From 3e3d45b2b137bf8f22893efc9b8ce313ff2e7c02 Mon Sep 17 00:00:00 2001
From: zakuro <z@kuro.red>
Date: Wed, 13 Jan 2021 14:03:23 +0900
Subject: [PATCH] parser: improve array init warning (#8024)

---
 vlib/v/parser/containers.v         |  6 ++++--
 vlib/v/parser/tests/array_init.out | 12 ++++++++++++
 vlib/v/parser/tests/array_init.vv  |  4 ++++
 3 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 vlib/v/parser/tests/array_init.out
 create mode 100644 vlib/v/parser/tests/array_init.vv

diff --git a/vlib/v/parser/containers.v b/vlib/v/parser/containers.v
index 35d3578d37..eb458f92ce 100644
--- a/vlib/v/parser/containers.v
+++ b/vlib/v/parser/containers.v
@@ -36,6 +36,7 @@ fn (mut p Parser) array_init() ast.ArrayInit {
 			array_type = table.new_type(idx)
 			has_type = true
 		}
+		last_pos = p.tok.position()
 	} else {
 		// [1,2,3] or [const]byte
 		for i := 0; p.tok.kind !in [.rsbr, .eof]; i++ {
@@ -57,6 +58,7 @@ fn (mut p Parser) array_init() ast.ArrayInit {
 		if exprs.len == 1 && p.tok.kind in [.name, .amp, .lsbr] && p.tok.line_nr == line_nr {
 			// [100]byte
 			elem_type = p.parse_type()
+			last_pos = p.tok.position()
 			is_fixed = true
 			if p.tok.kind == .lcbr {
 				p.next()
@@ -75,7 +77,7 @@ fn (mut p Parser) array_init() ast.ArrayInit {
 				p.check(.rcbr)
 			} else {
 				p.warn_with_pos('use e.g. `x := [1]Type{}` instead of `x := [1]Type`',
-					last_pos)
+					first_pos.extend(last_pos))
 			}
 		} else {
 			if p.tok.kind == .not && p.tok.line_nr == p.prev_tok.line_nr {
@@ -92,7 +94,7 @@ fn (mut p Parser) array_init() ast.ArrayInit {
 		}
 	}
 	if exprs.len == 0 && p.tok.kind != .lcbr && has_type {
-		p.warn_with_pos('use `x := []Type{}` instead of `x := []Type`', last_pos)
+		p.warn_with_pos('use `x := []Type{}` instead of `x := []Type`', first_pos.extend(last_pos))
 	}
 	mut has_len := false
 	mut has_cap := false
diff --git a/vlib/v/parser/tests/array_init.out b/vlib/v/parser/tests/array_init.out
new file mode 100644
index 0000000000..75bdbe31a6
--- /dev/null
+++ b/vlib/v/parser/tests/array_init.out
@@ -0,0 +1,12 @@
+vlib/v/parser/tests/array_init.vv:2:7: warning: use `x := []Type{}` instead of `x := []Type`
+    1 | fn main() {
+    2 |     _ := []int
+      |          ~~~~~
+    3 |     _ := [1]int
+    4 | }
+vlib/v/parser/tests/array_init.vv:3:7: warning: use e.g. `x := [1]Type{}` instead of `x := [1]Type`
+    1 | fn main() {
+    2 |     _ := []int
+    3 |     _ := [1]int
+      |          ~~~~~~
+    4 | }
diff --git a/vlib/v/parser/tests/array_init.vv b/vlib/v/parser/tests/array_init.vv
new file mode 100644
index 0000000000..4bbfb88ed2
--- /dev/null
+++ b/vlib/v/parser/tests/array_init.vv
@@ -0,0 +1,4 @@
+fn main() {
+	_ := []int
+	_ := [1]int
+}