[C++] Fix-it info for duplicate tokens

Hi,

the following patch adds fix-it info to error messages in 4 places
where the C++ parser complains about duplicate tokens.
The fix-it infos suggest to remove the duplicates.

Bootstrapped and regtested on x86_64-pc-linux-gnu.

OK for trunk?

Regards,
Volker


2017-04-21  Volker Reichelt  <v.reichelt@netcologne.de>

	* parser.c (cp_parser_cv_qualifier_seq_opt): Add fix-it info to
	error message.
	(cp_parser_virt_specifier_seq_opt): Likewise.
	(set_and_check_decl_spec_loc): Likewise twice.

===================================================================

On 04/21/2017 12:01 PM, Volker Reichelt wrote:
> Hi,
> 
> the following patch adds fix-it info to error messages in 4 places
> where the C++ parser complains about duplicate tokens.
> The fix-it infos suggest to remove the duplicates.
> 
> Bootstrapped and regtested on x86_64-pc-linux-gnu.
> 
> OK for trunk?
> 

ok

On Fri, 2017-04-21 at 18:01 +0200, Volker Reichelt wrote:
> Hi,
> 
> the following patch adds fix-it info to error messages in 4 places
> where the C++ parser complains about duplicate tokens.
> The fix-it infos suggest to remove the duplicates.
> 
> Bootstrapped and regtested on x86_64-pc-linux-gnu.
> 
> OK for trunk?

OK for trunk (with my "diagnostic messages" maintainer hat on).

Ideally we'd put a secondary range into each of these messages, via
   rich_loc.add_range (other_token_loc, false)
highlighting the other token, but I don't think the parser retains the
pertinent location_t information.


Thanks
Dave

> Regards,
> Volker
> 
> 
> 2017-04-21  Volker Reichelt  <v.reichelt@netcologne.de>
> 
>         * parser.c (cp_parser_cv_qualifier_seq_opt): Add fix-it info
> to
>         error message.
>         (cp_parser_virt_specifier_seq_opt): Likewise.
>         (set_and_check_decl_spec_loc): Likewise twice.
> 
> Index: gcc/cp/parser.c
> ===================================================================
> --- gcc/cp/parser.c     (revision 246880)
> +++ gcc/cp/parser.c     (working copy)
> @@ -20258,7 +20258,9 @@
>  
>        if (cv_quals & cv_qualifier)
>         {
> -         error_at (token->location, "duplicate cv-qualifier");
> +         gcc_rich_location richloc (token->location);
> +         richloc.add_fixit_remove ();
> +         error_at_rich_loc (&richloc, "duplicate cv-qualifier");
>           cp_lexer_purge_token (parser->lexer);
>         }
>        else
> @@ -20405,7 +20407,9 @@
>  
>        if (virt_specifiers & virt_specifier)
>         {
> -         error_at (token->location, "duplicate virt-specifier");
> +         gcc_rich_location richloc (token->location);
> +         richloc.add_fixit_remove ();
> +         error_at_rich_loc (&richloc, "duplicate virt-specifier");
>           cp_lexer_purge_token (parser->lexer);
>         }
>        else
> @@ -27665,7 +27669,11 @@
>             error_at (location,
>                       "both %<__thread%> and %<thread_local%>
> specified");
>           else
> -           error_at (location, "duplicate %qD", token->u.value);
> +           {
> +             gcc_rich_location richloc (location);
> +             richloc.add_fixit_remove ();
> +             error_at_rich_loc (&richloc, "duplicate %qD", token
> ->u.value);
> +           }
>         }
>        else
>         {
> @@ -27686,8 +27694,9 @@
>              "constexpr",
>             "__complex"
>           };
> -         error_at (location,
> -                   "duplicate %qs", decl_spec_names[ds]);
> +         gcc_rich_location richloc (location);
> +         richloc.add_fixit_remove ();
> +         error_at_rich_loc (&richloc, "duplicate %qs",
> decl_spec_names[ds]);
>         }
>      }
>  }
> 
> 2017-04-21  Volker Reichelt  <v.reichelt@netcologne.de>
> 
>         * g++.dg/diagnostic/duplicate1.C: New test.
>         * g++.dg/cpp0x/duplicate1.C: New test.
> 
> Index: gcc/testsuite/g++.dg/diagnostic/duplicate1.C
> ===================================================================
> --- gcc/testsuite/g++.dg/diagnostic/duplicate1.C        2017-04-21
> +++ gcc/testsuite/g++.dg/diagnostic/duplicate1.C        2017-04-21
> @@ -0,0 +1,18 @@
> +// { dg-options "-fdiagnostics-show-caret" }
> +
> +struct A
> +{
> +  void foo() const const;  /* { dg-error "duplicate cv-qualifier" }
> +  { dg-begin-multiline-output "" }
> +   void foo() const const;
> +                    ^~~~~
> +                    -----
> +  { dg-end-multiline-output "" } */
> +};
> +
> +volatile volatile int i = 0;  /* { dg-error "duplicate" }
> +  { dg-begin-multiline-output "" }
> + volatile volatile int i = 0;
> +          ^~~~~~~~
> +          --------
> +  { dg-end-multiline-output "" } */
> Index: gcc/testsuite/g++.dg/cpp0x/duplicate1.C
> ===================================================================
> --- gcc/testsuite/g++.dg/cpp0x/duplicate1.C     2017-04-21
> +++ gcc/testsuite/g++.dg/cpp0x/duplicate1.C     2017-04-21
> @@ -0,0 +1,29 @@
> +// { dg-options "-fdiagnostics-show-caret" }
> +// { dg-do compile { target c++11 } }
> +
> +struct A
> +{
> +  virtual void foo() const;
> +};
> +
> +struct B final final : A  /* { dg-error "duplicate virt-specifier" }
> +  { dg-begin-multiline-output "" }
> + struct B final final : A
> +                ^~~~~
> +                -----
> +  { dg-end-multiline-output "" } */
> +{
> +  virtual void foo() const override final override;  /* { dg-error
> "duplicate virt-specifier" }
> +  { dg-begin-multiline-output "" }
> +   virtual void foo() const override final override;
> +                                           ^~~~~~~~
> +                                           --------
> +  { dg-end-multiline-output "" } */
> +};
> +
> +thread_local thread_local int i = 0;  /* { dg-error "duplicate" }
> +  { dg-begin-multiline-output "" }
> + thread_local thread_local int i = 0;
> +              ^~~~~~~~~~~~
> +              ------------
> +  { dg-end-multiline-output "" } */
> ===================================================================
>