vala: Allow to override virtual interface implementations

Fixes https://gitlab.gnome.org/GNOME/vala/issues/852

diff --git a/codegen/valaccodemethodmodule.vala b/codegen/valaccodemethodmodule.vala
index f11e501baedf78a3b673ccab8b08c5b512a1c33a..354e1839f7ceca57e01b257e33dece41119793a4 100644 (file)
--- a/codegen/valaccodemethodmodule.vala
+++ b/codegen/valaccodemethodmodule.vala
@@ -534,7 +534,7 @@ public abstract class Vala.CCodeMethodModule : CCodeStructModule {
                                        if (m.overrides || (m.base_interface_method != null && !m.is_abstract && !m.is_virtual)) {
                                                Method base_method;
                                                ReferenceType base_expression_type;
-                                               if (m.overrides) {
+                                               if (m.overrides && m.base_method != null) {
                                                        base_method = m.base_method;
                                                        base_expression_type = new ObjectType ((Class) base_method.parent_symbol);
                                                } else {

diff --git a/tests/Makefile.am b/tests/Makefile.am
index bb374221a1d69b6bb4f3310025909c57b02d9af2..f6e4b08819e04ff1daf239be5a5ce66f273b6323 100644 (file)
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -314,6 +314,7 @@ TESTS = \
        objects/interface_only.vala \
        objects/interfaces.vala \
        objects/interface-generics.vala \
+       objects/interface-virtual-override.vala \
        objects/methods.vala \
        objects/paramspec.vala \
        objects/plugin-module-init.vala \

diff --git a/tests/objects/interface-virtual-override.vala b/tests/objects/interface-virtual-override.vala
new file mode 100644 (file)
index 0000000..62fcb65
--- /dev/null
+++ b/tests/objects/interface-virtual-override.vala
@@ -0,0 +1,16 @@
+interface IFoo : Object {
+       public virtual int foo () {
+               assert_not_reached ();
+       }
+}
+
+class Bar : Object, IFoo {
+       public override int foo () {
+               return 42;
+       }
+}
+
+void main () {
+       var bar = new Bar ();
+       assert (bar.foo () == 42);
+}

diff --git a/vala/valamethod.vala b/vala/valamethod.vala
index e91da89eb093c4a19bec984c0f55a4fbaf8c7f24..29e7171a2a0a55f870a9b9f010d147ddebebd4f3 100644 (file)
--- a/vala/valamethod.vala
+++ b/vala/valamethod.vala
@@ -880,7 +880,7 @@ public class Vala.Method : Subroutine, Callable {
                                Report.error (source_reference, "A struct member `%s' cannot be marked as override, virtual, or abstract".printf (get_full_name ()));
                                return false;
                        }
-               } else if (overrides && base_method == null) {
+               } else if (overrides && base_method == null && base_interface_method == null) {
                        Report.error (source_reference, "`%s': no suitable method found to override".printf (get_full_name ()));
                } else if ((is_abstract || is_virtual || overrides) && access == SymbolAccessibility.PRIVATE) {
                        error = true;