Re: [PATCH] C++: add fixit for '>>' template error

[Jason Merrill <jason at redhat dot com>]

OK.

On Tue, Aug 30, 2016 at 10:43 AM, David Malcolm <dmalcolm@redhat.com> wrote:
> This patch adds fix-it hints to our warning for >>
> within a nested template argument list (for -std=c++98).
>
> For example:
>
> double-greater-than-fixit.C:5:12: error: ‘>>’ should be ‘> >’ within a nested template argument list
>  foo<foo<int>> i;
>             ^~
>             > >
>
> In conjunction with the not-yet-in-trunk -fdiagnostics-generate-patch,
> this can generate patches like this:
>
> --- double-greater-than-fixit.C
> +++ double-greater-than-fixit.C
> @@ -4,3 +4,3 @@
>
> -foo<foo<int>> i;
> +foo<foo<int> > i;
>
> Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu.
>
> OK for trunk?
>
> gcc/cp/ChangeLog:
>         * parser.c (cp_parser_enclosed_template_argument_list): Add fix-it
>         hint to ">>" within nested template argument list error.
>
> gcc/testsuite/ChangeLog:
>         * g++.dg/template/double-greater-than-fixit.C: New test case.
> ---
>  gcc/cp/parser.c                                           |  6 ++++--
>  gcc/testsuite/g++.dg/template/double-greater-than-fixit.C | 10 ++++++++++
>  2 files changed, 14 insertions(+), 2 deletions(-)
>  create mode 100644 gcc/testsuite/g++.dg/template/double-greater-than-fixit.C
>
> diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> index 48dbca1..ca9f8b9 100644
> --- a/gcc/cp/parser.c
> +++ b/gcc/cp/parser.c
> @@ -26342,8 +26342,10 @@ cp_parser_enclosed_template_argument_list (cp_parser* parser)
>             global source location is still on the token before the
>             '>>', so we need to say explicitly where we want it.  */
>           cp_token *token = cp_lexer_peek_token (parser->lexer);
> -         error_at (token->location, "%<>>%> should be %<> >%> "
> -                   "within a nested template argument list");
> +         gcc_rich_location richloc (token->location);
> +         richloc.add_fixit_replace ("> >");
> +         error_at_rich_loc (&richloc, "%<>>%> should be %<> >%> "
> +                            "within a nested template argument list");
>
>           token->type = CPP_GREATER;
>         }
> diff --git a/gcc/testsuite/g++.dg/template/double-greater-than-fixit.C b/gcc/testsuite/g++.dg/template/double-greater-than-fixit.C
> new file mode 100644
> index 0000000..f0de4ec
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/template/double-greater-than-fixit.C
> @@ -0,0 +1,10 @@
> +/* { dg-options "-fdiagnostics-show-caret -std=c++98" } */
> +template <typename T>
> +struct foo {};
> +
> +foo<foo<int>> i; // { dg-error "12: .>>. should be .> >. within a nested template argument list" }
> +/* { dg-begin-multiline-output "" }
> + foo<foo<int>> i;
> +            ^~
> +            > >
> +   { dg-end-multiline-output "" } */
> --
> 1.8.5.3
>