[flang] Cope with specific procedures with same name as generic

[klausler]

Summary

When accessing a specific procedure of a USE-associated generic
interface, we need to allow for the case in which that specific
procedure has the same name as the generic when testing for
its availability in the current scope.

flang/lib/Semantics/expression.cpp

 const Symbol &ExpressionAnalyzer::AccessSpecific(
     const Symbol &originalGeneric, const Symbol &specific) {
   if (const auto *hosted{
           originalGeneric.detailsIf<semantics::HostAssocDetails>()}) {
     return AccessSpecific(hosted->symbol(), specific);
   } else if (const auto *used{
                  originalGeneric.detailsIf<semantics::UseDetails>()}) {
     const auto &scope{originalGeneric.owner()};
-    auto iter{scope.find(specific.name())};
-    if (iter != scope.end() && iter->second->has<semantics::UseDetails>() &&
-        &iter->second->get<semantics::UseDetails>().symbol() == &specific) {
+    if (auto iter{scope.find(specific.name())}; iter != scope.end()) {
+      if (const auto *useDetails{
+              iter->second->detailsIf<semantics::UseDetails>()}) {
+        const Symbol &usedSymbol{useDetails->symbol()};
+        const auto *usedGeneric{
+            usedSymbol.detailsIf<semantics::GenericDetails>()};
+        if (&usedSymbol == &specific ||
+            (usedGeneric && usedGeneric->specific() == &specific)) {
           return specific;
-    } else {
-      // Create a renaming USE of the specific procedure.
-      auto rename{context_.SaveTempName(
-          used->symbol().owner().GetName().value().ToString() + "$" +
-          specific.name().ToString())};
-      return *const_cast<semantics::Scope &>(scope)
-                  .try_emplace(rename, specific.attrs(),
-                      semantics::UseDetails{rename, specific})
-                  .first->second;
-    }
+        }
+      }
+    }
   } else {
     return specific;
   }
 }
 
 void ExpressionAnalyzer::EmitGenericResolutionError(const Symbol &symbol) {
   if (semantics::IsGenericDefinedOp(symbol)) {
     Say("No specific procedure of generic operator '%s' matches the actual arguments"_err_en_US,