re PR c++/45329 (When printing a list of candidate functions, explain why each function failed to match.)

	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.

Co-Authored-By: Jason Merrill <jason@redhat.com>

From-SVN: r176365

13 files changed, 17 insertions, 17 deletions

diff --git a/gcc/testsuite/g++.old-deja/g++.brendan/crash56.C b/gcc/testsuite/g++.old-deja/g++.brendan/crash56.C
index a22615d..e3bff80 100644
--- a/gcc/testsuite/g++.old-deja/g++.brendan/crash56.C
+++ b/gcc/testsuite/g++.old-deja/g++.brendan/crash56.C
@@ -278,7 +278,7 @@ SetLD<T>::remove(const T& item)
     Vix x;
     for (first(x); 0 != x && this->REMOVE_CURRENT != a; next(x, a))
 	a = operator()(x) == item ? this->REMOVE_CURRENT: this->NORMAL; // { dg-error "" } .*
-    // { dg-message "candidate" "candidate note" { target *-*-* } 280 }
+    // { dg-message "(candidate|not derived from)" "candidate note" { target *-*-* } 280 }
 }
 template<class T>
 bool
@@ -287,7 +287,7 @@ SetLD<T>::contains(const T& item) const
     Vix x;
     for (first(x); 0 != x; next(x)) {
 	if (operator()(x) == item)// { dg-error "" } .*
-	  // { dg-message "candidate" "candidate note" { target *-*-* } 289 }
+	  // { dg-message "(candidate|not derived from)" "candidate note" { target *-*-* } 289 }
 	    return TRUE;
     }
     return FALSE;
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/crash28.C b/gcc/testsuite/g++.old-deja/g++.pt/crash28.C
index 2cfed93..81ed85a 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/crash28.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/crash28.C
@@ -11,5 +11,5 @@ void f(unsigned int n) {
   int x[n];
 
   asize(x); // { dg-error "" } no matching function
-  // { dg-message "candidate" "candidate note" { target *-*-* } 13 }
+  // { dg-message "(candidate|not a valid template argument)" "candidate note" { target *-*-* } 13 }
 }
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/crash60.C b/gcc/testsuite/g++.old-deja/g++.pt/crash60.C
index 1aad621..747af9b 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/crash60.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/crash60.C
@@ -7,7 +7,7 @@
 template< typename SID, class SDR >
 void k( SID sid, SDR* p,
  void (SDR::*)
- ( typename SID::T ) );		// { dg-message "note" }
+ ( typename SID::T ) );		// { dg-error "no type named 'T'" }
 
 struct E { };
 struct S { void f( int ); };
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/explicit41.C b/gcc/testsuite/g++.old-deja/g++.pt/explicit41.C
index 560370a..c27d131 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/explicit41.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/explicit41.C
@@ -1,6 +1,6 @@
 // { dg-do assemble  }
 template <int I>
-void f(int i);			// { dg-message "note" }
+void f(int i);			// { dg-message "void f" }
 
 void g()
 {
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/explicit77.C b/gcc/testsuite/g++.old-deja/g++.pt/explicit77.C
index 1213a15..b97c1cd 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/explicit77.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/explicit77.C
@@ -15,5 +15,5 @@ void g() {
   
   f<0>(s0, s2);
   f(s0, s2); // { dg-error "" } no matching function
-  // { dg-message "candidate" "candidate note" { target *-*-* } 17 }
+  // { dg-message "(candidate|deduced conflicting types|ambiguous base class)" "candidate note" { target *-*-* } 17 }
 }
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/expr2.C b/gcc/testsuite/g++.old-deja/g++.pt/expr2.C
index 0dcc65f..06d22d5 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/expr2.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/expr2.C
@@ -9,5 +9,5 @@ void foo(S<J + 2>);		// { dg-message "note" }
 void bar()
 {
   foo(S<3>()); // { dg-error "" } no way to deduce J from this.
-  // { dg-message "candidate" "candidate note" { target *-*-* } 11 }
+  // { dg-message "(candidate|deduce template parameter)" "candidate note" { target *-*-* } 11 }
 }
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/ptrmem6.C b/gcc/testsuite/g++.old-deja/g++.pt/ptrmem6.C
index 85d3e73..8802e98 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/ptrmem6.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/ptrmem6.C
@@ -13,9 +13,9 @@ public:
 };
 
