Another C++ PATCH for c++/52748 (N3276 and operator overloading)

[Jason Merrill <jason at redhat dot com>]

My earlier N3276 work only affected the function call syntax, but it 
needs to affect implicit function calls from overloaded operators as well.

Tested x86_64-pc-linux-gnu, applying to trunk and 4.8.

commit c3deee14326a96c9b058fb5433cf98fd64f8d618
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Apr 11 13:46:49 2013 -0400

    	PR c++/52748
    	* parser.c (complain_flags): New.
    	(cp_parser_postfix_expression): Use it.
    	(cp_parser_unary_expression): Likewise.
    	(cp_parser_binary_expression): Likewise.
    	(cp_parser_assignment_expression): Likewise.
    	(cp_parser_expression): Likewise.
    	(cp_parser_postfix_open_square_expression): Take decltype_p.
    	(cp_parser_builtin_offsetof): Adjust.
    	(cp_convert_range_for): Pass complain to finish_unary_op_expr.
    	* semantics.c (finish_unary_op_expr): Add complain parm.

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index e1d1238..f7c65b6 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5241,7 +5241,7 @@ extern void maybe_make_one_only			(tree);
 extern bool vague_linkage_p			(tree);
 extern void grokclassfn				(tree, tree,
 						 enum overload_flags);
-extern tree grok_array_decl			(location_t, tree, tree);
+extern tree grok_array_decl			(location_t, tree, tree, bool);
 extern tree delete_sanity			(tree, tree, bool, int, tsubst_flags_t);
 extern tree check_classfn			(tree, tree, tree);
 extern void check_member_template		(tree);
@@ -5706,7 +5706,8 @@ extern tree finish_call_expr			(tree, vec<tree, va_gc> **, bool,
 extern tree finish_increment_expr		(tree, enum tree_code);
 extern tree finish_this_expr			(void);
 extern tree finish_pseudo_destructor_expr       (tree, tree, tree);
-extern tree finish_unary_op_expr		(location_t, enum tree_code, tree);
+extern tree finish_unary_op_expr		(location_t, enum tree_code, tree,
+						 tsubst_flags_t);
 extern tree finish_compound_literal		(tree, tree, tsubst_flags_t);
 extern tree finish_fname			(tree);
 extern void finish_translation_unit		(void);
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 407b461..a5b2655 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -335,10 +335,11 @@ grokclassfn (tree ctype, tree function, enum overload_flags flags)
 }
 
 /* Create an ARRAY_REF, checking for the user doing things backwards
-   along the way.  */
+   along the way.  DECLTYPE_P is for N3276, as in the parser.  */
 
 tree
-grok_array_decl (location_t loc, tree array_expr, tree index_exp)
+grok_array_decl (location_t loc, tree array_expr, tree index_exp,
+		 bool decltype_p)
 {
   tree type;
   tree expr;
@@ -364,8 +365,13 @@ grok_array_decl (location_t loc, tree array_expr, tree index_exp)
 
   /* If they have an `operator[]', use that.  */
   if (MAYBE_CLASS_TYPE_P (type) || MAYBE_CLASS_TYPE_P (TREE_TYPE (index_exp)))
-    expr = build_new_op (loc, ARRAY_REF, LOOKUP_NORMAL, array_expr, index_exp,
-			 NULL_TREE, /*overload=*/NULL, tf_warning_or_error);
+    {
+      tsubst_flags_t complain = tf_warning_or_error;
+      if (decltype_p)
+	complain |= tf_decltype;
+      expr = build_new_op (loc, ARRAY_REF, LOOKUP_NORMAL, array_expr,
+			   index_exp, NULL_TREE, /*overload=*/NULL, complain);
+    }
   else
     {
       tree p1, p2, i1, i2;
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index e015c4f..6b5020e 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -1852,7 +1852,7 @@ static tree cp_parser_qualifying_entity
 static tree cp_parser_postfix_expression
   (cp_parser *, bool, bool, bool, bool, cp_id_kind *);
 static tree cp_parser_postfix_open_square_expression
-  (cp_parser *, tree, bool);
+  (cp_parser *, tree, bool, bool);
 static tree cp_parser_postfix_dot_deref_expression
   (cp_parser *, enum cpp_ttype, tree, bool, cp_id_kind *, location_t);
 static vec<tree, va_gc> *cp_parser_parenthesized_expression_list
@@ -3891,6 +3891,18 @@ cp_parser_translation_unit (cp_parser* parser)
   return success;
 }
 
