Re: [PATCH] c++, contracts: Fix incorrect parameter mapping for postconditions in functions with template parameter packs. [PR124395]

On 8/14/26 4:47 PM, Wang Jinghao wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu.
> 
> -- >8 --
> 
> `check_postconditions_in_redecl()' assumes that the parameters in a
> function redeclaration correspond one to one with those in the
> previous declaration.  This assumption does not hold for parameter
> packs.  As a result, if the original declaration contains a parameter
> pack and the pack is instantiated with no arguments, a segmentation
> fault occurs.
> 
> Likewise, when the parameter pack is instantiated with multiple
> arguments, type checking is skipped for all instantiated parameters
> except the first one.
> 
> 	PR c++/124395
> 
> gcc/cp/ChangeLog:
> 
> 	* contracts.cc (maybe_propagate_used_in_post_flag): New
> 	function.  Contains the logic moved from
> 	check_postconditions_in_redecl for checking parameters in
> 	redeclarations.
> 	(check_postconditions_in_redecl): Fix parameter pack handing
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/contracts/cpp26/pr124395.C: New test.
And then fold2.C.