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* [gcc r12-7562] c++: merge default targs for function templates [PR65396]
@ 2022-03-09 13:44 Patrick Palka
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From: Patrick Palka @ 2022-03-09 13:44 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:fe548eb8436f3906e6a3c6e3e8707d24e60ec0fa
commit r12-7562-gfe548eb8436f3906e6a3c6e3e8707d24e60ec0fa
Author: Patrick Palka <ppalka@redhat.com>
Date: Wed Mar 9 08:42:19 2022 -0500
c++: merge default targs for function templates [PR65396]
We currently merge default template arguments for class templates, but
not for function templates. This patch fixes this by factoring out the
argument merging logic in redeclare_class_template into a separate
function and using it in duplicate_decls as well.
PR c++/65396
gcc/cp/ChangeLog:
* cp-tree.h (merge_default_template_args): Declare.
* decl.cc (merge_default_template_args): Define, factored out
from redeclare_class_template.
(duplicate_decls): Use it when merging member function template
and free function declarations.
* pt.cc (redeclare_class_template): Factor out default argument
merging logic into merge_default_template_args. Improve location
of a note when there's a template parameter kind mismatch.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/vt-34314.C: Adjust expected location of
"redeclared here" note.
* g++.dg/template/pr92440.C: Likewise.
* g++.old-deja/g++.pt/redecl1.C: Adjust expected location of
"redefinition of default argument" error.
* g++.dg/template/defarg23.C: New test.
* g++.dg/template/defarg23a.C: New test.
Diff:
---
gcc/cp/cp-tree.h | 1 +
gcc/cp/decl.cc | 58 ++++++++++++++++++++++++++++-
gcc/cp/pt.cc | 31 ++-------------
gcc/testsuite/g++.dg/cpp0x/vt-34314.C | 12 +++---
gcc/testsuite/g++.dg/template/defarg23.C | 21 +++++++++++
gcc/testsuite/g++.dg/template/defarg23a.C | 24 ++++++++++++
gcc/testsuite/g++.dg/template/pr92440.C | 4 +-
gcc/testsuite/g++.old-deja/g++.pt/redecl1.C | 12 +++---
8 files changed, 121 insertions(+), 42 deletions(-)
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index cf08e16e172..757711bc03a 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6787,6 +6787,7 @@ extern void note_iteration_stmt_body_end (bool);
extern void determine_local_discriminator (tree);
extern int decls_match (tree, tree, bool = true);
extern bool maybe_version_functions (tree, tree, bool);
+extern bool merge_default_template_args (tree, tree, bool);
extern tree duplicate_decls (tree, tree,
bool hiding = false,
bool was_hidden = false);
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index de41b4de5ed..48763c44518 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -1470,6 +1470,43 @@ duplicate_function_template_decls (tree newdecl, tree olddecl)
return false;
}
+/* OLD_PARMS is the innermost set of template parameters for some template
+ declaration, and NEW_PARMS is the corresponding set of template parameters
+ for a redeclaration of that template. Merge the default arguments within
+ these two sets of parameters. CLASS_P is true iff the template in
+ question is a class template. */
+
+bool
+merge_default_template_args (tree new_parms, tree old_parms, bool class_p)
+{
+ gcc_checking_assert (TREE_VEC_LENGTH (new_parms)
+ == TREE_VEC_LENGTH (old_parms));
+ for (int i = 0; i < TREE_VEC_LENGTH (new_parms); i++)
+ {
+ tree new_parm = TREE_VALUE (TREE_VEC_ELT (new_parms, i));
+ tree old_parm = TREE_VALUE (TREE_VEC_ELT (old_parms, i));
+ tree& new_default = TREE_PURPOSE (TREE_VEC_ELT (new_parms, i));
+ tree& old_default = TREE_PURPOSE (TREE_VEC_ELT (old_parms, i));
+ if (new_default != NULL_TREE && old_default != NULL_TREE)
+ {
+ auto_diagnostic_group d;
+ error ("redefinition of default argument for %q+#D", new_parm);
+ inform (DECL_SOURCE_LOCATION (old_parm),
+ "original definition appeared here");
+ return false;
+ }
+ else if (new_default != NULL_TREE)
+ /* Update the previous template parameters (which are the ones
+ that will really count) with the new default value. */
+ old_default = new_default;
+ else if (class_p && old_default != NULL_TREE)
+ /* Update the new parameters, too; they'll be used as the
+ parameters for any members. */
+ new_default = old_default;
+ }
+ return true;
+}
+
/* If NEWDECL is a redeclaration of OLDDECL, merge the declarations.
If the redeclaration is invalid, a diagnostic is issued, and the
error_mark_node is returned. Otherwise, OLDDECL is returned.
