Remove the CanDeriveDebug::Extra associated type

Similar to `HasVtable::Extra`, it is no longer needed.

Author: fitzgen

src/codegen/mod.rs

@@ -1414,7 +1414,7 @@ impl CodeGenerator for CompInfo {
 
         let is_union = self.kind() == CompKind::Union;
         let mut derives = vec![];
-        if item.can_derive_debug(ctx, ()) {
+        if item.can_derive_debug(ctx) {
             derives.push("Debug");
         }
 

src/ir/context.rs

@@ -40,10 +40,8 @@ impl ItemId {
 }
 
 impl CanDeriveDebug for ItemId {
-    type Extra = ();
-
-    fn can_derive_debug(&self, ctx: &BindgenContext, _: ()) -> bool {
-        ctx.resolve_item(*self).can_derive_debug(ctx, ())
+    fn can_derive_debug(&self, ctx: &BindgenContext) -> bool {
+        ctx.options().derive_debug && ctx.lookup_item_id_can_derive_debug(*self)
     }
 }
 

src/ir/derive.rs

@@ -10,17 +10,9 @@ use super::context::BindgenContext;
 /// derive debug or not, because of the limit rust has on 32 items as max in the
 /// array.
 pub trait CanDeriveDebug {
-    /// Implementations can define this type to get access to any extra
-    /// information required to determine whether they can derive `Debug`. If
-    /// extra information is unneeded, then this should simply be the unit type.
-    type Extra;
-
     /// Return `true` if `Debug` can be derived for this thing, `false`
     /// otherwise.
-    fn can_derive_debug(&self,
-                        ctx: &BindgenContext,
-                        extra: Self::Extra)
-                        -> bool;
+    fn can_derive_debug(&self, ctx: &BindgenContext) -> bool;
 }
 
 /// A trait that encapsulates the logic for whether or not we can derive `Debug`.

src/ir/item.rs

@@ -271,9 +271,7 @@ impl Trace for Item {
 }
 
 impl CanDeriveDebug for Item {
-    type Extra = ();
-
-    fn can_derive_debug(&self, ctx: &BindgenContext, _: ()) -> bool {
+    fn can_derive_debug(&self, ctx: &BindgenContext) -> bool {
         ctx.options().derive_debug && ctx.lookup_item_id_can_derive_debug(self.id())
     }
 }