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| author | Jason Merrill <jason@redhat.com> | 2019-03-20 16:31:40 -0400 |
|---|---|---|
| committer | Jason Merrill <jason@gcc.gnu.org> | 2019-03-20 16:31:40 -0400 |
| commit | 292a8bbb27fd13e87552ca7c98a9d4e82c21b385 (patch) | |
| tree | 2150935ef639b1e97f5dcdda3907facd092ba69b /gcc | |
| parent | 3ad7fed1cc87d281881757477c5197d9d3a97232 (diff) | |
| download | gcc-292a8bbb27fd13e87552ca7c98a9d4e82c21b385.zip gcc-292a8bbb27fd13e87552ca7c98a9d4e82c21b385.tar.gz gcc-292a8bbb27fd13e87552ca7c98a9d4e82c21b385.tar.bz2 | |
PR c++/87480 - decltype of member access in default template arg
The issue here is that declval<T>().d is considered instantiation-dependent
within a template, as the access to 'd' might depend on the particular
specialization. But when we're deducing template arguments for a call, we
know that the call and the arguments are non-dependent, so we can do the
substitution as though we aren't in a template. Which strictly speaking we
aren't, since the default argument is considered a separate definition.
* pt.c (type_unification_real): Accept a dependent result in
template context.
From-SVN: r269826
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/cp/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/cp/pt.c | 9 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp0x/fntmpdefarg11.C | 15 |
3 files changed, 29 insertions, 1 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 2157496..09fb3f2 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,9 @@ +2019-03-20 Jason Merrill <jason@redhat.com> + + PR c++/87480 - decltype of member access in default template arg + * pt.c (type_unification_real): Accept a dependent result in + template context. + 2019-03-19 Martin Sebor <msebor@redhat.com> PR tree-optimization/89688 diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 0acc16d..6c15419 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -21005,8 +21005,15 @@ type_unification_real (tree tparms, } else { + /* Even if the call is happening in template context, getting + here means it's non-dependent, and a default argument is + considered a separate definition under [temp.decls], so we can + do this substitution without processing_template_decl. This + is important if the default argument contains something that + might be instantiation-dependent like access (87480). */ + processing_template_decl_sentinel s; tree substed = NULL_TREE; - if (saw_undeduced == 1 && processing_template_decl == 0) + if (saw_undeduced == 1) { /* First instatiate in template context, in case we still depend on undeduced template parameters. */ diff --git a/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg11.C b/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg11.C new file mode 100644 index 0000000..86c8ea9 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg11.C @@ -0,0 +1,15 @@ +// PR c++/87480 +// { dg-do compile { target c++11 } } + +template<typename T> T&& declval(); + +template <typename T, typename = decltype(declval<T>().d)> void f(T) { } + +struct A { + double d; +}; + +template <typename> +void j(A& a) { + f(a); +} |