codegen: Use properly checked implicit interface implementations

Collect implicit interface implementations in AST and avoid doing the same
checks twice.

This caused double vfunc assignments if an implementation is provided while
a method with the same name is available in prerequisite class.

See https://bugzilla.gnome.org/show_bug.cgi?id=536863
and https://bugzilla.gnome.org/show_bug.cgi?id=652098

Fixes https://gitlab.gnome.org/GNOME/vala/issues/548

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/objects/classes-interfaces.vala b/tests/objects/classes-interfaces.vala
new file mode 100644
index 000000000..9f2474653
--- /dev/null
+++ b/tests/objects/classes-interfaces.vala
@@ -0,0 +1,27 @@
+class Base : Object {
+	public void foo () {
+	}
+}
+
+interface IFoo : Base {
+	public abstract string foo ();
+}
+
+interface IBar : Base {
+	public abstract int foo ();
+}
+
+class Manam : Base, IFoo, IBar {
+	public int IBar.foo () {
+		return 23;
+	}
+	public string IFoo.foo () {
+		return "foo";
+	}
+}
+
+void main () {
+	var manam = new Manam ();
+	assert (((IFoo) manam).foo () == "foo");
+	assert (((IBar) manam).foo () == 23);
+}