+/* Return the appropriate tsubst flags for parsing, possibly in N3276
+   decltype context.  */
+
+static inline tsubst_flags_t
+complain_flags (bool decltype_p)
+{
+  tsubst_flags_t complain = tf_warning_or_error;
+  if (decltype_p)
+    complain |= tf_decltype;
+  return complain;
+}
+
 /* Expressions [gram.expr] */
 
 /* Parse a primary-expression.
@@ -5726,7 +5738,8 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
 	  postfix_expression
 	    = cp_parser_postfix_open_square_expression (parser,
 							postfix_expression,
-							false);
+							false,
+							decltype_p);
 	  idk = CP_ID_KIND_NONE;
           is_member_access = false;
 	  break;
@@ -5738,12 +5751,9 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
 	    bool is_builtin_constant_p;
 	    bool saved_integral_constant_expression_p = false;
 	    bool saved_non_integral_constant_expression_p = false;
-	    int complain = tf_warning_or_error;
+	    tsubst_flags_t complain = complain_flags (decltype_p);
 	    vec<tree, va_gc> *args;
 
-	    if (decltype_p)
-	      complain |= tf_decltype;
-
             is_member_access = false;
 
 	    is_builtin_constant_p
@@ -5972,7 +5982,8 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
 static tree
 cp_parser_postfix_open_square_expression (cp_parser *parser,
 					  tree postfix_expression,
-					  bool for_offsetof)
+					  bool for_offsetof,
+					  bool decltype_p)
 {
   tree index;
   location_t loc = cp_lexer_peek_token (parser->lexer)->location;
@@ -6006,7 +6017,8 @@ cp_parser_postfix_open_square_expression (cp_parser *parser,
   cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE);
 
   /* Build the ARRAY_REF.  */
-  postfix_expression = grok_array_decl (loc, postfix_expression, index);
+  postfix_expression = grok_array_decl (loc, postfix_expression,
+					index, decltype_p);
 
   /* When not doing offsetof, array references are not permitted in
      constant-expressions.  */
@@ -6702,6 +6714,7 @@ cp_parser_unary_expression (cp_parser *parser, bool address_p, bool cast_p,
       tree expression = error_mark_node;
       non_integral_constant non_constant_p = NIC_NONE;
       location_t loc = token->location;
+      tsubst_flags_t complain = complain_flags (decltype_p);
 
       /* Consume the operator token.  */
       token = cp_lexer_consume_token (parser->lexer);
@@ -6719,7 +6732,7 @@ cp_parser_unary_expression (cp_parser *parser, bool address_p, bool cast_p,
 	  non_constant_p = NIC_STAR;
 	  expression = build_x_indirect_ref (loc, cast_expression,
 					     RO_UNARY_STAR,
-                                             tf_warning_or_error);
+                                             complain);
 	  break;
 
 	case ADDR_EXPR:
@@ -6728,7 +6741,7 @@ cp_parser_unary_expression (cp_parser *parser, bool address_p, bool cast_p,
 	case BIT_NOT_EXPR:
 	  expression = build_x_unary_op (loc, unary_operator,
 					 cast_expression,
-                                         tf_warning_or_error);
+                                         complain);
 	  break;
 
 	case PREINCREMENT_EXPR:
@@ -6740,7 +6753,7 @@ cp_parser_unary_expression (cp_parser *parser, bool address_p, bool cast_p,
 	case NEGATE_EXPR:
 	case TRUTH_NOT_EXPR:
 	  expression = finish_unary_op_expr (loc, unary_operator,
-					     cast_expression);
+					     cast_expression, complain);
 	  break;
 
 	default:
@@ -7567,7 +7580,7 @@ cp_parser_binary_expression (cp_parser* parser, bool cast_p,
 	current.lhs = build_x_binary_op (current.loc, current.tree_type,
 					 current.lhs, current.lhs_type,
 					 rhs, rhs_type, &overload,
-					 tf_warning_or_error);
+					 complain_flags (decltype_p));
       current.lhs_type = current.tree_type;
       if (EXPR_P (current.lhs))
 	SET_EXPR_LOCATION (current.lhs, current.loc);
@@ -7722,7 +7735,7 @@ cp_parser_assignment_expression (cp_parser* parser, bool cast_p,
 	      expr = build_x_modify_expr (loc, expr,
 					  assignment_operator,
 					  rhs,
-					  tf_warning_or_error);
+					  complain_flags (decltype_p));
 	      input_location = saved_input_location;
 	    }
 	}
@@ -7868,7 +7881,7 @@ cp_parser_expression (cp_parser* parser, bool cast_p, bool decltype_p,
       else
 	expression = build_x_compound_expr (loc, expression,
 					    assignment_expression,
-                                            tf_warning_or_error);
+					    complain_flags (decltype_p));
       /* If the next token is not a comma, then we are done with the
 	 expression.  */
       if (cp_lexer_next_token_is_not (parser->lexer, CPP_COMMA))
@@ -8019,12 +8032,14 @@ cp_parser_builtin_offsetof (cp_parser *parser)
 	{
 	case CPP_OPEN_SQUARE:
 	  /* offsetof-member-designator "[" expression "]" */
-	  expr = cp_parser_postfix_open_square_expression (parser, expr, true);
+	  expr = cp_parser_postfix_open_square_expression (parser, expr,
+							   true, false);
 	  break;
 
