Hide host effect params from docs

(cherry picked from commit c4e61fa)

Author: oli-obk

src/librustdoc/clean/mod.rs

@@ -542,7 +542,7 @@ fn clean_generic_param_def<'tcx>(
                 },
             )
         }
-        ty::GenericParamDefKind::Const { has_default, .. } => (
+        ty::GenericParamDefKind::Const { has_default, is_host_effect } => (
             def.name,
             GenericParamDefKind::Const {
                 ty: Box::new(clean_middle_ty(
@@ -562,6 +562,7 @@ fn clean_generic_param_def<'tcx>(
                     )),
                     false => None,
                 },
+                is_host_effect,
             },
         ),
     };
@@ -618,6 +619,7 @@ fn clean_generic_param<'tcx>(
                 ty: Box::new(clean_ty(ty, cx)),
                 default: default
                     .map(|ct| Box::new(ty::Const::from_anon_const(cx.tcx, ct.def_id).to_string())),
+                is_host_effect: cx.tcx.has_attr(param.def_id, sym::rustc_host),
             },
         ),
     };

src/librustdoc/clean/types.rs

@@ -1315,7 +1315,7 @@ impl WherePredicate {
 pub(crate) enum GenericParamDefKind {
     Lifetime { outlives: Vec<Lifetime> },
     Type { did: DefId, bounds: Vec<GenericBound>, default: Option<Box<Type>>, synthetic: bool },
-    Const { ty: Box<Type>, default: Option<Box<String>> },
+    Const { ty: Box<Type>, default: Option<Box<String>>, is_host_effect: bool },
 }
 
 impl GenericParamDefKind {
@@ -1335,9 +1335,10 @@ impl GenericParamDef {
         Self { name, kind: GenericParamDefKind::Lifetime { outlives: Vec::new() } }
     }
 
-    pub(crate) fn is_synthetic_type_param(&self) -> bool {
+    pub(crate) fn is_synthetic_param(&self) -> bool {
         match self.kind {
-            GenericParamDefKind::Lifetime { .. } | GenericParamDefKind::Const { .. } => false,
+            GenericParamDefKind::Lifetime { .. } => false,
+            GenericParamDefKind::Const { is_host_effect, .. } => is_host_effect,
             GenericParamDefKind::Type { synthetic, .. } => synthetic,
         }
     }

src/librustdoc/html/format.rs

@@ -250,8 +250,7 @@ impl clean::Generics {
         cx: &'a Context<'tcx>,
     ) -> impl fmt::Display + 'a + Captures<'tcx> {
         display_fn(move |f| {
-            let mut real_params =
-                self.params.iter().filter(|p| !p.is_synthetic_type_param()).peekable();
+            let mut real_params = self.params.iter().filter(|p| !p.is_synthetic_param()).peekable();
             if real_params.peek().is_none() {
                 return Ok(());
             }

src/librustdoc/json/conversions.rs

@@ -453,7 +453,7 @@ impl FromWithTcx<clean::GenericParamDefKind> for GenericParamDefKind {
                 default: default.map(|x| (*x).into_tcx(tcx)),
                 synthetic,
             },
-            Const { ty, default } => GenericParamDefKind::Const {
+            Const { ty, default, is_host_effect: _ } => GenericParamDefKind::Const {
                 type_: (*ty).into_tcx(tcx),
                 default: default.map(|x| *x),
             },
@@ -491,12 +491,14 @@ impl FromWithTcx<clean::WherePredicate> for WherePredicate {
                                 default: default.map(|ty| (*ty).into_tcx(tcx)),
                                 synthetic,
                             },
-                            clean::GenericParamDefKind::Const { ty, default } => {
-                                GenericParamDefKind::Const {
-                                    type_: (*ty).into_tcx(tcx),
-                                    default: default.map(|d| *d),
-                                }
-                            }
+                            clean::GenericParamDefKind::Const {
+                                ty,
+                                default,
+                                is_host_effect: _,
+                            } => GenericParamDefKind::Const {
+                                type_: (*ty).into_tcx(tcx),
+                                default: default.map(|d| *d),
+                            },
                         };
                         GenericParamDef { name, kind }
                     })

tests/rustdoc/const-fn-effects.rs

@@ -2,14 +2,14 @@
 #![feature(effects)]
 
 // @has foo/fn.bar.html
-// @has - '//pre[@class="rust item-decl"]' 'pub const fn bar<const host: bool = true>() -> '
+// @has - '//pre[@class="rust item-decl"]' 'pub const fn bar() -> '
 /// foo
 pub const fn bar() -> usize {
     2
 }
 
 // @has foo/struct.Foo.html
-// @has - '//*[@class="method"]' 'const fn new<const host: bool = true>()'
+// @has - '//*[@class="method"]' 'const fn new()'
 pub struct Foo(usize);
 
 impl Foo {