Index: flang/test/Semantics/collectives02.f90
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--- /dev/null
+++ flang/test/Semantics/collectives02.f90
@@ -0,0 +1,104 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+! XFAIL: *
+! This test checks for semantic errors in co_min subroutine calls based on
+! the co_min interface defined in section 16.9.48 of the Fortran 2018 standard.
+! To Do: add co_min to the list of intrinsics
+
+program test_co_min
+  implicit none
+
+  integer          i, integer_array(1), coindexed_integer[*], status
+  character(len=1) c, character_array(1), coindexed_character[*], message
+  double precision d, double_precision_array(1)
+  real             r, real_array(1), coindexed_real[*]
+  complex          complex_type
+  logical          bool
+  
+  !___ standard-conforming calls with no keyword arguments ___
+  call co_min(i)
+  call co_min(c)
+  call co_min(d)
+  call co_min(r)
+  call co_min(i, 1)
+  call co_min(c, 1, status)
+  call co_min(d, 1, status, message)
+  call co_min(r, 1, status, message)
+  call co_min(integer_array)
+  call co_min(character_array, 1)
+  call co_min(double_precision_array, 1, status)
+  call co_min(real_array, 1, status, message)
+
+  !___ standard-conforming calls with keyword arguments ___
+
+  ! all arguments present
+  call co_min(a=i, result_image=1, stat=status, errmsg=message) 
+  call co_min(result_image=1, a=i, errmsg=message, stat=status) 
+
+  ! one optional argument not present
+  call co_min(a=i,                 stat=status, errmsg=message) 
+  call co_min(a=i, result_image=1,              errmsg=message)
+  call co_min(a=i, result_image=1, stat=status                )
+
+  ! two optional arguments not present
+  call co_min(a=i, result_image=1                             ) 
+  call co_min(a=i,                 stat=status                )
+  call co_min(a=i,                              errmsg=message) 
+
+  ! no optional arguments present
+  call co_min(a=i) 
+
+  !___ non-standard-conforming calls ___
+
+  ! argument 'a' shall be of numeric type
+  !ERROR: Actual argument for 'a=' has bad type 'LOGICAL(4)'
+  call co_min(bool)
+  
+  ! argument 'a' shall be of numeric type
+  !ERROR: Actual argument for 'a=' has bad type 'COMPLEX(4)'
+  call co_min(complex_type)
+  
+  ! argument 'a' is intent(inout)
+  !ERROR: Actual argument associated with INTENT(IN OUT) dummy argument 'a=' must be definable
+  call co_min(a=1+1)
+  
+  ! argument 'a' shall not be a coindexed object
+  !ERROR: to be determined
+  call co_min(a=coindexed_real[1])
+  
+  ! 'result_image' argument shall be a scalar
+  !ERROR: too many actual arguments for intrinsic 'co_min'
+  call co_min(i, result_image=bool)
+  
+  ! 'result_image' argument shall be an integer scalar
+  !ERROR: too many actual arguments for intrinsic 'co_min'
+  call co_min(c, result_image=integer_array)
+  
+  ! 'stat' argument shall be noncoindexed
+  !ERROR: to be determined
+  call co_min(d, stat=coindexed_integer[1])
+ 
+  ! 'stat' argument shall be an integer
+  !ERROR: Actual argument for 'stat=' has bad type 'CHARACTER(KIND=1,LEN=1_8)'
+  call co_min(r, stat=message)
+ 
+  ! 'stat' argument shall be an integer scalar
+  !ERROR: 'stat=' argument has unacceptable rank 1
+  call co_min(i, stat=integer_array)
+ 
+  ! 'errmsg' argument shall be noncoindexed
+  !ERROR: to be determined
+  call co_min(c, errmsg=coindexed_character[1])
+ 
+  ! 'errmsg' argument shall be character scalar
+  !ERROR: 'errmsg=' argument has unacceptable rank 1
+  call co_min(d, errmsg=character_array)
+ 
+  ! the error is seen as too many arguments to the co_min() call
+  !ERROR: too many actual arguments for intrinsic 'co_min'
+  call co_min(r, result_image=1, stat=status, errmsg=message, 3.4)
+  
+  ! keyword argument with incorrect name
+  !ERROR: unknown keyword argument to intrinsic 'co_min'
+  call co_min(fake=3.4)
+  
+end program test_co_min