| Submitter | Jason Merrill |
|---|---|
| Date | March 16, 2011, 4:23 p.m. |
| Message ID | <4D80E409.10507@redhat.com> |
| Download | mbox | patch |
| Permalink | /patch/87279/ |
| State | New |
| Headers | show |
Comments
On Wed, Mar 16, 2011 at 9:23 AM, Jason Merrill <jason@redhat.com> wrote: > In templates, we do overload resolution and then throw away most of it, > going back to the pre-conversion arguments. But when the call returns a > reference, we shouldn't elide the dereference and pretend it returns by > value, as that confuses lvalue_p. > > Tested x86_64-pc-linux-gnu, applying to trunk. > > > commit 79330512f8ade4ecff47ab8cb8c050440d9648e0 > Author: Jason Merrill <jason@redhat.com> > Date: Tue Mar 8 08:46:41 2011 -0500 > > PR c++/47999 > * semantics.c (finish_call_expr): Preserve reference semantics > in templates. > This may have caused: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48162
Patch
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c index 53497f3..ce24d46 100644 --- a/gcc/cp/semantics.c +++ b/gcc/cp/semantics.c @@ -2150,11 +2150,17 @@ finish_call_expr (tree fn, VEC(tree,gc) **args, bool disallow_virtual, /* A call where the function is unknown. */ result = cp_build_function_call_vec (fn, args, complain); - if (processing_template_decl) + if (processing_template_decl && result != error_mark_node) { + if (TREE_CODE (result) == INDIRECT_REF) + result = TREE_OPERAND (result, 0); + gcc_assert (TREE_CODE (result) == CALL_EXPR + || TREE_CODE (fn) == PSEUDO_DTOR_EXPR + || errorcount); result = build_call_vec (TREE_TYPE (result), orig_fn, orig_args); KOENIG_LOOKUP_P (result) = koenig_p; release_tree_vector (orig_args); + result = convert_from_reference (result); } return result; diff --git a/gcc/testsuite/g++.dg/cpp0x/auto22.C b/gcc/testsuite/g++.dg/cpp0x/auto22.C new file mode 100644 index 0000000..66630e5 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/auto22.C @@ -0,0 +1,21 @@ +// PR c++/47999 +// { dg-options -std=c++0x } + +int& identity(int& i) +{ + return i; +} + +// In a function template, auto type deduction works incorrectly. +template <typename = void> +void f() +{ + int i = 0; + auto&& x = identity(i); // Type of x should be `int&`, but it is `int&&`. +} + +int main (int argc, char* argv[]) +{ + f(); + return 0; +}
In templates, we do overload resolution and then throw away most of it, going back to the pre-conversion arguments. But when the call returns a reference, we shouldn't elide the dereference and pretend it returns by value, as that confuses lvalue_p. Tested x86_64-pc-linux-gnu, applying to trunk. commit 79330512f8ade4ecff47ab8cb8c050440d9648e0 Author: Jason Merrill <jason@redhat.com> Date: Tue Mar 8 08:46:41 2011 -0500 PR c++/47999 * semantics.c (finish_call_expr): Preserve reference semantics in templates.