Avoid spurrious auto-loading/parsing due to artificial classes.

artificial/synthetic classes are created in the support of I/O customization rules.

core/foundation/src/TClassEdit.cxx

@@ -838,6 +838,13 @@ void TClassEdit::GetNormalizedName(std::string &norm_name, std::string_view name
    }
 
    norm_name = std::string(name); // NOTE: Is that the shortest version?
+
+   if (name.find('@')) {
+      // If there is a @ symbol (followed by a version number) then this is a synthetic class name created
+      // from an already normalized name for the purpose of supporting schema evolution.
+      return;
+   }
+
    // Remove the std:: and default template argument and insert the Long64_t and change basic_string to string.
    TClassEdit::TSplitType splitname(norm_name.c_str(),(TClassEdit::EModType)(TClassEdit::kLong64 | TClassEdit::kDropStd | TClassEdit::kDropStlDefault | TClassEdit::kKeepOuterConst));
    splitname.ShortType(norm_name, TClassEdit::kDropStd | TClassEdit::kDropStlDefault | TClassEdit::kResolveTypedef | TClassEdit::kKeepOuterConst);

core/meta/src/TClass.cxx

@@ -1445,7 +1445,7 @@ void TClass::Init(const char *name, Version_t cversion,
    // We need to check if the class it is not fwd declared for the cases where we
    // created a TClass directly in the kForwardDeclared state. Indeed in those cases
    // fClassInfo will always be nullptr.
-   if (fState!=kForwardDeclared && !fClassInfo) {
+   if (fState!=kForwardDeclared && !fClassInfo && fName.First('@')==kNPOS) {
 
       if (fState == kHasTClassInit) {
          // If the TClass is being generated from a ROOT dictionary,
@@ -2971,6 +2971,15 @@ TClass *TClass::GetClass(const char *name, Bool_t load, Bool_t silent)
       load = kTRUE;
    }
 
+   if (strchr(name, '@') != nullptr) {
+      // If there is a @ symbol (followed by a version number) then this is a synthetic class name created
+      // from an already normalized name for the purpose of supporting schema evolution.
+      // There is no dictionary or interpreter information about this kind of class, the only
+      // (undesirable) side-effect of doing the search would be a waste of CPU time and potential
+      // auto-loading or auto-parsing based on the scope of the name.
+      return cl;
+   }
+
    // To avoid spurious auto parsing, let's check if the name as-is is
    // known in the TClassTable.
    DictFuncPtr_t dict = TClassTable::GetDictNorm(name);