cp-tree.h (REF_PARENTHESIZED_P): New.

* cp-tree.h (REF_PARENTHESIZED_P): New.
	* semantics.c (force_paren_expr): Set it.
	* pt.c (do_auto_deduction): Check it.
	(tsubst) [COMPONENT_REF]: Copy it.
	* typeck.c (maybe_warn_about_useless_cast): Don't strip dereference.

From-SVN: r208412

gcc/cp/ChangeLog

@@ -1,5 +1,11 @@
 2014-03-07  Jason Merrill  <jason@redhat.com>
 
+	* cp-tree.h (REF_PARENTHESIZED_P): New.
+	* semantics.c (force_paren_expr): Set it.
+	* pt.c (do_auto_deduction): Check it.
+	(tsubst) [COMPONENT_REF]: Copy it.
+	* typeck.c (maybe_warn_about_useless_cast): Don't strip dereference.
+
 	* decl.c (create_array_type_for_decl): Only warn about invalid
 	C++1y VLA if flag_iso or warn_vla>0.
 	(grokdeclarator): Likewise.

gcc/cp/cp-tree.h

@@ -100,6 +100,7 @@ c-common.h, not after.
       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, SCOPE_REF)
    3: (TREE_REFERENCE_EXPR) (in NON_LVALUE_EXPR) (commented-out).
       ICS_BAD_FLAG (in _CONV)
       FN_TRY_BLOCK_P (in TRY_BLOCK)
@@ -3031,6 +3032,12 @@ 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.  Currently
+   only set some of the time in C++14 mode.  */
+
+#define REF_PARENTHESIZED_P(NODE) \
+  TREE_LANG_FLAG_2 (COMPONENT_REF_CHECK (NODE))
+
 /* Nonzero if this AGGR_INIT_EXPR provides for initialization via a
    constructor call, rather than an ordinary function call.  */
 #define AGGR_INIT_VIA_CTOR_P(NODE) \

gcc/cp/pt.c

@@ -14915,6 +14915,7 @@ tsubst_copy_and_build (tree t,
 	tree object;
 	tree object_type;
 	tree member;
+	tree r;
 
 	object = tsubst_non_call_postfix_expression (TREE_OPERAND (t, 0),
 						     args, complain, in_decl);
@@ -14999,11 +15000,19 @@ tsubst_copy_and_build (tree t,
 	    RETURN (error_mark_node);
 	  }
 	else if (TREE_CODE (member) == FIELD_DECL)
-	  RETURN (finish_non_static_data_member (member, object, NULL_TREE));
+	  {
+	    r = finish_non_static_data_member (member, object, NULL_TREE);
+	    if (TREE_CODE (r) == COMPONENT_REF)
+	      REF_PARENTHESIZED_P (r) = REF_PARENTHESIZED_P (t);
+	    RETURN (r);
+	  }
 
-	RETURN (finish_class_member_access_expr (object, member,
-						/*template_p=*/false,
-						complain));
+	r = finish_class_member_access_expr (object, member,
+					     /*template_p=*/false,
+					     complain);
+	if (TREE_CODE (r) == COMPONENT_REF)
+	  REF_PARENTHESIZED_P (r) = REF_PARENTHESIZED_P (t);
+	RETURN (r);
       }
 
     case THROW_EXPR:
@@ -21619,7 +21628,8 @@ do_auto_deduction (tree type, tree init, tree auto_node)
   targs = make_tree_vec (1);
   if (AUTO_IS_DECLTYPE (auto_node))
     {
-      bool id = (DECL_P (init) || TREE_CODE (init) == COMPONENT_REF);
+      bool id = (DECL_P (init) || (TREE_CODE (init) == COMPONENT_REF
+				   && !REF_PARENTHESIZED_P (init)));
       TREE_VEC_ELT (targs, 0)
 	= finish_decltype_type (init, id, tf_warning_or_error);
       if (type != auto_node)

gcc/cp/semantics.c

@@ -1605,11 +1605,18 @@ force_paren_expr (tree expr)
   if (cxx_dialect < cxx1y)
     return expr;
 
+  /* If we're in unevaluated context, we can't be deducing a
+     return/initializer type, so we don't need to mess with this.  */
+  if (cp_unevaluated_operand)
+    return expr;
+
   if (!DECL_P (expr) && TREE_CODE (expr) != COMPONENT_REF
       && TREE_CODE (expr) != SCOPE_REF)
     return expr;
 
-  if (type_dependent_expression_p (expr))
+  if (TREE_CODE (expr) == COMPONENT_REF)
+    REF_PARENTHESIZED_P (expr) = true;
+  else if (type_dependent_expression_p (expr))
     expr = build1 (PAREN_EXPR, TREE_TYPE (expr), expr);
   else
     {
@@ -1619,7 +1626,7 @@ force_paren_expr (tree expr)
 	  tree type = unlowered_expr_type (expr);
 	  bool rval = !!(kind & clk_rvalueref);
 	  type = cp_build_reference_type (type, rval);
-	  expr = build_static_cast (type, expr, tf_warning_or_error);
+	  expr = build_static_cast (type, expr, tf_error);
 	}
     }
 

gcc/cp/typeck.c

@@ -6291,7 +6291,10 @@ maybe_warn_about_useless_cast (tree type, tree expr, tsubst_flags_t complain)
   if (warn_useless_cast
       && complain & tf_warning)
     {
-      if (REFERENCE_REF_P (expr))
+      /* In C++14 mode, this interacts badly with force_paren_expr.  And it
+	 isn't necessary in any mode, because the code below handles
+	 glvalues properly.  For 4.9, just skip it in C++14 mode.  */
+      if (cxx_dialect < cxx1y && REFERENCE_REF_P (expr))
 	expr = TREE_OPERAND (expr, 0);
 
       if ((TREE_CODE (type) == REFERENCE_TYPE