Message ID | 20230223215245.1513700-1-ppalka@redhat.com |
---|---|
State | New |
Headers | show |
Series | c++: non-dependent variable template-id [PR108848] | expand |
On 2/23/23 16:52, Patrick Palka wrote: > Here we're incorrectly treating the non-dependent variable template-id > tag<int> as dependent ever since r226642 gave variable TEMPLATE_ID_EXPR > an empty type which causes the call to finish_template_variable from > finish_id_expression_1 to be dead code at template parse time. Thus > we're led into treating tag<int>.var<void> as a dependent name at parse > time. > > This patch fixes this by making finish_id_expression_1 instantiate a > variable template-id as long as the template and args are non-dependent > according to the dependence test in lookup_and_finish_template_variable > and not according to type_dependent_expression_p. This patch also moves > said dependence test into finish_template_variable. > > bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk? > > PR c++/108848 > > gcc/cp/ChangeLog: > > * pt.cc (finish_template_variable): Move dependence check > to here from ... > (lookup_and_finish_template_variable): ... here. > * semantics.cc (finish_id_expression_1): Call > finish_template_variable sooner and regardless of > type_dependent_expression_p. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp1y/noexcept1.C: Don't expect bogus "different > exception specifier" error. Expect a separate "not usable > in a constant expression" error. > * g++.dg/cpp1y/var-templ70.C: New test. > * g++.dg/cpp1y/var-templ71.C: New test. > --- > gcc/cp/pt.cc | 18 ++++++++++-------- > gcc/cp/semantics.cc | 14 +++++--------- > gcc/testsuite/g++.dg/cpp1y/noexcept1.C | 4 ++-- > gcc/testsuite/g++.dg/cpp1y/var-templ70.C | 20 ++++++++++++++++++++ > gcc/testsuite/g++.dg/cpp1y/var-templ71.C | 10 ++++++++++ > 5 files changed, 47 insertions(+), 19 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp1y/var-templ70.C > create mode 100644 gcc/testsuite/g++.dg/cpp1y/var-templ71.C > > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc > index b1ac7d4beb4..11c0baa0119 100644 > --- a/gcc/cp/pt.cc > +++ b/gcc/cp/pt.cc > @@ -10317,7 +10317,8 @@ lookup_template_variable (tree templ, tree arglist) > return build2 (TEMPLATE_ID_EXPR, NULL_TREE, templ, arglist); > } > > -/* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */ > +/* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's > + not dependent. */ > > tree > finish_template_variable (tree var, tsubst_flags_t complain) > @@ -10325,6 +10326,12 @@ finish_template_variable (tree var, tsubst_flags_t complain) > tree templ = TREE_OPERAND (var, 0); > tree arglist = TREE_OPERAND (var, 1); > > + /* If the template or arguments are dependent, then we > + can't instantiate yet. */ > + if (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (templ)) != 1 > + || any_dependent_template_arguments_p (arglist)) > + return var; > + > tree parms = DECL_TEMPLATE_PARMS (templ); > arglist = coerce_template_parms (parms, arglist, templ, complain); > if (arglist == error_mark_node) > @@ -10352,13 +10359,8 @@ lookup_and_finish_template_variable (tree templ, tree targs, > tsubst_flags_t complain) > { > tree var = lookup_template_variable (templ, targs); > - if (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (templ)) == 1 > - && !any_dependent_template_arguments_p (targs)) > - { > - var = finish_template_variable (var, complain); > - mark_used (var); > - } > - > + var = finish_template_variable (var, complain); > + mark_used (var); > return convert_from_reference (var); > } > > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc > index c2df0b69b30..a18364dda4f 100644 > --- a/gcc/cp/semantics.cc > +++ b/gcc/cp/semantics.cc > @@ -4208,6 +4208,11 @@ finish_id_expression_1 (tree id_expression, > } > else > { We could use a comment here about why this needs to come before checking type_dep*. OK with that change. > + if (TREE_CODE (decl) == TEMPLATE_ID_EXPR > + && variable_template_p (TREE_OPERAND (decl, 0)) > + && !concept_check_p (decl)) > + decl = finish_template_variable (decl); > + > bool dependent_p = type_dependent_expression_p (decl); > > /* If the declaration was explicitly qualified indicate > @@ -4275,15 +4280,6 @@ finish_id_expression_1 (tree id_expression, > /* Replace an evaluated use of the thread_local variable with > a call to its wrapper. */ > decl = wrap; > - else if (TREE_CODE (decl) == TEMPLATE_ID_EXPR > - && !dependent_p > - && variable_template_p (TREE_OPERAND (decl, 0)) > - && !concept_check_p (decl)) > - { > - decl = finish_template_variable (decl); > - mark_used (decl); > - decl = convert_from_reference (decl); > - } > else if (concept_check_p (decl)) > { > /* Nothing more to do. All of the analysis for concept checks > diff --git a/gcc/testsuite/g++.dg/cpp1y/noexcept1.C b/gcc/testsuite/g++.dg/cpp1y/noexcept1.C > index 86e46c96148..caa4a056a2e 100644 > --- a/gcc/testsuite/g++.dg/cpp1y/noexcept1.C > +++ b/gcc/testsuite/g++.dg/cpp1y/noexcept1.C > @@ -5,9 +5,9 @@ template <int> bool b; > > template <typename> > struct C { > - template <typename> friend int foo() noexcept(b<1>); // { dg-error "not usable in a constant expression|different exception specifier" } > + template <typename> friend int foo() noexcept(b<1>); // { dg-error "not usable in a constant expression" } > }; > > -template <typename> int foo() noexcept(b<1>); > +template <typename> int foo() noexcept(b<1>); // { dg-error "not usable in a constant expression" } > > auto a = C<int>(); > diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ70.C