Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
Since C++20 P0846, a name followed by a < can be treated as a template-name
even though name lookup did not find a template-name. That happens
in this test with "i < foo ()":
for (int id = 0; i < foo(); ++id);
and results in a raft of errors about non-constant foo(). The problem
is that the require_potential_constant_expression call in
cp_parser_template_argument emits errors even when we're parsing
tentatively. So we repeat the error when we're trying to parse
as a nested-name-specifier, type-name, etc.
Guarding the call with !cp_parser_uncommitted_to_tentative_parse_p would
mean that require_potential_constant_expression never gets called. But
we don't need the call at all as far as I can tell. Stuff like
template<int N> struct S { };
int foo () { return 4; }
void
g ()
{
S<foo()> s;
}
gets diagnosed in convert_nontype_argument. In fact, with this patch,
we only emit "call to non-constexpr function" once. (That is, in C++17
only; C++14 uses a different path.)
PR c++/118516
gcc/cp/ChangeLog:
* parser.cc (cp_parser_template_argument): Don't call
require_potential_constant_expression.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/fn-template11.C:
* g++.dg/template/fn-template1.C: New test.
* g++.dg/template/fn-template2.C: New test.
---
gcc/cp/parser.cc | 1 -
gcc/testsuite/g++.dg/cpp2a/fn-template11.C | 2 +-
gcc/testsuite/g++.dg/template/fn-template1.C | 12 ++++++++++++
gcc/testsuite/g++.dg/template/fn-template2.C | 9 +++++++++
4 files changed, 22 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/template/fn-template1.C
create mode 100644 gcc/testsuite/g++.dg/template/fn-template2.C
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 0578aad1b1c..84b36a21767 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -20315,7 +20315,6 @@ cp_parser_template_argument (cp_parser* parser)
/* With C++17 generalized non-type template arguments we need to handle
lvalue constant expressions, too. */
argument = cp_parser_assignment_expression (parser);
- require_potential_constant_expression (argument);
}
if (!maybe_type_id)
diff --git a/gcc/testsuite/g++.dg/cpp2a/fn-template11.C
b/gcc/testsuite/g++.dg/cpp2a/fn-template11.C
index 1a6b6882900..ca25403f39b 100644
--- a/gcc/testsuite/g++.dg/cpp2a/fn-template11.C
+++ b/gcc/testsuite/g++.dg/cpp2a/fn-template11.C
@@ -7,5 +7,5 @@ int nonconst ();
int foo ()
{
return blah < // { dg-error "not declared" }
- nonconst (), nonconst (); // { dg-error "call to non-.constexpr. function"
}
+ nonconst (), nonconst ();
}
diff --git a/gcc/testsuite/g++.dg/template/fn-template1.C
b/gcc/testsuite/g++.dg/template/fn-template1.C
new file mode 100644
index 00000000000..14b98836880
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/fn-template1.C
@@ -0,0 +1,12 @@
+// PR c++/118516
+// { dg-do compile }
+// Like cpp2a/fn-template11.C but with blah declared.
+
+int nonconst ();
+
+int foo ()
+{
+ int blah = 20;
+ return blah <
+ nonconst (), nonconst ();
+}
diff --git a/gcc/testsuite/g++.dg/template/fn-template2.C
b/gcc/testsuite/g++.dg/template/fn-template2.C
new file mode 100644
index 00000000000..c7c31dd9b30
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/fn-template2.C
@@ -0,0 +1,9 @@
+// PR c++/118516
+// { dg-do compile }
+
+int foo();
+int main()
+{
+ for (int id = 0; i < // { dg-error "not declared in this
scope" }
+ foo(); ++id); // { dg-bogus "call to non-.constexpr." }
+}
base-commit: 4e9ee99647ebb9a7cab1497d78477f75d1157ac5
--
2.48.1
