[flang] Fix bogus error under IMPLICIT NONE(EXTERNAL)

[klausler]

Summary

Don't emit an error message for a possible implicit use of an
external procedure when it is known that the symbol is not
a procedure (e.g., an array).

Fixes https://github.com/llvm/llvm-project/issues/62047

[PeteSteinfeld]

All builds and tests correctly and looks good.

flang/lib/Semantics/resolve-names.cpp

if (IsIntrinsic(name.source, flag)) {
       // Check if it is a builtin from the predefined module
       symbol = FindSymbol(*ppcBuiltinScope, name);
       if (!symbol)
         symbol = &MakeSymbol(context().globalScope(), name.source, Attrs{});
     } else {
       symbol = &MakeSymbol(context().globalScope(), name.source, Attrs{});
     }
     Resolve(name, *symbol);
+    ConvertToProcEntity(*symbol);
     if (!symbol->attrs().test(Attr::INTRINSIC)) {
       if (CheckImplicitNoneExternal(name.source, *symbol)) {
         MakeExternal(*symbol);
       }
     }
     CheckEntryDummyUse(name.source, symbol);
-    ConvertToProcEntity(*symbol);
     SetProcFlag(name, *symbol, flag);
   } else if (CheckUseError(name)) {
     // error was reported
   } else {
     auto &nonUltimateSymbol{*symbol};
     symbol = &Resolve(name, symbol)->GetUltimate();
     CheckEntryDummyUse(name.source, symbol);
     bool convertedToProcEntity{ConvertToProcEntity(*symbol)};
     if (convertedToProcEntity && !symbol->attrs().test(Attr::EXTERNAL) &&
         IsIntrinsic(symbol->name(), flag) && !IsDummy(*symbol)) {
       AcquireIntrinsicProcedureFlags(*symbol);
     }
     if (!SetProcFlag(name, *symbol, flag)) {
       return; // reported error
     }
-    if (!symbol->has<GenericDetails>()) {
-      CheckImplicitNoneExternal(name.source, *symbol);
-    }
     if (IsProcedure(*symbol) || symbol->has<DerivedTypeDetails>() ||
         symbol->has<AssocEntityDetails>()) {
       // Symbols with DerivedTypeDetails and AssocEntityDetails are accepted
       // here as procedure-designators because this means the related
       // FunctionReference are mis-parsed structure constructors or array
       // references that will be fixed later when analyzing expressions.
     } else if (symbol->has<ObjectEntityDetails>()) {
       // Symbols with ObjectEntityDetails are also accepted because this can be
-      // a mis-parsed array references that will be fixed later. Ensure that if
+      // a mis-parsed array reference that will be fixed later. Ensure that if
       // this is a symbol from a host procedure, a symbol with HostAssocDetails
       // is created for the current scope.
       // Operate on non ultimate symbol so that HostAssocDetails are also
       // created for symbols used associated in the host procedure.
       if (IsUplevelReference(nonUltimateSymbol)) {
         MakeHostAssocSymbol(name, nonUltimateSymbol);
       }
     } else if (symbol->test(Symbol::Flag::Implicit)) {
       Say(name,
           "Use of '%s' as a procedure conflicts with its implicit definition"_err_en_US);
     } else {
       SayWithDecl(name, *symbol,
           "Use of '%s' as a procedure conflicts with its declaration"_err_en_US);
     }
   }
 }
 
 bool ResolveNamesVisitor::CheckImplicitNoneExternal(
     const SourceName &name, const Symbol &symbol) {
-  if (isImplicitNoneExternal() && !symbol.attrs().test(Attr::EXTERNAL) &&
+  if (symbol.has<ProcEntityDetails>() && isImplicitNoneExternal() &&
+      !symbol.attrs().test(Attr::EXTERNAL) &&
       !symbol.attrs().test(Attr::INTRINSIC) && !symbol.HasExplicitInterface()) {
     Say(name,
-        "'%s' is an external procedure without the EXTERNAL"
-        " attribute in a scope with IMPLICIT NONE(EXTERNAL)"_err_en_US);
+        "'%s' is an external procedure without the EXTERNAL attribute in a scope with IMPLICIT NONE(EXTERNAL)"_err_en_US);
     return false;
   }
   return true;
 }
 
 // Variant of HandleProcedureName() for use while skimming the executable
 // part of a subprogram to catch calls to dummy procedures that are part
 // of the subprogram's interface, and to mark as procedures any symbols

flang/test/Semantics/implicit07.f90

 ! RUN: %python %S/test_errors.py %s %flang_fc1
 implicit none(external)
 external x
-integer :: f, i
+integer :: f, i, arr(1) = [0]
 call x
 !ERROR: 'y' is an external procedure without the EXTERNAL attribute in a scope with IMPLICIT NONE(EXTERNAL)
 call y
 !ERROR: 'f' is an external procedure without the EXTERNAL attribute in a scope with IMPLICIT NONE(EXTERNAL)
 i = f()
 block
   !ERROR: 'z' is an external procedure without the EXTERNAL attribute in a scope with IMPLICIT NONE(EXTERNAL)
   call z
 end block
+print *, arr(1) ! no error
 end