| Message ID | 20200423200948.1949802-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: Lambda in friend of constrained class [PR94645] | expand |
On 4/23/20 4:09 PM, Patrick Palka wrote: > In the testcase below, when grokfndecl processes the operator() decl for the > lambda inside the friend function foo, processing_template_decl is rightly 1, > but template_class_depth on the lambda's closure type incorrectly returns 0 > instead of 1. > > Since processing_template_decl > template_class_depth, this makes grokfndecl > think that the operator() has its own set of template arguments, and so we > attach the innermost set of constraints -- those belonging to struct l -- to the > operator() decl. We then get confused when checking constraints_satisfied_p on > the operator() because it doesn't have template information and yet has > constraints associated with it. > > This patch fixes template_class_depth to return the correct template nesting > level in cases like these, so that when it hits a friend function it walks into > the DECL_FRIEND_CONTEXT of the friend rather than into the CP_DECL_CONTEXT. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, and also tested on cmcstl2, > range-v3, and fmt libraries. OK. > gcc/cp/ChangeLog: > > PR c++/94645 > * pt.c (template_class_depth): Walk into the DECL_FRIEND_CONTEXT of a > friend declaration rather than into its CP_DECL_CONTEXT. > > gcc/testsuite/ChangeLog: > > PR c++/94645 > * g++.dg/cpp2a/concepts-lambda6.C: New test. > --- > gcc/cp/pt.c | 7 ++++++- > gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C | 19 +++++++++++++++++++ > 2 files changed, 25 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C > > diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c > index 0e3e7b2039a..08a35c41007 100644 > --- a/gcc/cp/pt.c > +++ b/gcc/cp/pt.c > @@ -390,7 +390,12 @@ template_class_depth (tree type) > ++depth; > > if (DECL_P (type)) > - type = CP_DECL_CONTEXT (type); > + { > + if (tree fctx = DECL_FRIEND_CONTEXT (type)) > + type = fctx; > + else > + type = CP_DECL_CONTEXT (type); > + } > else if (LAMBDA_TYPE_P (type) && LAMBDA_TYPE_EXTRA_SCOPE (type)) > type = LAMBDA_TYPE_EXTRA_SCOPE (type); > else > diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C > new file mode 100644 > index 00000000000..244421e64ec > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C > @@ -0,0 +1,19 @@ > +// PR c++/94632 > +// { dg-do compile { target concepts } } > + > +struct unordered_map { > + int cend() const noexcept; > +}; > + > +template <typename a> concept HasMapInterface = requires(a t) { t.cend(); }; > + > +template <typename Mapper> requires HasMapInterface<decltype(Mapper::map())> > +struct l { > + friend void foo(l opt) { ([]() {})(); } > +}; > + > +struct p { > + static unordered_map map(); > +}; > + > +void g(l<p> *y) { foo(*y); } >
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 0e3e7b2039a..08a35c41007 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -390,7 +390,12 @@ template_class_depth (tree type) ++depth; if (DECL_P (type)) - type = CP_DECL_CONTEXT (type); + { + if (tree fctx = DECL_FRIEND_CONTEXT (type)) + type = fctx; + else + type = CP_DECL_CONTEXT (type); + } else if (LAMBDA_TYPE_P (type) && LAMBDA_TYPE_EXTRA_SCOPE (type)) type = LAMBDA_TYPE_EXTRA_SCOPE (type); else diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C new file mode 100644 index 00000000000..244421e64ec --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C @@ -0,0 +1,19 @@ +// PR c++/94632 +// { dg-do compile { target concepts } } + +struct unordered_map { + int cend() const noexcept; +}; + +template <typename a> concept HasMapInterface = requires(a t) { t.cend(); }; + +template <typename Mapper> requires HasMapInterface<decltype(Mapper::map())> +struct l { + friend void foo(l opt) { ([]() {})(); } +}; + +struct p { + static unordered_map map(); +}; + +void g(l<p> *y) { foo(*y); }