https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79553
Bug ID: 79553
Summary: Infinite gfortran loop on invalid code with procedures
parameters
Product: gcc
Version: 6.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: luthaf at luthaf dot fr
Target Milestone: ---
Trying to compile the following (invalid) code make the compiler send errors
and then enter in infinite loop:
```
program error
implicit none
! Define a procedure with the same name as its type
procedure(procname), pointer :: procname
interface
subroutine procname(a)
implicit none
integer :: a
end subroutine
end interface
contains
! And use it as an argument for another procedure
subroutine use_procname(proc)
procedure(procname) :: proc
end subroutine
end program
```
The compiler output before entering the loop is not really helpful in
determining the cause of the error:
```
loop.f90:7:30:
subroutine procname(a)
1
Error: Symbol 'procname' at (1) already has an explicit interface
loop.f90:8:25:
implicit none
1
Error: Unexpected IMPLICIT NONE statement in INTERFACE block at (1)
loop.f90:9:24:
integer :: a
1
Error: Unexpected data declaration statement in INTERFACE block at (1)
loop.f90:10:11:
end subroutine
1
Error: Expecting END INTERFACE statement at (1)
```
Removing the soubroutine make the error clearer (PROCEDURE 'procname' at (1)
may not be used as its own interface):
```
loop.f90:7:30:
subroutine procname(a)
1
Error: Symbol 'procname' at (1) already has an explicit interface
loop.f90:8:25:
implicit none
1
Error: Unexpected IMPLICIT NONE statement in INTERFACE block at (1)
loop.f90:9:24:
integer :: a
1
Error: Unexpected data declaration statement in INTERFACE block at (1)
loop.f90:10:11:
end subroutine
1
Error: Expecting END INTERFACE statement at (1)
loop.f90:7:27:
subroutine procname(a)
1
Error: PROCEDURE 'procname' at (1) may not be used as its own interface
```
