diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index d0f5ab4..82c090b 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -379,7 +379,7 @@ uint8_t *Node::partialKey() {
     return ((Node48 *)this)->partialKey();
   case Type_Node256:
     return ((Node256 *)this)->partialKey();
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }
@@ -476,7 +476,7 @@ Node *&getChildExists(Node *self, uint8_t index) {
     assert(self256->bitSet.test(index));
     return self256->children[index].child;
   }
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }
@@ -509,7 +509,7 @@ Node *getChild(Node *self, uint8_t index) {
     auto *self256 = static_cast<Node256 *>(self);
     return self256->children[index].child;
   }
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }
@@ -590,7 +590,7 @@ int getChildGeq(Node *self, int child) {
     auto *self48 = static_cast<Node48 *>(self);
     return self48->bitSet.firstSetGeq(child);
   }
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }
@@ -653,7 +653,7 @@ Node *&getOrCreateChild(Node *&self, uint8_t index,
       return result;
     }
   } break;
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 
@@ -786,7 +786,7 @@ Node *&getOrCreateChild(Node *&self, uint8_t index,
     self256->bitSet.set(index);
     return self256->children[index].child;
   }
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }
@@ -921,7 +921,7 @@ void freeAndMakeCapacityAtLeast(Node *&self, int capacity,
     }
     self = newSelf;
   } break;
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }
@@ -1069,7 +1069,7 @@ void maybeDownsize(Node *self, NodeAllocators *allocators,
       allocators->node256.release(self256);
     }
     break;
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }
@@ -1119,7 +1119,7 @@ Node *erase(Node *self, NodeAllocators *allocators, ConflictSet::Impl *impl,
   case Type_Node256:
     allocators->node256.release((Node256 *)self);
     break;
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 
@@ -1168,7 +1168,7 @@ Node *erase(Node *self, NodeAllocators *allocators, ConflictSet::Impl *impl,
     parent256->bitSet.reset(parentsIndex);
     parent256->children[parentsIndex].child = nullptr;
   } break;
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 
@@ -1520,7 +1520,7 @@ int64_t maxBetweenExclusive(Node *n, int begin, int end) {
         begin, end);
     break;
   }
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 #if DEBUG_VERBOSE && !defined(NDEBUG)
@@ -1734,7 +1734,7 @@ struct CheckRangeLeftSide {
       assert(c >= 0);
       n = getChildExists(n, c);
     } break;
-    default:
+    default:                   // GCOVR_EXCL_LINE
       __builtin_unreachable(); // GCOVR_EXCL_LINE
     }
     return false;
@@ -1862,7 +1862,7 @@ struct CheckRangeRightSide {
       assert(c >= 0);
       n = getChildExists(n, c);
     } break;
-    default:
+    default:                   // GCOVR_EXCL_LINE
       __builtin_unreachable(); // GCOVR_EXCL_LINE
     }
     return false;
@@ -2398,7 +2398,7 @@ int64_t &maxVersion(Node *n, ConflictSet::Impl *impl) {
     assert(n256->bitSet.test(index));
     return n256->children[index].childMaxVersion;
   }
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }
@@ -2670,7 +2670,7 @@ Iterator firstGeq(Node *n, std::string_view key) {
   case Type_Node256:
     minNumChildren = kMinChildrenNode256;
     break;
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
   if (node->numChildren + int(node->entryPresent) < minNumChildren) {
@@ -2729,7 +2729,7 @@ int64_t getNodeSize(struct Node *n) {
     return sizeof(Node48);
   case Type_Node256:
     return sizeof(Node256);
-  default:
+  default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 }