v.checker: allow for a `f(unsafe{voidptr(0)})` call of `fn f(x &Interface){}`

vlib/v/checker/checker.v

@@ -2698,9 +2698,12 @@ fn (mut c Checker) type_implements(typ ast.Type, interface_type ast.Type, pos to
 			}
 			continue
 		}
+		// voidptr is an escape hatch, it should be allowed to be passed
+		if utyp != ast.voidptr_type {
 			c.error("`$styp` doesn't implement method `$imethod.name` of interface `$inter_sym.name`",
 				pos)
 		}
+	}
 	// Verify fields
 	if mut inter_sym.info is ast.Interface {
 		for ifield in inter_sym.info.fields {

vlib/v/tests/interface_edge_cases/pass_voidptr_as_interface_reference_test.v

@@ -0,0 +1,19 @@
+interface IAbc {
+	xyz()
+}
+
+struct Abc {}
+
+fn (a Abc) xyz() {}
+
+fn f(i &IAbc) string {
+	return '$i'
+}
+
+fn test_passing_voidptr_as_an_interface_reference() {
+	i := IAbc(Abc{})
+	assert f(&i) == '&IAbc(Abc{})'
+	// a voidptr() cast is an escape hatch, that should be allowed
+	// but perhaps it should be forced by the compiler to be in unsafe{}
+	assert f(unsafe { voidptr(0) }) == '&IAbc(0)'
+}