKind::Lifetime { outlives: ThinVec::new() } }
     }
 
     pub(crate) fn is_synthetic_param(&self) -> bool {

src/librustdoc/html/format.rs

@@ -188,7 +188,7 @@ impl clean::GenericParamDef {
         cx: &'a Context<'tcx>,
     ) -> impl fmt::Display + 'a + Captures<'tcx> {
         display_fn(move |f| match &self.kind {
-            clean::GenericParamDefKind::Lifetime { outlives } => {
+            clean::GenericParamDefKind::Lifetime { outlives, .. } => {
                 write!(f, "{}", self.name)?;
 
                 if !outlives.is_empty() {

src/librustdoc/json/conversions.rs

@@ -456,7 +456,7 @@ impl FromWithTcx<clean::GenericParamDefKind> for GenericParamDefKind {
             Lifetime { outlives } => GenericParamDefKind::Lifetime {
                 outlives: outlives.into_iter().map(convert_lifetime).collect(),
             },
-            Type { did: _, bounds, default, synthetic } => GenericParamDefKind::Type {
+            Type { bounds, default, synthetic } => GenericParamDefKind::Type {
                 bounds: bounds.into_tcx(tcx),
                 default: default.map(|x| (*x).into_tcx(tcx)),
                 synthetic,
@@ -486,19 +486,16 @@ impl FromWithTcx<clean::WherePredicate> for WherePredicate {
                                     outlives: outlives.iter().map(|lt| lt.0.to_string()).collect(),
                                 }
                             }
-                            clean::GenericParamDefKind::Type {
-                                did: _,
-                                bounds,
-                                default,
-                                synthetic,
-                            } => GenericParamDefKind::Type {
-                                bounds: bounds
-                                    .into_iter()
-                                    .map(|bound| bound.into_tcx(tcx))
-                                    .collect(),
-                                default: default.map(|ty| (*ty).into_tcx(tcx)),
-                                synthetic,
-                            },
+                            clean::GenericParamDefKind::Type { bounds, default, synthetic } => {
+                                GenericParamDefKind::Type {
+                                    bounds: bounds
+                                        .into_iter()
+                                        .map(|bound| bound.into_tcx(tcx))
+                                        .collect(),
+                                    default: default.map(|ty| (*ty).into_tcx(tcx)),
+                                    synthetic,
+                                }
+                            }
                             clean::GenericParamDefKind::Const {
                                 ty,
                                 default,

tests/rustdoc/inline_cross/auxiliary/early-late-bound-lifetime-params.rs

@@ -0,0 +1,17 @@
+// Here, `'a` and `'c` are late-bound and `'b`, `'d`, `T` and `N` are early-bound.
+
+pub fn f<'a, 'b, 'c, 'd, T, const N: usize>()
+where
+    'b:,
+    'd:,
+{}
+
+pub struct Ty;
+
+impl Ty {
+    pub fn f<'a, 'b, 'c, 'd, T, const N: usize>()
+    where
+        'b:,
+        'd:,
+    {}
+}

tests/rustdoc/inline_cross/early-late-bound-lifetime-params.rs

@@ -0,0 +1,17 @@
+// Check that we correctly render late-bound lifetime params in source order
+// even if early-bound generic params are present.
+//
+// For context, at the time of writing early- and late-bound params are stored
+// separately in rustc and therefore rustdoc needs to manually merge them.
+
+#![crate_name = "usr"]
+// aux-crate:dep=early-late-bound-lifetime-params.rs
+// edition:2021
+
+// @has usr/fn.f.html
+// @has - '//pre[@class="rust item-decl"]' "fn f<'a, 'b, 'c, 'd, T, const N: usize>()"
+pub use dep::f;
+
+// @has usr/struct.Ty.html
+// @has - '//*[@id="method.f"]' "fn f<'a, 'b, 'c, 'd, T, const N: usize>()"
+pub use dep::Ty;