c++: explicit ctor and list-initialization [PR109159]

When I implemented explicit(bool) in r9-3735, I added this code to
add_template_candidate_real:
+  /* Now the explicit specifier might have been deduced; check if this
+     declaration is explicit.  If it is and we're ignoring non-converting
+     constructors, don't add this function to the set of candidates.  */
+  if ((flags & LOOKUP_ONLYCONVERTING) && DECL_NONCONVERTING_P (fn))
+    return NULL;
but as this test demonstrates, that's incorrect when we're initializing
from a {}: for list-initialization we consider explicit constructors and
complain if one is chosen.

	PR c++/109159

gcc/cp/ChangeLog:

	* call.cc (add_template_candidate_real): Add explicit decls to the
	set of candidates when the initializer is a braced-init-list.

libstdc++-v3/ChangeLog:

	* testsuite/20_util/pair/cons/explicit_construct.cc: Adjust dg-error.
	* testsuite/20_util/tuple/cons/explicit_construct.cc: Likewise.
	* testsuite/23_containers/span/explicit.cc: Likewise.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/explicit16.C: New test.

diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index c01e7b82457fedd93d55e0bd373260f61c464047..c52a09b9be24b98f655e2979f8c0b6b11e81fdb1 100644 (file)
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -3612,7 +3612,9 @@ add_template_candidate_real (struct z_candidate **candidates, tree tmpl,
   /* Now the explicit specifier might have been deduced; check if this
      declaration is explicit.  If it is and we're ignoring non-converting
      constructors, don't add this function to the set of candidates.  */
-  if ((flags & LOOKUP_ONLYCONVERTING) && DECL_NONCONVERTING_P (fn))
+  if (((flags & (LOOKUP_ONLYCONVERTING|LOOKUP_LIST_INIT_CTOR))
+       == LOOKUP_ONLYCONVERTING)
+      && DECL_NONCONVERTING_P (fn))
     return NULL;
 
   if (DECL_CONSTRUCTOR_P (fn) && nargs == 2)

diff --git a/gcc/testsuite/g++.dg/cpp0x/explicit16.C b/gcc/testsuite/g++.dg/cpp0x/explicit16.C
new file mode 100644 (file)
index 0000000..bb5a823
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/explicit16.C
@@ -0,0 +1,18 @@
+// PR c++/109159
+// { dg-do compile { target c++11 } }
+
+struct A {
+  A(float) {}
+  template<class U>
+  explicit A(U) {}
+};
+
+void f(A t)
+{
+  t = {1}; // { dg-error "explicit constructor" }
+  t = 1;
+  A a1{1};
+  A a2 = {1}; // { dg-error "explicit constructor" }
+  A a3 = 1;
+  A a4(1);
+}

diff --git a/libstdc++-v3/testsuite/20_util/pair/cons/explicit_construct.cc b/libstdc++-v3/testsuite/20_util/pair/cons/explicit_construct.cc
index e875f0cbcd2cccbaccc579136143f4d941dc224f..d550e9c604bf1be04cd6b27d29377e5845b19ae0 100644 (file)
--- a/libstdc++-v3/testsuite/20_util/pair/cons/explicit_construct.cc
+++ b/libstdc++-v3/testsuite/20_util/pair/cons/explicit_construct.cc
@@ -37,7 +37,7 @@ struct ExplicitDefaultDefault
 
 std::pair<int, int> f1() {return {1,2};}
 
-std::pair<Explicit, Explicit> f2() {return {1,2};} // { dg-error "could not convert" }
+std::pair<Explicit, Explicit> f2() {return {1,2};} // { dg-error "explicit constructor" }
 
 std::pair<long, long> f3() {return std::pair<int, int>{1,2};}
 
@@ -52,7 +52,7 @@ std::pair<int, int> v0{1,2};
 
 std::pair<Explicit, Explicit> v1{1,2};
 
