[v3,11/11] c: Add new -Wdeclaration-missing-parameter-type permerror

  This used to be a warning, enabled by default, without its own option.

A subsequent change could improve diagnostics and provide spelling
hints for declarations like “void function (int32t);”.

gcc/c-family/

	* c.opt (Wdeclaration-missing-parameter-type): New.

gcc/c/ChangeLog:

	PR other/44209
	* c-decl.cc (grokparms): Issue permerror for
	OPT_Wdeclaration_missing_parameter_type instead of a pedwarn.

gcc/ChangeLog:

	* doc/invoke.texi (Warning Options): Document
	-Wdeclaration-missing-parameter-type.

gcc/testsuite/ChangeLog:

	* gcc.dg/permerror-default.c (missing_parameter_type):
	Expect error.
	* gcc.dg/permerror-fpermissive.c (missing_parameter_type):
	Expect -Wdeclaration-missing-parameter-type warning.
	* gcc.dg/permerror-gnu89-nopermissive.c (missing_parameter_type):
	Expect -Wdeclaration-missing-parameter-type error.
	* gcc.dg/permerror-gnu89-pedantic.c (missing_parameter_type):
	Likewise.
	* gcc.dg/permerror-gnu89.c (missing_parameter_type):
	Expect -Wdeclaration-missing-parameter-type warning.
	* gcc.dg/permerror-noerror.c: Add
	-Wno-error=declaration-missing-parameter-type to build flags.
	(missing_parameter_type): Expect
	-Wdeclaration-missing-parameter-type warning.
	* gcc.dg/permerror-nowarning.c: Build with
	-Wno-declaration-missing-parameter-type.  Remove previously
	expected warning.
	* gcc.dg/permerror-fpermissive-nowarning.c: Likewise.
	* gcc.dg/permerror-pedantic.c (missing_parameter_type):
	Expect -Wdeclaration-missing-parameter-type error.
	* gcc.dg/permerror-system.c (missing_parameter_type):
	Likewise.
---
 gcc/c-family/c.opt                              |  4 ++++
 gcc/c/c-decl.cc                                 |  6 ++++--
 gcc/doc/invoke.texi                             | 17 ++++++++++++++++-
 gcc/testsuite/gcc.dg/permerror-default.c        |  2 +-
 .../gcc.dg/permerror-fpermissive-nowarning.c    |  7 +------
 gcc/testsuite/gcc.dg/permerror-fpermissive.c    |  2 +-
 .../gcc.dg/permerror-gnu89-nopermissive.c       |  2 +-
 gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c |  2 +-
 gcc/testsuite/gcc.dg/permerror-gnu89.c          |  2 +-
 gcc/testsuite/gcc.dg/permerror-noerror.c        |  4 ++--
 gcc/testsuite/gcc.dg/permerror-nowarning.c      |  7 +------
 gcc/testsuite/gcc.dg/permerror-pedantic.c       |  2 +-
 gcc/testsuite/gcc.dg/permerror-system.c         |  2 ++
 13 files changed, 36 insertions(+), 23 deletions(-)
  

On Mon, Nov 20, 2023 at 4:58 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> This used to be a warning, enabled by default, without its own option.

Right, I meant to ask: why create a new option of
-Wdeclaration-missing-parameter-type instead of reusing the existing
-Wmissing-parameter-type for this?

