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c++: hard error w/ ptr+N and incomplete type [PR103700]

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In pointer_int_sum when called from a SFINAE context, we need to avoid
calling size_in_bytes_loc on an incomplete pointed-to type since this
latter function isn't SFINAE-enabled and always emits an error on such
input.

	PR c++/103700

gcc/c-family/ChangeLog:

	* c-common.c (pointer_int_sum): When quiet, return
	error_mark_node for an incomplete pointed-to type and don't
	call size_in_bytes_loc.

gcc/testsuite/ChangeLog:

	* g++.dg/template/sfinae32.C: New test.
This commit is contained in:
Patrick Palka 2021-12-27 09:05:17 -05:00
parent 9407058a43
commit 88cdcb5c18
2 changed files with 26 additions and 0 deletions
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2
gcc/c-family/c-common.c
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@ -3308,6 +3308,8 @@ pointer_int_sum (location_t loc, enum tree_code resultcode,
size_exp = integer_one_node;
else
{
if (!complain && !COMPLETE_TYPE_P (TREE_TYPE (result_type)))
return error_mark_node;
size_exp = size_in_bytes_loc (loc, TREE_TYPE (result_type));
/* Wrap the pointer expression in a SAVE_EXPR to make sure it
is evaluated first when the size expression may depend

24
gcc/testsuite/g++.dg/template/sfinae32.C Normal file
View file

@ -0,0 +1,24 @@
// PR c++/103700
// { dg-do compile { target c++11 } }
template<class T, int N> auto f(T* p) -> decltype(p + N);
template<class T, int N> auto f(T* p) -> decltype(p - N);
template<class T, int N> auto f(T* p) -> decltype(N + p);
template<class T, int N> void f(T* p);
template<class T> auto g(T* p, int n) -> decltype(p + n);
template<class T> auto g(T* p, int n) -> decltype(p - n);
template<class T> auto g(T* p, int n) -> decltype(n + p);
template<class T> void g(T* p, int n);
struct Incomplete;
int main() {
f<Incomplete, 0>(nullptr);
f<Incomplete, 1>(nullptr);
f<Incomplete, -1>(nullptr);
f<Incomplete, 7>(nullptr);
f<Incomplete, -7>(nullptr);
g<Incomplete>(nullptr, 0);
}