Filter: Fix scope handling in for loops

Changes in scope implementation broke scope handling in for loops.
The term in for loops is supposed to be parsed in the parent scope.

filter/config.Y

@@ -20,6 +20,7 @@ static inline u32 pair_a(u32 p) { return p >> 16; }
 static inline u32 pair_b(u32 p) { return p & 0xFFFF; }
 
 static struct symbol *this_function;
+static struct sym_scope *this_for_scope;
 
 static struct f_method_scope {
   struct f_inst *object;
@@ -993,7 +994,9 @@ cmd:
      new_config->current_scope->slots += 2;
    } for_var IN
    /* Parse term in the parent scope */
-   { new_config->current_scope->active = 0; } term { new_config->current_scope->active = 1; }
+   { this_for_scope = new_config->current_scope; new_config->current_scope = this_for_scope->next; }
+   term
+   { new_config->current_scope = this_for_scope; this_for_scope = NULL; }
    DO cmd {
      cf_pop_block_scope(new_config);
      $$ = f_for_cycle($3, $6, $9);

filter/test.conf

@@ -1938,6 +1938,63 @@ bt_test_suite(t_if_else, "Testing if-else statement");
 
 
 
+/*
+ * 	Test for-in statement
+ * 	---------------------
+ */
+
+function t_for_in()
+{
+	bgppath p = +empty+.prepend(5).prepend(4).prepend(3).prepend(2).prepend(1);
+	bgppath q = +empty+.prepend(30).prepend(20).prepend(10);
+	int a;
+
+	# basic for loop
+	a = 0;
+	for int i in p do {
+		a = 2 * a + i;
+	}
+	bt_assert(a = 57);
+
+	# basic for loop, no braces
+	a = 0;
+	for int i in p do a = 2 * a + i;
+	bt_assert(a = 57);
+
+	# for loop with empty body
+	a = 0;
+	for int i in p do { }
+	bt_assert(a = 0);
+
+	# for loop over empty path
+	a = 0;
+	for int i in +empty+ do a = 1;
+	bt_assert(a = 0);
+
+	# for loop with var name shadowing
+	a = 0;
+	for int p in p do {
+		a = 2 * a + p;
+	}
+	bt_assert(a = 57);
+
+	# nested for loops
+	a = 0;
+	int n = 1;
+	for int i in p do {
+		for int j in q do {
+			a = a + i * j * n;
+			n = n + 1;
+		}
+	}
+	bt_assert(a = 9300);
+}
+
+bt_test_suite(t_for_in, "Testing for-in statement");
+
+
+
+
 /*
  *	Unused functions -- testing only parsing
  *	----------------------------------------