Replace under-used ImplPolarity enum with a boolean

src/librustdoc/clean/auto_trait.rs

@@ -84,14 +84,14 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                         new_generics
                     });
 
-                let polarity;
+                let negative_polarity;
                 let new_generics = match result {
                     AutoTraitResult::PositiveImpl(new_generics) => {
-                        polarity = None;
+                        negative_polarity = false;
                         new_generics
                     }
                     AutoTraitResult::NegativeImpl => {
-                        polarity = Some(ImplPolarity::Negative);
+                        negative_polarity = true;
 
                         // For negative impls, we use the generic params, but *not* the predicates,
                         // from the original type. Otherwise, the displayed impl appears to be a
@@ -130,7 +130,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                         trait_: Some(trait_ref.clean(self.cx).get_trait_type().unwrap()),
                         for_: ty.clean(self.cx),
                         items: Vec::new(),
-                        polarity,
+                        negative_polarity,
                         synthetic: true,
                         blanket_impl: None,
                     }),

src/librustdoc/clean/blanket_impl.rs

@@ -131,7 +131,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                             .in_definition_order()
                             .collect::<Vec<_>>()
                             .clean(self.cx),
-                        polarity: None,
+                        negative_polarity: false,
                         synthetic: false,
                         blanket_impl: Some(trait_ref.self_ty().clean(self.cx)),
                     }),

src/librustdoc/clean/inline.rs

@@ -428,7 +428,7 @@ crate fn build_impl(
             trait_,
             for_,
             items: trait_items,
-            polarity: Some(polarity.clean(cx)),
+            negative_polarity: polarity.clean(cx),
             synthetic: false,
             blanket_impl: None,
         }),

src/librustdoc/clean/mod.rs

@@ -2069,13 +2069,14 @@ impl Clean<Item> for hir::Variant<'_> {
     }
 }
 
-impl Clean<ImplPolarity> for ty::ImplPolarity {
+impl Clean<bool> for ty::ImplPolarity {
-    fn clean(&self, _: &DocContext<'_>) -> ImplPolarity {
+    /// Returns whether the impl has negative polarity.
+    fn clean(&self, _: &DocContext<'_>) -> bool {
         match self {
             &ty::ImplPolarity::Positive |
             // FIXME: do we want to do something else here?
-            &ty::ImplPolarity::Reservation => ImplPolarity::Positive,
+            &ty::ImplPolarity::Reservation => false,
-            &ty::ImplPolarity::Negative => ImplPolarity::Negative,
+            &ty::ImplPolarity::Negative => true,
         }
     }
 }
@@ -2116,7 +2117,7 @@ fn clean_impl(impl_: &hir::Item<'_>, cx: &DocContext<'_>) -> Vec<Item> {
             trait_,
             for_,
             items,
-            polarity: Some(cx.tcx.impl_polarity(def_id).clean(cx)),
+            negative_polarity: cx.tcx.impl_polarity(def_id).clean(cx),
             synthetic: false,
             blanket_impl: None,
         });

src/librustdoc/clean/types.rs

@@ -175,9 +175,11 @@ impl Item {
     }
 
     crate fn is_crate(&self) -> bool {
-        matches!(*self.kind,
+        matches!(
+            *self.kind,
             StrippedItem(box ModuleItem(Module { is_crate: true, .. }))
-            | ModuleItem(Module { is_crate: true, .. }))
+                | ModuleItem(Module { is_crate: true, .. })
+        )
     }
     crate fn is_mod(&self) -> bool {
         self.type_() == ItemType::Module
@@ -1858,12 +1860,6 @@ crate struct Constant {
     crate is_literal: bool,
 }
 
-#[derive(Clone, PartialEq, Debug)]
-crate enum ImplPolarity {
-    Positive,
-    Negative,
-}
-
 #[derive(Clone, Debug)]
 crate struct Impl {
     crate unsafety: hir::Unsafety,
@@ -1872,7 +1868,7 @@ crate struct Impl {
     crate trait_: Option<Type>,
     crate for_: Type,
     crate items: Vec<Item>,
-    crate polarity: Option<ImplPolarity>,
+    crate negative_polarity: bool,
     crate synthetic: bool,
     crate blanket_impl: Option<Type>,
 }

src/librustdoc/html/format.rs

@@ -870,7 +870,7 @@ impl clean::Impl {
             }
 
             if let Some(ref ty) = self.trait_ {
-                if self.polarity == Some(clean::ImplPolarity::Negative) {
+                if self.negative_polarity {
                     write!(f, "!")?;
                 }
 

src/librustdoc/html/render/mod.rs

@@ -4327,16 +4327,15 @@ fn sidebar_assoc_items(cx: &Context<'_>, it: &clean::Item) -> String {
 
                 let mut ret = impls
                     .iter()
-                    .filter_map(|i| {
+                    .filter_map(|it| {
-                        let is_negative_impl = is_negative_impl(i.inner_impl());
+                        if let Some(ref i) = it.inner_impl().trait_ {
-                        if let Some(ref i) = i.inner_impl().trait_ {
                             let i_display = format!("{:#}", i.print());
                             let out = Escape(&i_display);
                             let encoded = small_url_encode(&format!("{:#}", i.print()));
                             let generated = format!(
                                 "<a href=\"#impl-{}\">{}{}</a>",
                                 encoded,
-                                if is_negative_impl { "!" } else { "" },
+                                if it.inner_impl().negative_polarity { "!" } else { "" },
                                 out
                             );
                             if links.insert(generated.clone()) { Some(generated) } else { None }
@@ -4503,10 +4502,6 @@ fn extract_for_impl_name(item: &clean::Item) -> Option<(String, String)> {
     }
 }
 
-fn is_negative_impl(i: &clean::Impl) -> bool {
-    i.polarity == Some(clean::ImplPolarity::Negative)
-}
-
 fn sidebar_trait(cx: &Context<'_>, buf: &mut Buffer, it: &clean::Item, t: &clean::Trait) {
     let mut sidebar = String::new();
 

src/librustdoc/json/conversions.rs

@@ -422,7 +422,7 @@ impl From<clean::Impl> for Impl {
             trait_,
             for_,
             items,
-            polarity,
+            negative_polarity,
             synthetic,
             blanket_impl,
         } = impl_;
@@ -436,7 +436,7 @@ impl From<clean::Impl> for Impl {
             trait_: trait_.map(Into::into),
             for_: for_.into(),
             items: ids(items),
-            negative: polarity == Some(clean::ImplPolarity::Negative),
+            negative: negative_polarity,
             synthetic,
             blanket_impl: blanket_impl.map(Into::into),
         }

src/librustdoc/theme.rs

@@ -70,7 +70,10 @@ impl Events {
     }
 
     fn is_comment(&self) -> bool {
-        matches!(self, Events::StartLineComment(_) | Events::StartComment(_) | Events::EndComment(_))
+        matches!(
+            self,
+            Events::StartLineComment(_) | Events::StartComment(_) | Events::EndComment(_)
+        )
     }
 }