Back out some of the 'explicits', proving that I have no idea what I'm doing here.

src/kaleidoscope_internal/array_like_storage.h

@@ -85,7 +85,7 @@ struct ArrayLikeStorage<StoredType__, true /* is of appropriate type */> {
 
  public:
 
-  explicit constexpr ArrayLikeStorage(StoredType__ entry)
+  constexpr ArrayLikeStorage(StoredType__ entry)
     : entry_(entry)
   {}
 
@@ -103,7 +103,7 @@ struct ArrayLikeStorage<StoredType__, false /* not of appropriate type */> {
  public:
 
   template<typename AnyType__>
-  explicit constexpr ArrayLikeStorage(AnyType__/* non-matching entity */) {}
+  constexpr ArrayLikeStorage(AnyType__/* non-matching entity */) {}
 
   static constexpr uint8_t n_entries = 0;
 

src/kaleidoscope_internal/sketch_exploration/keymap_exploration.h

@@ -35,7 +35,7 @@ class KeymapAdaptor {
   static constexpr uint8_t n_layers = _n_layers;
   static constexpr uint8_t layer_size = _layer_size;
 
-  explicit constexpr KeymapAdaptor(const Key(&keymap)[_n_layers][_layer_size])
+  constexpr KeymapAdaptor(const Key(&keymap)[_n_layers][_layer_size])
     :  keymap_{keymap}
   {}
 
@@ -119,7 +119,7 @@ class EmptyKeymapAccumulationHelper {
 
  public:
 
-  explicit constexpr EmptyKeymapAccumulationHelper(const _Accumulation &op)
+  constexpr EmptyKeymapAccumulationHelper(const _Accumulation &op)
     :   op_{op}
   {}
 
@@ -147,7 +147,7 @@ struct NumKeysEqual {
   typedef uint8_t ResultType;
   static constexpr ResultType init_value = 0;
 
-  explicit constexpr NumKeysEqual(Key k) : k_{k} {}
+  constexpr NumKeysEqual(Key k) : k_{k} {}
 
   constexpr ResultType apply(Key test_key, ResultType r) const {
     return (test_key == k_) ? r + 1 : r;
@@ -163,7 +163,7 @@ struct HasKey {
   typedef bool ResultType;
   static constexpr ResultType init_value = false;
 
-  explicit constexpr HasKey(Key k) : k_{k} {}
+  constexpr HasKey(Key k) : k_{k} {}
 
   constexpr ResultType apply(Key test_key, ResultType r) const {
     return (test_key == k_) ? true : r;