When we see a reference to a struct, class, or union like "struct X"

that is neither a definition nor a forward declaration and where X has
not yet been declared as a tag, introduce a declaration
into the appropriate scope (which is likely *not* to be the current
scope). The rules for the placement of the declaration differ slightly
in C and C++, so we implement both and test the various corner
cases. This implementation isn't 100% correct due to some lingering
issues with the function prototype scope (for a function parameter
list) not being the same scope as the scope of the function
definition. Testcase is FIXME'd; this probably isn't an important issue.

Addresses <rdar://problem/6484805>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@62014 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 48 insertions, 0 deletions

diff --git a/test/SemaCXX/elaborated-type-specifier.cpp b/test/SemaCXX/elaborated-type-specifier.cpp
new file mode 100644
index 0000000000..b9ba508789
--- /dev/null
+++ b/test/SemaCXX/elaborated-type-specifier.cpp
@@ -0,0 +1,48 @@
+// RUN: clang -fsyntax-only -verify %s
+
+// Test the use of elaborated-type-specifiers to inject the names of
+// structs (or classes or unions) into an outer scope as described in
+// C++ [basic.scope.pdecl]p5.
+typedef struct S1 {
+  union {
+    struct S2 *x;
+    struct S3 *y;
+  };
+} S1;
+
+bool test_elab(S1 *s1, struct S2 *s2, struct S3 *s3) {
+  if (s1->x == s2) return true;
+  if (s1->y == s3) return true;
+  return false;
+}
+
+namespace NS {
+  class X {
+  public:
+    void test_elab2(struct S4 *s4);
+  };
+
+  void X::test_elab2(S4 *s4) { }
+}
+
+void test_X_elab(NS::X x) {
+  struct S4 *s4 = 0;
+  x.test_elab2(s4); // expected-error{{incompatible type passing 'struct S4 *', expected 'struct S4 *'}}
+}
+
+namespace NS {
+  S4 *get_S4();
+}
+
+void test_S5_scope() {
+  S4 *s4; // expected-error{{use of undeclared identifier 'S4'}}
+}
+
+// FIXME: the warning below should be an error!
+int test_funcparam_scope(struct S5 * s5) {
+  struct S5 { int y; } *s5_2 = 0;
+  if (s5 == s5_2) return 1; // expected-warning {{comparison of distinct pointer types ('struct S5 *' and 'struct S5 *')}}
+  return 0;
+}
+
+