Improve the unused-value check to look into comma expressions and filter out
voids in sub-expressions.  Patch by Mike M!

Fixes PR4806.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@98335 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/warn-unused-value.cpp b/test/SemaCXX/warn-unused-value.cpp
new file mode 100644
index 0000000..775c3cf
--- /dev/null
+++ b/test/SemaCXX/warn-unused-value.cpp
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wunused-value %s
+
+// PR4806
+namespace test0 {
+  class Box {
+  public:
+    int i;
+    volatile int j;
+  };
+
+  void doit() {
+    // pointer to volatile has side effect (thus no warning)
+    Box* box = new Box;
+    box->i; // expected-warning {{expression result unused}}
+    box->j;
+  }
+}