Index: flang/test/Semantics/event01.f90
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--- /dev/null
+++ flang/test/Semantics/event01.f90
@@ -0,0 +1,110 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+! This test checks for semantic errors in event post statements based on the
+! statement specification in section 11.6.7 of the Fortran 2018 standard.
+
+program test_event_post
+  use iso_fortran_env, only : event_type
+  implicit none
+
+  ! event_type variables must be coarrays
+  type(event_type) non_coarray
+
+  type(event_type) concert[*], occurrences(2)[*]
+  integer non_event[*], sync_status, co_indexed_integer[*], superfluous_stat, non_scalar(1)
+  character(len=128) error_message, co_indexed_character[*], superfluous_errmsg
+  logical invalid_type
+
+  !___ standard-conforming statement ___
+
+  event post(concert)
+  event post(concert[1])
+  event post(occurrences(1))
+  event post(occurrences(1)[1])
+  event post(concert, stat=sync_status)
+  event post(concert,                   errmsg=error_message)
+  event post(concert, stat=sync_status, errmsg=error_message)
+
+  !___ non-standard-conforming statement ___
+
+  !______ invalid event-variable ____________________________
+
+  ! event-variable must be event_type
+  event post(non_event)
+
+  ! event-variable must be a coarray
+  event post(non_coarray)
+
+  ! event-variable must be a scalar variable
+  event post(occurrences)
+
+  ! event-variable must be a scalar variable
+  event post(occurrences[1])
+
+  ! event-variable has an unknown keyword argument
+  !ERROR: expected ')'
+  event post(event=concert)
+
+  !______ invalid sync-stat-lists: invalid stat= ____________
+
+  ! Invalid stat-variable keyword
+  !ERROR: expected ')'
+  event post(concert, status=sync_status)
+
+  ! Stat-variable must an integer scalar
+  event post(concert, stat=invalid_type)
+
+  ! Stat-variable must an integer scalar
+  event post(concert, stat=non_scalar)
+
+  ! Invalid sync-stat-list: missing stat-variable
+  !ERROR: expected ')'
+  event post(concert, stat)
+
+  ! Invalid sync-stat-list: missing 'stat='
+  !ERROR: expected ')'
+  event post(concert, sync_status)
+
+  !______ invalid sync-stat-lists: invalid errmsg= ____________
+
+  ! Invalid errmsg-variable keyword
+  !ERROR: expected ')'
+  event post(concert, errormsg=error_message)
+
+  ! Invalid errmsg-variable argument typing
+  event post(concert, errmsg=invalid_type)
+
+  ! Invalid sync-stat-list: missing 'errmsg='
+  !ERROR: expected ')'
+  event post(concert, error_message)
+
+  ! Invalid sync-stat-list: missing errmsg-variable
+  !ERROR: expected ')'
+  event post(concert, errmsg)
+
+  !______ invalid event-variable: redundant event-variable ____________
+
+  ! Too many arguments
+  !ERROR: expected ')'
+  event post(concert, occurrences(1))
+
+  ! Too many arguments
+  !ERROR: expected ')'
+  event post(concert, occurrences(1), stat=sync_status, errmsg=error_message)
+
+  !______ invalid sync-stat-lists: redundant sync-stat-list ____________
+
+  ! No specifier shall appear more than once in a given sync-stat-list
+  event post(concert, stat=sync_status, stat=superfluous_stat)
+
+  ! No specifier shall appear more than once in a given sync-stat-list
+  event post(concert, errmsg=error_message, errmsg=superfluous_errmsg)
+
+  !______ invalid sync-stat-lists: coindexed stat-variable ____________
+
+  ! Check constraint C1173 from the Fortran 2018 standard
+  event post(concert, stat=co_indexed_integer[1])
+
+  ! Check constraint C1173 from the Fortran 2018 standard
+  event post(concert, errmsg=co_indexed_character[1])
+
+end program test_event_post