Re: [v2 PATCH] c++: ICE with erroneous template redeclaration [PR106311]

[Jason Merrill <jason@redhat.com>]

On 7/25/22 14:43, Marek Polacek wrote:
> On Fri, Jul 22, 2022 at 05:21:58PM -0400, Jason Merrill wrote:
>> On 7/15/22 11:29, Marek Polacek wrote:
>>> Here we ICE trying to get DECL_SOURCE_LOCATION of the parm that happens
>>> to be error_mark_node in this ill-formed test.  I kept running into this
>>> while reducing code, so it'd be good to have it fixed.
>>>
>>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>>>
>>> 	PR c++/106311
>>>
>>> gcc/cp/ChangeLog:
>>>
>>> 	* pt.cc (redeclare_class_template): Check DECL_P before accessing
>>> 	DECL_SOURCE_LOCATION.
>>>
>>> gcc/testsuite/ChangeLog:
>>>
>>> 	* g++.dg/template/redecl5.C: New test.
>>> ---
>>>    gcc/cp/pt.cc                            | 3 ++-
>>>    gcc/testsuite/g++.dg/template/redecl5.C | 5 +++++
>>>    2 files changed, 7 insertions(+), 1 deletion(-)
>>>    create mode 100644 gcc/testsuite/g++.dg/template/redecl5.C
>>>
>>> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
>>> index 718dfa5bfa8..0a294e91a79 100644
>>> --- a/gcc/cp/pt.cc
>>> +++ b/gcc/cp/pt.cc
>>> @@ -6377,7 +6377,8 @@ redeclare_class_template (tree type, tree parms, tree cons)
>>>    	{
>>>    	  auto_diagnostic_group d;
>>>    	  error ("template parameter %q+#D", tmpl_parm);
>>> -	  inform (DECL_SOURCE_LOCATION (parm), "redeclared here as %q#D", parm);
>>> +	  inform (DECL_P (parm) ? DECL_SOURCE_LOCATION (parm) : input_location,
>>> +		  "redeclared here as %q#D", parm);
>>
>> If we're checking DECL_P, probably we also should avoid passing it to %q#D
>> if it's false?
> 
> Right, I suppose printing "<error node>" isn't all that helpful.  How about
> this?
> 
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

OK.

> -- >8 --
> Here we ICE trying to get DECL_SOURCE_LOCATION of the parm that happens
> to be error_mark_node in this ill-formed test.  I kept running into this
> while reducing code, so it'd be good to have it fixed.
> 
> 	PR c++/106311
> 
> gcc/cp/ChangeLog:
> 
> 	* pt.cc (redeclare_class_template): Check DECL_P before accessing
> 	DECL_SOURCE_LOCATION.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/template/redecl5.C: New test.
> ---
>   gcc/cp/pt.cc                            | 5 ++++-
>   gcc/testsuite/g++.dg/template/redecl5.C | 5 +++++
>   2 files changed, 9 insertions(+), 1 deletion(-)
>   create mode 100644 gcc/testsuite/g++.dg/template/redecl5.C
> 
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index c415db304c9..6c581fe0fb7 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -6377,7 +6377,10 @@ redeclare_class_template (tree type, tree parms, tree cons)
>   	{
>   	  auto_diagnostic_group d;
>   	  error ("template parameter %q+#D", tmpl_parm);
> -	  inform (DECL_SOURCE_LOCATION (parm), "redeclared here as %q#D", parm);
> +	  if (DECL_P (parm))
> +	    inform (DECL_SOURCE_LOCATION (parm), "redeclared here as %q#D", parm);
> +	  else
> +	    inform (input_location, "redeclared here");
>   	  return false;
>   	}
>   
> diff --git a/gcc/testsuite/g++.dg/template/redecl5.C b/gcc/testsuite/g++.dg/template/redecl5.C
> new file mode 100644
> index 00000000000..fb2d698e6bc
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/template/redecl5.C
> @@ -0,0 +1,5 @@
> +// PR c++/106311
> +// { dg-do compile }
> +
> +template <typename, long> struct array; // { dg-error "template parameter" }
> +template <typename, size_t X> struct array { }; // { dg-error "declared" }
> 
> base-commit: 16aafa3194d4851a07cc204f56a5f0618f77e5d7