We've been passing C++11 attributes that appertain to a type-specifier
down to decl_attributes, which gave a warning and ignored them, but it
was confused by the pack expansion. It seems easiest to deal with
this by ignoring them directly in grokdeclarator.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 8ff034b7db80ef05cd97bb4c56a1d472b990afa8
Author: Jason Merrill <ja...@redhat.com>
Date: Mon Mar 26 11:16:04 2018 -0400
PR c++/85062 - ICE with alignas in wrong place.
* decl.c (grokdeclarator): Ignore attributes on type-specifiers
here.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 96d4b723b4a..ba456737e0e 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -10946,10 +10946,10 @@ grokdeclarator (const cp_declarator *declarator,
if (declspecs->std_attributes)
{
- /* Apply the c++11 attributes to the type preceding them. */
- input_location = declspecs->locations[ds_std_attribute];
- decl_attributes (&type, declspecs->std_attributes, 0);
- input_location = saved_loc;
+ location_t attr_loc = declspecs->locations[ds_std_attribute];
+ if (warning_at (attr_loc, OPT_Wattributes, "attribute ignored"))
+ inform (attr_loc, "an attribute that appertains to a type-specifier "
+ "is ignored");
}
/* Determine the type of the entity declared by recurring on the
diff --git a/gcc/testsuite/g++.dg/cpp0x/alignas16.C b/gcc/testsuite/g++.dg/cpp0x/alignas16.C
new file mode 100644
index 00000000000..7c349929786
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alignas16.C
@@ -0,0 +1,9 @@
+// PR c++/85062
+// { dg-do compile { target c++11 } }
+
+template<typename... T> struct A
+{
+ int alignas(T...) i; // { dg-warning "ignored" }
+};
+
+A<int> a;
