Allow a declaration of an array to complete a prior, incomplete

declaration of that array in C++.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81309 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 25 insertions, 0 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 6f04f7b162..a72ca1d01f 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -980,6 +980,13 @@ void Sema::MergeVarDecl(VarDecl *New, Decl *OldD) {
   if (getLangOptions().CPlusPlus) {
     if (Context.hasSameType(New->getType(), Old->getType()))
       MergedT = New->getType();
+    // C++ [basic.types]p7:
+    //   [...] The declared type of an array object might be an array of 
+    //   unknown size and therefore be incomplete at one point in a 
+    //   translation unit and complete later on; [...]
+    else if (Old->getType()->isIncompleteArrayType() && 
+             New->getType()->isArrayType())
+      MergedT = New->getType();
   } else {
     MergedT = Context.mergeTypes(New->getType(), Old->getType());
   }
diff --git a/test/SemaCXX/static-array-member.cpp b/test/SemaCXX/static-array-member.cpp
new file mode 100644
index 0000000000..dac70cd2ea
--- /dev/null
+++ b/test/SemaCXX/static-array-member.cpp
@@ -0,0 +1,18 @@
+// RUN: clang-cc -fsyntax-only %s
+
+struct X0 {
+  static int array[];
+  
+  int x;
+  int y;
+};
+
+int X0::array[sizeof(X0) * 2];
+
+template<typename T, int N>
+struct X1 {
+  static T array[];
+};
+
+template<typename T, int N>
+T X1<T, N>::array[N];