When we're parsing tentatively, we shouldn't do something, like
requiring a constant-expression, that will produce an error. This patch
delays checking whether the expression is constant until we know that
we're actually looking at a designator.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 77da076687dac5f406f4e929497a8b7b747d287a
Author: Jason Merrill <ja...@redhat.com>
Date: Wed Dec 5 17:47:52 2012 -0500
PR c++/54947
* parser.c (cp_parser_initializer_list): Don't require an
expression in [] to be constant until we know it's a C99
designator.
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 190b8d9..a010f1f 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -17923,11 +17923,14 @@ cp_parser_initializer_list (cp_parser* parser, bool* non_constant_p)
/* In C++11, [ could start a lambda-introducer. */
cp_parser_parse_tentatively (parser);
cp_lexer_consume_token (parser->lexer);
- designator = cp_parser_constant_expression (parser, false, NULL);
+ bool non_const = false;
+ designator = cp_parser_constant_expression (parser, true, &non_const);
cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE);
cp_parser_require (parser, CPP_EQ, RT_EQ);
if (!cp_parser_parse_definitely (parser))
designator = NULL_TREE;
+ else if (non_const)
+ require_potential_rvalue_constant_expression (designator);
}
else
designator = NULL_TREE;
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-initlist2.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-initlist2.C
new file mode 100644
index 0000000..daaa339
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-initlist2.C
@@ -0,0 +1,27 @@
+// PR c++/54947
+// { dg-options -std=gnu++11 }
+
+struct X
+{
+ template<typename L>
+ X(L)
+ { }
+};
+
+template<typename A>
+ void
+ test()
+ {
+ int i = 0;
+
+ A a_ok_1( [=] { return i; } ); // OK
+ A a_ok_2( [i] { return i; } ); // OK
+
+ A a_err_1{ [i] { return i; } }; // error
+ A a_err_2{ [=] { return i; } }; // error
+ }
+
+int main()
+{
+ test<X>();
+}
