[m-rev.] for review: disable_warnings scope

[Paul Bone]

On Thu, Jan 19, 2017 at 10:47:19AM +1100, Zoltan Somogyi wrote:
> 
> The attached diff implements option (a), as the above email and the reply
> to it agreed. It fixes the failure of the require_tailrec_1 test case in MLDS grades.
> 
> Once this is installed, we can publically document the ability to disable
> warnings about non-tail recursive calls.
> 
> For review by anyone.
> 


> diff --git a/compiler/ml_code_gen.m b/compiler/ml_code_gen.m
> index ea2dc5d..3f6a469 100644
> --- a/compiler/ml_code_gen.m
> +++ b/compiler/ml_code_gen.m
> @@ -666,19 +667,47 @@ ml_gen_goal_expr(GoalExpr, CodeModel, Context, GoalInfo, Decls, Statements,
>          ml_gen_negation(SubGoal, CodeModel, Context, Decls, Statements, !Info)
>      ;
>          GoalExpr = scope(Reason, SubGoal),
> -        ( if
> -            Reason = from_ground_term(TermVar, from_ground_term_construct)
> -        then
> +        (
> +            Reason = from_ground_term(TermVar, from_ground_term_construct),
>              ml_gen_ground_term(TermVar, SubGoal, Statements, !Info),
>              Decls = []
> -        else
> +        ;
> +            ( Reason = from_ground_term(_, from_ground_term_deconstruct)
> +            ; Reason = from_ground_term(_, from_ground_term_other)
> +            ; Reason = promise_purity(_)
> +            ; Reason = require_detism(_)
> +            ; Reason = require_complete_switch(_)
> +            ; Reason = require_switch_arms_detism(_, _)
> +            ; Reason = trace_goal(_, _, _, _, _)
> +            ; Reason = loop_control(_, _, _)                    % XXX NYI

Loop control isn't implemented for the MLDS.  We can throw an exception here
and if it's implmeneted in the future we'll know to come back and fix it.

> +            ),
> +            ml_gen_goal(CodeModel, SubGoal, Decls, Statements, !Info)
> +        ;
> +            ( Reason = exist_quant(_)
> +            ; Reason = commit(_)
> +            ; Reason = barrier(_)
> +            ; Reason = promise_solutions(_, _)
> +            ),
>              ml_gen_commit(SubGoal, CodeModel, Context, Decls, Statements,
>                  !Info)
> +        ;
> +            Reason = disable_warnings(HeadWarning, TailWarnings),
> +            ml_gen_info_get_disabled_warnings(!.Info, Warnings0),
> +            set.insert_list([HeadWarning | TailWarnings], Warnings0, Warnings),
> +            ml_gen_info_set_disabled_warnings(Warnings, !Info),
> +            ml_gen_commit(SubGoal, CodeModel, Context, Decls, Statements,
> +                !Info),

What's the purpose of ml_gen_commit here?  Why not ml_gen_goal?

> +            ml_gen_info_set_disabled_warnings(Warnings0, !Info)
> +        ;
> +            Reason = from_ground_term(_, from_ground_term_initial),
> +            % These should have been replaced by one of the other
> +            % from_ground_term_* scopes.
> +            unexpected($module, "unexpected from_ground_term_initial")
>          )
>      ;
>          GoalExpr = shorthand(_),
> -        % these should have been expanded out by now
> -        unexpected($module, $pred, "unexpected shorthand")
> +        % These should have been expanded out by now.
> +        unexpected($module, "unexpected shorthand")
>      ).
>  
>  %-----------------------------------------------------------------------------%

The rest is good.  Thanks.


-- 
Paul Bone
http://paul.bone.id.au