-std::pair<Explicit, Explicit> v2 = {1,2}; // { dg-error "could not convert" }
+std::pair<Explicit, Explicit> v2 = {1,2}; // { dg-error "explicit constructor" }
 
 std::pair<Explicit, Explicit> v3{std::pair<int,int>{1,2}};
 
@@ -99,7 +99,7 @@ void test_arg_passing()
 {
   f6(v0); // { dg-error "could not convert" }
   f6(v1);
-  f6({1,2}); // { dg-error "could not convert" }
+  f6({1,2}); // { dg-error "explicit constructor" }
   f6(std::pair<Explicit, Explicit>{});
   f6(std::pair<int, int>{}); // { dg-error "could not convert" }
   f7(v0);
@@ -130,6 +130,6 @@ std::pair<int*, ExplicitMoveOnly> v14{nullptr, MoveOnly{}};
 std::pair<ExplicitMoveOnly, int*> v15{MoveOnly{}, nullptr};
 
 std::pair<int*, ExplicitMoveOnly> v16 =
-  {nullptr, MoveOnly{}}; // { dg-error "could not convert" }
+  {nullptr, MoveOnly{}}; // { dg-error "explicit constructor" }
 std::pair<ExplicitMoveOnly, int*> v17 =
-  {MoveOnly{}, nullptr}; // { dg-error "could not convert" }
+  {MoveOnly{}, nullptr}; // { dg-error "explicit constructor" }

diff --git a/libstdc++-v3/testsuite/20_util/tuple/cons/explicit_construct.cc b/libstdc++-v3/testsuite/20_util/tuple/cons/explicit_construct.cc
index 820ddef30b4237d506c9d8afd15640384e9accc3..3352dd15f7d969d7063f45fdfcf5c91b966cd9a3 100644 (file)
--- a/libstdc++-v3/testsuite/20_util/tuple/cons/explicit_construct.cc
+++ b/libstdc++-v3/testsuite/20_util/tuple/cons/explicit_construct.cc
@@ -45,11 +45,11 @@ std::tuple<int, int> f1b() {return {1,2};}
 std::tuple<int, int, int> f1c() {return {1,2,3};}
 
 std::tuple<Explicit> f2_a()
-{return {1};} // { dg-error "could not convert" }
+{return {1};} // { dg-error "explicit constructor" }
 std::tuple<Explicit, Explicit> f2_b()
-{return {1,2};} // { dg-error "could not convert" }
+{return {1,2};} // { dg-error "explicit constructor" }
 std::tuple<Explicit, Explicit, Explicit> f2_c()
-{return {1,2,3};} // { dg-error "could not convert" }
+{return {1,2,3};} // { dg-error "explicit constructor" }
 
 std::tuple<long> f3_a() {return std::tuple<int>{1};}
 std::tuple<long, long> f3_b() {return std::tuple<int, int>{1,2};}
@@ -73,22 +73,22 @@ std::tuple<long, long> f5_b() {return {1,2};}
 std::tuple<long, long, long> f5_c() {return {1,2,3};}
 
 std::tuple<ExplicitDefault> f6_a()
-{return {};} // { dg-error "could not convert" }
+{return {};} // { dg-error "explicit constructor" }
 std::tuple<ExplicitDefault, ExplicitDefault> f6_b()
-{return {};} // { dg-error "could not convert" }
+{return {};} // { dg-error "explicit constructor" }
 std::tuple<ExplicitDefault, ExplicitDefault, ExplicitDefault> f6_c()
-{return {};} // { dg-error "could not convert" }
+{return {};} // { dg-error "explicit constructor" }
 std::tuple<ExplicitDefault, int> f6_d()
-{return {};} // { dg-error "could not convert" }
+{return {};} // { dg-error "explicit constructor" }
 
