[Flang] Incorrect diagnostic on multiple type-bound procedure binding-names point to the same specific procedure-name

[DanielCChen]

Consider the following code:

module m

   type base
      integer :: i = -999
      contains
         procedure, pass(b) :: base1 => base_base_base
         procedure, pass(b) :: base2 => base_base_base
         generic :: operator(+) => base1, base2
   end type

   contains

   type(base) function base_base_base ( a, b )
      class(base), intent(in) :: a
      class(base), intent(in) :: b
   end function

end module

Flang currently issues an error as:

error: Semantic errors in t.f
./t.f:8:21: error: Generic 'OPERATOR(+)' may not have specific procedures 'base%base1' and 'base%base2' as their interfaces are not distinguishable
           generic :: operator(+) => base1, base2
                      ^^^^^^^^^^^
./t.f:13:24: Procedure 'base1' of type 'base' is bound to 'base_base_base'
     type(base) function base_base_base ( a, b )
                         ^^^^^^^^^^^^^^
./t.f:13:24: Procedure 'base2' of type 'base' is bound to 'base_base_base'
     type(base) function base_base_base ( a, b )
                         ^^^^^^^^^^^^^^

The code seems conforming to me as I can't find any wording in the standard prohibit this usage.

Note: This could be a duplicate to issue #124766

[llvmbot]

@llvm/issue-subscribers-flang-frontend

Author: Daniel Chen (DanielCChen)

Consider the following code: ``` module m

type base
integer :: i = -999
contains
procedure, pass(b) :: base1 => base_base_base
procedure, pass(b) :: base2 => base_base_base
generic :: operator(+) => base1, base2
end type

contains

type(base) function base_base_base ( a, b )
class(base), intent(in) :: a
class(base), intent(in) :: b
end function

end module

Flang currently issues an error as:

error: Semantic errors in t.f
./t.f:8:21: error: Generic 'OPERATOR(+)' may not have specific procedures 'base%base1' and 'base%base2' as their interfaces are not distinguishable
generic :: operator(+) => base1, base2
^^^^^^^^^^^
./t.f:13:24: Procedure 'base1' of type 'base' is bound to 'base_base_base'
type(base) function base_base_base ( a, b )
^^^^^^^^^^^^^^
./t.f:13:24: Procedure 'base2' of type 'base' is bound to 'base_base_base'
type(base) function base_base_base ( a, b )
^^^^^^^^^^^^^^

The code seems conforming to me as I can't find any wording in the standard prohibit this usage.

Note: This could be a duplicate to issue #<!-- -->124766 
</details>

[klausler]

It's a duplicate of #124766 and working as intended.

[DanielCChen]

Also invalid code as explained in #124766 .