diff --git a/src/interpret.c b/src/interpret.c
index 365a051242ee..14ec5a1474ed 100644
--- a/src/interpret.c
+++ b/src/interpret.c
@@ -3027,7 +3027,8 @@ class Interpreter : public Visitor
                     for (size_t i = 0; i < exps->dim; i++)
                     {
                         Expression *ex = (*e->arguments)[i];
-                        ex = ex->interpret(istate);
+                        if (ex)
+                            ex = ex->interpret(istate);
                         if (exceptionOrCantInterpret(ex))
                         {
                             result = ex;
diff --git a/src/optimize.c b/src/optimize.c
index 00752edce2e3..ce7c76343b6f 100644
--- a/src/optimize.c
+++ b/src/optimize.c
@@ -469,6 +469,8 @@ Expression *Expression_optimize(Expression *e, int result, bool keepLvalue)
                 for (size_t i = 0; i < e->arguments->dim; i++)
                 {
                     Expression *arg = (*e->arguments)[i];
+                    if (!arg)
+                        continue;
                     arg = arg->optimize(WANTvalue);
                     (*e->arguments)[i] = arg;
                 }
diff --git a/test/runnable/structlit.d b/test/runnable/structlit.d
index 2130bdd358e0..1622d3a9a3e3 100644
--- a/test/runnable/structlit.d
+++ b/test/runnable/structlit.d
@@ -853,6 +853,14 @@ void test6937()
 /********************************************/
 // 12681
 
+struct HasUnion12774
+{
+    union
+    {
+        int a, b;
+    }
+}
+
 bool test12681()
 {
     immutable int x = 42;
@@ -881,6 +889,8 @@ bool test12681()
     assert(s3.p == &x);
     assert(s3.foo() == 42);
 
+    auto x12774 = new HasUnion12774();
+
     return true;
 }
 static assert(test12681());