| Message ID | 66a1c9fb-3e86-1556-5804-7a8abcd448f4@oracle.com |
|---|---|
| State | New |
| Headers | show |
OK. On Fri, Jan 13, 2017 at 5:58 PM, Paolo Carlini <paolo.carlini@oracle.com> wrote: > Hi, > > On 13/01/2017 18:33, Jason Merrill wrote: >> >> On Fri, Jan 13, 2017 at 11:42 AM, Paolo Carlini >> <paolo.carlini@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. > > I see, thanks a lot. The below passes testing on x86_64-linux. > > Paolo. > > ///////////////////////
Index: c-family/c-common.c =================================================================== --- c-family/c-common.c (revision 244405) +++ c-family/c-common.c (working copy) @@ -7419,16 +7419,18 @@ set_underlying_type (tree x) if (TYPE_NAME (TREE_TYPE (x)) == 0) TYPE_NAME (TREE_TYPE (x)) = x; } - else if (TREE_TYPE (x) != error_mark_node - && DECL_ORIGINAL_TYPE (x) == NULL_TREE) + else if (DECL_ORIGINAL_TYPE (x) == NULL_TREE) { tree tt = TREE_TYPE (x); DECL_ORIGINAL_TYPE (x) = tt; - tt = build_variant_type_copy (tt); - TYPE_STUB_DECL (tt) = TYPE_STUB_DECL (DECL_ORIGINAL_TYPE (x)); - TYPE_NAME (tt) = x; - TREE_USED (tt) = TREE_USED (x); - TREE_TYPE (x) = tt; + if (tt != error_mark_node) + { + tt = build_variant_type_copy (tt); + TYPE_STUB_DECL (tt) = TYPE_STUB_DECL (DECL_ORIGINAL_TYPE (x)); + TYPE_NAME (tt) = x; + TREE_USED (tt) = TREE_USED (x); + TREE_TYPE (x) = tt; + } } } Index: testsuite/g++.dg/cpp0x/pr71737.C =================================================================== --- testsuite/g++.dg/cpp0x/pr71737.C (revision 0) +++ testsuite/g++.dg/cpp0x/pr71737.C (working copy) @@ -0,0 +1,13 @@ +// PR c++/78765 +// { dg-do compile { target c++11 } } + +template <template <typename ...> class TT> +struct quote { + template <typename ...Ts> + using apply = TT<Ts...>; // { dg-error "pack expansion" } +}; + +template <typename> +using to_int_t = int; + +using t = quote<quote<to_int_t>::apply>::apply<int>;