diff --git a/lldb/source/DataFormatters/VectorType.cpp b/lldb/source/DataFormatters/VectorType.cpp
index 8a842b8675f57..28a5cad9cc044 100644
--- a/lldb/source/DataFormatters/VectorType.cpp
+++ b/lldb/source/DataFormatters/VectorType.cpp
@@ -276,7 +276,13 @@ class VectorTypeSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
                                      name.AsCString());
     }
     uint32_t idx = *optional_idx;
-    if (idx >= CalculateNumChildrenIgnoringErrors())
+    auto num_children_or_err = CalculateNumChildren();
+    if (!num_children_or_err) {
+      llvm::consumeError(num_children_or_err.takeError());
+      return llvm::createStringError("Type has no child named '%s'",
+                                     name.AsCString());
+    }
+    if (idx >= *num_children_or_err)
       return llvm::createStringError("Type has no child named '%s'",
                                      name.AsCString());
     return idx;
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
index 4bcdf01c221a3..70cf0f6922831 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
@@ -279,7 +279,13 @@ lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
diff --git a/lldb/source/Plugins/Language/ObjC/NSArray.cpp b/lldb/source/Plugins/Language/ObjC/NSArray.cpp
index 25376e064879d..e1a3a7636929a 100644
--- a/lldb/source/Plugins/Language/ObjC/NSArray.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSArray.cpp
@@ -534,7 +534,13 @@ llvm::Expected<size_t> lldb_private::formatters::NSArrayMSyntheticFrontEndBase::
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
diff --git a/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp b/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
index ef1c2c89fe125..dfaea46f2af37 100644
--- a/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
@@ -593,7 +593,13 @@ llvm::Expected<size_t> lldb_private::formatters::
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
@@ -731,7 +737,13 @@ llvm::Expected<size_t> lldb_private::formatters::
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
@@ -868,7 +880,13 @@ lldb_private::formatters::NSConstantDictionarySyntheticFrontEnd::
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
@@ -1073,7 +1091,13 @@ lldb_private::formatters::GenericNSDictionaryMSyntheticFrontEnd<
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
@@ -1235,7 +1259,13 @@ llvm::Expected<size_t> lldb_private::formatters::Foundation1100::
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
diff --git a/lldb/source/Plugins/Language/ObjC/NSIndexPath.cpp b/lldb/source/Plugins/Language/ObjC/NSIndexPath.cpp
index b5360195e91d2..4e805c4f17e37 100644
--- a/lldb/source/Plugins/Language/ObjC/NSIndexPath.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSIndexPath.cpp
@@ -133,7 +133,13 @@ class NSIndexPathSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
                                      name.AsCString());
     }
     uint32_t idx = *optional_idx;
-    if (idx >= CalculateNumChildrenIgnoringErrors())
+    auto num_children_or_err = CalculateNumChildren();
+    if (!num_children_or_err) {
+      llvm::consumeError(num_children_or_err.takeError());
+      return llvm::createStringError("Type has no child named '%s'",
+                                     name.AsCString());
+    }
+    if (idx >= *num_children_or_err)
       return llvm::createStringError("Type has no child named '%s'",
                                      name.AsCString());
     return idx;
diff --git a/lldb/source/Plugins/Language/ObjC/NSSet.cpp b/lldb/source/Plugins/Language/ObjC/NSSet.cpp
index 7d814e656dc5f..19b87828b6258 100644
--- a/lldb/source/Plugins/Language/ObjC/NSSet.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSSet.cpp
@@ -395,7 +395,13 @@ lldb_private::formatters::NSSetISyntheticFrontEnd::GetIndexOfChildWithName(
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
@@ -533,7 +539,13 @@ lldb_private::formatters::NSCFSetSyntheticFrontEnd::GetIndexOfChildWithName(
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;
@@ -672,7 +684,13 @@ llvm::Expected<size_t> lldb_private::formatters::GenericNSSetMSyntheticFrontEnd<
                                    name.AsCString());
   }
   uint32_t idx = *optional_idx;
-  if (idx >= CalculateNumChildrenIgnoringErrors())
+  auto num_children_or_err = CalculateNumChildren();
+  if (!num_children_or_err) {
+    llvm::consumeError(num_children_or_err.takeError());
+    return llvm::createStringError("Type has no child named '%s'",
+                                   name.AsCString());
+  }
+  if (idx >= *num_children_or_err)
     return llvm::createStringError("Type has no child named '%s'",
                                    name.AsCString());
   return idx;