cxx: Fix some warnings from -Wextra

Summary:
- As we don't have C++17's [[fallthrough]], rely on GCC'd detection
  of fallthrough comments.

  See https://developers.redhat.com/blog/2017/03/10/wimplicit-fallthrough-in-gcc-7/

- Replaced some copy constructors with typecast operators.

  Previously, a constructor with remove_const/remove_cv were used
  to allow const iterators to be constructed from non-const iterators.
  This had the side effect of making these constructors actual copy
  constructors for non const lists. As we did not define other
  special constructors/operators, the rule of 5 were violated for these
  cases.

  This commit replaces these constructors with actual typecast operators
  that promote non const iterators to their const counterparts.

- Cast a Eina_Bool/bool narrowing conversion

- Add a missing break statement from D10050

Reviewers: zmike, brunobelo, felipealmeida

Reviewed By: brunobelo

Subscribers: cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D9934

src/bindings/cxx/eina_cxx/eina_inlist.hh

@@ -101,11 +101,12 @@ struct _inlist_iterator
     : _list(list), _node(node) {}
 
   /**
-   * @brief Copy constructor. Creates a copy of the given iterator.
+   * @brief Create a const iterator from this one.
    * @param other Other iterator.
    */
-  _inlist_iterator(_inlist_iterator<typename std::remove_const<T>::type> const& other)
-    : _list(other._list), _node(other._node) {}
+  operator _inlist_iterator<T const>() {
+    return _inlist_iterator<T const>{_list, _node};
+  }
 
   /**
    * @brief Move the iterator to the next position in the list.

src/bindings/cxx/eina_cxx/eina_ptrarray.hh

@@ -46,9 +46,9 @@ struct _ptr_array_iterator
 
   {
   }
-  _ptr_array_iterator(_ptr_array_iterator<typename remove_cv<value_type>::type> const& other)
-    : _ptr(other._ptr)
+  operator _ptr_array_iterator<T const>()
   {
+    return _ptr_array_iterator<T const>{_ptr};
   }
   _ptr_array_iterator<T>& operator++()
   {

src/bindings/cxx/eina_cxx/eina_ptrlist.hh

@@ -62,9 +62,9 @@ struct _ptr_list_iterator : _ptr_list_iterator_base
     : _ptr_list_iterator_base(list, node)
   {
   }
-  _ptr_list_iterator(_ptr_list_iterator<value_type> const& other)
-    : _ptr_list_iterator_base(static_cast<_ptr_list_iterator_base const&>(other))
+  operator _ptr_list_iterator<T const>()
   {
+    return _ptr_list_iterator<T const>{_list, _node};
   }
 
   _ptr_list_iterator<T>& operator++()

src/lib/eolian_cxx/grammar/html_escaped_string.hpp

@@ -26,7 +26,8 @@ struct html_escaped_string_generator
                case '\'': out.append("'"); break;
                case '<':  out.append("&lt;"); break;
                case '>':  out.append("&gt;"); break;
-               case '\\': if (pos < input.size() - 1) pos++; // Deliberate fallthrough
+               case '\\': if (pos < input.size() - 1) pos++;
+                    // fall through
                default:   out.append(&input[pos], 1); break;
             }
         }

src/lib/eolian_cxx/grammar/klass_def.hpp

@@ -495,7 +495,7 @@ inline void type_def::set(Eolian_Type const* eolian_type, Eolian_Unit const* uni
                 complex.subtypes.push_back({stp
                                             , unit
                                             , ::eolian_type_c_type_get(stp)
-                                            , eolian_type_is_move(stp)
+                                            , static_cast<bool>(eolian_type_is_move(stp))
                                             , is_by::value});
                 stp = eolian_type_next_type_get(stp);
              }
@@ -532,6 +532,7 @@ inline void type_def::set(Eolian_Expression_Type eolian_exp_type)
         break;
       case EOLIAN_EXPR_STRING:
         set("string", "const char *");
+        break;
       case EOLIAN_EXPR_BOOL:
         set("bool", "Eina_Bool");
         break;