Add testcase for nested C struct name conflict

Issue #1305

Examples/test-suite/nested.i

@@ -114,4 +114,50 @@ typedef struct OutSt {
 
 #endif
 
+%inline %{
+  typedef struct {
+    union x_union {
+      int x;
+    } duplicate_p;
+  } x_t;
+
+  typedef struct {
+    union y_union {
+      int y;
+    } duplicate_p;
+  } y_t;
+
+  typedef struct A {
+    union a_union {
+      int a;
+    } duplicate_p;
+  } a_t;
+
+  typedef struct B {
+    union b_union {
+      int b;
+    } duplicate_p;
+  } b_t;
+
+  typedef struct {
+    union {
+      int c;
+    } duplicate_p;
+  } c_t;
+
+  typedef struct {
+    union {
+      int d;
+    } duplicate_p;
+  } d_t;
+
+  void set_union_values(int startval, x_t *x, y_t *y, a_t *a, b_t *b, c_t *c, d_t *d) {
+    x->duplicate_p.x = startval++;
+    y->duplicate_p.y = startval++;
+    a->duplicate_p.a = startval++;
+    b->duplicate_p.b = startval++;
+    c->duplicate_p.c = startval++;
+    d->duplicate_p.d = startval++;
+  }
+%}