>
> A subsequent change could improve diagnostics and provide spelling
> hints for declarations like “void function (int32t);”.
>
> gcc/c-family/
>
>         * c.opt (Wdeclaration-missing-parameter-type): New.
>
> gcc/c/ChangeLog:
>
>         PR other/44209
>         * c-decl.cc (grokparms): Issue permerror for
>         OPT_Wdeclaration_missing_parameter_type instead of a pedwarn.
>
> gcc/ChangeLog:
>
>         * doc/invoke.texi (Warning Options): Document
>         -Wdeclaration-missing-parameter-type.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.dg/permerror-default.c (missing_parameter_type):
>         Expect error.
>         * gcc.dg/permerror-fpermissive.c (missing_parameter_type):
>         Expect -Wdeclaration-missing-parameter-type warning.
>         * gcc.dg/permerror-gnu89-nopermissive.c (missing_parameter_type):
>         Expect -Wdeclaration-missing-parameter-type error.
>         * gcc.dg/permerror-gnu89-pedantic.c (missing_parameter_type):
>         Likewise.
>         * gcc.dg/permerror-gnu89.c (missing_parameter_type):
>         Expect -Wdeclaration-missing-parameter-type warning.
>         * gcc.dg/permerror-noerror.c: Add
>         -Wno-error=declaration-missing-parameter-type to build flags.
>         (missing_parameter_type): Expect
>         -Wdeclaration-missing-parameter-type warning.
>         * gcc.dg/permerror-nowarning.c: Build with
>         -Wno-declaration-missing-parameter-type.  Remove previously
>         expected warning.
>         * gcc.dg/permerror-fpermissive-nowarning.c: Likewise.
>         * gcc.dg/permerror-pedantic.c (missing_parameter_type):
>         Expect -Wdeclaration-missing-parameter-type error.
>         * gcc.dg/permerror-system.c (missing_parameter_type):
>         Likewise.
> ---
>  gcc/c-family/c.opt                              |  4 ++++
>  gcc/c/c-decl.cc                                 |  6 ++++--
>  gcc/doc/invoke.texi                             | 17 ++++++++++++++++-
>  gcc/testsuite/gcc.dg/permerror-default.c        |  2 +-
>  .../gcc.dg/permerror-fpermissive-nowarning.c    |  7 +------
>  gcc/testsuite/gcc.dg/permerror-fpermissive.c    |  2 +-
>  .../gcc.dg/permerror-gnu89-nopermissive.c       |  2 +-
>  gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c |  2 +-
>  gcc/testsuite/gcc.dg/permerror-gnu89.c          |  2 +-
>  gcc/testsuite/gcc.dg/permerror-noerror.c        |  4 ++--
>  gcc/testsuite/gcc.dg/permerror-nowarning.c      |  7 +------
>  gcc/testsuite/gcc.dg/permerror-pedantic.c       |  2 +-
>  gcc/testsuite/gcc.dg/permerror-system.c         |  2 ++
>  13 files changed, 36 insertions(+), 23 deletions(-)
>
> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> index b10c6057cd1..723e8c3e27b 100644
> --- a/gcc/c-family/c.opt
> +++ b/gcc/c-family/c.opt
> @@ -591,6 +591,10 @@ Wdeclaration-after-statement
>  C ObjC Var(warn_declaration_after_statement) Init(-1) Warning
>  Warn when a declaration is found after a statement.
>
> +Wdeclaration-missing-parameter-type
> +C ObjC Var(warn_declaration_missing_parameter) Warning Init(1)
> +Warn for missing parameter types in function declarations.
> +
>  Wdelete-incomplete
>  C++ ObjC++ Var(warn_delete_incomplete) Init(1) Warning
>  Warn when deleting a pointer to incomplete type.
> diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
> index d16958113a8..3d9bee54259 100644
> --- a/gcc/c/c-decl.cc
> +++ b/gcc/c/c-decl.cc
> @@ -8337,8 +8337,10 @@ grokparms (struct c_arg_info *arg_info, bool funcdef_flag)
>      {
>        if (!funcdef_flag)
>         {
> -         pedwarn (input_location, 0, "parameter names (without types) in "
> -                  "function declaration");
> +         permerror_opt (input_location,
> +                        OPT_Wdeclaration_missing_parameter_type,
> +                        "parameter names (without types) in "
> +                        "function declaration");
>           arg_info->parms = NULL_TREE;
>         }
>        else
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index be33da71c44..7f5da45dcea 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -504,7 +504,8 @@ Objective-C and Objective-C++ Dialects}.
>
>  @item C and Objective-C-only Warning Options
