[flang][Semantics] Flang is unable to `use` a module it compiled

[inaki-amatria]

• flang-new version is: flang-new version 20.0.0git (https://github.com/llvm/llvm-project.git bafe3a4b0ca0e9294a18a9ec4fea8567cb98dabe)
• Reduced test case:

! foo.f90
module foo
  use iso_c_binding, only : c_ptr, c_null_ptr

  implicit none

  private
  public :: foo_t

  type :: foo_t
    real(kind=4), dimension(:), contiguous, pointer :: buffer => null()
    type(c_ptr) :: c_ptr = c_null_ptr
  end type foo_t
contains
end module foo

! bar.f90
module bar
  use foo, only : foo_t

  implicit none

  private
  public :: bar_t

  type :: bar_t
    type(foo_t) :: buffer = foo_t()
  end type bar_t
end module bar

! main.f90
program main
  use bar
end program main

• flang-new invocation is: flang-new foo.f90 bar.f90 main.f90
• Expected behavior is: The code compiles successfully without errors.
• Actual behavior: Compilation fails with the following error:

bar.mod:9:47: error: Value in structure constructor of type 'REAL(4)' is incompatible with component 'c_ptr' of type 'c_ptr'
  type(foo_t)::buffer=foo_t(buffer=NULL(),c_ptr=c_ptr(__address=0_8))
                                                ^^^^^^^^^^^^^^^^^^^^
foo.mod:12:14: Declaration of 'c_ptr'
  type(c_ptr)::c_ptr=__builtin_c_ptr(__address=0_8)
               ^^^^^
bar.mod:9:53: error: Keyword '__address=' may not appear in a reference to a procedure with an implicit interface
  type(foo_t)::buffer=foo_t(buffer=NULL(),c_ptr=c_ptr(__address=0_8))
                                                      ^^^^^^^^^

[llvmbot]

@llvm/issue-subscribers-flang-frontend

Author: Iñaki Amatria Barral (inaki-amatria)

- `flang-new` version is: `flang-new version 20.0.0git (https://github.com/llvm/llvm-project.git bafe3a4)` - Reduced test case: ```f90 ! foo.f90 module foo use iso_c_binding, only : c_ptr, c_null_ptr

implicit none

private
public :: foo_t

type :: foo_t
real(kind=4), dimension(:), contiguous, pointer :: buffer => null()
type(c_ptr) :: c_ptr = c_null_ptr
end type foo_t
contains
end module foo

! bar.f90
module bar
use foo, only : foo_t

implicit none

private
public :: bar_t

type :: bar_t
type(foo_t) :: buffer = foo_t()
end type bar_t
end module bar

! main.f90
program main
use bar
end program main

- `flang-new` invocation is: `flang-new foo.f90 bar.f90 main.f90`
- Expected behavior is: The code compiles successfully without errors.
- Actual behavior: Compilation fails with the following error:

bar.mod:9:47: error: Value in structure constructor of type 'REAL(4)' is incompatible with component 'c_ptr' of type 'c_ptr'
type(foo_t)::buffer=foo_t(buffer=NULL(),c_ptr=c_ptr(__address=0_8))
^^^^^^^^^^^^^^^^^^^^
foo.mod:12:14: Declaration of 'c_ptr'
type(c_ptr)::c_ptr=__builtin_c_ptr(__address=0_8)
^^^^^
bar.mod:9:53: error: Keyword '__address=' may not appear in a reference to a procedure with an implicit interface
type(foo_t)::buffer=foo_t(buffer=NULL(),c_ptr=c_ptr(__address=0_8))
^^^^^^^^^

</details>

[klausler]

#108892