diff --git a/vlib/builtin/map_test.v b/vlib/builtin/map_test.v
index c6003cfc70..b1bb61db91 100644
--- a/vlib/builtin/map_test.v
+++ b/vlib/builtin/map_test.v
@@ -73,8 +73,8 @@ fn test_string_map() {
 fn test_large_map() {
 	//ticks := time.ticks()
 	mut nums := map[string]int
-	N := 30 * 1000
-	for i in 0..N {
+	n := 30 * 1000
+	for i in 0..n {
 	        key := i.str()
 	        nums[key] = i
 	}
@@ -166,7 +166,8 @@ fn mut_map(m mut map[string]int) {
 fn test_mut_arg() {
 	mut m := map[string]int
 	mut_map(mut m)
-	assert m['a'] == 10
+	a := m['a']
+	assert a == 10
 }
 
 fn test_delete() {
@@ -175,8 +176,8 @@ fn test_delete() {
 	m['two'] = 2
 	println(m['two']) // => "2"
 	m.delete('two')
-	println(m['two']) // => 0
-	assert 'two' in m == false
+	println(m['two'].str()) // => 0
+	assert ('two' in m) == false
 	println('two' in m) // => true, on Linux  and Windows  <-- wrong !
 }
 
@@ -205,4 +206,3 @@ fn test_delete_size() {
         }
     }
 }
-
diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 6b12b397e7..faab350cda 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -337,6 +337,7 @@ pub:
 	index          Expr // [0], [start..end] etc
 mut:
 	container_type table.Type // array, map, fixed array
+	is_setter      bool
 }
 
 pub struct IfExpr {
diff --git a/vlib/v/ast/str.v b/vlib/v/ast/str.v
index ecfbf6c3f5..8e5a946714 100644
--- a/vlib/v/ast/str.v
+++ b/vlib/v/ast/str.v
@@ -77,6 +77,9 @@ pub fn (x Expr) str() string {
 		ParExpr {
 			return it.expr.str()
 		}
+		IndexExpr {
+			return '${it.left.str()}[${it.index.str()}]'
+		}
 		else {
 			return '[unhandled expr type ${typeof(x)}]'
 		}
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 489c713a30..7da8751dcf 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -1681,8 +1681,8 @@ fn (g mut Gen) index_expr(node ast.IndexExpr) {
 					is_selector = true
 				}
 				else {}
-	}
-			if g.is_assign_lhs && !is_selector {
+			}
+			if g.is_assign_lhs && !is_selector && node.is_setter {
 				g.is_array_set = true
 				g.write('array_set(&')
 				g.expr(node.left)
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index 9630be02f6..b533d8f327 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -436,6 +436,13 @@ pub fn (p mut Parser) assign_expr(left ast.Expr) ast.AssignExpr {
 	op := p.tok.kind
 	p.next()
 	val := p.expr(0)
+	match left {
+		ast.IndexExpr {
+			//it.mark_as_setter()
+			it.is_setter = true
+		}
+		else{}
+	}
 	node := ast.AssignExpr{
 		left: left
 		val: val