>  @gccoptlist{-Wbad-function-cast  -Wmissing-declarations
> --Wmissing-parameter-type -Wmissing-prototypes -Wmissing-variable-declarations
> +-Wmissing-parameter-type -Wdeclaration-missing-parameter-type
> +-Wmissing-prototypes -Wmissing-variable-declarations
>  -Wnested-externs -Wold-style-declaration  -Wold-style-definition
>  -Wstrict-prototypes  -Wtraditional  -Wtraditional-conversion
>  -Wdeclaration-after-statement  -Wpointer-sign}
> @@ -9734,6 +9735,20 @@ void foo(bar) @{ @}
>
>  This warning is also enabled by @option{-Wextra}.
>
> +@opindex Wno-declaration-missing-parameter-type
> +@opindex Wdeclaration-missing-parameter-type
> +@item -Wno-declaration-missing-parameter-type @r{(C and Objective-C only)}
> +Do not warn if a function declaration contains a parameter name without
> +a type.  Such function declarations do not provide a function prototype
> +and prevent most type checking in function calls.
> +
> +This warning is enabled by default.  In C99 and later dialects of C, it
> +is treated as an error.  The error can be downgraded to a warning using
> +@option{-fpermissive} (along with certain other errors), or for this
> +error alone, with @option{-Wno-error=declaration-missing-parameter-type}.
> +
> +This warning is upgraded to an error by @option{-pedantic-errors}.
> +
>  @opindex Wmissing-prototypes
>  @opindex Wno-missing-prototypes
>  @item -Wmissing-prototypes @r{(C and Objective-C only)}
> diff --git a/gcc/testsuite/gcc.dg/permerror-default.c b/gcc/testsuite/gcc.dg/permerror-default.c
> index 45b58b0131d..c674d689081 100644
> --- a/gcc/testsuite/gcc.dg/permerror-default.c
> +++ b/gcc/testsuite/gcc.dg/permerror-default.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-error "return type defaults to 'int' \\\[-Wimplicit-i
>    (const) 0; /* { dg-error "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" } */
>  }
>
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>
>
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-fpermissive-nowarning.c b/gcc/testsuite/gcc.dg/permerror-fpermissive-nowarning.c
> index f15b21ef43d..d07c8636677 100644
> --- a/gcc/testsuite/gcc.dg/permerror-fpermissive-nowarning.c
> +++ b/gcc/testsuite/gcc.dg/permerror-fpermissive-nowarning.c
> @@ -1,11 +1,6 @@
> -/* { dg-options "-fpermissive -Wno-implicit-function-declaration -Wno-implicit-int -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-return-mismatch" } */
> +/* { dg-options "-fpermissive -Wno-implicit-function-declaration -Wno-implicit-int -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-return-mismatch -Wno-declaration-missing-parameter-type" } */
>
>  /* This test checks that permerrors can be disabled using -Wno-* options even
>     if -fpermissive is used.  */
>
>  #include "permerror-default.c"
> -
> -/* Ideally, we do not want to see any warnings here, but this warning is not
> -   yet controlled by its own option.  */
> -
> -/* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" "" { target *-*-* } 22 } */
> diff --git a/gcc/testsuite/gcc.dg/permerror-fpermissive.c b/gcc/testsuite/gcc.dg/permerror-fpermissive.c
> index 139f35ad1c0..fd3020d75ee 100644
> --- a/gcc/testsuite/gcc.dg/permerror-fpermissive.c
> +++ b/gcc/testsuite/gcc.dg/permerror-fpermissive.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-warning "return type defaults to 'int' \\\[-Wimplicit
>    (const) 0; /* { dg-warning "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" } */
>  }
>
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>
>
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-gnu89-nopermissive.c b/gcc/testsuite/gcc.dg/permerror-gnu89-nopermissive.c
> index 93504b94139..aba4b2498f7 100644
> --- a/gcc/testsuite/gcc.dg/permerror-gnu89-nopermissive.c
> +++ b/gcc/testsuite/gcc.dg/permerror-gnu89-nopermissive.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-bogus "-Wimplicit-int" } */
>    (const) 0; /* { dg-bogus "-Wimplicit-int" } */
>  }
>
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>
>
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c b/gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c
> index 465a16f5f9a..ef4dbfc86c5 100644
> --- a/gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c
