<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/128608>128608</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Flang] Compilation error when using the type is statement in select type construct
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            flang:frontend
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          ohno-fj
      </td>
    </tr>
</table>

<pre>
    ```
Version of flang : 21.0.0(f75126eeabba13ce2aab53c2e4296fca12b9da0d)/AArch64
```

In the attached program, the `type is` statement is defined in `select type` construct, and the type of variable `x` is treated as `integer` instead of `polyphasic` in subsequent blocks.  
This is mentioned in `Fortran standard 2023: 11.1.11.2 Execution of the SELECT TYPE construct`, so it seems correct that this should not result in a compilation error.  
However, this program results in compilation error in Flang.  

The following are the test program, Flang, Gfortran and ifx compilation/execution result.

sngtatm013_2.f90:
```fortran
subroutine ss2
 class(*),allocatable::x(:)
  allocate(x,source=[1])
  select type(x)
 type is(integer)
     do concurrent(ii=1:10000:1,.true.)
        x(ii)=ii
 end do
  end select
end subroutine ss2
```

```
$ flang -c sngtatm013_2.f90
error: Semantic errors in sngtatm013_2.f90
./sngtatm013_2.f90:7:9: error: Deallocation of a polymorphic entity caused by assignment not allowed in DO CONCURRENT
 x(ii)=ii
          ^^^^^
./sngtatm013_2.f90:2:25: Declaration of 'x'
 class(*),allocatable::x(:)
                          ^
$ 
```

```
$ gfortran -c sngtatm013_2.f90
$ 
```

```
$ ifx -c sngtatm013_2.f90
$ 
```


</pre>
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