From cd5b304cbf35f07bdf5eb5974fe4e0365aad9368 Mon Sep 17 00:00:00 2001
From: 05st <60903484+05st@users.noreply.github.com>
Date: Fri, 8 Oct 2021 11:04:24 -0500
Subject: [PATCH] cgen: add interface case for gen_struct_equality_fn (#12094)

---
 vlib/v/gen/c/auto_eq_methods.v                |  3 +++
 .../tests/struct_auto_eq_gen_interface_test.v | 23 +++++++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 vlib/v/tests/struct_auto_eq_gen_interface_test.v

diff --git a/vlib/v/gen/c/auto_eq_methods.v b/vlib/v/gen/c/auto_eq_methods.v
index 9fe60bc8d8..f21280b59f 100644
--- a/vlib/v/gen/c/auto_eq_methods.v
+++ b/vlib/v/gen/c/auto_eq_methods.v
@@ -155,6 +155,9 @@ fn (mut g Gen) gen_struct_equality_fn(left_type ast.Type) string {
 				fn_builder.write_string('${eq_fn}_alias_eq(a.$field_name, b.$field_name)')
 			} else if field_type.sym.kind == .function {
 				fn_builder.write_string('*((voidptr*)(a.$field_name)) == *((voidptr*)(b.$field_name))')
+			} else if field_type.sym.kind == .interface_ {
+				eq_fn := g.gen_interface_equality_fn(field.typ)
+				fn_builder.write_string('${eq_fn}_interface_eq(a.$field_name, b.$field_name)')
 			} else {
 				fn_builder.write_string('a.$field_name == b.$field_name')
 			}
diff --git a/vlib/v/tests/struct_auto_eq_gen_interface_test.v b/vlib/v/tests/struct_auto_eq_gen_interface_test.v
new file mode 100644
index 0000000000..69dfca5afe
--- /dev/null
+++ b/vlib/v/tests/struct_auto_eq_gen_interface_test.v
@@ -0,0 +1,23 @@
+interface IExample {
+	thing() bool
+}
+
+struct Foo {}
+
+fn (n Foo) thing() bool {
+	return true
+}
+
+struct Test {
+	a IExample
+}
+
+fn new() Test {
+	return Test{Foo{}}
+}
+
+fn test_struct_auto_eq_gen_interface_case() {
+	w1 := new()
+	w2 := new()
+	assert w1 == w2
+}