We were complaining about a function with deduced return type in C++11
mode, but leaving it alone and then assuming it couldn't have happened
later. Fixed by removing that assumption.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 94709718a2b25596677385adbf8a298c621ff8d0
Author: Jason Merrill <ja...@redhat.com>
Date: Fri Feb 10 15:40:21 2017 -0500
PR c++/77790 - ICE with auto function in C++11 mode
* decl.c (undeduced_auto_decl): Remove C++14 limitation.
(require_deduced_type): Add complain parm, return bool.
* cp-tree.h: Adjust.
* decl2.c (mark_used): Use require_deduced_type.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index a410926..0146332 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5909,7 +5909,7 @@ extern tree reshape_init (tree,
tree, tsubst_flags_t);
extern tree next_initializable_field (tree);
extern tree fndecl_declared_return_type (tree);
extern bool undeduced_auto_decl (tree);
-extern void require_deduced_type (tree);
+extern bool require_deduced_type (tree, tsubst_flags_t =
tf_warning_or_error);
extern tree finish_case_label (location_t, tree, tree);
extern tree cxx_maybe_build_cleanup (tree, tsubst_flags_t);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 734a6c7..2292a3a 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -16138,24 +16138,29 @@ fndecl_declared_return_type (tree fn)
return TREE_TYPE (TREE_TYPE (fn));
}
-/* Returns true iff DECL was declared with an auto return type and it has
+/* Returns true iff DECL was declared with an auto type and it has
not yet been deduced to a real type. */
bool
undeduced_auto_decl (tree decl)
{
- if (cxx_dialect < cxx14)
+ if (cxx_dialect < cxx11)
return false;
return type_uses_auto (TREE_TYPE (decl));
}
/* Complain if DECL has an undeduced return type. */
-void
-require_deduced_type (tree decl)
+bool
+require_deduced_type (tree decl, tsubst_flags_t complain)
{
if (undeduced_auto_decl (decl))
- error ("use of %qD before deduction of %<auto%>", decl);
+ {
+ if (complain & tf_error)
+ error ("use of %qD before deduction of %<auto%>", decl);
+ return false;
+ }
+ return true;
}
#include "gt-cp-decl.h"
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index cecb6a1..efc0b0e 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -5084,12 +5084,9 @@ mark_used (tree decl, tsubst_flags_t complain)
|| DECL_LANG_SPECIFIC (decl) == NULL
|| DECL_THUNK_P (decl))
{
- if (!processing_template_decl && type_uses_auto (TREE_TYPE (decl)))
- {
- if (complain & tf_error)
- error ("use of %qD before deduction of %<auto%>", decl);
- return false;
- }
+ if (!processing_template_decl
+ && !require_deduced_type (decl, complain))
+ return false;
return true;
}
@@ -5117,12 +5114,8 @@ mark_used (tree decl, tsubst_flags_t complain)
&& uses_template_parms (DECL_TI_ARGS (decl)))
return true;
- if (undeduced_auto_decl (decl))
- {
- if (complain & tf_error)
- error ("use of %qD before deduction of %<auto%>", decl);
- return false;
- }
+ if (!require_deduced_type (decl, complain))
+ return false;
/* If we don't need a value, then we don't need to synthesize DECL. */
if (cp_unevaluated_operand || in_discarded_stmt)
diff --git a/gcc/testsuite/g++.dg/cpp0x/auto41.C
b/gcc/testsuite/g++.dg/cpp0x/auto41.C
index b1551e2..a1065af 100644
--- a/gcc/testsuite/g++.dg/cpp0x/auto41.C
+++ b/gcc/testsuite/g++.dg/cpp0x/auto41.C
@@ -2,4 +2,4 @@
// { dg-do compile { target c++11 } }
auto foo(); // { dg-error "auto" "" { target { ! c++14 } } }
-auto fp = foo; // { dg-error "auto" "" { target c++14 } }
+auto fp = foo; // { dg-error "auto" }
diff --git a/gcc/testsuite/g++.dg/cpp1y/auto-fn35.C
b/gcc/testsuite/g++.dg/cpp1y/auto-fn35.C
new file mode 100644
index 0000000..a408174
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/auto-fn35.C
@@ -0,0 +1,11 @@
+// PR c++/77790
+// { dg-do compile { target c++11 } }
+
+template < typename S > struct A
+{
+ // { dg-error "" "" { target c++11_only } .+1 }
+ template < typename T > static auto f () { return 0; }
+ template < class U = decltype (f < S > ()) > int g () { return 0; }
+};
+
+auto a = A < int > {}.g ();
