[flang][NFC] Make semantics test dosemantics03.f90 warning-correct

[ekieri]

Summary

This is a preparation for D125804, which makes test_errors.py test
warnings the same way it already tests errors, i.e., assert that the
emitted and expected errors are identical. The following changes are
made to the test:

• Add the WARNING directive where warnings are expected.
• Remove -Werror in the RUN line. It does not serve much purpose here: with -Werror flang makes compilation fail in the presence of warnings, but warnings are still printed as warnings and not as errors. And I anyway find it better to test the warnings as warnings instead of promoting them and test both warnings and errors as errors.
• Update the header comment describing the test case, mostly in response to the removal of -Werror.
• Remove the reference to 'issue 458', referring to https://github.com/flang-compiler/f18/issues/458, from the header. I think the relevant reference here is to C1120 of the standard, and references to bug trackers from other projects (from before upstreaming) can be confusing.

[PeteSteinfeld]

Looks good!

Thanks for cleaning this up.

flang/test/Semantics/dosemantics03.f90

-! RUN: %python %S/test_errors.py %s %flang_fc1 -pedantic -Werror
-
-! Issue 458 -- semantic checks for a normal DO loop.  The DO variable
-! and the initial, final, and step expressions must be INTEGER if the
-! options for standard conformance and turning warnings into errors
-! are both in effect.  This test turns on the options for standards
-! conformance and turning warnings into errors.  This produces error
-! messages for the cases where REAL and DOUBLE PRECISION variables
-! and expressions are used in the DO controls.
-
+! RUN: %python %S/test_errors.py %s %flang_fc1 -pedantic
+!
 ! C1120 -- DO variable (and associated expressions) must be INTEGER.
 ! This is extended by allowing REAL and DOUBLE PRECISION
+!
+! The standard requires the DO variable and the initial, final, and step
+! expressions to be INTEGER. As an extension, we do however allow them to be
+! REAL or DOUBLE PRECISION. This test turns on the option for standard
+! conformance checking to test that we get portability warnings for these
+! cases. We also check that other types, such as CHARACTER and LOGICAL, yield
+! errors when used in the DO controls.
 
 MODULE share
   INTEGER :: intvarshare
   REAL :: realvarshare
   DOUBLE PRECISION :: dpvarshare
 END MODULE share
 
 PROGRAM do_issue_458

 
 ! DO variables
 ! INTEGER DO variable
   DO ivar = 1, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! REAL DO variable
+!WARNING: DO controls should be INTEGER
   DO rvar = 1, 10, 3
     PRINT *, "rvar is: ", rvar
   END DO
 
 ! DOUBLE PRECISISON DO variable
+!WARNING: DO controls should be INTEGER
   DO dvar = 1, 10, 3
     PRINT *, "dvar is: ", dvar
   END DO
 
 ! Pointer to INTEGER DO variable
   ALLOCATE(pivar)
   DO pivar = 1, 10, 3
     PRINT *, "pivar is: ", pivar
   END DO
 
 ! Pointer to REAL DO variable
   ALLOCATE(prvar)
+!WARNING: DO controls should be INTEGER
   DO prvar = 1, 10, 3
     PRINT *, "prvar is: ", prvar
   END DO
 
 ! Pointer to DOUBLE PRECISION DO variable
   ALLOCATE(pdvar)
+!WARNING: DO controls should be INTEGER
   DO pdvar = 1, 10, 3
     PRINT *, "pdvar is: ", pdvar
   END DO
 
 ! CHARACTER DO variable
 !ERROR: DO controls should be INTEGER
   DO chvar = 1, 10, 3
     PRINT *, "chvar is: ", chvar
!ERROR: No explicit type declared for 'undeclared'
   END DO
 
 ! Shared association INTEGER DO variable
   DO intvarshare = 1, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Shared association REAL DO variable
+!WARNING: DO controls should be INTEGER
   DO realvarshare = 1, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Shared association DOUBLE PRECISION DO variable
+!WARNING: DO controls should be INTEGER
   DO dpvarshare = 1, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Initial expressions
 ! REAL initial expression
+!WARNING: DO controls should be INTEGER
   DO ivar = rvar, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! DOUBLE PRECISION initial expression
+!WARNING: DO controls should be INTEGER
   DO ivar = dvar, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to INTEGER initial expression
   DO ivar = pivar, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to REAL initial expression
+!WARNING: DO controls should be INTEGER
   DO ivar = prvar, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to DOUBLE PRECISION initial expression
+!WARNING: DO controls should be INTEGER
   DO ivar = pdvar, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! LOGICAL initial expression
 !ERROR: DO controls should be INTEGER
   DO ivar = lvar, 10, 3
     PRINT *, "ivar is: ", ivar

 ! Invalid initial expression
 !ERROR: Integer literal is too large for INTEGER(KIND=4)
   DO ivar = -2147483648_4, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Final expression
 ! REAL final expression
+!WARNING: DO controls should be INTEGER
   DO ivar = 1, rvar, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! DOUBLE PRECISION final expression
+!WARNING: DO controls should be INTEGER
   DO ivar = 1, dvar, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to INTEGER final expression
   DO ivar = 1, pivar, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to REAL final expression
+!WARNING: DO controls should be INTEGER
   DO ivar = 1, prvar, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to DOUBLE PRECISION final expression
+!WARNING: DO controls should be INTEGER
   DO ivar = pdvar, 10, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! COMPLEX final expression
 !ERROR: DO controls should be INTEGER
   DO ivar = 1, cvar, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Invalid final expression
 !ERROR: Integer literal is too large for INTEGER(KIND=4)
   DO ivar = 1, -2147483648_4, 3
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Step expression
 ! REAL step expression
+!WARNING: DO controls should be INTEGER
   DO ivar = 1, 10, rvar
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! DOUBLE PRECISION step expression
+!WARNING: DO controls should be INTEGER
   DO ivar = 1, 10, dvar
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to INTEGER step expression
   DO ivar = 1, 10, pivar
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to REAL step expression
+!WARNING: DO controls should be INTEGER
   DO ivar = 1, 10, prvar
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! Pointer to DOUBLE PRECISION step expression
+!WARNING: DO controls should be INTEGER
   DO ivar = 1, 10, pdvar
     PRINT *, "ivar is: ", ivar
   END DO
 
 ! COMPLEX Step expression
 !ERROR: DO controls should be INTEGER
   DO ivar = 1, 10, cvar
     PRINT *, "ivar is: ", ivar