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? Jason