@@ -1990,7 +2027,21 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
template shall be specified on the initial declaration
of the member function within the class template. */
|| CLASSTYPE_TEMPLATE_INFO (CP_DECL_CONTEXT (olddecl))))
- check_redeclaration_no_default_args (newdecl);
+ {
+ check_redeclaration_no_default_args (newdecl);
+
+ if (DECL_TEMPLATE_INFO (olddecl)
+ && DECL_MEMBER_TEMPLATE_P (DECL_TI_TEMPLATE (olddecl)))
+ {
+ tree new_parms = DECL_TEMPLATE_INFO (newdecl)
+ ? DECL_INNERMOST_TEMPLATE_PARMS (DECL_TI_TEMPLATE (newdecl))
+ : INNERMOST_TEMPLATE_PARMS (current_template_parms);
+ tree old_parms
+ = DECL_INNERMOST_TEMPLATE_PARMS (DECL_TI_TEMPLATE (olddecl));
+ merge_default_template_args (new_parms, old_parms,
+ /*class_p=*/false);
+ }
+ }
else
{
tree t1 = FUNCTION_FIRST_USER_PARMTYPE (olddecl);
@@ -2235,6 +2286,11 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
translation unit." */
check_no_redeclaration_friend_default_args
(old_result, new_result);
+
+ tree new_parms = DECL_INNERMOST_TEMPLATE_PARMS (newdecl);
+ tree old_parms = DECL_INNERMOST_TEMPLATE_PARMS (olddecl);
+ merge_default_template_args (new_parms, old_parms,
+ /*class_p=*/false);
}
if (!DECL_UNIQUE_FRIEND_P (old_result))
DECL_UNIQUE_FRIEND_P (new_result) = false;
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index d47483dd4f2..c93676ed8d2 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -6274,8 +6274,6 @@ redeclare_class_template (tree type, tree parms, tree cons)
{
tree tmpl_parm;
tree parm;
- tree tmpl_default;
- tree parm_default;
if (TREE_VEC_ELT (tmpl_parms, i) == error_mark_node
|| TREE_VEC_ELT (parms, i) == error_mark_node)
@@ -6286,8 +6284,6 @@ redeclare_class_template (tree type, tree parms, tree cons)
return false;
parm = TREE_VALUE (TREE_VEC_ELT (parms, i));
- tmpl_default = TREE_PURPOSE (TREE_VEC_ELT (tmpl_parms, i));
- parm_default = TREE_PURPOSE (TREE_VEC_ELT (parms, i));
/* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
TEMPLATE_DECL. */
@@ -6303,7 +6299,7 @@ redeclare_class_template (tree type, tree parms, tree cons)
{
auto_diagnostic_group d;
error ("template parameter %q+#D", tmpl_parm);
- inform (input_location, "redeclared here as %q#D", parm);
+ inform (DECL_SOURCE_LOCATION (parm), "redeclared here as %q#D", parm);
return false;
}
@@ -6321,28 +6317,6 @@ redeclare_class_template (tree type, tree parms, tree cons)
return false;
}
- if (tmpl_default != NULL_TREE && parm_default != NULL_TREE)
- {
- /* We have in [temp.param]:
-
- A template-parameter may not be given default arguments
- by two different declarations in the same scope. */
- auto_diagnostic_group d;
- error_at (input_location, "redefinition of default argument for %q#D", parm);
- inform (DECL_SOURCE_LOCATION (tmpl_parm),
- "original definition appeared here");
- return false;
- }
-
- if (parm_default != NULL_TREE)
- /* Update the previous template parameters (which are the ones
- that will really count) with the new default value. */
- TREE_PURPOSE (TREE_VEC_ELT (tmpl_parms, i)) = parm_default;
- else if (tmpl_default != NULL_TREE)
- /* Update the new parameters, too; they'll be used as the
- parameters for any members. */
- TREE_PURPOSE (TREE_VEC_ELT (parms, i)) = tmpl_default;
-
/* Give each template template parm in this redeclaration a
DECL_CONTEXT of the template for which they are a parameter. */
if (TREE_CODE (parm) == TEMPLATE_DECL)
@@ -6352,6 +6326,9 @@ redeclare_class_template (tree type, tree parms, tree cons)
}
}
+ if (!merge_default_template_args (parms, tmpl_parms, /*class_p=*/true))
+ return false;
+
tree ci = get_constraints (tmpl);
tree req1 = ci ? CI_TEMPLATE_REQS (ci) : NULL_TREE;
tree req2 = cons ? CI_TEMPLATE_REQS (cons) : NULL_TREE;
diff --git a/gcc/testsuite/g++.dg/cpp0x/vt-34314.C b/gcc/testsuite/g++.dg/cpp0x/vt-34314.C
index b37cac53223..704a975cc95 100644
--- a/gcc/testsuite/g++.dg/cpp0x/vt-34314.C
+++ b/gcc/testsuite/g++.dg/cpp0x/vt-34314.C
@@ -3,8 +3,8 @@
template<typename Fun, typename... Args> // { dg-error "template parameter" }
struct call;
-template<typename Fun, typename Arg0>
