Consider the test case g++.dg/other/offsetof5.C:
#include <stddef.h>
struct A
{
char c;
int &i;
};
int j = offsetof (A, i); // { dg-warning "invalid
access|offsetof" }
template <typename T>
struct S
{
T h;
T &i;
static const int j = offsetof (S, i); // { dg-warning "invalid
access|offsetof" }
};
int k = S<int>::j; // { dg-message "required from here" }
The second warning (that involves the instantiation of the S template)
is not emitted when -ftrack-macro-expansion is on.
This is because during the instantiation of the member j of S
template, the location that is used for the warning is the one for the
DECL j (set by instantiate_decl). And that location is inaccurately
set to the locus of 'offsetof', which is a macro defined in a system
header, so it's discarded by the diagnostics machinery.
Note that when we reach the point where we emit the warning in
build_class_member_access_expr offsetof expression has long been
folded, so we cannot use e.g, the location of the ')' token that would
have been in the source code. So I believe the location of 'j' is the
best we can get at this point.
The patch below sets the location of the DECL for 'j' to what I
believe is its precise location; with that, the test case passes with
and without -ftrack-macro-expansion. But I had to adjust
g++.dg/template/sfinae6_neg.C for that.
Tested on x86_64-unknown-linux-gnu against trunk.
gcc/cp
* decl.c (grokdeclarator): Use the location carried by the
declarator for the DECL of the static class member.
gcc/testsuite/
* g++.dg/template/sfinae6_neg.C: Adjust.
---
gcc/cp/decl.c | 3 ++-
gcc/testsuite/g++.dg/template/sfinae6_neg.C | 4 ++--
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 28c7cee..40818a3 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -10267,7 +10267,8 @@ grokdeclarator (const cp_declarator *declarator,
{
/* C++ allows static class members. All other work
for this is done by grokfield. */
- decl = build_lang_decl (VAR_DECL, unqualified_id, type);
+ decl = build_lang_decl_loc (declarator->id_loc,
+ VAR_DECL, unqualified_id, type);
set_linkage_for_static_data_member (decl);
/* Even if there is an in-class initialization, DECL
is considered undefined until an out-of-class
diff --git a/gcc/testsuite/g++.dg/template/sfinae6_neg.C
b/gcc/testsuite/g++.dg/template/sfinae6_neg.C
index d4be5dd..9b7bdfd1 100644
--- a/gcc/testsuite/g++.dg/template/sfinae6_neg.C
+++ b/gcc/testsuite/g++.dg/template/sfinae6_neg.C
@@ -21,9 +21,9 @@ no_type check_is_callable2(...);
template<typename F, typename T1, typename T2 = T1>
struct is_callable2
{
- static const bool value =
+ static const bool value = // { dg-error "within this context" }
(sizeof(check_is_callable2(type<F>(), type<T1>(), type<T2>()))
- == sizeof(yes_type)); // { dg-error "within this context" }
+ == sizeof(yes_type));
};
#define JOIN( X, Y ) DO_JOIN( X, Y )
--
Dodji
