1 files changed, 99 insertions, 0 deletions
diff --git a/test/SemaCXX/decomposed-condition.cpp b/test/SemaCXX/decomposed-condition.cpp
new file mode 100644
index 000000000000..ab011f6ae4ba
--- /dev/null
+++ b/test/SemaCXX/decomposed-condition.cpp
@@ -0,0 +1,99 @@
+// RUN: %clang_cc1 -std=c++1z -Wno-binding-in-condition -verify %s
+
+struct X {
+  bool flag;
+  int data;
+  constexpr explicit operator bool() const {
+    return flag;
+  }
+  constexpr operator int() const {
+    return data;
+  }
+};
+
+namespace CondInIf {
+constexpr int f(X x) {
+  if (auto [ok, d] = x)
+    return d + int(ok);
+  else
+    return d * int(ok);
+  ok = {}; // expected-error {{use of undeclared identifier 'ok'}}
+  d = {};  // expected-error {{use of undeclared identifier 'd'}}
+}
+
+static_assert(f({true, 2}) == 3);
+static_assert(f({false, 2}) == 0);
+
+constexpr char g(char const (&x)[2]) {
+  if (auto &[a, b] = x)
+    return a;
+  else
+    return b;
+
+  if (auto [a, b] = x) // expected-error {{an array type is not allowed here}}
+    ;
+}
+
+static_assert(g("x") == 'x');
+} // namespace CondInIf
+
+namespace CondInSwitch {
+constexpr int f(int n) {
+  switch (X s = {true, n}; auto [ok, d] = s) {
+    s = {};
+  case 0:
+    return int(ok);
+  case 1:
+    return d * 10;
+  case 2:
+    return d * 40;
+  default:
+    return 0;
+  }
+  ok = {}; // expected-error {{use of undeclared identifier 'ok'}}
+  d = {};  // expected-error {{use of undeclared identifier 'd'}}
+  s = {};  // expected-error {{use of undeclared identifier 's'}}
+}
+
+static_assert(f(0) == 1);
+static_assert(f(1) == 10);
+static_assert(f(2) == 80);
+} // namespace CondInSwitch
+
+namespace CondInWhile {
+constexpr int f(int n) {
+  int m = 1;
+  while (auto [ok, d] = X{n > 1, n}) {
+    m *= d;
+    --n;
+  }
+  return m;
+  return ok; // expected-error {{use of undeclared identifier 'ok'}}
+}
+
+static_assert(f(0) == 1);
+static_assert(f(1) == 1);
+static_assert(f(4) == 24);
+} // namespace CondInWhile
+
+namespace CondInFor {
+constexpr int f(int n) {
+  int a = 1, b = 1;
+  for (X x = {true, n}; auto &[ok, d] = x; --d) {
+    if (d < 2)
+      ok = false;
+    else {
+      int x = b;
+      b += a;
+      a = x;
+    }
+  }
+  return b;
+  return d; // expected-error {{use of undeclared identifier 'd'}}
+}
+
+static_assert(f(0) == 1);
+static_assert(f(1) == 1);
+static_assert(f(2) == 2);
+static_assert(f(5) == 8);
+} // namespace CondInFor