> +++ b/gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-bogus "-Wimplicit-int" } */
>    (const) 0; /* { dg-bogus "-Wimplicit-int" } */
>  }
>
> -extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>
>
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-gnu89.c b/gcc/testsuite/gcc.dg/permerror-gnu89.c
> index 66f7789269f..83792ecfaac 100644
> --- a/gcc/testsuite/gcc.dg/permerror-gnu89.c
> +++ b/gcc/testsuite/gcc.dg/permerror-gnu89.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-bogus "-Wimplicit-int" } */
>    (const) 0; /* { dg-bogus "-Wimplicit-int" } */
>  }
>
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>
>
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-noerror.c b/gcc/testsuite/gcc.dg/permerror-noerror.c
> index cd1c2013cb5..fc68dfa8bb9 100644
> --- a/gcc/testsuite/gcc.dg/permerror-noerror.c
> +++ b/gcc/testsuite/gcc.dg/permerror-noerror.c
> @@ -1,4 +1,4 @@
> -/* { dg-options "-Wno-error=implicit-function-declaration -Wno-error=implicit-int -Wno-error=int-conversion -Wno-error=incompatible-pointer-types -Wno-error=return-mismatch" } */
> +/* { dg-options "-Wno-error=implicit-function-declaration -Wno-error=implicit-int -Wno-error=int-conversion -Wno-error=incompatible-pointer-types -Wno-error=return-mismatch -Wno-error=declaration-missing-parameter-type" } */
>
>  /* This test should emulate the effect of -fpermissive by adding all the
>     -Wno-error= options that are implied by -fpermissive.  It needs to be
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-warning "return type defaults to 'int' \\\[-Wimplicit
>    (const) 0; /* { dg-warning "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" } */
>  }
>
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>
>
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-nowarning.c b/gcc/testsuite/gcc.dg/permerror-nowarning.c
> index da6bd08245d..b1cf7990127 100644
> --- a/gcc/testsuite/gcc.dg/permerror-nowarning.c
> +++ b/gcc/testsuite/gcc.dg/permerror-nowarning.c
> @@ -1,10 +1,5 @@
> -/* { dg-options "-Wno-implicit-function-declaration -Wno-implicit-int -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-return-mismatch" } */
> +/* { dg-options "-Wno-implicit-function-declaration -Wno-implicit-int -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-return-mismatch -Wno-declaration-missing-parameter-type" } */
>
>  /* This test checks that permerrors can be disabled using -Wno-* options.  */
>
>  #include "permerror-default.c"
> -
> -/* Ideally, we do not want to see any warnings here, but this warning is not
> -   yet controlled by its own option.  */
> -
> -/* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" "" { target *-*-* } 22 } */
> diff --git a/gcc/testsuite/gcc.dg/permerror-pedantic.c b/gcc/testsuite/gcc.dg/permerror-pedantic.c
> index 95dda18acd4..2380bb2583c 100644
> --- a/gcc/testsuite/gcc.dg/permerror-pedantic.c
> +++ b/gcc/testsuite/gcc.dg/permerror-pedantic.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-error "return type defaults to 'int' \\\[-Wimplicit-i
>    (const) 0; /* { dg-error "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" } */
>  }
>
> -extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>
>
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-system.c b/gcc/testsuite/gcc.dg/permerror-system.c
> index bd923138461..790e4f03d66 100644
> --- a/gcc/testsuite/gcc.dg/permerror-system.c
> +++ b/gcc/testsuite/gcc.dg/permerror-system.c
> @@ -17,6 +17,8 @@
>  /* { dg-error "type of 'i' defaults to 'int' \\\[-Wimplicit-int\\\]" "" { target *-*-*} 16 } */
>  /* { dg-error "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" "" { target *-*-* } 19 } */
>
> +/* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" "" { target *-*-* } 22 } */
> +
>  /* { dg-error "pointer/integer type mismatch in conditional expression \\\[-Wint-conversion\\\]" "" { target *-*-* } 29 } */
>  /* { dg-error "pointer/integer type mismatch in conditional expression \\\[-Wint-conversion\\\]" "" { target *-*-* } 30 } */
>  /* { dg-error "passing argument 1 of 'f2' makes pointer from integer without a cast \\\[-Wint-conversion\\\]" "" { target *-*-* } 31 } */
> --
> 2.42.0
>
  

