message: Carried on impl implementation.
  Added forced coverage for unused impl methods.
diff: @@ -233,7 +233,7 @@ fn process_items(items: &[Item], ctx: &Context, analysis: &mut LineAnalysis) {
  Item::Enum(i) => visit_enum(i, analysis),
  Item::Union(i) => visit_union(i, analysis),
  Item::Trait(i) => visit_trait(i, analysis),
  - Item::Impl(i) => visit_impl(i, analysis),
  + Item::Impl(i) => visit_impl(i, analysis, ctx),
  _ =>{}
  }
  }
  @@ -327,7 +327,14 @@ fn visit_trait(trait_item: &ItemTrait, analysis: &mut LineAnalysis) {
  }
  -fn visit_impl(impl_blk: &ItemImpl, analysis: &mut LineAnalysis) {
  +fn visit_impl(impl_blk: &ItemImpl, analysis: &mut LineAnalysis, ctx: &Context) {
  + for item in &impl_blk.items {
  + if let ImplItem::Method(ref i) = item {
  + analysis.cover_span(&i.sig.decl.fn_token.0, None);
  + analysis.cover_span(&i.block.brace_token.0, Some(ctx.file_contents));
  + process_statements(&i.block.stmts, ctx, analysis);
  + }
  + }
  visit_generics(&impl_blk.generics, analysis);
  }
  