From 37927235cd6769b5c05421e0a8c9542549320a47 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kr=C3=BCger?=
 <45282134+UweKrueger@users.noreply.github.com>
Date: Sat, 20 Jun 2020 14:30:03 +0200
Subject: [PATCH] parser: trigger declaration of array element as error

---
 vlib/v/checker/tests/array_declare_element_a.out | 5 +++++
 vlib/v/checker/tests/array_declare_element_a.vv  | 3 +++
 vlib/v/checker/tests/array_declare_element_b.out | 6 ++++++
 vlib/v/checker/tests/array_declare_element_b.vv  | 4 ++++
 vlib/v/checker/tests/array_declare_element_c.out | 6 ++++++
 vlib/v/checker/tests/array_declare_element_c.vv  | 4 ++++
 vlib/v/parser/assign.v                           | 3 +++
 7 files changed, 31 insertions(+)
 create mode 100644 vlib/v/checker/tests/array_declare_element_a.out
 create mode 100644 vlib/v/checker/tests/array_declare_element_a.vv
 create mode 100644 vlib/v/checker/tests/array_declare_element_b.out
 create mode 100644 vlib/v/checker/tests/array_declare_element_b.vv
 create mode 100644 vlib/v/checker/tests/array_declare_element_c.out
 create mode 100644 vlib/v/checker/tests/array_declare_element_c.vv

diff --git a/vlib/v/checker/tests/array_declare_element_a.out b/vlib/v/checker/tests/array_declare_element_a.out
new file mode 100644
index 0000000000..5b51a6a338
--- /dev/null
+++ b/vlib/v/checker/tests/array_declare_element_a.out
@@ -0,0 +1,5 @@
+vlib/v/checker/tests/array_declare_element_a.v:2:9: error: non-name `arr[0]` on left side of `:=` 
+    1 | fn main() {
+    2 |     arr[0] := 2
+      |            ~~
+    3 | }
diff --git a/vlib/v/checker/tests/array_declare_element_a.vv b/vlib/v/checker/tests/array_declare_element_a.vv
new file mode 100644
index 0000000000..ac074987fd
--- /dev/null
+++ b/vlib/v/checker/tests/array_declare_element_a.vv
@@ -0,0 +1,3 @@
+fn main() {
+	arr[0] := 2
+}
diff --git a/vlib/v/checker/tests/array_declare_element_b.out b/vlib/v/checker/tests/array_declare_element_b.out
new file mode 100644
index 0000000000..e603d3dcf7
--- /dev/null
+++ b/vlib/v/checker/tests/array_declare_element_b.out
@@ -0,0 +1,6 @@
+vlib/v/checker/tests/array_declare_element_b.v:3:9: error: non-name `arr[1]` on left side of `:=` 
+    1 | fn main() {
+    2 |     arr := [1, 2]
+    3 |     arr[1] := 1
+      |            ~~
+    4 | }
diff --git a/vlib/v/checker/tests/array_declare_element_b.vv b/vlib/v/checker/tests/array_declare_element_b.vv
new file mode 100644
index 0000000000..a87a0e575a
--- /dev/null
+++ b/vlib/v/checker/tests/array_declare_element_b.vv
@@ -0,0 +1,4 @@
+fn main() {
+	arr := [1, 2]
+	arr[1] := 1
+}
diff --git a/vlib/v/checker/tests/array_declare_element_c.out b/vlib/v/checker/tests/array_declare_element_c.out
new file mode 100644
index 0000000000..237da0682b
--- /dev/null
+++ b/vlib/v/checker/tests/array_declare_element_c.out
@@ -0,0 +1,6 @@
+vlib/v/checker/tests/array_declare_element_c.v:3:12: error: non-name `arr[1][0]` on left side of `:=` 
+    1 | fn main() {
+    2 |     arr := [[1, 2], [0, 3]]
+    3 |     arr[1][0] := 1
+      |               ~~
+    4 | }
diff --git a/vlib/v/checker/tests/array_declare_element_c.vv b/vlib/v/checker/tests/array_declare_element_c.vv
new file mode 100644
index 0000000000..aacad5550d
--- /dev/null
+++ b/vlib/v/checker/tests/array_declare_element_c.vv
@@ -0,0 +1,4 @@
+fn main() {
+	arr := [[1, 2], [0, 3]]
+	arr[1][0] := 1
+}
diff --git a/vlib/v/parser/assign.v b/vlib/v/parser/assign.v
index 9a817796b1..e7727856eb 100644
--- a/vlib/v/parser/assign.v
+++ b/vlib/v/parser/assign.v
@@ -111,6 +111,9 @@ fn (mut p Parser) partial_assign_stmt(left []ast.Expr) ast.Stmt {
 				}
 			}
 			ast.IndexExpr {
+				if op == .decl_assign {
+					p.error_with_pos('non-name `$lx.left[$lx.index]` on left side of `:=`', lx.pos)
+				}
 				lx.is_setter = true
 			}
 			ast.ParExpr {}