cgen: use overloaded eq op in auto eq method (#9475)

vlib/v/gen/c/auto_eq_methods.v

@@ -68,7 +68,18 @@ fn (mut g Gen) gen_struct_equality_fn(left table.Type) string {
 	info := left_sym.struct_info()
 	g.type_definitions.writeln('static bool ${ptr_typ}_struct_eq($ptr_typ a, $ptr_typ b); // auto')
 	mut fn_builder := strings.new_builder(512)
+	defer {
+		g.auto_fn_definitions << fn_builder.str()
+	}
 	fn_builder.writeln('static bool ${ptr_typ}_struct_eq($ptr_typ a, $ptr_typ b) {')
+
+	// orverloaded
+	if left_sym.has_method('==') {
+		fn_builder.writeln('\treturn ${ptr_typ}__eq(a, b);')
+		fn_builder.writeln('}')
+		return ptr_typ
+	}
+
 	for field in info.fields {
 		sym := g.table.get_type_symbol(field.typ)
 		if sym.kind == .string {
@@ -101,7 +112,6 @@ fn (mut g Gen) gen_struct_equality_fn(left table.Type) string {
 	}
 	fn_builder.writeln('\treturn true;')
 	fn_builder.writeln('}')
-	g.auto_fn_definitions << fn_builder.str()
 	return ptr_typ
 }
 

vlib/v/gen/c/cgen.v

@@ -3301,7 +3301,6 @@ fn (mut g Gen) enum_expr(node ast.Expr) {
 }
 
 fn (mut g Gen) infix_gen_equality(node ast.InfixExpr, left_type table.Type, left_sym table.TypeSymbol, right_sym table.TypeSymbol) {
-	has_eq_overloaded := left_sym.has_method('==')
 	if left_sym.kind != right_sym.kind {
 		return
 	}
@@ -3396,22 +3395,12 @@ fn (mut g Gen) infix_gen_equality(node ast.InfixExpr, left_type table.Type, left
 			g.write(')')
 		}
 		.struct_ {
-			if has_eq_overloaded {
-				// Define `==` as negation of Autogenerated `!=`
-				styp := g.typ(left_type)
-				if node.op == .ne {
-					g.write('!${styp}__eq(')
-				} else if node.op == .eq {
-					g.write('${styp}__eq(')
-				}
-			} else {
-				// Auto generate both `==` and `!=`
-				ptr_typ := g.gen_struct_equality_fn(left_type)
-				if node.op == .eq {
-					g.write('${ptr_typ}_struct_eq(')
-				} else if node.op == .ne {
-					g.write('!${ptr_typ}_struct_eq(')
-				}
+			// Auto generate both `==` and `!=`
+			ptr_typ := g.gen_struct_equality_fn(left_type)
+			if node.op == .eq {
+				g.write('${ptr_typ}_struct_eq(')
+			} else if node.op == .ne {
+				g.write('!${ptr_typ}_struct_eq(')
 			}
 			if node.left_type.is_ptr() {
 				g.write('*')

vlib/v/tests/struct_equality_test.v

@@ -1,11 +1,21 @@
+struct Company {
+	name        string
+	description string
+}
+
+fn (lhs Company) == (rhs Company) bool {
+	return lhs.name == rhs.name
+}
+
 struct User {
-	name string
-	age  int
+	name    string
+	age     int
+	company Company
 }
 
 fn test_struct_equality() {
-	mut usr1 := User{'sanath', 28}
-	mut usr2 := User{'sanath', 28}
+	mut usr1 := User{'sanath', 28, Company{'awesome company', 'we are awesome'}}
+	mut usr2 := User{'sanath', 28, Company{'awesome company', 'we are awesome too'}}
 	if usr1 == usr2 {
 		println('Same User')
 	} else {