On Fri, Apr 13, 2018 at 1:05 PM, Paolo Carlini <paolo.carl...@oracle.com> wrote:
> Hi,
> On 13/04/2018 16:06, Jason Merrill wrote:
>> On Fri, Apr 13, 2018 at 5:05 AM, Paolo Carlini <paolo.carl...@oracle.com>
>> wrote:
>>> Hi,
>>> in this error-recovery regression, after a sensible error message issued
>>> by
>>> cxx_constant_init, store_init_value stores an error_mark_node as
>>> DECL_INITIAL of the VAR_DECL for 'j'. This error_mark_node reappears much
>>> later, to cause a crash during gimplification. As far as I know, the
>>> choice
>>> of storing error_mark_nodes too is the outcome of a rather delicate
>>> error-recovery strategy and I don't think we want to revisit it at this
>>> time, thus the remaining option is catching later the error_mark_node, at
>>> a
>>> "good" time. I note, in passing, that the do loop in gimplify_expr which
>>> uses the crashing STRIP_USELESS_TYPE_CONVERSION seems a bit lacking from
>>> the
>>> error-recovery point of view, because at each iteration it *does* cover
>>> for
>>> error_operand_p (save_expr) but only immediately after the call, when
>>> it's
>>> too late.
>>> All the above said, I believe that at least for the 8.1.0 needs we may
>>> want
>>> to catch the error_mark_node in cp_build_modify_expr, when we are
>>> handling
>>> the assignment 'a.n = j;': convert_for_assignment produces a NOP_EXPR
>>> from
>>> the VAR_DECL for 'j' which then cp_convert_and_check regenerates (deep in
>>> convert_to_integer_1 via maybe_fold_build1_loc) in the final bare-bone
>>> form,
>>> with the error_mark_node as the first operand. Passes testing on
>>> x86_64-linux.
>> We should avoid wrapping an error_mark_node in a NOP_EXPR in the first
>> place.
> Basing on my analysis, that's easy to do, in convert_to_integer_1.

Are we passing an error_mark_node down into convert_to_integer_1?
Where are we folding away the VAR_DECL?


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