[flang] Don't resolve names in derived type definitions to generics

[klausler]

Summary

There's code in name resolution that handles resolution of references
that appear in the definitions of derived types -- it checks for
existing components in the type being defined, as well as for
non-parent components in its ancestors. Special case code prevents
resolution of a name to the symbol of a procedure binding. This
code needs to be extended so that names of generic procedures
are similarly prevented from shadowing symbols in the scope around
the type.

[vzakhari]

@klausler is it possible to write a LIT test for this? Can you please add one?

[klausler]

In D134398#3807420, @vzakhari wrote:

@klausler is it possible to write a LIT test for this? Can you please add one?

I didn't think that this case merited one, but I'll extract one for you.

[klausler]

Add test.

[vzakhari]

Thank you for the test! If I understand it correctly, this allows resolving foo inside ext to the module's subroutine foo rather than to the generic identifier foo inside base.
LGTM

flang/lib/Semantics/resolve-names.cpp

   if (scope.IsDerivedType()) {
     if (Symbol * symbol{scope.FindComponent(name.source)}) {
       if (!symbol->has<ProcBindingDetails>() &&
+          !symbol->has<GenericDetails>() &&
           !symbol->test(Symbol::Flag::ParentComp)) {
         return Resolve(name, symbol);
       }