P0305R0: Semantic analysis and code generation for C++17 init-statement for 'if' and 'switch':

  if (stmt; condition) { ... }

Patch by Anton Bikineev! Some minor formatting and comment tweets by me.

llvm-svn: 275350

1 files changed, 91 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/cxx1z-init-statement.cpp b/clang/test/SemaCXX/cxx1z-init-statement.cpp
new file mode 100644
index 00000000000..4afe0402d13
--- /dev/null
+++ b/clang/test/SemaCXX/cxx1z-init-statement.cpp
@@ -0,0 +1,91 @@
+// RUN: %clang_cc1 -std=c++1z -verify %s
+
+void testIf() {
+  int x = 0;
+  if (x; x) ++x;
+  if (int t = 0; t) ++t; else --t;
+
+  if (int x, y = 0; y) // expected-note 2 {{previous definition is here}}
+    int x = 0; // expected-error {{redefinition of 'x'}}
+  else
+    int x = 0; // expected-error {{redefinition of 'x'}}
+
+  if (x; int a = 0) ++a;
+  if (x, +x; int a = 0) // expected-note 2 {{previous definition is here}} expected-warning {{unused}}
+    int a = 0; // expected-error {{redefinition of 'a'}}
+  else
+    int a = 0; // expected-error {{redefinition of 'a'}}
+
+  if (int b = 0; b)
+    ;
+  b = 2; // expected-error {{use of undeclared identifier}}
+}
+
+void testSwitch() {
+  int x = 0;
+  switch (x; x) {
+    case 1:
+      ++x;
+  }
+
+  switch (int x, y = 0; y) {
+    case 1:
+      ++x;
+    default:
+      ++y;
+  }
+
+  switch (int x, y = 0; y) { // expected-note 2 {{previous definition is here}}
+    case 0:
+      int x = 0; // expected-error {{redefinition of 'x'}}
+    case 1:
+      int y = 0; // expected-error {{redefinition of 'y'}}
+  };
+
+  switch (x; int a = 0) {
+    case 0:
+      ++a;
+  }
+
+  switch (x, +x; int a = 0) { // expected-note {{previous definition is here}} expected-warning {{unused}}
+    case 0:
+      int a = 0; // expected-error {{redefinition of 'a'}} // expected-note {{previous definition is here}}
+    case 1:
+      int a = 0; // expected-error {{redefinition of 'a'}}
+  }
+
+  switch (int b = 0; b) {
+    case 0:
+      break;
+  }
+  b = 2; // expected-error {{use of undeclared identifier}}
+}
+
+constexpr bool constexpr_if_init(int n) {
+  if (int a = n; ++a > 0)
+    return true;
+  else
+    return false;
+}
+
+constexpr int constexpr_switch_init(int n) {
+  switch (int p = n + 2; p) {
+    case 0:
+      return 0;
+    case 1:
+      return 1;
+    default:
+      return -1;
+  }
+}
+
+void test_constexpr_init_stmt() {
+  constexpr bool a = constexpr_if_init(-2);
+  static_assert(!a, "");
+  static_assert(constexpr_if_init(1), "");
+
+  constexpr int b = constexpr_switch_init(-1);
+  static_assert(b == 1, "");
+  static_assert(constexpr_switch_init(-2) == 0, "");
+  static_assert(constexpr_switch_init(-5) == -1, "");
+}