* Eric Gallager:

> On Mon, Nov 20, 2023 at 4:58 AM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> This used to be a warning, enabled by default, without its own option.
>
> Right, I meant to ask: why create a new option of
> -Wdeclaration-missing-parameter-type instead of reusing the existing
> -Wmissing-parameter-type for this?

It's documented as:

‘-Wmissing-parameter-type (C and Objective-C only)’
     A function parameter is declared without a type specifier in
     K&R-style functions:

          void foo(bar) { }

     This warning is also enabled by ‘-Wextra’.


What this doesn't say is that this has been subsumed by -Wimplicit-int
in C99 and later language modes.

Maybe we can tweak things such that -Wmissing-parameter-type controls
declarations only in C99 and later language modes, and turn just that
into a permerror.  But the situation is confusing enough already, which
is why I opted for the separate warning.

Thanks,
Florian
  

On Mon, Nov 20, 2023 at 10:56:42AM +0100, Florian Weimer wrote:
> This used to be a warning, enabled by default, without its own option.

I think this patch is OK now.
 
> A subsequent change could improve diagnostics and provide spelling
> hints for declarations like “void function (int32t);”.

Feel free to open a PR.
 
> gcc/c-family/
> 
> 	* c.opt (Wdeclaration-missing-parameter-type): New.
> 
> gcc/c/ChangeLog:
> 
> 	PR other/44209

FWIW, these usually go before the whole ChangeLog entry.

Thanks, and sorry about the wait.

