[Bug c++/45329] When printing a list of candidate functions, explain why each function failed to match.

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45329

--- Comment #6 from Jason Merrill <jason at gcc dot gnu.org> 2011-07-17 
02:34:15 UTC ---
Author: jason
Date: Sun Jul 17 02:34:10 2011
New Revision: 176365

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=176365
Log:
    PR c++/45329
    PR c++/48934
    * cp-tree.h (fn_type_unification): Add `bool' parameter.
    * pt.c (enum template_base_result): Define.
    (unify_success, unify_unknown): Define.
    (unify_parameter_deduction_failure): Define.
    (unify_invalid, unify_cv_qual_mismatch, unify_type_mismatch): Define.
    (unify_parameter_pack_mismatch): Define.
    (unify_parameter_pack_inconsistent): Define.
    (unify_ptrmem_cst_mismatch, unify_vla_arg): Define.
    (unify_expression_unequal, unify_inconsistency): Define.
    (unify_method_type_error, unify_arity): Likewise.
    (unify_too_many_parameters, unify_too_few_parameters): Define.
    (unify_arg_conversion, unify_no_common_base): Define.
    (unify_illformed_ptrmem_cst_expr): Define.
    (unify_substitution_failure): Define.
    (unify_inconsistent_template_template_parameters): Define.
    (unify_template_deduction_failure): Define.
    (unify_template_argument_mismatch): Define.
    (unify_overload_resolution_failure): Define.
    (comp_template_args_with_info): New function, split out from...
    (comp_template_args): ...here.    Call it.
    (deduction_tsubst_fntype): Add `complain' parameter'.  Pass it
    to tsubst.
    (unify): Add `explain_p' parameter.  Pass to all relevant calls.
    Call above status functions when appropriate.
    (resolve_overloaded_unification, try_one_overload): Likewise.
    (type_unification, type_unification_real): Likewise.
    (unify_pack_expansion): Likewise.
    (get_template_base, try_class_unification): Likewise.
    (get_bindings, more_specialized_fn): Pass false to unification
    calls.
    (get_class_bindings, do_auto_deduction): Likewise.
    (convert_nontype_argument): Likewise.
    (fn_type_unification): Likewise.  Pass tf_warning_or_error if
    explain_p.
    (get_template_base): Add `explain_p' parameter and pass it to
    try_class_unification.    Return an enum template_base_result.
    * class.c (resolve_address_of_overloaded_function): Pass false to
    fn_type_unification.
    * call.c (enum rejection_reason_code): Add new codes.
    (struct rejection_reason): Add template_unification field.
    Add template_instantiation field.
    (template_unification_rejection): Define.
    (template_unification_error_rejection): Define.
    (template_instantiation_rejection): Define.
    (invalid_copy_with_fn_template_rejection): Define.
    (add_template_candidate): Pass false to unify.
    Provide more rejection reasons when possible.
    (print_template_unification_rejection): Define.
    (print_arity_rejection): Define, split out from...
    (print_z_candidate): ...here.  Add cases for new rejection
    reasons.

Added:
    trunk/gcc/testsuite/g++.dg/overload/template5.C
    trunk/gcc/testsuite/g++.dg/template/overload12.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/call.c
    trunk/gcc/cp/class.c
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/pt.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/cpp0x/decltype29.C
    trunk/gcc/testsuite/g++.dg/cpp0x/error4.C
    trunk/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice2.C
    trunk/gcc/testsuite/g++.dg/cpp0x/nullptr15.C
    trunk/gcc/testsuite/g++.dg/cpp0x/pr31431-2.C
    trunk/gcc/testsuite/g++.dg/cpp0x/pr31431.C
    trunk/gcc/testsuite/g++.dg/cpp0x/pr31434.C
    trunk/gcc/testsuite/g++.dg/cpp0x/sfinae11.C
    trunk/gcc/testsuite/g++.dg/cpp0x/sfinae26.C
    trunk/gcc/testsuite/g++.dg/cpp0x/temp_default2.C
    trunk/gcc/testsuite/g++.dg/cpp0x/trailing4.C
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic-ex3.C
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic-ex4.C
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic105.C
    trunk/gcc/testsuite/g++.dg/cpp0x/vt-37737-2.C
    trunk/gcc/testsuite/g++.dg/ext/vla2.C
    trunk/gcc/testsuite/g++.dg/other/ptrmem10.C
    trunk/gcc/testsuite/g++.dg/other/ptrmem11.C
    trunk/gcc/testsuite/g++.dg/overload/unknown1.C
    trunk/gcc/testsuite/g++.dg/template/conv11.C
    trunk/gcc/testsuite/g++.dg/template/deduce3.C
    trunk/gcc/testsuite/g++.dg/template/dependent-expr5.C
    trunk/gcc/testsuite/g++.dg/template/error45.C
    trunk/gcc/testsuite/g++.dg/template/friend.C
    trunk/gcc/testsuite/g++.dg/template/incomplete2.C
    trunk/gcc/testsuite/g++.dg/template/local4.C
    trunk/gcc/testsuite/g++.dg/template/local6.C
    trunk/gcc/testsuite/g++.dg/template/operator9.C
    trunk/gcc/testsuite/g++.dg/template/ptrmem2.C
    trunk/gcc/testsuite/g++.dg/template/sfinae2.C
    trunk/gcc/testsuite/g++.dg/template/ttp25.C
    trunk/gcc/testsuite/g++.dg/template/unify10.C
    trunk/gcc/testsuite/g++.dg/template/unify11.C
    trunk/gcc/testsuite/g++.dg/template/unify6.C
    trunk/gcc/testsuite/g++.dg/template/unify7.C
    trunk/gcc/testsuite/g++.dg/template/unify9.C
    trunk/gcc/testsuite/g++.dg/template/varmod1.C
    trunk/gcc/testsuite/g++.old-deja/g++.brendan/crash56.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/crash28.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/crash60.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/explicit41.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/explicit77.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/expr2.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/ptrmem6.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/spec5.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/spec6.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/unify4.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/unify6.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/unify8.C
    trunk/gcc/testsuite/g++.old-deja/g++.robertl/eb98.C