[flang] Handle assumed-type dummy arguments in ExtractDataRef (#169080)

Assumed-type dummy argument symbols s are never packaged in DataRefs
since the only way they can be used in Fortran is by forwarded as actual
arguments to other calls. When an ActualArgument comprising a forwarded
assumed-type dummy argument is presented to ExtractDataRef, it fails,
because ExtractDataRef for ActualArgument only handles actual argument
expressions (including variable references). Add support for actual
arguments that are assumed-type dummy arguments.

Fixes #168978.

Author: klausler

flang/lib/Evaluate/tools.cpp

@@ -63,7 +63,11 @@ Expr<SomeType> Parenthesize(Expr<SomeType> &&expr) {
 
 std::optional<DataRef> ExtractDataRef(
     const ActualArgument &arg, bool intoSubstring, bool intoComplexPart) {
-  return ExtractDataRef(arg.UnwrapExpr(), intoSubstring, intoComplexPart);
+  if (const Symbol *assumedType{arg.GetAssumedTypeDummy()}) {
+    return DataRef{*assumedType};
+  } else {
+    return ExtractDataRef(arg.UnwrapExpr(), intoSubstring, intoComplexPart);
+  }
 }
 
 std::optional<DataRef> ExtractSubstringBase(const Substring &substring) {

flang/test/Evaluate/bug168978.f90

@@ -0,0 +1,6 @@
+!RUN: %flang_fc1 -fdebug-unparse %s 2>&1 | FileCheck %s
+subroutine sub(dd)
+  type(*)::dd(..)
+  !CHECK: PRINT *, size(lbound(dd))
+  print *, size(lbound(dd)) ! do not fold
+end