cleanup

src/librustc_ast_lowering/lib.rs

@@ -936,7 +936,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 })
             });
 
-        lowered_generics.params = lowered_generics.params.into_iter().chain(in_band_defs).collect();
+        lowered_generics.params.extend(in_band_defs);
 
         let lowered_generics = lowered_generics.into_generics(self.arena);
         (lowered_generics, res)

src/librustc_resolve/late/lifetimes.rs

@@ -1299,8 +1299,8 @@ fn object_lifetime_defaults_for_item(
             GenericParamKind::Const { .. } => {
                 // Generic consts don't impose any constraints.
                 //
-                // We still store a dummy value here to allow generic paramters
-                // in arbitrary order.
+                // We still store a dummy value here to allow generic parameters
+                // in an arbitrary order.
                 Some(Set1::Empty)
             }
         })

src/librustc_typeck/collect.rs

@@ -1374,7 +1374,7 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
                         |lint| {
                             lint.build(
                                 "defaults for type parameters are only allowed in \
-                                            `struct`, `enum`, `type`, or `trait` definitions.",
+                                 `struct`, `enum`, `type`, or `trait` definitions.",
                             )
                             .emit();
                         },