Jason Merrill <ja...@redhat.com> writes:
> Oops, thought I had sent this before.
No problem. Thank you for replying now×
> On 11/17/2012 10:23 AM, Dodji Seketeli wrote:
> > - if (cp_parser_parse_definitely (parser))
> > + /* Note that if we actually see the '=' token after the
> > + identifier, cp_parser_alias_declaration commits the
> > + tentative parse. In that case, we really expects an
> > + alias-declaration. Otherwise, we expect a using
> > + declaration. */
> > + alias_decl_expected =
> > + !cp_parser_uncommitted_to_tentative_parse_p (parser);
> > + cp_parser_parse_definitely (parser);
>
> Maybe just check whether decl is error_mark_node?
As we further discussed this on IRC, when cp_parser_alias_declaration
returns error_mark_node, it is either because we encountered an error
before the hypothetical '=', in which case we might want to try to
parse a using declaration, or it is because we encountered an error
after the the '=', in which case we committed to parsing an alias
declaration and we must emit a hard error.
And I believe what we want here is to tell the two possible cases
apart.
>
> > + if (type == error_mark_node)
> > + return error_mark_node;
>
> I think for error-recovery we might want to
> cp_parser_skip_to_end_of_block_or_statement as well.
Right, done.
Bootstrapped and tested on x86_64-unknown-linux-gnu against trunk.
gcc/cp/
* parser.c (cp_parser_alias_declaration): Commit to tentative
parse when see the '=' token. Get out if the type-id is invalid.
Update function comment.
(cp_parser_member_declaration): Don't try to parse a using
declaration if we know that we expected an alias declaration; that
is, if we see the '=' token after the identifier.
gcc/testsuite/
* g++.dg/cpp0x/alias-decl-28.C: New test.
* g++.dg/cpp0x/alias-decl-16.C: Update.
---
gcc/cp/parser.c | 31 +++++++++++++++++++++++++++---
gcc/testsuite/g++.dg/cpp0x/alias-decl-16.C | 2 +-
gcc/testsuite/g++.dg/cpp0x/alias-decl-28.C | 7 +++++++
3 files changed, 36 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/alias-decl-28.C
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index a010f1f..c39ef30 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -15262,7 +15262,11 @@ cp_parser_using_declaration (cp_parser* parser,
/* Parse an alias-declaration.
alias-declaration:
- using identifier attribute-specifier-seq [opt] = type-id */
+ using identifier attribute-specifier-seq [opt] = type-id
+
+ Note that if this function is used in the context of a tentative
+ parse, it commits the currently active tentative parse after it
+ sees the '=' token. */
static tree
cp_parser_alias_declaration (cp_parser* parser)
@@ -15295,6 +15299,8 @@ cp_parser_alias_declaration (cp_parser* parser)
if (cp_parser_error_occurred (parser))
return error_mark_node;
+ cp_parser_commit_to_tentative_parse (parser);
+
/* Now we are going to parse the type-id of the declaration. */
/*
@@ -15324,10 +15330,19 @@ cp_parser_alias_declaration (cp_parser* parser)
if (parser->num_template_parameter_lists)
parser->type_definition_forbidden_message = saved_message;
+ if (type == error_mark_node)
+ {
+ cp_parser_skip_to_end_of_block_or_statement (parser);
+ return error_mark_node;
+ }
+
cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
if (cp_parser_error_occurred (parser))
- return error_mark_node;
+ {
+ cp_parser_skip_to_end_of_block_or_statement (parser);
+ return error_mark_node;
+ }
/* A typedef-name can also be introduced by an alias-declaration. The
identifier following the using keyword becomes a typedef-name. It has
@@ -19063,9 +19078,19 @@ cp_parser_member_declaration (cp_parser* parser)
else
{
tree decl;
+ bool alias_decl_expected;
cp_parser_parse_tentatively (parser);
decl = cp_parser_alias_declaration (parser);
- if (cp_parser_parse_definitely (parser))
+ /* Note that if we actually see the '=' token after the
+ identifier, cp_parser_alias_declaration commits the
+ tentative parse. In that case, we really expects an
+ alias-declaration. Otherwise, we expect a using
+ declaration. */
+ alias_decl_expected =
+ !cp_parser_uncommitted_to_tentative_parse_p (parser);
+ cp_parser_parse_definitely (parser);
+
+ if (alias_decl_expected)
finish_member_declaration (decl);
else
cp_parser_using_declaration (parser,
diff --git a/gcc/testsuite/g++.dg/cpp0x/alias-decl-16.C
b/gcc/testsuite/g++.dg/cpp0x/alias-decl-16.C
index d66660a..ce6ad0a 100644
--- a/gcc/testsuite/g++.dg/cpp0x/alias-decl-16.C
+++ b/gcc/testsuite/g++.dg/cpp0x/alias-decl-16.C
@@ -23,6 +23,6 @@ template<class T>
using A3 =
enum B3 {b = 0;}; //{ dg-error "types may not be defined in alias
template" }
-A3<int> a3;
+A3<int> a3; // { dg-error "'A3' does not name a type" }
int main() { }
diff --git a/gcc/testsuite/g++.dg/cpp0x/alias-decl-28.C
b/gcc/testsuite/g++.dg/cpp0x/alias-decl-28.C
new file mode 100644
index 0000000..086b5e5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alias-decl-28.C
@@ -0,0 +1,7 @@
+// Origin: PR c++/54401
+// { dg-do compile { target c++11 } }
+
+template<typename>
+struct X {
+ using type = T; // { dg-error "expected type-specifier|does not name a
type" }
+};
--
1.7.11.7
--
Dodji