 std::tuple<ExplicitDefaultDefault> f7_a()
-{return {};} // { dg-error "could not convert" }
+{return {};} // { dg-error "explicit constructor" }
 std::tuple<ExplicitDefaultDefault, ExplicitDefaultDefault> f7_b()
-{return {};} // { dg-error "could not convert" }
+{return {};} // { dg-error "explicit constructor" }
 std::tuple<ExplicitDefaultDefault,
            ExplicitDefaultDefault,
            ExplicitDefaultDefault> f7_c()
-{return {};} // { dg-error "could not convert" }
+{return {};} // { dg-error "explicit constructor" }
 
 std::tuple<int, int> fp1() {return std::pair<int, int>{1,2}; }
 std::tuple<long, long> fp2() {return std::pair<int, int>{1,2}; }
@@ -103,9 +103,9 @@ std::tuple<Explicit> v1_a{1};
 std::tuple<Explicit, Explicit> v1_b{1,2};
 std::tuple<Explicit, Explicit, Explicit> v1_c{1,2,3};
 
-std::tuple<Explicit> v2_a = {1}; // { dg-error "could not convert" }
-std::tuple<Explicit, Explicit> v2_b = {1,2}; // { dg-error "could not convert" }
-std::tuple<Explicit, Explicit, Explicit> v2_c = {1,2,3}; // { dg-error "could not convert" }
+std::tuple<Explicit> v2_a = {1}; // { dg-error "explicit constructor" }
+std::tuple<Explicit, Explicit> v2_b = {1,2}; // { dg-error "explicit constructor" }
+std::tuple<Explicit, Explicit, Explicit> v2_c = {1,2,3}; // { dg-error "explicit constructor" }
 
 std::tuple<Explicit> v3_a{std::tuple<int>{1}};
 std::tuple<Explicit, Explicit> v3_b{std::tuple<int,int>{1,2}};
@@ -196,11 +196,11 @@ std::tuple<long, long, long>
   v31_c{std::allocator_arg, std::allocator<int>{}, 1,2,3};
 
 std::tuple<Explicit> v32_a
-  = {std::allocator_arg, std::allocator<int>{ }, 1}; // { dg-error "could not convert" }
+  = {std::allocator_arg, std::allocator<int>{ }, 1}; // { dg-error "explicit constructor" }
 std::tuple<Explicit, Explicit> v32_b
-  = {std::allocator_arg, std::allocator<int>{}, 1, 2}; // { dg-error "could not convert" }
+  = {std::allocator_arg, std::allocator<int>{}, 1, 2}; // { dg-error "explicit constructor" }
 std::tuple<Explicit, Explicit, Explicit> v32_c
-  = {std::allocator_arg, std::allocator<int>{}, 1,2,3}; // { dg-error "could not convert" }
+  = {std::allocator_arg, std::allocator<int>{}, 1,2,3}; // { dg-error "explicit constructor" }
 
 std::tuple<int, int> v33{std::allocator_arg, std::allocator<int>{},
   std::pair<int, int>{1, 2}};
@@ -218,7 +218,7 @@ std::tuple<long, long> v37 = {std::allocator_arg, std::allocator<int>{},
   std::pair<int, int>{1, 2}};
 
 std::tuple<Explicit, Explicit> v38
-= {std::allocator_arg, std::allocator<int>{}, std::pair<int, int>{1, 2}}; // { dg-error "could not convert" }
+= {std::allocator_arg, std::allocator<int>{}, std::pair<int, int>{1, 2}}; // { dg-error "explicit constructor" }
 
 std::tuple<int, int> v39{std::allocator_arg, std::allocator<int>{}, v20};
 
@@ -232,18 +232,18 @@ std::tuple<int, int> v42 = {std::allocator_arg, std::allocator<int>{}, v20};
 std::tuple<long, long> v43 = {std::allocator_arg, std::allocator<int>{}, v20};
 
 std::tuple<Explicit, Explicit> v44
-= {std::allocator_arg, std::allocator<int>{ }, v20}; // { dg-error "could not convert" }
+= {std::allocator_arg, std::allocator<int>{ }, v20}; // { dg-error "explicit constructor" }
 std::tuple<ExplicitDefault> v45_a{};
 std::tuple<ExplicitDefault, int> v45_b{};
 
