From ac63fa1b115f6318c9800251d66908142d681011 Mon Sep 17 00:00:00 2001
From: Swastik Baranwal <swstkbaranwal@gmail.com>
Date: Thu, 20 Oct 2022 16:06:13 +0530
Subject: [PATCH] parser: improve error for fixed array, when it has `len` and
 `cap` attributes in the initialisation list (#16120)

---
 vlib/v/checker/tests/with_check_option/v_tictactoe.out | 2 +-
 vlib/v/parser/containers.v                             | 7 ++++++-
 vlib/v/parser/tests/fixed_arr_len_cap_attr_err.out     | 6 ++++++
 vlib/v/parser/tests/fixed_arr_len_cap_attr_err.vv      | 7 +++++++
 4 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 vlib/v/parser/tests/fixed_arr_len_cap_attr_err.out
 create mode 100644 vlib/v/parser/tests/fixed_arr_len_cap_attr_err.vv

diff --git a/vlib/v/checker/tests/with_check_option/v_tictactoe.out b/vlib/v/checker/tests/with_check_option/v_tictactoe.out
index f41153ee5..8682a2439 100644
--- a/vlib/v/checker/tests/with_check_option/v_tictactoe.out
+++ b/vlib/v/checker/tests/with_check_option/v_tictactoe.out
@@ -1,4 +1,4 @@
-vlib/v/checker/tests/with_check_option/v_tictactoe.vv:4:31: error: expected `init:`, not `len`
+vlib/v/checker/tests/with_check_option/v_tictactoe.vv:4:31: error: `len` and `cap` are invalid attributes for fixed array dimension
     2 | 
     3 | fn new_board() [][]string {
     4 |     mut board := [3][]string{ len: 3, init: []string{ len: 3, init: '' } }
diff --git a/vlib/v/parser/containers.v b/vlib/v/parser/containers.v
index bc2847fbb..481c0af2e 100644
--- a/vlib/v/parser/containers.v
+++ b/vlib/v/parser/containers.v
@@ -80,7 +80,12 @@ fn (mut p Parser) array_init() ast.ArrayInit {
 					pos := p.tok.pos()
 					n := p.check_name()
 					if n != 'init' {
-						p.error_with_pos('expected `init:`, not `$n`', pos)
+						if is_fixed {
+							p.error_with_pos('`len` and `cap` are invalid attributes for fixed array dimension',
+								pos)
+						} else {
+							p.error_with_pos('expected `init:`, not `$n`', pos)
+						}
 						return ast.ArrayInit{}
 					}
 					p.check(.colon)
diff --git a/vlib/v/parser/tests/fixed_arr_len_cap_attr_err.out b/vlib/v/parser/tests/fixed_arr_len_cap_attr_err.out
new file mode 100644
index 000000000..8a96a6d2a
--- /dev/null
+++ b/vlib/v/parser/tests/fixed_arr_len_cap_attr_err.out
@@ -0,0 +1,6 @@
+vlib/v/parser/tests/fixed_arr_len_cap_attr_err.vv:2:31: error: `len` and `cap` are invalid attributes for fixed array dimension
+    1 | fn new_board() [][]string {
+    2 |     mut board := [3][]string{ len: 3, init: []string{ len: 3, init: '' } }
+      |                               ~~~
+    3 |     for i in 0..9 {
+    4 |         board[i / 3][i % 3] = (i + 1).str()
diff --git a/vlib/v/parser/tests/fixed_arr_len_cap_attr_err.vv b/vlib/v/parser/tests/fixed_arr_len_cap_attr_err.vv
new file mode 100644
index 000000000..a35bea551
--- /dev/null
+++ b/vlib/v/parser/tests/fixed_arr_len_cap_attr_err.vv
@@ -0,0 +1,7 @@
+fn new_board() [][]string {
+    mut board := [3][]string{ len: 3, init: []string{ len: 3, init: '' } }
+    for i in 0..9 {
+        board[i / 3][i % 3] = (i + 1).str()
+    }
+    return board
+}
-- 
2.39.5