b/gcc/testsuite/g++.dg/cpp1y/var-templ70.C > new file mode 100644 > index 00000000000..aed2db5de88 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp1y/var-templ70.C > @@ -0,0 +1,20 @@ > +// PR c++/108848 > +// { dg-do compile { target c++14 } } > + > +template<class T> > +struct tag_t { > + template<class Sig> > + static constexpr const Sig* var = nullptr; > + > + template<class Sig> > + static const Sig* fun(); > +}; > + > +template <class T> > +constexpr tag_t<T> tag {}; > + > +template<class T> > +void f() { > + tag<int>.var<void>; // { dg-bogus "expected 'template' keyword" } > + tag<int>.fun<void>(); // { dg-bogus "expected 'template' keyword" } > +}; > diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ71.C b/gcc/testsuite/g++.dg/cpp1y/var-templ71.C > new file mode 100644 > index 00000000000..df33c62ec3e > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp1y/var-templ71.C > @@ -0,0 +1,10 @@ > +// Verify we can evaluate a non-dependent variable template-id ahead of time. > +// { dg-do compile { target c++14 } } > + > +template<class Sig> > +static constexpr int var = 0; > + > +template<class T> > +void f() { > + static_assert(var<void>); // { dg-error "assert" } > +}
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index b1ac7d4beb4..11c0baa0119 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -10317,7 +10317,8 @@ lookup_template_variable (tree templ, tree arglist) return build2 (TEMPLATE_ID_EXPR, NULL_TREE, templ, arglist); } -/* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */ +/* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's + not dependent. */ tree finish_template_variable (tree var, tsubst_flags_t complain) @@ -10325,6 +10326,12 @@ finish_template_variable (tree var, tsubst_flags_t complain) tree templ = TREE_OPERAND (var, 0); tree arglist = TREE_OPERAND (var, 1); + /* If the template or arguments are dependent, then we + can't instantiate yet. */ + if (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (templ)) != 1 + || any_dependent_template_arguments_p (arglist)) + return var; + tree parms = DECL_TEMPLATE_PARMS (templ); arglist = coerce_template_parms (parms, arglist, templ, complain); if (arglist == error_mark_node) @@ -10352,13 +10359,8 @@ lookup_and_finish_template_variable (tree templ, tree targs, tsubst_flags_t complain) { tree var = lookup_template_variable (templ, targs); - if (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (templ)) == 1 - && !any_dependent_template_arguments_p (targs)) - { - var = finish_template_variable (var, complain); - mark_used (var); - } - + var = finish_template_variable (var, complain); + mark_used (var); return convert_from_reference (var); } diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc index c2df0b69b30..a18364dda4f 100644 --- a/gcc/cp/semantics.cc +++ b/gcc/cp/semantics.cc @@ -4208,6 +4208,11 @@ finish_id_expression_1 (tree id_expression, } else { + if (TREE_CODE (decl) == TEMPLATE_ID_EXPR + && variable_template_p (TREE_OPERAND (decl, 0)) + && !concept_check_p (decl)) + decl = finish_template_variable (decl); + bool dependent_p = type_dependent_expression_p (decl); /* If the declaration was explicitly qualified indicate @@ -4275,15 +4280,6 @@ finish_id_expression_1 (tree id_expression, /* Replace an evaluated use of the thread_local variable with a call to its wrapper. */ decl = wrap; - else if (TREE_CODE (decl) == TEMPLATE_ID_EXPR - && !dependent_p - && variable_template_p (TREE_OPERAND (decl, 0)) - && !concept_check_p (decl)) - { - decl = finish_template_variable (decl); - mark_used (decl); - decl = convert_from_reference (decl); - } else if (concept_check_p (decl)) { /* Nothing more to do. All of the analysis for concept checks diff --git a/gcc/testsuite/g++.dg/cpp1y/noexcept1.C b/gcc/testsuite/g++.dg/cpp1y/noexcept1.C index 86e46c96148..caa4a056a2e 100644 --- a/gcc/testsuite/g++.dg/cpp1y/noexcept1.C +++ b/gcc/testsuite/g++.dg/cpp1y/noexcept1.C @@ -5,9 +5,9 @@ template <int> bool b; template <typename> struct C { - template <typename> friend int foo() noexcept(b<1>); // { dg-error "not usable in a constant expression|different exception specifier" } + template <typename> friend int foo() noexcept(b<1>); // { dg-error "not usable in a constant expression" } }; -template <typename> int foo() noexcept(b<1>); +template <typename> int foo() noexcept(b<1>); // { dg-error "not usable in a constant expression" } auto a = C<int>(); diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ70.C b/gcc/testsuite/g++.dg/cpp1y/var-templ70.C new file mode 100644 index 00000000000..aed2db5de88 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/var-templ70.C @@ -0,0 +1,20 @@ +// PR c++/108848 +// { dg-do compile { target c++14 } } + +template<class T> +struct tag_t { + template<class Sig> + static constexpr const Sig* var = nullptr; + + template<class Sig> + static const Sig* fun(); +}; + +template <class T> +constexpr tag_t<T> tag {}; + +template<class T> +void f() { + tag<int>.var<void>; // { dg-bogus "expected 'template' keyword" } + tag<int>.fun<void>(); // { dg-bogus "expected 'template' keyword" } +}; diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ71.C b/gcc/testsuite/g++.dg/cpp1y/var-templ71.C new file mode 100644 index 00000000000..df33c62ec3e --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/var-templ71.C @@ -0,0 +1,10 @@ +// Verify we can evaluate a non-dependent variable template-id ahead of time. +// { dg-do compile { target c++14 } } + +template<class Sig> +static constexpr int var = 0; + +template<class T> +void f() { + static_assert(var<void>); // { dg-error "assert" } +}