[vala/wip/issue/442: 2/2] codegen: Transfer memory when casting pointer to non-pointer variable

[Rico Tzschichholz <ricotz src gnome org>]

commit f04a01161c7220034b7b4b7390dea9036f9a6f00
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Mar 22 12:29:34 2021 +0100

    codegen: Transfer memory when casting pointer to non-pointer variable

 codegen/valaccodebasemodule.vala              |  5 ++++-
 tests/Makefile.am                             |  2 ++
 tests/objects/compact-class-pointer-cast.vala | 20 ++++++++++++++++++++
 tests/structs/struct-pointer-cast.vala        | 20 ++++++++++++++++++++
 4 files changed, 46 insertions(+), 1 deletion(-)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 814c14c8e..207063a82 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -4398,7 +4398,10 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
                        }
 
                        // memory management, implicit casts, and boxing/unboxing
-                       if (expr.value_type != null) {
+                       if (expr is CastExpression && expr.value_type != null && !(expr.value_type is 
PointerType)
+                           && ((CastExpression) expr).inner.value_type is PointerType) {
+                               // allow ownership transfer from pointer to non-pointer
+                       } else if (expr.value_type != null) {
                                // FIXME: temporary workaround until the refactoring is complete, not all 
target_value have a value_type
                                expr.target_value.value_type = expr.value_type;
                                expr.target_value = transform_value (expr.target_value, expr.target_type, 
expr);
diff --git a/tests/Makefile.am b/tests/Makefile.am
index e4567227a..5c1c7b7c1 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -360,6 +360,7 @@ TESTS = \
        structs/struct-initializer-list-nested.vala \
        structs/struct-no-gtype.vala \
        structs/struct-no-gtype-inherit.vala \
+       structs/struct-pointer-cast.vala \
        structs/struct-static-field-initializer.vala \
        structs/struct-static-field-initializer-2.test \
        structs/struct-static-property-initializer.test \
@@ -471,6 +472,7 @@ TESTS = \
        objects/classes-implicit-implementation.vala \
        objects/compact-class.vala \
        objects/compact-class-destructor.vala \
+       objects/compact-class-pointer-cast.vala \
        objects/compact-class-refcount.vala \
        objects/compact-class-custom-ref.vala \
        objects/constructor-abstract-public.test \
diff --git a/tests/objects/compact-class-pointer-cast.vala b/tests/objects/compact-class-pointer-cast.vala
new file mode 100644
index 000000000..4511a4884
--- /dev/null
+++ b/tests/objects/compact-class-pointer-cast.vala
@@ -0,0 +1,20 @@
+[Compact]
+class Foo {
+       public int i;
+}
+
+void main () {
+       {
+               Foo foo = (Foo) Slice.alloc (sizeof (int));
+               foo.i = 23;
+               unowned Foo foo_r = foo;
+               assert (foo_r.i == 23);
+       }
+       {
+               Foo* foo_p = Slice.alloc (sizeof (int));
+               foo_p->i = 42;
+               Foo foo = (Foo) foo_p;
+               unowned Foo foo_r = foo;
+               assert (foo_r.i == 42);
+       }
+}
diff --git a/tests/structs/struct-pointer-cast.vala b/tests/structs/struct-pointer-cast.vala
new file mode 100644
index 000000000..92011b0e3
--- /dev/null
+++ b/tests/structs/struct-pointer-cast.vala
@@ -0,0 +1,20 @@
+[CCode (has_type_id = false)]
+struct Foo {
+       public int i;
+}
+
+void main () {
+       {
+               Foo? foo = (Foo?) GLib.malloc (sizeof (int));
+               foo.i = 23;
+               unowned Foo? foo_r = foo;
+               assert (foo_r.i == 23);
+       }
+       {
+               Foo* foo_p = GLib.malloc (sizeof (int));
+               foo_p->i = 42;
+               Foo? foo = (Foo?) foo_p;
+               unowned Foo? foo_r = foo;
+               assert (foo_r.i == 42);
+       }
+}