[Flang] Incorrect diagnostic on array constructor using intrinsic functions.

[DanielCChen]

Consider the following code

character(3) :: arr(5)
  arr = [character(3):: 'aa.', 'bb.', 'cc.', 'dd.', 'ee.']
  print*, [integer:: (mod(iachar(arr(i:i-1:-1)(1:1)),5)+1, i=2,5,3)]
  print*, [character(3):: arr(5:2:-1)]
!  arr([4,3,2,1]) = &                                                            !! Same vector script as the line below.
  arr([integer:: (mod(iachar(arr(i:i-1:-1)(1:1)),5)+1, i=2,5,3)]) = &            !! Unexpected rror
   [character(3):: arr(5:2:-1)]
  print *, '10:', arr
end

Flang currently issues a compile time error as

./t.f:6:3: error: Dimension 1 of left-hand side has extent 2, but right-hand side has extent 4
    arr([integer:: (mod(iachar(arr(i:i-1:-1)(1:1)),5)+1, i=2,5,3)]) = &
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The vector subscript is [4,3,2,1] as indicated in the print statement. The error is in incorrect.
All ifort, gfortran and XLF compile and run the code successfully.

[llvmbot]

@llvm/issue-subscribers-flang-frontend

Author: Daniel Chen (DanielCChen)

Consider the following code ``` character(3) :: arr(5) arr = [character(3):: 'aa.', 'bb.', 'cc.', 'dd.', 'ee.'] print*, [integer:: (mod(iachar(arr(i:i-1:-1)(1:1)),5)+1, i=2,5,3)] print*, [character(3):: arr(5:2:-1)] ! arr([4,3,2,1]) = & !! Same vector script as the line below. arr([integer:: (mod(iachar(arr(i:i-1:-1)(1:1)),5)+1, i=2,5,3)]) = & !! Unexpected rror [character(3):: arr(5:2:-1)] print *, '10:', arr end ```

Flang currently issues a compile time error as

./t.f:6:3: error: Dimension 1 of left-hand side has extent 2, but right-hand side has extent 4
    arr([integer:: (mod(iachar(arr(i:i-1:-1)(1:1)),5)+1, i=2,5,3)]) = &
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The vector subscript is [4,3,2,1] as indicated in the print statement. The error is in incorrect.
All ifort, gfortran and XLF compile and run the code successfully.