[Bug fortran/120107] New: -fc-prototypes for ISO_FORTRAN_ENV generates duplicate typedefs

[ryan.gambord at oregonstate dot edu via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120107

            Bug ID: 120107
           Summary: -fc-prototypes for ISO_FORTRAN_ENV generates duplicate
                    typedefs
           Product: gcc
           Version: 15.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ryan.gambord at oregonstate dot edu
  Target Milestone: ---

See terminal dump below. Looks like event/lock/team_type structs and typedefs
are being emitted for every module in a source file. It broke my build system
that uses a jinja template to generate several templated versions of a module
within a single source file.


$gfortran -v
Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/15.1.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure
--enable-languages=ada,c,c++,d,fortran,go,lto,m2,objc,obj-c++,rust,cobol
--enable-bootstrap --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib
--mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://gitlab.archlinux.org/archlinux/packaging/packages/gcc/-/issues
--with-build-config=bootstrap-lto --with-linker-hash-style=gnu
--with-system-zlib --enable-__cxa_atexit --enable-cet=auto
--enable-checking=release --enable-clocale=gnu --enable-default-pie
--enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object
--enable-libstdcxx-backtrace --enable-link-serialization=1
--enable-linker-build-id --enable-lto --enable-multilib --enable-plugin
--enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch
--disable-werror
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 15.1.1 20250425 (GCC)


$cat test.f90
module a
   use, intrinsic :: ISO_FORTRAN_ENV
end module a
module b
   use, intrinsic :: ISO_FORTRAN_ENV
end module b

$gfortran -fc-prototypes -c -o test.o test.f90
#include <stddef.h>
#ifdef __cplusplus
#include <complex>
#define __GFORTRAN_FLOAT_COMPLEX std::complex<float>
#define __GFORTRAN_DOUBLE_COMPLEX std::complex<double>
#define __GFORTRAN_LONG_DOUBLE_COMPLEX std::complex<long double>
extern "C" {
#else
#define __GFORTRAN_FLOAT_COMPLEX float _Complex
#define __GFORTRAN_DOUBLE_COMPLEX double _Complex
#define __GFORTRAN_LONG_DOUBLE_COMPLEX long double _Complex
#endif

typedef struct event_type {
} event_type;

typedef struct lock_type {
} lock_type;

typedef struct team_type {
} team_type;

typedef struct event_type {
} event_type;

typedef struct lock_type {
} lock_type;

typedef struct team_type {
} team_type;


#ifdef __cplusplus
}
#endif