Fix a double free of the implicit variable

interpreter.c

@@ -1661,13 +1661,13 @@ ValueObject *castStringExplicit(ValueObject *node,
  * prototype to allow this function to be stored in a jump table for fast
  * execution.
  *
- * \return A pointer to the value of \a scope's implicit variable.
+ * \return A pointer to a copy of the value of \a scope's implicit variable.
  */
 ValueObject *interpretImpVarExprNode(ExprNode *node,
                                      ScopeObject *scope)
 {
 	node = NULL;
-	return scope->impvar;
+	return copyValueObject(scope->impvar);
 }
 
 /**

test/1.3-Tests/7-Operators/1-Addition/12-ImplicitVariable/CMakeLists.txt

@@ -0,0 +1,2 @@
+INCLUDE(AddLolTest)
+ADD_LOL_TEST(12-ImplicitVariable OUTPUT test.out)

test/1.3-Tests/7-Operators/1-Addition/12-ImplicitVariable/test.lol

@@ -0,0 +1,4 @@
+HAI 1.3
+	SUM OF 1 AN 2
+	VISIBLE SUM OF IT AN 3
+KTHXBYE

test/1.3-Tests/7-Operators/1-Addition/12-ImplicitVariable/test.out

@@ -0,0 +1 @@
+6

test/1.3-Tests/7-Operators/1-Addition/12-ImplicitVariable/test.readme

@@ -0,0 +1,2 @@
+This test checks that the implicit variable (IT) for the addition operator is
+functional.

test/1.3-Tests/7-Operators/1-Addition/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_subdirectory(1-Intergers)
 add_subdirectory(10-ArityCheck)
 add_subdirectory(11-OptionalAN)
+add_subdirectory(12-ImplicitVariable)
 add_subdirectory(2-FloatInteger)
 add_subdirectory(3-IntegerFloat)
 add_subdirectory(4-Floats)