 template <void (A::*)() >
-void g() {}			// { dg-message "note" }
+void g() {}			// { dg-message "void g" }
 template <int A::*>
-void h() {}			// { dg-message "note" }
+void h() {}			// { dg-message "void h" }
 
 
 int main() {
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/spec5.C b/gcc/testsuite/g++.old-deja/g++.pt/spec5.C
index df7112a..96e8cf9 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/spec5.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/spec5.C
@@ -14,9 +14,9 @@ template void g(int i, int j);
 void h()
 {
   f(3, 'c'); // { dg-error "" } no matching function
-  // { dg-message "candidate" "candidate note" { target *-*-* } 16 }
+  // { dg-message "(candidate|deduced conflicting types)" "candidate note" { target *-*-* } 16 }
   g(3, 'c'); // { dg-error "" } no matching function
-  // { dg-message "candidate" "candidate note" { target *-*-* } 18 }
+  // { dg-message "(candidate|deduced conflicting types)" "candidate note" { target *-*-* } 18 }
 }
 
 
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/spec6.C b/gcc/testsuite/g++.old-deja/g++.pt/spec6.C
index fc19c3c..b8f6673 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/spec6.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/spec6.C
@@ -25,9 +25,9 @@ void h()
 {
   S1 s1;
   s1.f(3, 'c'); // { dg-error "" } no matching function
-  // { dg-message "candidate" "candidate note" { target *-*-* } 27 }
+  // { dg-message "(candidate|deduced conflicting types)" "candidate note" { target *-*-* } 27 }
 
   S2<char> s2;
   s2.f(3, 'c'); // { dg-error "" } no matching function
-  // { dg-message "candidate" "candidate note" { target *-*-* } 31 }
+  // { dg-message "(candidate|deduced conflicting types)" "candidate note" { target *-*-* } 31 }
 }
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/unify4.C b/gcc/testsuite/g++.old-deja/g++.pt/unify4.C
index 6dd9961..9285b21 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/unify4.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/unify4.C
@@ -8,6 +8,6 @@ int
 main ()
 {
   f (g);			// { dg-error "" } ambiguous unification
-  // { dg-message "candidate" "candidate note" { target *-*-* } 10 }
+  // { dg-message "(candidate|deduce template parameter)" "candidate note" { target *-*-* } 10 }
   return 0;
 }
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/unify6.C b/gcc/testsuite/g++.old-deja/g++.pt/unify6.C
index 0e5c034..a6f7674 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/unify6.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/unify6.C
@@ -19,7 +19,7 @@ template<> void fn<int &>() {} // ok, specialize A
 template<> void fn<void ()>() {} // ok, specialize A
 
 // now make sure we moan when we really should
-template<class T> void foo(T const *){} // { dg-message "note" }
+template<class T> void foo(T const *){} // { dg-error "pointer to reference" }
 
 void f()
 {
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/unify8.C b/gcc/testsuite/g++.old-deja/g++.pt/unify8.C
index 3209260..3a86d97 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/unify8.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/unify8.C
@@ -16,6 +16,6 @@ void Foo (float);     // { dg-message "note" } candidate
 void baz (int **p1)
 {
   Foo (p1);   // { dg-error "match" } no such function
-  // { dg-message "candidate" "candidate note" { target *-*-* } 18 }
+  // { dg-message "(candidate|incompatible cv-qualifiers)" "candidate note" { target *-*-* } 18 }
   Bar (p1);   // OK
 }
diff --git a/gcc/testsuite/g++.old-deja/g++.robertl/eb98.C b/gcc/testsuite/g++.old-deja/g++.robertl/eb98.C
index c562031..410a336 100644
--- a/gcc/testsuite/g++.old-deja/g++.robertl/eb98.C
+++ b/gcc/testsuite/g++.old-deja/g++.robertl/eb98.C
@@ -15,5 +15,5 @@
     void f()
     {
       extent(b);  // { dg-error "" } no matching function
-      // { dg-message "candidate" "candidate note" { target *-*-* } 17 }
+      // { dg-message "(candidate|mismatched types)" "candidate note" { target *-*-* } 17 }
     }