> 	* c-decl.cc (grokparms): Issue permerror for
> 	OPT_Wdeclaration_missing_parameter_type instead of a pedwarn.
> 
> gcc/ChangeLog:
> 
> 	* doc/invoke.texi (Warning Options): Document
> 	-Wdeclaration-missing-parameter-type.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.dg/permerror-default.c (missing_parameter_type):
> 	Expect error.
> 	* gcc.dg/permerror-fpermissive.c (missing_parameter_type):
> 	Expect -Wdeclaration-missing-parameter-type warning.
> 	* gcc.dg/permerror-gnu89-nopermissive.c (missing_parameter_type):
> 	Expect -Wdeclaration-missing-parameter-type error.
> 	* gcc.dg/permerror-gnu89-pedantic.c (missing_parameter_type):
> 	Likewise.
> 	* gcc.dg/permerror-gnu89.c (missing_parameter_type):
> 	Expect -Wdeclaration-missing-parameter-type warning.
> 	* gcc.dg/permerror-noerror.c: Add
> 	-Wno-error=declaration-missing-parameter-type to build flags.
> 	(missing_parameter_type): Expect
> 	-Wdeclaration-missing-parameter-type warning.
> 	* gcc.dg/permerror-nowarning.c: Build with
> 	-Wno-declaration-missing-parameter-type.  Remove previously
> 	expected warning.
> 	* gcc.dg/permerror-fpermissive-nowarning.c: Likewise.
> 	* gcc.dg/permerror-pedantic.c (missing_parameter_type):
> 	Expect -Wdeclaration-missing-parameter-type error.
> 	* gcc.dg/permerror-system.c (missing_parameter_type):
> 	Likewise.
> ---
>  gcc/c-family/c.opt                              |  4 ++++
>  gcc/c/c-decl.cc                                 |  6 ++++--
>  gcc/doc/invoke.texi                             | 17 ++++++++++++++++-
>  gcc/testsuite/gcc.dg/permerror-default.c        |  2 +-
>  .../gcc.dg/permerror-fpermissive-nowarning.c    |  7 +------
>  gcc/testsuite/gcc.dg/permerror-fpermissive.c    |  2 +-
>  .../gcc.dg/permerror-gnu89-nopermissive.c       |  2 +-
>  gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c |  2 +-
>  gcc/testsuite/gcc.dg/permerror-gnu89.c          |  2 +-
>  gcc/testsuite/gcc.dg/permerror-noerror.c        |  4 ++--
>  gcc/testsuite/gcc.dg/permerror-nowarning.c      |  7 +------
>  gcc/testsuite/gcc.dg/permerror-pedantic.c       |  2 +-
>  gcc/testsuite/gcc.dg/permerror-system.c         |  2 ++
>  13 files changed, 36 insertions(+), 23 deletions(-)
> 
> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> index b10c6057cd1..723e8c3e27b 100644
> --- a/gcc/c-family/c.opt
> +++ b/gcc/c-family/c.opt
> @@ -591,6 +591,10 @@ Wdeclaration-after-statement
>  C ObjC Var(warn_declaration_after_statement) Init(-1) Warning
>  Warn when a declaration is found after a statement.
>  
> +Wdeclaration-missing-parameter-type
> +C ObjC Var(warn_declaration_missing_parameter) Warning Init(1)
> +Warn for missing parameter types in function declarations.
> +
>  Wdelete-incomplete
>  C++ ObjC++ Var(warn_delete_incomplete) Init(1) Warning
>  Warn when deleting a pointer to incomplete type.
> diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
> index d16958113a8..3d9bee54259 100644
> --- a/gcc/c/c-decl.cc
> +++ b/gcc/c/c-decl.cc
> @@ -8337,8 +8337,10 @@ grokparms (struct c_arg_info *arg_info, bool funcdef_flag)
>      {
>        if (!funcdef_flag)
>  	{
> -	  pedwarn (input_location, 0, "parameter names (without types) in "
> -		   "function declaration");
> +	  permerror_opt (input_location,
> +			 OPT_Wdeclaration_missing_parameter_type,
> +			 "parameter names (without types) in "
> +			 "function declaration");
>  	  arg_info->parms = NULL_TREE;
>  	}
>        else
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index be33da71c44..7f5da45dcea 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -504,7 +504,8 @@ Objective-C and Objective-C++ Dialects}.
>  
>  @item C and Objective-C-only Warning Options
>  @gccoptlist{-Wbad-function-cast  -Wmissing-declarations
> --Wmissing-parameter-type -Wmissing-prototypes -Wmissing-variable-declarations
> +-Wmissing-parameter-type -Wdeclaration-missing-parameter-type
> +-Wmissing-prototypes -Wmissing-variable-declarations
>  -Wnested-externs -Wold-style-declaration  -Wold-style-definition
>  -Wstrict-prototypes  -Wtraditional  -Wtraditional-conversion
>  -Wdeclaration-after-statement  -Wpointer-sign}
> @@ -9734,6 +9735,20 @@ void foo(bar) @{ @}
>  
>  This warning is also enabled by @option{-Wextra}.
>  
> +@opindex Wno-declaration-missing-parameter-type
> +@opindex Wdeclaration-missing-parameter-type
