[gcc(refs/vendors/axis/heads/cris-decc0)] c++: Fix template arguments comparison with class NTTP [PR91754]
Hans-Peter Nilsson
hp@gcc.gnu.org
Wed Feb 12 06:12:00 GMT 2020
https://gcc.gnu.org/g:e3b60da8e07030b1417067295f047b25015f21f2
commit e3b60da8e07030b1417067295f047b25015f21f2
Author: Marek Polacek <polacek@redhat.com>
Date: Wed Jan 29 12:02:14 2020 -0500
c++: Fix template arguments comparison with class NTTP [PR91754]
Here we fail to compile the attached test, stating that the use of
T<s> in T<s>::T() {} is "invalid use of incomplete type". It is a
function definition so grokdeclarator checks that the qualifying type
is complete.
When we parsed the class T, finish_struct gave the class a non-null
TYPE_SIZE, making it COMPLETE_TYPE_P. But then we're parsing T<s>,
a TEMPLATE_ID, in
T<s>::T() {}
so try to lookup_template_class T. This failed because we couldn't
find such a class: comp_template_args told us that the argument lists
don't match, because one of the args was wrapped in a VIEW_CONVERT_EXPR
to make it look const. It seems to me that we should see through
these artificial wrappers and consider the args same.
2020-01-29 Marek Polacek <polacek@redhat.com>
PR c++/91754 - Fix template arguments comparison with class NTTP.
* pt.c (class_nttp_const_wrapper_p): New.
(template_args_equal): See through class_nttp_const_wrapper_p
arguments.
* g++.dg/cpp2a/nontype-class30.C: New test.
Diff:
---
gcc/cp/ChangeLog | 7 +++++++
gcc/cp/pt.c | 18 ++++++++++++++++++
gcc/testsuite/ChangeLog | 5 +++++
gcc/testsuite/g++.dg/cpp2a/nontype-class30.C | 15 +++++++++++++++
4 files changed, 45 insertions(+)
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 10ef419..3029714 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,12 @@
2020-01-29 Marek Polacek <polacek@redhat.com>
+ PR c++/91754 - Fix template arguments comparison with class NTTP.
+ * pt.c (class_nttp_const_wrapper_p): New.
+ (template_args_equal): See through class_nttp_const_wrapper_p
+ arguments.
+
+2020-01-29 Marek Polacek <polacek@redhat.com>
+
PR c++/92948 - Fix class NTTP with template arguments.
* pt.c (convert_nontype_argument): Use IMPLICIT_CONV_EXPR when
converting a value-dependent expression to a class type.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index fccf4e9..416ff63 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -8989,6 +8989,19 @@ coerce_innermost_template_parms (tree parms,
return coerced_args;
}
+/* Returns true if T is a wrapper to make a C++20 template parameter
+ object const. */
+
+static bool
+class_nttp_const_wrapper_p (tree t)
+{
+ if (cxx_dialect < cxx2a)
+ return false;
+ return (TREE_CODE (t) == VIEW_CONVERT_EXPR
+ && CP_TYPE_CONST_P (TREE_TYPE (t))
+ && TREE_CODE (TREE_OPERAND (t, 0)) == TEMPLATE_PARM_INDEX);
+}
+
/* Returns 1 if template args OT and NT are equivalent. */
int
@@ -9001,6 +9014,11 @@ template_args_equal (tree ot, tree nt, bool partial_order /* = false */)
if (nt == any_targ_node || ot == any_targ_node)
return true;
+ if (class_nttp_const_wrapper_p (nt))
+ nt = TREE_OPERAND (nt, 0);
+ if (class_nttp_const_wrapper_p (ot))
+ ot = TREE_OPERAND (ot, 0);
+
if (TREE_CODE (nt) == TREE_VEC)
/* For member templates */
return TREE_CODE (ot) == TREE_VEC && comp_template_args (ot, nt);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a8db2cb..e38c4da 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
2020-01-29 Marek Polacek <polacek@redhat.com>
+ PR c++/91754 - Fix template arguments comparison with class NTTP.
+ * g++.dg/cpp2a/nontype-class30.C: New test.
+
+2020-01-29 Marek Polacek <polacek@redhat.com>
+
PR c++/92948 - Fix class NTTP with template arguments.
* g++.dg/cpp2a/nontype-class28.C: New test.
* g++.dg/cpp2a/nontype-class29.C: New test.
diff --git a/gcc/testsuite/g++.dg/cpp2a/nontype-class30.C b/gcc/testsuite/g++.dg/cpp2a/nontype-class30.C
new file mode 100644
index 0000000..b2e174c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/nontype-class30.C
@@ -0,0 +1,15 @@
+// PR c++/91754 - Fix template arguments comparison with class NTTP.
+// { dg-do compile { target c++2a } }
+
+struct S {};
+
+template<S s>
+struct T {
+ T();
+};
+
+template<S s>
+T<s>::T() {}
+
+S s;
+T<s> t;
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