[flang] Catch error: base of DATA statement object can't be a pointer

[klausler]

Summary

A pointer with subscripts, substring indices, or components cannot
be initialized by a DATA statement (although of course a whole pointer
can be so). Catch the missing cases.

[klausler]

ping

[clementval]

LGTM.

flang/lib/Semantics/check-data.cpp

if (const char *whyNot{IsAutomatic(symbol) ? "Automatic variable"
                 : IsInitialized(symbol, true)  ? "Default-initialized"
                 : IsInBlankCommon(symbol)      ? "Blank COMMON object"
                 : IsProcedure(symbol) && !IsPointer(symbol) ? "Procedure"
                 // remaining checks don't apply to components
                 : !isFirstSymbol                   ? nullptr
                 : IsHostAssociated(symbol, scope)  ? "Host-associated object"
                 : IsUseAssociated(symbol, scope)   ? "USE-associated object"
                 : symbol.has<AssocEntityDetails>() ? "Construct association"
-                                                   : nullptr}) {
+                : IsPointer(symbol) && (hasComponent_ || hasSubscript_)
+                ? "Target of pointer"
       context_.Say(source_,
           "%s '%s' must not be initialized in a DATA statement"_err_en_US,
           whyNot, symbol.name());
       return false;
     } else if (IsProcedurePointer(symbol)) {
       context_.Say(source_,
           "Procedure pointer '%s' in a DATA statement is not standard"_en_US,
           symbol.name());

flang/test/Semantics/data04.f90

subroutine CheckObject(i)
         integer val
         type(specialNumbers) numsArray(5)
       end type
       type(large) largeNumber
       type(large), allocatable :: allocatableLarge
       type(large) :: largeNumberArray(i)
       type(large) :: largeArray(5)
       character :: name(i)
+      type small
+        real :: x
+      end type
+      type(small), pointer :: sp
       !C877
       !ERROR: Default-initialized 'largenumber' must not be initialized in a DATA statement
       DATA(largeNumber % numsArray(j) % headOfTheList, j = 1, 10) / 10 * NULL() /
       !C877
       !ERROR: Data object must not contain pointer 'headofthelist' as a non-rightmost part
       DATA(largeNumber % numsArray(j) % headOfTheList % one, j = 1, 10) / 10 * 1 /
       !C877
       !ERROR: Rightmost data object pointer 'ptoarray' must not be subscripted
subroutine CheckObject(i)
       !ERROR: Allocatable 'allocatablelarge' must not be initialized in a DATA statement
       DATA allocatableLarge % val / 1 /
       !C876
       !ERROR: Automatic variable 'largenumberarray' must not be initialized in a DATA statement
       DATA(largeNumberArray(j) % val, j = 1, 10) / 10 * NULL() /
       !C876
       !ERROR: Automatic variable 'name' must not be initialized in a DATA statement
       DATA name( : 2) / 'Ancd' /
+      !ERROR: Target of pointer 'sp' must not be initialized in a DATA statement
+      DATA sp%x / 1.0 /
     end
   end
 
   block data foo
           integer :: a,b
           common /c/ a,b
           !C876
           !OK: Correct use