> +@item -Wno-declaration-missing-parameter-type @r{(C and Objective-C only)}
> +Do not warn if a function declaration contains a parameter name without
> +a type.  Such function declarations do not provide a function prototype
> +and prevent most type checking in function calls.
> +
> +This warning is enabled by default.  In C99 and later dialects of C, it
> +is treated as an error.  The error can be downgraded to a warning using
> +@option{-fpermissive} (along with certain other errors), or for this
> +error alone, with @option{-Wno-error=declaration-missing-parameter-type}.
> +
> +This warning is upgraded to an error by @option{-pedantic-errors}.
> +
>  @opindex Wmissing-prototypes
>  @opindex Wno-missing-prototypes
>  @item -Wmissing-prototypes @r{(C and Objective-C only)}
> diff --git a/gcc/testsuite/gcc.dg/permerror-default.c b/gcc/testsuite/gcc.dg/permerror-default.c
> index 45b58b0131d..c674d689081 100644
> --- a/gcc/testsuite/gcc.dg/permerror-default.c
> +++ b/gcc/testsuite/gcc.dg/permerror-default.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-error "return type defaults to 'int' \\\[-Wimplicit-i
>    (const) 0; /* { dg-error "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" } */
>  }
>  
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>  
>  
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-fpermissive-nowarning.c b/gcc/testsuite/gcc.dg/permerror-fpermissive-nowarning.c
> index f15b21ef43d..d07c8636677 100644
> --- a/gcc/testsuite/gcc.dg/permerror-fpermissive-nowarning.c
> +++ b/gcc/testsuite/gcc.dg/permerror-fpermissive-nowarning.c
> @@ -1,11 +1,6 @@
> -/* { dg-options "-fpermissive -Wno-implicit-function-declaration -Wno-implicit-int -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-return-mismatch" } */
> +/* { dg-options "-fpermissive -Wno-implicit-function-declaration -Wno-implicit-int -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-return-mismatch -Wno-declaration-missing-parameter-type" } */
>  
>  /* This test checks that permerrors can be disabled using -Wno-* options even
>     if -fpermissive is used.  */
>  
>  #include "permerror-default.c"
> -
> -/* Ideally, we do not want to see any warnings here, but this warning is not
> -   yet controlled by its own option.  */
> -
> -/* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" "" { target *-*-* } 22 } */
> diff --git a/gcc/testsuite/gcc.dg/permerror-fpermissive.c b/gcc/testsuite/gcc.dg/permerror-fpermissive.c
> index 139f35ad1c0..fd3020d75ee 100644
> --- a/gcc/testsuite/gcc.dg/permerror-fpermissive.c
> +++ b/gcc/testsuite/gcc.dg/permerror-fpermissive.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-warning "return type defaults to 'int' \\\[-Wimplicit
>    (const) 0; /* { dg-warning "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" } */
>  }
>  
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>  
>  
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-gnu89-nopermissive.c b/gcc/testsuite/gcc.dg/permerror-gnu89-nopermissive.c
> index 93504b94139..aba4b2498f7 100644
> --- a/gcc/testsuite/gcc.dg/permerror-gnu89-nopermissive.c
> +++ b/gcc/testsuite/gcc.dg/permerror-gnu89-nopermissive.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-bogus "-Wimplicit-int" } */
>    (const) 0; /* { dg-bogus "-Wimplicit-int" } */
>  }
>  
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>  
>  
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c b/gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c
> index 465a16f5f9a..ef4dbfc86c5 100644
> --- a/gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c
> +++ b/gcc/testsuite/gcc.dg/permerror-gnu89-pedantic.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-bogus "-Wimplicit-int" } */
>    (const) 0; /* { dg-bogus "-Wimplicit-int" } */
>  }
>  
> -extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>  
>  
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-gnu89.c b/gcc/testsuite/gcc.dg/permerror-gnu89.c
> index 66f7789269f..83792ecfaac 100644
> --- a/gcc/testsuite/gcc.dg/permerror-gnu89.c
> +++ b/gcc/testsuite/gcc.dg/permerror-gnu89.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-bogus "-Wimplicit-int" } */
>    (const) 0; /* { dg-bogus "-Wimplicit-int" } */
>  }
>  
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>  
>  
