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

[David Malcolm]

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