--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/cpp2a/explicit5.C	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,71 @@
+// P0892R2
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+constexpr int fn0 () { return 0; }
+constexpr int fn1 () { return 1; }
+
+struct S0 {
+  explicit(false) operator int();
+  explicit(1 == 0) operator double();
+  explicit(fn0()) operator char();
+};
+
+struct S1 {
+  explicit(true) operator int();
+  explicit(1 == 1) operator double();
+  explicit(fn1()) operator char();
+};
+
+struct X {
+  static const bool value = true;
+  static constexpr bool foo () { return 1; }
+};
+
+struct T {
+  explicit(true ? 1 : throw 1) operator int();
+  explicit(true || true ? 1 : throw 1) operator double();
+  explicit(X::value) operator char();
+  explicit(X::foo ()) operator long();
+};
+
+struct W {
+  constexpr operator bool() { return true; };
+};
+
+struct W2 {
+  constexpr operator bool() { return false; };
+};
+
+struct U1 {
+  explicit(W()) operator int();
+};
+
+struct U2 {
+  explicit(W2()) operator int();
+};
+
+int
+main ()
+{
+  S0 s0;
+  S1 s1;
+  int i0 = s0;
+  int i1 = s1; // { dg-error "cannot convert" }
+  double d0 = s0;
+  double d1 = s1; // { dg-error "cannot convert" }
+  char c0 = s0;
+  char c1 = s1; // { dg-error "cannot convert" }
+
+  T t;
+  int i2 = t; // { dg-error "cannot convert" }
+  double d2 = t; // { dg-error "cannot convert" }
+  char c2 = t; // { dg-error "cannot convert" }
+  long l1 = t; // { dg-error "cannot convert" }
+
+  U1 u1;
+  int i3 = u1; // { dg-error "cannot convert" }
+
+  U2 u2;
+  int i4 = u2;
+}