-Wcase-enum improvements

[Gaius Mulley]

Hello,

the singular/plural fix has been applied to -Wcase-enum and also it has
been extended to include subrange types.  (Maybe the option should be
separated to: -Wcase-enum -Wcase-subrange (and -Wcase enabling both)?).
It could also check for any ordinal type (-Wcase-ordinal maybe), but I
was wondering if the ordinal case warnings might be too aggressive and
cause too much clutter?

regards,
Gaius


Here are the testcode and warning diagnostics in action:

MODULE calendar ;


TYPE
   DayRange = [1..30] ;


PROCEDURE sept1752 (day: DayRange) : BOOLEAN ;
BEGIN
   CASE day OF

   1..2,
   14..30:  RETURN TRUE

   END ;
   RETURN FALSE
END sept1752 ;


BEGIN
   IF sept1752 (4)
   THEN
   END
END calendar.


$ gm2 -Wcase-enum calendar.mod

calendar.mod:10:4: warning: In procedure 'sept1752': not all subrange
values in the CASE statements are specified, hint you either need to
specify each value of 'DayRange' or use an ELSE clause

   10 | CASE day OF
      | ^~~~
calendar.mod:10:4: warning: there are a total of 11 missing values in
the subrange, the CASE statement needs labels (or an ELSE statement) for
the following values: 3..13


MODULE missingclause ;  (*!m2iso+gm2*)


TYPE
   colour = (red, green, blue) ;


PROCEDURE init (c: colour) ;
BEGIN
   CASE c OF

   red,
   blue: (* User forget green.  *)

   END
END init ;


VAR
   rgb: colour ;
BEGIN
   init (rgb)
END missingclause.


$ gm2 -Wcase-enum missingclause.mod
missingclause.mod:10:4: warning: In procedure 'init': not all
enumeration type values in the CASE statements are specified, hint
you either need to specify each value of 'colour' or use an ELSE
clause
   
   10 |    CASE c OF
      |    ^~~~
missingclause.mod:10:4: warning: the missing enumeration field is: green


MODULE subrangecase2 ;  (*!m2iso+gm2*)


TYPE
   DateRange = [1710..1720] ;


PROCEDURE init (d: DateRange) ;
BEGIN
   CASE d OF

   1711..1720: |

   END
END init ;


VAR
   year: DateRange ;
BEGIN
   init (year)
END subrangecase2.


$ gm2 -Wcase-enum subrangecase2.mod
subrangecase2.mod:10:4: warning: In procedure 'init': not all subrange
values in the CASE statements are specified, hint you either need to
specify each value of 'DateRange' or use an ELSE clause
   
   10 |    CASE d OF
      |    ^~~~
subrangecase2.mod:10:4: warning: there is a total of 1 missing values in
the subrange, the CASE statement needs labels (or an ELSE statement) for
the following values: 1710


MODULE subrangecase3 ;  (*!m2iso+gm2*)


TYPE
   DateRange = [1710..1720] ;


PROCEDURE init (d: DateRange) ;
BEGIN
   CASE d OF

   1710: |
   1712..1719: |

   END
END init ;


VAR
   year: DateRange ;
BEGIN
   init (year)
END subrangecase3.


$ gm2 -Wcase-enum subrangecase3.mod
subrangecase3.mod:10:4: warning: In procedure 'init': not all subrange
values in the CASE statements are specified, hint you either need to
specify each value of 'DateRange' or use an ELSE clause

   10 |    CASE d OF
      |    ^~~~
subrangecase3.mod:10:4: warning: there are a total of 2 missing values
in the subrange, the CASE statement needs labels (or an ELSE statement)
for the following values: 1711 and 1720


MODULE subrangecase4 ;  (*!m2iso+gm2*)


TYPE
   DateRange = [1710..1720] ;


PROCEDURE init (d: DateRange) ;
BEGIN
   CASE d OF

   1710: |
   1713..1718: |

   END
END init ;


VAR
   year: DateRange ;
BEGIN
   init (year)
END subrangecase4.


$ gm2 -Wcase-enum subrangecase4.mod

subrangecase4.mod:10:4: warning: In procedure 'init': not all subrange
values in the CASE statements are specified, hint you either need to
specify each value of 'DateRange' or use an ELSE clause

   10 |    CASE d OF
      |    ^~~~
subrangecase4.mod:10:4: warning: there are a total of 4 missing values
in the subrange, the CASE statement needs labels (or an ELSE statement)
for the following values: 1711..1712 and 1719..1720


MODULE subrangecase5 ;  (*!m2iso+gm2*)


TYPE
   alphabet = ['a'..'z'] ;


PROCEDURE init (a: alphabet) ;
BEGIN
   CASE a OF

   'a',
   'e'..'x':

   END
END init ;


VAR
   a: alphabet ;
BEGIN
   init (a)
END subrangecase5.


$ gm2 -Wcase-enum subrangecase5.mod

subrangecase5.mod:10:4: warning: In procedure 'init': not all subrange
values in the CASE statements are specified, hint you either need to
specify each value of 'alphabet' or use an ELSE clause

   10 |    CASE a OF
      |    ^~~~

subrangecase5.mod:10:4: warning: there are a total of 5 missing values
in the subrange, the CASE statement needs labels (or an ELSE statement)
for the following values: 'b'..'d' and 'y'..'z'

MODULE subrangecase6 ;  (*!m2iso+gm2*)


TYPE
   alphabet = [MIN (CHAR)..MAX (CHAR)] ;


PROCEDURE init (a: alphabet) ;
BEGIN
   CASE a OF

   'a',
   'e'..'x':

   END
END init ;


VAR
   a: alphabet ;
BEGIN
   init (a)
END subrangecase6.


$ gm2 -Wcase-enum subrangecase6.mod

subrangecase6.mod:10:4: warning: In procedure 'init': not all subrange
values in the CASE statements are specified, hint you either need to
specify each value of 'alphabet' or use an ELSE clause

   10 |    CASE a OF
      |    ^~~~

subrangecase6.mod:10:4: warning: there are a total of 235 missing values
in the subrange, the CASE statement needs labels (or an ELSE statement)
for the following values: CHR (0)..'`', 'b'..'d' and 'y'..CHR (255)

MODULE subrangecase ;  (*!m2iso+gm2*)


TYPE
   DateRange = [1710..1720] ;


PROCEDURE init (d: DateRange) ;
BEGIN
   CASE d OF

   (* 1710: |  *)
   1711..1719: |
   1720: |

   END
END init ;


VAR
   year: DateRange ;
BEGIN
   init (year)
END subrangecase.


$ gm2 -Wcase-enum subrangecase.mod

subrangecase.mod:10:4: warning: In procedure 'init': not all subrange
values in the CASE statements are specified, hint you either need to
specify each value of 'DateRange' or use an ELSE clause

   10 |    CASE d OF
      |    ^~~~

subrangecase.mod:10:4: warning: there is a total of 1 missing values in
the subrange, the CASE statement needs labels (or an ELSE statement) for
the following values: 1710