 	case CPP_DEREF:
 	  /* offsetof-member-designator "->" identifier */
-	  expr = grok_array_decl (token->location, expr, integer_zero_node);
+	  expr = grok_array_decl (token->location, expr,
+				  integer_zero_node, false);
 	  /* FALLTHRU */
 
 	case CPP_DOT:
@@ -9766,7 +9781,8 @@ cp_convert_range_for (tree statement, tree range_decl, tree range_expr)
 
   /* The new increment expression.  */
   expression = finish_unary_op_expr (input_location,
-				     PREINCREMENT_EXPR, begin);
+				     PREINCREMENT_EXPR, begin,
+				     tf_warning_or_error);
   finish_for_expr (expression, statement);
 
   /* The declaration is initialized with *__begin inside the loop body.  */
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 0631833..a09a7f4 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -2408,10 +2408,12 @@ finish_pseudo_destructor_expr (tree object, tree scope, tree destructor)
 /* Finish an expression of the form CODE EXPR.  */
 
 tree
-finish_unary_op_expr (location_t loc, enum tree_code code, tree expr)
+finish_unary_op_expr (location_t loc, enum tree_code code, tree expr,
+		      tsubst_flags_t complain)
 {
-  tree result = build_x_unary_op (loc, code, expr, tf_warning_or_error);
-  if (TREE_OVERFLOW_P (result) && !TREE_OVERFLOW_P (expr))
+  tree result = build_x_unary_op (loc, code, expr, complain);
+  if ((complain & tf_warning)
+      && TREE_OVERFLOW_P (result) && !TREE_OVERFLOW_P (expr))
     overflow_warning (input_location, result);
 
   return result;
diff --git a/gcc/testsuite/g++.dg/cpp0x/decltype-call3.C b/gcc/testsuite/g++.dg/cpp0x/decltype-call3.C
new file mode 100644
index 0000000..1d12b01
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/decltype-call3.C
@@ -0,0 +1,86 @@
+// Testcase for N3276 and operator overloading
+// { dg-require-effective-target c++11 }
+
+struct A;
+struct B {
+  A operator()(int);
+  A operator[](int);
+  A operator=(int);
+  A operator+=(int);
+  A operator-=(int);
+  A operator*=(int);
+  A operator/=(int);
+  A operator^=(int);
+  A operator&=(int);
+  A operator|=(int);
+  A operator<<=(int);
+  A operator>>=(int);
+};
+
+A operator-(B);
+A operator+(B);
+A operator*(B);
+A operator&(B);
+A operator!(B);
+A operator~(B);
+A operator++(B);
+A operator--(B);
+
+A operator+(B,B);
+A operator-(B,B);
+A operator*(B,B);
+A operator/(B,B);
+A operator%(B,B);
+A operator^(B,B);
+A operator&(B,B);
+A operator|(B,B);
+A operator<(B,B);
+A operator>(B,B);
+A operator,(B,B);
+A operator<<(B,B);
+A operator>>(B,B);
+A operator==(B,B);
+A operator->*(B,B);
+
+#define TRY(E) static_cast<decltype(E)*>(0)
+int main()
+{
+  B b;
+  TRY(b(0));
+  TRY(b[0]);
+  TRY(b=0);
+  TRY(b+=0);
+  TRY(b-=0);
+  TRY(b*=0);
+  TRY(b/=0);
+  TRY(b^=0);
+  TRY(b&=0);
+  TRY(b|=0);
+  TRY(b<<=0);
+  TRY(b>>=0);
+
+  TRY(-b);
+  TRY(+b);
+  TRY(*b);
+  TRY(&b);
+  TRY(!b);
+  TRY(~b);
+  TRY(++b);
+  TRY(--b);
+
+  TRY(b+b);
+  TRY(b-b);
+  TRY(b*b);
+  TRY(b/b);
+  TRY(b%b);
+  TRY(b^b);
+  TRY(b&b);
+  TRY(b|b);
+  TRY(b>b);
+  TRY(b<b);
+  TRY((b,b));
+  TRY(b<<b);
+  TRY(b>>b);
+  TRY(b==b);
+  TRY(b->*b);
+}