[vala/wip/issue/781] codegen: Always assign original variable when consuming instance to destroy

[Rico Tzschichholz <ricotz src gnome org>]

commit c6afcf7840995adf1f05d4ee5d31c560414b8c54
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Apr 8 10:00:19 2019 +0200

    codegen: Always assign original variable when consuming instance to destroy
    
    Fixes https://gitlab.gnome.org/GNOME/vala/issues/781

 codegen/valaccodebasemodule.vala            | 18 ++++++++++++++-
 tests/objects/compact-class-destructor.vala | 35 ++++++++++++++++++++++++++++-
 2 files changed, 51 insertions(+), 2 deletions(-)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 7ce434783..18418a949 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -4069,9 +4069,25 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
                                expr.target_value.value_type = expr.value_type;
 
                                if (is_compact_class_destructor_call (expr)) {
+                                       // FIXME This is awful https://gitlab.gnome.org/GNOME/vala/issues/781
+                                       CCodeExpression cexpr;
+                                       unowned Variable? variable = expr.symbol_reference as Variable;
+                                       if (variable != null) {
+                                               if (variable is LocalVariable) {
+                                                       cexpr = get_local_cexpression ((LocalVariable) 
variable);
+                                               } else if (variable is Parameter) {
+                                                       cexpr = get_parameter_cexpression ((Parameter) 
variable);
+                                               } else if (variable is Field) {
+                                                       cexpr = get_cexpression (get_ccode_name (variable));
+                                               } else {
+                                                       cexpr = new CCodeInvalidExpression ();
+                                               }
+                                       } else {
+                                               cexpr = get_cvalue (expr);
+                                       }
                                        // transfer ownership here and consume given instance
                                        var temp_value = store_temp_value (expr.target_value, expr);
-                                       ccode.add_assignment (get_cvalue (expr), new CCodeConstant ("NULL"));
+                                       ccode.add_assignment (cexpr, new CCodeConstant ("NULL"));
                                        expr.target_value = temp_value;
                                } else {
                                        expr.target_value = transform_value (expr.target_value, 
expr.target_type, expr);
diff --git a/tests/objects/compact-class-destructor.vala b/tests/objects/compact-class-destructor.vala
index 2d6d8a442..3a2a6c194 100644
--- a/tests/objects/compact-class-destructor.vala
+++ b/tests/objects/compact-class-destructor.vala
@@ -9,9 +9,42 @@ class Foo {
        }
 }
 
-void main () {
+Foo faz;
+
+void bar () throws Error {
+}
+
+void field () {
+       bar ();
+
+       faz = new Foo ();
+       var res = faz.destroy ();
+
+       assert (faz == null);
+       assert (res == 42);
+}
+
+void local () {
+       bar ();
+
        var foo = new Foo ();
        var res = foo.destroy ();
+
        assert (foo == null);
        assert (res == 42);
 }
+
+void parameter (owned Foo foo) {
+       bar ();
+
+       var res = foo.destroy ();
+
+       assert (foo == null);
+       assert (res == 42);
+}
+
+void main () {
+       field ();
+       local ();
+       parameter (new Foo ());
+}