-struct call // { dg-message "note: redeclared here" }
+template<typename Fun, typename Arg0> // { dg-message "note: redeclared here" }
+struct call
{
template<typename Sig>
struct result;
@@ -20,8 +20,8 @@ struct call // { dg-message "note: redeclared here" }
template<typename Fun, int... N> // { dg-error "template parameter" }
struct call2;
-template<typename Fun, int N>
-struct call2 // { dg-message "note: redeclared here" }
+template<typename Fun, int N> // { dg-message "note: redeclared here" }
+struct call2
{
template<typename Sig>
struct result;
@@ -36,8 +36,8 @@ struct call2 // { dg-message "note: redeclared here" }
template<typename Fun, template<typename> class... TT> // { dg-error "template parameter" }
struct call3;
-template<typename Fun, template<typename> class TT>
-struct call3 // { dg-message "note: redeclared here" }
+template<typename Fun, template<typename> class TT> // { dg-message "note: redeclared here" }
+struct call3
{
template<typename Sig>
struct result;
diff --git a/gcc/testsuite/g++.dg/template/defarg23.C b/gcc/testsuite/g++.dg/template/defarg23.C
new file mode 100644
index 00000000000..443d02656cc
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/defarg23.C
@@ -0,0 +1,21 @@
+// PR c++/65396
+// { dg-do compile { target c++11 } }
+
+template<class T> void f();
+template<class T=int> void f();
+
+template<class T=int> void g(); // { dg-message "original definition" }
+template<class T=int> void g(); // { dg-error "redefinition of default" }
+
+template<class T, class U=bool> void h();
+template<class T=char, class U>
+void h() {
+ static_assert(__is_same(T, char), "");
+ static_assert(__is_same(U, bool), "");
+}
+
+int main() {
+ f();
+ g();
+ h();
+}
diff --git a/gcc/testsuite/g++.dg/template/defarg23a.C b/gcc/testsuite/g++.dg/template/defarg23a.C
new file mode 100644
index 00000000000..3de0306112e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/defarg23a.C
@@ -0,0 +1,24 @@
+// PR c++/65396
+// { dg-do compile { target c++11 } }
+// Like defarg23.C, but for member functions.
+
+struct A {
+ template<class T> void f();
+ template<class T=int> void g(); // { dg-message "original definition" }
+ template<class T=char, class U> void h();
+};
+
+template<class T=int> void A::f() { }
+template<class T=int> void A::g() { } // { dg-error "redefinition of default" }
+template<class T, class U=bool>
+void A::h() {
+ static_assert(__is_same(T, char), "");
+ static_assert(__is_same(U, bool), "");
+}
+
+int main() {
+ A a;
+ a.f();
+ a.g();
+ a.h();
+}
diff --git a/gcc/testsuite/g++.dg/template/pr92440.C b/gcc/testsuite/g++.dg/template/pr92440.C
index 20db5f10586..f1e9281ab86 100644
--- a/gcc/testsuite/g++.dg/template/pr92440.C
+++ b/gcc/testsuite/g++.dg/template/pr92440.C
@@ -3,8 +3,8 @@
template <int T> // { dg-error "template parameter" }
struct S {
- template <class U>
- friend struct S; // { dg-message "note: redeclared here as" }
+ template <class U> // { dg-message "note: redeclared here as" }
+ friend struct S;
};
S<0> s;
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/redecl1.C b/gcc/testsuite/g++.old-deja/g++.pt/redecl1.C
index 48517f5d1d3..7596513acc0 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/redecl1.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/redecl1.C
@@ -9,14 +9,14 @@ struct S1 {}; // { dg-error "redeclared" } used 1 template parameter
template <class T = int> // { dg-message "original definition" }
struct S2;
-template <class T = int>
-struct S2; // { dg-error "redefinition of default" }
+template <class T = int> // { dg-error "redefinition of default" }
+struct S2;
template <class T> // { dg-error "template parameter" }
struct S3;
-template <int I>
-struct S3; // { dg-message "note: redeclared here" }
+template <int I> // { dg-message "note: redeclared here" }
+struct S3;
-template <template <class T> class C>
-struct S3; // { dg-message "note: redeclared here" }
+template <template <class T> class C> // { dg-message "note: redeclared here" }
+struct S3;
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