-std::tuple<ExplicitDefault> v46_a = {}; // { dg-error "could not convert" }
-std::tuple<ExplicitDefault, int> v46_b = {}; // { dg-error "could not convert" }
+std::tuple<ExplicitDefault> v46_a = {}; // { dg-error "explicit constructor" }
+std::tuple<ExplicitDefault, int> v46_b = {}; // { dg-error "explicit constructor" }
 
 std::tuple<ExplicitDefaultDefault> v47_a{};
 std::tuple<ExplicitDefaultDefault, int> v47_b{};
 
-std::tuple<ExplicitDefaultDefault> v48_a = {}; // { dg-error "could not convert" }
-std::tuple<ExplicitDefaultDefault, int> v48_b = { }; // { dg-error "could not convert" }
+std::tuple<ExplicitDefaultDefault> v48_a = {}; // { dg-error "explicit constructor" }
+std::tuple<ExplicitDefaultDefault, int> v48_b = { }; // { dg-error "explicit constructor" }
 
 
 struct DeletedCopy
@@ -295,9 +295,9 @@ void test_arg_passing()
   f8_b(v1_b);
   f8_c(v1_c);
 
-  f8_a({1}); // { dg-error "could not convert" }
-  f8_b({1,2}); // { dg-error "could not convert" }
-  f8_c({1,2,3}); // { dg-error "could not convert" }
+  f8_a({1}); // { dg-error "explicit constructor" }
+  f8_b({1,2}); // { dg-error "explicit constructor" }
+  f8_c({1,2,3}); // { dg-error "explicit constructor" }
 
   f8_a(std::tuple<Explicit>{});
   f8_b(std::tuple<Explicit, Explicit>{});
@@ -330,10 +330,10 @@ void test_arg_passing()
   f9_b(std::tuple<long, long>{});
   f9_c(std::tuple<long, long, long>{});
 
-  f10_a({}); // { dg-error "could not convert" }
-  f10_b({}); // { dg-error "could not convert" }
-  f11_a({}); // { dg-error "could not convert" }
-  f11_b({}); // { dg-error "could not convert" }
+  f10_a({}); // { dg-error "explicit constructor" }
+  f10_b({}); // { dg-error "explicit constructor" }
+  f11_a({}); // { dg-error "explicit constructor" }
+  f11_b({}); // { dg-error "explicit constructor" }
 
   f10_a(std::tuple<ExplicitDefault>{});
   f10_b(std::tuple<ExplicitDefault, int>{});

diff --git a/libstdc++-v3/testsuite/23_containers/span/explicit.cc b/libstdc++-v3/testsuite/23_containers/span/explicit.cc
index 580d69e4f0939fafb41de13ae3f4fd25a53a66e0..b0a1311f02c6d113084bece467cf8c26bcc3b50d 100644 (file)
--- a/libstdc++-v3/testsuite/23_containers/span/explicit.cc
+++ b/libstdc++-v3/testsuite/23_containers/span/explicit.cc
@@ -31,11 +31,11 @@ auto first = std::begin(r), last = std::end(r);
 
 // span(It, size_type)
 std::span<int> s1 = {first, 2};
-std::span<int, 2> s2 = {first, 2}; // { dg-error "could not convert" }
+std::span<int, 2> s2 = {first, 2}; // { dg-error "explicit constructor" }
 
 // span(It, End)
 std::span<int> s3 = {first, last};
-std::span<int, 2> s4 = {first, last}; // { dg-error "could not convert" }
+std::span<int, 2> s4 = {first, last}; // { dg-error "explicit constructor" }
 
 // span(R&&)
 std::span<int> s5 = r;