Some syntax of and constraints on sync-all-stmt not enforced by flang frontend

[ktras]

The flang frontend doesn't currently enforce some of the constraints stated in the Fortran 2018 standard in relation to sync-all-stmt. This is shown in a semantics test for sync-all-stmt which uses the XFAIL directive so that the test passes and uses ERROR directives with to be determined error messages where errors should occur, but do not currently. When the XFAIL directive and all of the ERROR directives with to be determined error messages are removed, the test passes, as the non-standard-conforming statements are not caught.

Constraints on sync-all-stmt not currently enforced:

• C1172 - that no specifier shall appear more than once in a given sync-stat-list
  • L62-68

  •  ! No specifier shall appear more than once in a given sync-stat-list
     !ERROR: to be determined
     sync all(stat=sync_status, stat=superfluous_stat)
    
     ! No specifier shall appear more than once in a given sync-stat-list
     !ERROR: to be determined
     sync all(errmsg=error_message, errmsg=superfluous_errmsg)
    

• C1173 - that a stat-variable or errmsg-variable in a sync-stat shall not be a coindexed object.
  • L72-78

  •  ! Check constraint C1173 from the Fortran 2018 standard
     !ERROR: to be determined
     sync all(stat=co_indexed_integer[1])
    
     ! Check constraint C1173 from the Fortran 2018 standard
     !ERROR: to be determined
     sync all(errmsg=co_indexed_character[1])
    

[llvmbot]

@llvm/issue-subscribers-flang-frontend

[ktras]

I just opened differential D133070 to address this.

[ktras]

I abandoned differential D133070 and simplified it and opened a new differential D136104 which includes changes that addresses this issue. The patch has landed and so this issue is now closed.