[vala/0.50] codegen: Don't leak array memory after it was implicitly copied

[Rico Tzschichholz <ricotz src gnome org>]

commit f23e8cbb3d9dd27cce2ef305c64f44f9d0dde123
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Tue Feb 2 10:34:54 2021 +0100

    codegen: Don't leak array memory after it was implicitly copied
    
    Found by -fsanitize=address

 codegen/valaccodebasemodule.vala | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 6f4eeb8d4..795c5c5ea 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -6148,6 +6148,11 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
                                Report.error (node.source_reference, "missing class prerequisite for 
interface `%s', add GLib.Object to interface declaration if unsure".printf 
(target_type.type_symbol.get_full_name ()));
                                return result;
                        }
+                       // need to free old array after copying it
+                       if (array_needs_copy && requires_destroy (type)) {
+                               result.value_type = type.copy ();
+                               ccode.add_expression (destroy_value (result));
+                       }
                        result = copy;
 
                        // implicit array copying is deprecated, but allow it for internal codegen usage