On 5/2/22 12:19, Marek Polacek wrote:
This patch fixes an oversight whereby we treated >= as the end of
a template argument. This causes problems in C++14, because in
cp_parser_template_argument we go different ways for C++14 and C++17:
/* It must be a non-type argument. In C++17 any constant-expression is
allowed. */
if (cxx_dialect > cxx14)
goto general_expr;
so in this testcase in C++14 we get "N" as the template argument but in
C++17 it is the whole "N >= 5" expression. So in C++14 the remaining
">= 5" triggered the newly-added diagnostic.
Hmm, I think >>= is questionable as well, as it could resolve to a
constexpr operator>>=. Seems like the two calls to
cp_parser_next_token_ends_template_argument_p in the C++14 non-type
argument parsing code need to be strictly correct to avoid the problem
in this testcase; maybe we want a separate overload or another parameter
to indicate that?
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
PR c++/105436
gcc/cp/ChangeLog:
* parser.cc (cp_parser_next_token_ends_template_argument_p): Don't
return true for CPP_GREATER_EQ.
gcc/testsuite/ChangeLog:
* g++.dg/parse/template31.C: New test.
---
gcc/cp/parser.cc | 1 -
gcc/testsuite/g++.dg/parse/template31.C | 4 ++++
2 files changed, 4 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/parse/template31.C
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index a5cbb3e896f..5fa743b5a8e 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -33224,7 +33224,6 @@ cp_parser_next_token_ends_template_argument_p
(cp_parser *parser)
|| ((cxx_dialect != cxx98) && token->type == CPP_RSHIFT)
/* For better diagnostics, treat >>= like that too, that
shouldn't appear non-nested in template arguments. */
- || token->type == CPP_GREATER_EQ
|| token->type == CPP_RSHIFT_EQ);
}
diff --git a/gcc/testsuite/g++.dg/parse/template31.C b/gcc/testsuite/g++.dg/parse/template31.C
new file mode 100644
index 00000000000..a5693e851f7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/template31.C
@@ -0,0 +1,4 @@
+// PR c++/105436
+
+template<bool> struct A;
+template<int N> A<N >= 5> f();
base-commit: 1cb220498e1f59021dab36c39c5d726e9f070c6a
