Consider this bogus code (from g++.dg/diagnostic/param-type-mismatch-2.C): struct s4 { static int member_1 (int one, const char **two, float three); };
int test_4 (int first, const char *second, float third) { return s4::member_1 (first, second, third); } Before this patch, g++ emits: demo.cc: In function 'int test_4(int, const char*, float)': demo.cc:5:44: error: no matching function for call to 's4::member_1(int&, const char*&, float&)' 5 | return s4::member_1 (first, second, third); | ^ demo.cc:1:24: note: candidate: 'static int s4::member_1(int, const char**, float)' 1 | struct s4 { static int member_1 (int one, const char **two, float three); }; | ^~~~~~~~ demo.cc:1:24: note: no known conversion for argument 2 from 'const char*' to 'const char**' With this patch, it highlights the pertinent parameter in the "no known conversion" note: demo.cc: In function 'int test_4(int, const char*, float)': demo.cc:5:44: error: no matching function for call to 's4::member_1(int&, const char*&, float&)' 5 | return s4::member_1 (first, second, third); | ^ demo.cc:1:24: note: candidate: 'static int s4::member_1(int, const char**, float)' 1 | struct s4 { static int member_1 (int one, const char **two, float three); }; | ^~~~~~~~ demo.cc:1:56: note: no known conversion for argument 2 from 'const char*' to 'const char**' 1 | struct s4 { static int member_1 (int one, const char **two, float three); }; | ~~~~~~~~~~~~~^~~ Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu; adds 15 PASS results to g++.sum. OK for trunk? I'm working on a followup to highlight the pertinent argument in the initial error diagnostic. gcc/cp/ChangeLog: PR c++/85110 * call.c (print_conversion_rejection): Add "fn" param and use it for "no known conversion" messages to underline the pertinent param. (print_z_candidate): Supply "fn" to the new param above. gcc/testsuite/ChangeLog: PR c++/85110 * g++.dg/diagnostic/param-type-mismatch-2.C: Update expected output to reflect underlining of pertinent parameter in decl for "no known conversion" messages. --- gcc/cp/call.c | 17 +++++++++------ .../g++.dg/diagnostic/param-type-mismatch-2.C | 25 +++++++++++++++++----- 2 files changed, 31 insertions(+), 11 deletions(-) diff --git a/gcc/cp/call.c b/gcc/cp/call.c index 626830c..ef445e0 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -3432,10 +3432,11 @@ equal_functions (tree fn1, tree fn2) return fn1 == fn2; } -/* Print information about a candidate being rejected due to INFO. */ +/* Print information about a candidate FN being rejected due to INFO. */ static void -print_conversion_rejection (location_t loc, struct conversion_info *info) +print_conversion_rejection (location_t loc, struct conversion_info *info, + tree fn) { tree from = info->from; if (!TYPE_P (from)) @@ -3466,8 +3467,12 @@ print_conversion_rejection (location_t loc, struct conversion_info *info) inform (loc, " no known conversion from %qH to %qI", from, info->to_type); else - inform (loc, " no known conversion for argument %d from %qH to %qI", - info->n_arg + 1, from, info->to_type); + { + if (TREE_CODE (fn) == FUNCTION_DECL) + loc = get_fndecl_argument_location (fn, info->n_arg); + inform (loc, " no known conversion for argument %d from %qH to %qI", + info->n_arg + 1, from, info->to_type); + } } /* Print information about a candidate with WANT parameters and we found @@ -3542,10 +3547,10 @@ print_z_candidate (location_t loc, const char *msgstr, r->u.arity.expected); break; case rr_arg_conversion: - print_conversion_rejection (cloc, &r->u.conversion); + print_conversion_rejection (cloc, &r->u.conversion, fn); break; case rr_bad_arg_conversion: - print_conversion_rejection (cloc, &r->u.bad_conversion); + print_conversion_rejection (cloc, &r->u.bad_conversion, fn); break; case rr_explicit_conversion: inform (cloc, " return type %qT of explicit conversion function " diff --git a/gcc/testsuite/g++.dg/diagnostic/param-type-mismatch-2.C b/gcc/testsuite/g++.dg/diagnostic/param-type-mismatch-2.C index 8cf2dab..4957f61 100644 --- a/gcc/testsuite/g++.dg/diagnostic/param-type-mismatch-2.C +++ b/gcc/testsuite/g++.dg/diagnostic/param-type-mismatch-2.C @@ -82,7 +82,10 @@ int test_4 (int first, const char *second, float third) ^~~~~~~~ { dg-end-multiline-output "" } */ // { dg-message "no known conversion for argument 2 from 'const char\\*' to 'const char\\*\\*'" "" { target *-*-* } s4_member_1 } - // TODO: underline the pertinent param + /* { dg-begin-multiline-output "" } + struct s4 { static int member_1 (int one, const char **two, float three); }; + ~~~~~~~~~~~~~^~~ + { dg-end-multiline-output "" } */ } /* non-static member, with argname. */ @@ -103,7 +106,10 @@ int test_5 (int first, const char *second, float third) ^~~~~~~~ { dg-end-multiline-output "" } */ // { dg-message "no known conversion for argument 2 from 'const char\\*' to 'const char\\*\\*'" "" { target *-*-* } s5_member_1 } - // TODO: underline the pertinent param + /* { dg-begin-multiline-output "" } + struct s5 { int member_1 (int one, const char **two, float three); }; + ~~~~~~~~~~~~~^~~ + { dg-end-multiline-output "" } */ } /* non-static member, with argname, via a ptr. */ @@ -123,7 +129,10 @@ int test_6 (int first, const char *second, float third, s6 *ptr) ^~~~~~~~ { dg-end-multiline-output "" } */ // { dg-message "no known conversion for argument 2 from 'const char\\*' to 'const char\\*\\*'" "" { target *-*-* } s6_member_1 } - // TODO: underline the pertinent param + /* { dg-begin-multiline-output "" } + struct s6 { int member_1 (int one, const char **two, float three); }; + ~~~~~~~~~~~~~^~~ + { dg-end-multiline-output "" } */ } /* Template function. */ @@ -170,7 +179,10 @@ int test_8 (int first, const char *second, float third) ^~~~~~~~ { dg-end-multiline-output "" } */ // { dg-message "no known conversion for argument 2 from 'const char\\*' to 'const char\\*\\*'" "" { target *-*-* } s8_member_1 } - // TODO: underline the pertinent param + /* { dg-begin-multiline-output "" } + struct s8 { static int member_1 (int one, T two, float three); }; + ~~^~~ + { dg-end-multiline-output "" } */ } /* Template class, non-static function. */ @@ -192,5 +204,8 @@ int test_9 (int first, const char *second, float third) ^~~~~~~~ { dg-end-multiline-output "" } */ // { dg-message "no known conversion for argument 2 from 'const char\\*' to 'const char\\*\\*'" "" { target *-*-* } s9_member_1 } - // TODO: underline the pertinent param + /* { dg-begin-multiline-output "" } + struct s9 { int member_1 (int one, T two, float three); }; + ~~^~~ + { dg-end-multiline-output "" } */ } -- 1.8.5.3