When defining a previously declared class template, we neglect to set TPARMS_PRIMARY_TEMPLATE for the in-scope template parameters, which the class members go on to inherit, and so the members' DECL_TEMPLATE_PARMS will have empty TPARMS_PRIMARY_TEMPLATE at those levels as well. This causes us to crash when diagnosing a constraint mismatch for an out-of-line declaration of a member of a constrained class template.
This patch fixes this by walking the context to get at the corresponding primary template instead. I spent a while trying to get us to set TPARMS_PRIMARY_TEMPLATE for templated class definitions that are redeclarations, but it proved to be hairy in particular for partial specializations and nested templates. Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk/13? PR c++/109655 gcc/cp/ChangeLog: * pt.cc (push_template_decl): Handle TPARMS_PRIMARY_TEMPLATE being empty when diagnosing a constraint mismatch for an enclosing template scope. Don't bother checking constraints if DECL_PARMS and SCOPE_PARMS are the same. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-class6.C: New test. * g++.dg/cpp2a/concepts-class6a.C: New test. --- gcc/cp/pt.cc | 19 +++++++-- gcc/testsuite/g++.dg/cpp2a/concepts-class6.C | 30 ++++++++++++++ gcc/testsuite/g++.dg/cpp2a/concepts-class6a.C | 40 +++++++++++++++++++ 3 files changed, 86 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-class6.C create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-class6a.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 17bf4d24151..f913b248345 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -6155,12 +6155,25 @@ push_template_decl (tree decl, bool is_friend) decl_parms = TREE_CHAIN (decl_parms); scope_parms = TREE_CHAIN (scope_parms); } - while (decl_parms) + while (decl_parms && decl_parms != scope_parms) { if (!template_requirements_equivalent_p (decl_parms, scope_parms)) { - error ("redeclaration of %qD with different constraints", - TPARMS_PRIMARY_TEMPLATE (TREE_VALUE (decl_parms))); + tree td = TPARMS_PRIMARY_TEMPLATE (TREE_VALUE (decl_parms)); + if (!td) + { + /* FIXME: TPARMS_PRIMARY_TEMPLATE doesn't always get + set for enclosing template scopes. Work around + this by walking the context to obtain the relevant + (primary) template whose constraints we mismatch. */ + int level = TMPL_PARMS_DEPTH (decl_parms); + td = TYPE_TI_TEMPLATE (ctx); + while (!PRIMARY_TEMPLATE_P (td) + || (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (td)) + != level)) + td = TYPE_TI_TEMPLATE (DECL_CONTEXT (td)); + } + error ("redeclaration of %qD with different constraints", td); break; } decl_parms = TREE_CHAIN (decl_parms); diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-class6.C b/gcc/testsuite/g++.dg/cpp2a/concepts-class6.C new file mode 100644 index 00000000000..dcef6a2c9d4 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-class6.C @@ -0,0 +1,30 @@ +// PR c++/109655 +// { dg-do compile { target c++20 } } + +class C { + template<class> + requires true + friend class D; + + template<class> + requires true + class E; +}; + +template<class> +requires true +class D { + void f(); +}; + +template<class T> +void D<T>::f() { } // { dg-error "class D' with different constraints" } + +template<class> +requires true +class C::E { + void f(); +}; + +template<class T> +void C::E<T>::f() { } // { dg-error "class C::E' with different constraints" } diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-class6a.C b/gcc/testsuite/g++.dg/cpp2a/concepts-class6a.C new file mode 100644 index 00000000000..751d13cdf6c --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-class6a.C @@ -0,0 +1,40 @@ +// PR c++/109655 +// { dg-do compile { target c++20 } } + +template<class T> +requires true +class C { + class D; + + template<class> + requires (!!true) + class E; +}; + +template<class T> +requires true +class C<T>::D { + void f(); +}; + +template<class T> // missing "requires true" +void C<T>::D::f() { } // { dg-error "class C' with different constraints" } + +template<class T> +requires true +template<class U> +requires (!!true) +class C<T>::E { + void f(); + void g(); +}; + +template<class T> +requires true +template<class U> +void C<T>::E<U>::f() { } // { dg-error "class C<T>::E' with different constraints" } + +template<class T> +template<class U> +requires (!!true) +void C<T>::E<U>::g() { } // { dg-error "class C' with different constraints" } -- 2.41.0.rc1.10.g9e49351c30