remove unused return types such as empty Results or Options that would always be Some(..)

remove unused return type of dropck::check_drop_obligations()
don't wrap return type in Option in get_macro_by_def_id() since we would always return Some(..)
remove redundant return type of back::write::optimize()
don't Option-wrap return type of compute_type_parameters() since we always return Some(..)
don't return empty Result in assemble_generator_candidates()
don't return empty Result in assemble_closure_candidates()
don't return empty result in assemble_fn_pointer_candidates()
don't return empty result in assemble_candidates_from_impls()
don't return empty result in assemble_candidates_from_auto_impls()
don't return emtpy result in assemble_candidates_for_trait_alias()
don't return empty result in assemble_builtin_bound_candidates()
don't return empty results in assemble_extension_candidates_for_traits_in_scope() and assemble_extension_candidates_for_trait()
remove redundant wrapping of return type of StripItem::strip() since it always returns Some(..)
remove unused return type of assemble_extension_candidates_for_all_traits()

1 files changed, 4 insertions, 4 deletions

diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index fa285f3488f..36a21b38c03 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
@@ -2322,13 +2322,13 @@ fn set_members_of_composite_type(
             DIB(cx),
             composite_type_metadata,
             Some(type_array),
-            type_params,
+            Some(type_params),
         );
     }
 }
 
 /// Computes the type parameters for a type, if any, for the given metadata.
-fn compute_type_parameters(cx: &CodegenCx<'ll, 'tcx>, ty: Ty<'tcx>) -> Option<&'ll DIArray> {
+fn compute_type_parameters(cx: &CodegenCx<'ll, 'tcx>, ty: Ty<'tcx>) -> &'ll DIArray {
     if let ty::Adt(def, substs) = *ty.kind() {
         if substs.types().next().is_some() {
             let generics = cx.tcx.generics_of(def.did);
@@ -2358,10 +2358,10 @@ fn compute_type_parameters(cx: &CodegenCx<'ll, 'tcx>, ty: Ty<'tcx>) -> Option<&'
                 })
                 .collect();
 
-            return Some(create_DIArray(DIB(cx), &template_params[..]));
+            return create_DIArray(DIB(cx), &template_params[..]);
         }
     }
-    return Some(create_DIArray(DIB(cx), &[]));
+    return create_DIArray(DIB(cx), &[]);
 
     fn get_parameter_names(cx: &CodegenCx<'_, '_>, generics: &ty::Generics) -> Vec<Symbol> {
         let mut names = generics