cgen: fix codegen for method call on rangeexpr

vlib/v/gen/c/fn.v

@@ -1681,7 +1681,9 @@ fn (mut g Gen) method_call(node ast.CallExpr) {
 			if idx is ast.RangeExpr {
 				// expr is arr[range].clone()
 				// use array_clone_static instead of array_clone
-				name = util.no_dots('${receiver_type_name}_${node.name}_static')
+				if node.name == 'clone' {
+					name = util.no_dots('${receiver_type_name}_${node.name}_static')
+				}
 				is_range_slice = true
 			}
 		}
@@ -1759,6 +1761,11 @@ fn (mut g Gen) method_call(node ast.CallExpr) {
 				&& g.typ(left_type) == g.typ(node.receiver_type)) {
 				g.write('&')
 			}
+		} else {
+			if node.name != 'clone' && !left_type.is_ptr() {
+				g.write('ADDR(${rec_cc_type}, ')
+				cast_n++
+			}
 		}
 	} else if !node.receiver_type.is_ptr() && left_type.is_ptr() && node.name != 'str'
 		&& node.from_embed_types.len == 0 {

vlib/v/tests/fns/method_call_on_rangeexpr_test.v

@@ -0,0 +1,16 @@
+type Buffer = []u8
+
+pub fn (mut sb Buffer) vbytes() string {
+	return sb[0..sb.len].a().str()
+}
+
+pub fn (mut sb Buffer) a() Buffer {
+	return sb
+}
+
+fn test_main() {
+	mut b := Buffer([]u8{cap: 10})
+	b << 1
+	b << 2
+	assert b.vbytes() == 'Buffer([1, 2])'
+}