diff --git a/lib/checkclass.cpp b/lib/checkclass.cpp
index 2845eee04..5020c07e4 100644
--- a/lib/checkclass.cpp
+++ b/lib/checkclass.cpp
@@ -86,6 +86,22 @@ void CheckClass::constructors()
             }
         }
 
+        // #3196 => bailout if there are nested unions
+        // TODO: handle union variables better
+        {
+            bool bailout = false;
+            for (std::list<Scope *>::const_iterator it = scope->nestedList.begin(); it != scope->nestedList.end(); ++it) {
+                const Scope * const nestedScope = *it;
+                if (nestedScope->type == Scope::eUnion) {
+                    bailout = true;
+                    break;
+                }
+            }
+            if (bailout)
+                continue;
+        }
+
+
         std::list<Function>::const_iterator func;
         std::vector<Usage> usage(scope->varlist.size());
 
diff --git a/test/testclass.cpp b/test/testclass.cpp
index 002d57834..c1d941b3f 100644
--- a/test/testclass.cpp
+++ b/test/testclass.cpp
@@ -80,6 +80,7 @@ private:
         TEST_CASE(uninitVarArray3D);
         TEST_CASE(uninitVarStruct1); // ticket #2172
         TEST_CASE(uninitVarStruct2); // ticket #838
+        TEST_CASE(uninitVarUnion); // ticket #3196
         TEST_CASE(uninitMissingFuncDef);	// can't expand function in constructor
         TEST_CASE(privateCtor1);        	// If constructor is private..
         TEST_CASE(privateCtor2);        	// If constructor is private..
@@ -2539,6 +2540,18 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void uninitVarUnion() { // ticket #3196
+        checkUninitVar("class Fred\n"
+                       "{\n"
+                       "private:\n"
+                       "    union { int a; int b; };\n"
+                       "public:\n"
+                       "    Fred()\n"
+                       "    { a = 0; }\n"
+                       "};\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void uninitMissingFuncDef() {
         // Unknown member function
         checkUninitVar("class Fred\n"
diff --git a/test/testconstructors.cpp b/test/testconstructors.cpp
index 49d485349..5622248b4 100644
--- a/test/testconstructors.cpp
+++ b/test/testconstructors.cpp
@@ -805,7 +805,7 @@ private:
               "    {\n"
               "    }\n"
               "};\n");
-        ASSERT_EQUALS("[test.cpp:9]: (warning) Member variable 'Fred::U' is not initialized in the constructor.\n", errout.str());
+        TODO_ASSERT_EQUALS("[test.cpp:9]: (warning) Member variable 'Fred::U' is not initialized in the constructor.\n", "", errout.str());
     }