| Message ID | 20200418144920.1479035-1-polacek@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: Fix crash with template spec in different namespace [PR94255] | expand |
On 4/18/20 10:49 AM, Marek Polacek wrote: > This is an ICE on invalid, because we're specializing S::foo in the > wrong namespace. cp_parser_class_specifier_1 parses S::foo in M > and then it tries to push the nested-name-specifier of foo, which is > S. By that, we're breaking the assumption of push_inner_scope that > the pushed scope must be a scope nested inside current scope: current > scope is M, but the namespace context of S is N, and N is not nested > in M, so we fell into an infinite loop in push_inner_scope_r. > > (cp_parser_class_head called check_specialization_namespace which already > gave a permerror.) > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? This doesn't seem to be a regresssion, so OK for stage 1. > PR c++/94255 > * parser.c (cp_parser_class_specifier_1): Check that the scope is > nested inside current scope before pushing it. > > * g++.dg/template/spec41.C: New test. > --- > gcc/cp/parser.c | 7 ++++++- > gcc/testsuite/g++.dg/template/spec41.C | 17 +++++++++++++++++ > 2 files changed, 23 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/template/spec41.C > > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > index d2f3f853cb4..d4482ef5a90 100644 > --- a/gcc/cp/parser.c > +++ b/gcc/cp/parser.c > @@ -23858,7 +23858,12 @@ cp_parser_class_specifier_1 (cp_parser* parser) > if (nested_name_specifier_p) > { > scope = CP_DECL_CONTEXT (TYPE_MAIN_DECL (type)); > - old_scope = push_inner_scope (scope); > + /* SCOPE must be a scope nested inside current scope. */ > + if (is_nested_namespace (current_namespace, > + decl_namespace_context (scope))) > + old_scope = push_inner_scope (scope); > + else > + nested_name_specifier_p = false; > } > type = begin_class_definition (type); > > diff --git a/gcc/testsuite/g++.dg/template/spec41.C b/gcc/testsuite/g++.dg/template/spec41.C > new file mode 100644 > index 00000000000..249fde74c3a > --- /dev/null > +++ b/gcc/testsuite/g++.dg/template/spec41.C > @@ -0,0 +1,17 @@ > +// PR c++/94255 - crash with template spec in different namespace. > +// { dg-do compile { target c++11 } } > + > +namespace N { > + class S { > + template <typename> struct foo; > + }; > + namespace M { > + using S = ::N::S; > + } > +} > + > +namespace N { > + namespace M { > + template <> struct S::foo<int> {}; // { dg-error "specialization of" } > + } > +} > > base-commit: b57e1621eb76ba80c949ad098829aa8171a8c4ab >
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index d2f3f853cb4..d4482ef5a90 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -23858,7 +23858,12 @@ cp_parser_class_specifier_1 (cp_parser* parser) if (nested_name_specifier_p) { scope = CP_DECL_CONTEXT (TYPE_MAIN_DECL (type)); - old_scope = push_inner_scope (scope); + /* SCOPE must be a scope nested inside current scope. */ + if (is_nested_namespace (current_namespace, + decl_namespace_context (scope))) + old_scope = push_inner_scope (scope); + else + nested_name_specifier_p = false; } type = begin_class_definition (type); diff --git a/gcc/testsuite/g++.dg/template/spec41.C b/gcc/testsuite/g++.dg/template/spec41.C new file mode 100644 index 00000000000..249fde74c3a --- /dev/null +++ b/gcc/testsuite/g++.dg/template/spec41.C @@ -0,0 +1,17 @@ +// PR c++/94255 - crash with template spec in different namespace. +// { dg-do compile { target c++11 } } + +namespace N { + class S { + template <typename> struct foo; + }; + namespace M { + using S = ::N::S; + } +} + +namespace N { + namespace M { + template <> struct S::foo<int> {}; // { dg-error "specialization of" } + } +}