Fix PR c++/70822 (bogus error with parenthesized SCOPE_REF)

gcc/cp/ChangeLog:

	PR c++/70822
	PR c++/70106
	* cp-tree.h (REF_PARENTHESIZED_P): Make this flag apply to
	SCOPE_REFs too.
	* pt.c (tsubst_qualified_id): If REF_PARENTHESIZED_P is set
	on the qualified_id then propagate it to the resulting
	expression.
	(do_auto_deduction): Check REF_PARENTHESIZED_P on SCOPE_REFs
	too.
	* semantics.c (force_paren_expr): If given a SCOPE_REF, just set
	its REF_PARENTHESIZED_P flag.

gcc/testsuite/ChangeLog:

	PR c++/70822
	PR c++/70106
	* g++.dg/cpp1y/auto-fn32.C: New test.
	* g++.dg/cpp1y/paren4.C: New test.



git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@236792 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 87 insertions, 19 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index f0cd5d9abc0..ff5d8f4825c 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,17 @@
+2016-05-26  Patrick Palka  <ppalka@gcc.gnu.org>
+
+	PR c++/70822
+	PR c++/70106
+	* cp-tree.h (REF_PARENTHESIZED_P): Make this flag apply to
+	SCOPE_REFs too.
+	* pt.c (tsubst_qualified_id): If REF_PARENTHESIZED_P is set
+	on the qualified_id then propagate it to the resulting
+	expression.
+	(do_auto_deduction): Check REF_PARENTHESIZED_P on SCOPE_REFs
+	too.
+	* semantics.c (force_paren_expr): If given a SCOPE_REF, just set
+	its REF_PARENTHESIZED_P flag.
+
 2016-05-25  Jason Merrill  <jason@redhat.com>
 
 	PR c++/71173
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 02ed5d69cc1..f562a5255b1 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -170,7 +170,7 @@ operator == (const cp_expr &lhs, tree rhs)
       TARGET_EXPR_DIRECT_INIT_P (in TARGET_EXPR)
       FNDECL_USED_AUTO (in FUNCTION_DECL)
       DECLTYPE_FOR_LAMBDA_PROXY (in DECLTYPE_TYPE)
-      REF_PARENTHESIZED_P (in COMPONENT_REF, INDIRECT_REF)
+      REF_PARENTHESIZED_P (in COMPONENT_REF, INDIRECT_REF, SCOPE_REF)
       AGGR_INIT_ZERO_FIRST (in AGGR_INIT_EXPR)
       CONSTRUCTOR_MUTABLE_POISON (in CONSTRUCTOR)
    3: (TREE_REFERENCE_EXPR) (in NON_LVALUE_EXPR) (commented-out).
@@ -3398,12 +3398,12 @@ extern void decl_shadowed_for_var_insert (tree, tree);
 #define PAREN_STRING_LITERAL_P(NODE) \
   TREE_LANG_FLAG_0 (STRING_CST_CHECK (NODE))
 
-/* Indicates whether a COMPONENT_REF has been parenthesized, or an
-   INDIRECT_REF comes from parenthesizing a _DECL.  Currently only set
-   some of the time in C++14 mode.  */
+/* Indicates whether a COMPONENT_REF or a SCOPE_REF has been parenthesized, or
+   an INDIRECT_REF comes from parenthesizing a _DECL.  Currently only set some
+   of the time in C++14 mode.  */
 
 #define REF_PARENTHESIZED_P(NODE) \
-  TREE_LANG_FLAG_2 (TREE_CHECK2 ((NODE), COMPONENT_REF, INDIRECT_REF))
+  TREE_LANG_FLAG_2 (TREE_CHECK3 ((NODE), COMPONENT_REF, INDIRECT_REF, SCOPE_REF))
 
 /* Nonzero if this AGGR_INIT_EXPR provides for initialization via a
    constructor call, rather than an ordinary function call.  */
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index df3d634687d..4a24c9840fc 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -13739,8 +13739,10 @@ tsubst_qualified_id (tree qualified_id, tree args,
     {
       if (is_template)
 	expr = build_min_nt_loc (loc, TEMPLATE_ID_EXPR, expr, template_args);
-      return build_qualified_name (NULL_TREE, scope, expr,
-				   QUALIFIED_NAME_IS_TEMPLATE (qualified_id));
+      tree r = build_qualified_name (NULL_TREE, scope, expr,
+				     QUALIFIED_NAME_IS_TEMPLATE (qualified_id));
+      REF_PARENTHESIZED_P (r) = REF_PARENTHESIZED_P (qualified_id);
+      return r;
     }
 
   if (!BASELINK_P (name) && !DECL_P (expr))
@@ -13820,6 +13822,9 @@ tsubst_qualified_id (tree qualified_id, tree args,
       && TREE_CODE (expr) != OFFSET_REF)
     expr = convert_from_reference (expr);
 
