On Fri, Jan 13, 2017 at 11:42 AM, Paolo Carlini <paolo.carl...@oracle.com> wrote: > Hi, > > On 13/01/2017 15:51, Nathan Sidwell wrote: >> >> On 01/13/2017 09:45 AM, Paolo Carlini wrote: >>> >>> Hi, >>> >>> in this error recovery issue get_underlying_template crashes when >>> TYPE_TEMPLATE_INFO_MAYBE_ALIAS is applied to a null orig_type. Simply >>> checking for that condition appears to solve the issue in a >>> straightforward way. Tested x86_64-linux. >> >> >> Wouldn't it be better if a scrogged alias got error_mark_node as the >> underlying type? (I have no idea whether that's an easy thing to >> accomplish) > > Your reply, Nathan, led me to investigate where exactly DECL_ORIGINAL_TYPE > becomes null, and turns out that in tsubst_decl we have code actively doing > that. That same code, a few lines below, only sets TYPE_DEPENDENT_P_VALID to > false if type != error_mark_node. I cannot say to fully understand yet all > the details, but certainly the patchlet below also passes testing. Do you > have comments about this too?
The clearing of DECL_ORIGINAL_TYPE is to allow set_underlying_type to then set it to something more appropriate. That function currently avoids setting DECL_ORIGINAL_TYPE to error_mark_node, perhaps that should be changed. Jason
