On Wed, Mar 28, 2018 at 4:44 PM, David Malcolm <dmalc...@redhat.com> wrote:
> This followup patch updates the specific error-handling path
> to add a note showing the pertinent parameter decl, taking
> the output from:
>
> test.cc: In function 'void caller(const char*)':
> test.cc:6:14: error: cannot convert 'const char*' to 'const char**' for
> argument '2' to 'void callee(int, const char**, int)'
> callee (1, fmt, 3);
> ^~~
>
> to:
>
> test.cc: In function 'void caller(const char*)':
> test.cc:6:14: error: cannot convert 'const char*' to 'const char**' for
> argument '2' to 'void callee(int, const char**, int)'
> callee (1, fmt, 3);
> ^~~
> test.cc:1:36: note: initializing argument 2 of 'void callee(int, const
> char**, int)'
> void callee (int one, const char **two, int three);
> ~~~~~~~~~~~~~^~~
>
> Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu; adds
> a further 18 PASS results to g++.sum.
>
> Again, not a regression as such, but I've been calling out the underlined
> arguments as a feature of gcc 8, so would be good to fix.
>
> OK for trunk?
>
> gcc/cp/ChangeLog:
> PR c++/85110
> * call.c (get_fndecl_argument_location): Make non-static.
> * cp-tree.h (get_fndecl_argument_location): New decl.
> * typeck.c (convert_for_assignment): When complaining due to
> conversions for an argument, show the location of the parameter
> within the decl.
>
> gcc/testsuite/ChangeLog:
> PR c++/85110
> * g++.dg/diagnostic/param-type-mismatch-2.C: Update for the cases
> where we now show the pertinent parameter.
> ---
> gcc/cp/call.c | 2 +-
> gcc/cp/cp-tree.h | 2 ++
> gcc/cp/typeck.c | 10 +++++++---
> .../g++.dg/diagnostic/param-type-mismatch-2.C | 21
> ++++++++++++++++++---
> 4 files changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/gcc/cp/call.c b/gcc/cp/call.c
> index 1a87f99..e1a0639 100644
> --- a/gcc/cp/call.c
> +++ b/gcc/cp/call.c
> @@ -6598,7 +6598,7 @@ maybe_print_user_conv_context (conversion *convs)
> ARGNUM is zero based, -1 indicates the `this' argument of a method.
> Return the location of the FNDECL itself if there are problems. */
>
> -static location_t
> +location_t
> get_fndecl_argument_location (tree fndecl, int argnum)
> {
> int i;
> diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
> index d5382c2..b45880d 100644
> --- a/gcc/cp/cp-tree.h
> +++ b/gcc/cp/cp-tree.h
> @@ -5965,6 +5965,8 @@ extern bool can_convert_arg
> (tree, tree, tree, int,
> tsubst_flags_t);
> extern bool can_convert_arg_bad (tree, tree, tree,
> int,
> tsubst_flags_t);
> +extern location_t get_fndecl_argument_location (tree, int);
> +
>
> /* A class for recording information about access failures (e.g. private
> fields), so that we can potentially supply a fix-it hint about
> diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
> index e733c79..742b2e9 100644
> --- a/gcc/cp/typeck.c
> +++ b/gcc/cp/typeck.c
> @@ -8781,9 +8781,13 @@ convert_for_assignment (tree type, tree rhs,
> parmnum, complain, flags);
> }
> else if (fndecl)
> - error_at (EXPR_LOC_OR_LOC (rhs, input_location),
> - "cannot convert %qH to %qI for argument %qP to %qD",
> - rhstype, type, parmnum, fndecl);
> + {
> + error_at (EXPR_LOC_OR_LOC (rhs, input_location),
> + "cannot convert %qH to %qI for argument %qP to
> %qD",
> + rhstype, type, parmnum, fndecl);
> + inform (get_fndecl_argument_location (fndecl, parmnum),
> + " initializing argument %P of %qD", parmnum,
> fndecl);
If you're adding the inform, you don't need the %P of %D in the initial error.
Jason