+  if (REF_PARENTHESIZED_P (qualified_id))
+    expr = force_paren_expr (expr);
+
   return expr;
 }
 
@@ -24016,8 +24021,10 @@ do_auto_deduction (tree type, tree init, tree auto_node,
 
   if (AUTO_IS_DECLTYPE (auto_node))
     {
-      bool id = (DECL_P (init) || (TREE_CODE (init) == COMPONENT_REF
-				   && !REF_PARENTHESIZED_P (init)));
+      bool id = (DECL_P (init)
+		 || ((TREE_CODE (init) == COMPONENT_REF
+		      || TREE_CODE (init) == SCOPE_REF)
+		     && !REF_PARENTHESIZED_P (init)));
       targs = make_tree_vec (1);
       TREE_VEC_ELT (targs, 0)
 	= finish_decltype_type (init, id, tf_warning_or_error);
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 8a3e7fd619b..0cef86758f8 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -1647,17 +1647,10 @@ force_paren_expr (tree expr)
       && TREE_CODE (expr) != SCOPE_REF)
     return expr;
 
-  if (TREE_CODE (expr) == COMPONENT_REF)
+  if (TREE_CODE (expr) == COMPONENT_REF
+      || TREE_CODE (expr) == SCOPE_REF)
     REF_PARENTHESIZED_P (expr) = true;
-  else if (type_dependent_expression_p (expr)
-	   /* When processing_template_decl, a SCOPE_REF may actually be
-	      referring to a non-static data member of the current class, in
-	      which case its TREE_TYPE may not be properly cv-qualified (the
-	      cv-qualifiers of the implicit *this object haven't yet been taken
-	      into account) so we have to delay building a static_cast until
-	      instantiation.  */
-	   || (processing_template_decl
-	       && TREE_CODE (expr) == SCOPE_REF))
+  else if (type_dependent_expression_p (expr))
     expr = build1 (PAREN_EXPR, TREE_TYPE (expr), expr);
   else if (VAR_P (expr) && DECL_HARD_REGISTER (expr))
     /* We can't bind a hard register variable to a reference.  */;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index fbd252098de..962421200cd 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2016-05-26  Patrick Palka  <ppalka@gcc.gnu.org>
+
+	PR c++/70822
+	PR c++/70106
+	* g++.dg/cpp1y/auto-fn32.C: New test.
+	* g++.dg/cpp1y/paren4.C: New test.
+
 2016-05-26  Nathan Sidwell  <nathan@acm.org>
 
 	* gcc.dg/20060410.c: Xfail on ptx.
diff --git a/gcc/testsuite/g++.dg/cpp1y/auto-fn32.C b/gcc/testsuite/g++.dg/cpp1y/auto-fn32.C
new file mode 100644
index 00000000000..0a5dafce858
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/auto-fn32.C
@@ -0,0 +1,33 @@
+// { dg-do compile { target c++14 } }
+
+template<class,class> struct same_type;
+template<class T> struct same_type<T,T> {};
+
+struct A
+{
+  static int b;
+  int c;
+
+  template <int>
+  decltype(auto) f() { return A::c; }
+
+  template <int>
+  decltype(auto) g() { return (A::c); }
+};
+
+A a;
+
+template <int>
+decltype(auto) f() { return A::b; }
+
+template <int>
+decltype(auto) g() { return (A::b); }
+
+int main()
+{
+  same_type<decltype(f<0>()), int>();
+  same_type<decltype(g<0>()), int&>();
+
+  same_type<decltype(a.f<0>()), int>();
+  same_type<decltype(a.g<0>()), int&>();
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/paren4.C b/gcc/testsuite/g++.dg/cpp1y/paren4.C
new file mode 100644
index 00000000000..71abe846dbf
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/paren4.C
@@ -0,0 +1,14 @@
+// PR c++/70822
+// { dg-do compile { target c++14 } }
+
+struct a
+{
+  static int b;
+};
+
+template <typename>
+void
+foo ()
+{
+  &(a::b);
+}