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-noerror.c b/gcc/testsuite/gcc.dg/permerror-noerror.c
> index cd1c2013cb5..fc68dfa8bb9 100644
> --- a/gcc/testsuite/gcc.dg/permerror-noerror.c
> +++ b/gcc/testsuite/gcc.dg/permerror-noerror.c
> @@ -1,4 +1,4 @@
> -/* { dg-options "-Wno-error=implicit-function-declaration -Wno-error=implicit-int -Wno-error=int-conversion -Wno-error=incompatible-pointer-types -Wno-error=return-mismatch" } */
> +/* { dg-options "-Wno-error=implicit-function-declaration -Wno-error=implicit-int -Wno-error=int-conversion -Wno-error=incompatible-pointer-types -Wno-error=return-mismatch -Wno-error=declaration-missing-parameter-type" } */
>  
>  /* This test should emulate the effect of -fpermissive by adding all the
>     -Wno-error= options that are implied by -fpermissive.  It needs to be
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-warning "return type defaults to 'int' \\\[-Wimplicit
>    (const) 0; /* { dg-warning "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" } */
>  }
>  
> -extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-warning "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>  
>  
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-nowarning.c b/gcc/testsuite/gcc.dg/permerror-nowarning.c
> index da6bd08245d..b1cf7990127 100644
> --- a/gcc/testsuite/gcc.dg/permerror-nowarning.c
> +++ b/gcc/testsuite/gcc.dg/permerror-nowarning.c
> @@ -1,10 +1,5 @@
> -/* { dg-options "-Wno-implicit-function-declaration -Wno-implicit-int -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-return-mismatch" } */
> +/* { dg-options "-Wno-implicit-function-declaration -Wno-implicit-int -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-return-mismatch -Wno-declaration-missing-parameter-type" } */
>  
>  /* This test checks that permerrors can be disabled using -Wno-* options.  */
>  
>  #include "permerror-default.c"
> -
> -/* Ideally, we do not want to see any warnings here, but this warning is not
> -   yet controlled by its own option.  */
> -
> -/* { dg-warning "parameter names \\\(without types\\\) in function declaration\n" "" { target *-*-* } 22 } */
> diff --git a/gcc/testsuite/gcc.dg/permerror-pedantic.c b/gcc/testsuite/gcc.dg/permerror-pedantic.c
> index 95dda18acd4..2380bb2583c 100644
> --- a/gcc/testsuite/gcc.dg/permerror-pedantic.c
> +++ b/gcc/testsuite/gcc.dg/permerror-pedantic.c
> @@ -19,7 +19,7 @@ implicit_int_4 (i) /* { dg-error "return type defaults to 'int' \\\[-Wimplicit-i
>    (const) 0; /* { dg-error "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" } */
>  }
>  
> -extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration\n" } */
> +extern int missing_parameter_type (i); /* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" } */
>  
>  
>  int *
> diff --git a/gcc/testsuite/gcc.dg/permerror-system.c b/gcc/testsuite/gcc.dg/permerror-system.c
> index bd923138461..790e4f03d66 100644
> --- a/gcc/testsuite/gcc.dg/permerror-system.c
> +++ b/gcc/testsuite/gcc.dg/permerror-system.c
> @@ -17,6 +17,8 @@
>  /* { dg-error "type of 'i' defaults to 'int' \\\[-Wimplicit-int\\\]" "" { target *-*-*} 16 } */
>  /* { dg-error "type defaults to 'int' in type name \\\[-Wimplicit-int\\\]" "" { target *-*-* } 19 } */
>  
> +/* { dg-error "parameter names \\\(without types\\\) in function declaration \\\[-Wdeclaration-missing-parameter-type\\\]" "" { target *-*-* } 22 } */
> +
>  /* { dg-error "pointer/integer type mismatch in conditional expression \\\[-Wint-conversion\\\]" "" { target *-*-* } 29 } */
>  /* { dg-error "pointer/integer type mismatch in conditional expression \\\[-Wint-conversion\\\]" "" { target *-*-* } 30 } */
>  /* { dg-error "passing argument 1 of 'f2' makes pointer from integer without a cast \\\[-Wint-conversion\\\]" "" { target *-*-* } 31 } */
> -- 
> 2.42.0
> 

Marek
  

* Marek Polacek:

> On Mon, Nov 20, 2023 at 10:56:42AM +0100, Florian Weimer wrote:
>> This used to be a warning, enabled by default, without its own option.
>
> I think this patch is OK now.
>  
>> A subsequent change could improve diagnostics and provide spelling
>> hints for declarations like “void function (int32t);”.
>
> Feel free to open a PR.

Good idea, it's now:

  Spelling hint for typos in parameter types in function prototypes
  <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112954>

Thanks,
Florian