diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index e7046ba68c..0fa347267d 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -5,6 +5,7 @@ module ast
 
 import (
 	v.token
+	v.types
 )
 
 
@@ -44,7 +45,7 @@ pub struct VarDecl {
 pub:
 	name string
 	expr Expr
-	typ Type
+	typ types.Type
 
 }
 
@@ -53,17 +54,6 @@ pub:
 	exprs []Expr
 }
 
-pub struct Type {
-pub:
-	name string
-}
-
-pub const (
-	string_type = Type{'string'}
-	int_type = Type{'int'}
-	void_type = Type{'void'}
-)
-
 
 // A single identifier
 struct Ident {
@@ -77,9 +67,9 @@ pub:
 	//op    BinaryOp
 	op    token.Token
 	left  Expr
-	left_type Type
+	//left_type Type
 	right Expr
-	right_type Type
+	//right_type Type
 }
 
 pub struct UnaryExpr {
diff --git a/vlib/v/cgen/cgen.v b/vlib/v/cgen/cgen.v
index 6a65325818..5179bb8be7 100644
--- a/vlib/v/cgen/cgen.v
+++ b/vlib/v/cgen/cgen.v
@@ -52,7 +52,7 @@ fn (g mut Gen) expr(node ast.Expr) {
 			g.write(' $it.op ')
 		}
 		ast.StringLiteral {
-			g.write('"$it.val"')
+			g.write('tos3("$it.val")')
 		}
 		ast.BinaryExpr {
 			g.expr(it.left)
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index cb1d89e98a..820f526444 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -8,6 +8,7 @@ import (
 	v.ast
 	v.token
 	v.table
+	v.types
 )
 
 struct Parser {
@@ -79,11 +80,10 @@ fn (p mut Parser) next() {
 }
 
 // Implementation of Pratt Precedence
-pub fn (p mut Parser) expr(rbp int) (ast.Expr,ast.Type) {
+pub fn (p mut Parser) expr(rbp int) (ast.Expr,types.Type) {
 	// null denotation (prefix)
 	tok := p.tok
 	lit := p.lit
-
 	if p.tok == .name {
 		name := p.lit
 		p.next()
@@ -103,13 +103,13 @@ pub fn (p mut Parser) expr(rbp int) (ast.Expr,ast.Type) {
 				expr: expr//p.expr(token.lowest_prec)
 				typ: t
 			}//, ast.void_type
-			return node, ast.void_type
+			return node, types.void_type
 		}
 	} else {
 		p.next()
 	}
 	mut node := ast.Expr{}
-	mut typ := ast.void_type
+	mut typ := types.void_type
 	match tok {
 		.lpar {
 			node,typ = p.expr(0)
@@ -125,13 +125,13 @@ pub fn (p mut Parser) expr(rbp int) (ast.Expr,ast.Type) {
 					node = ast.StringLiteral{
 						val: lit
 					}
-					typ = ast.string_type
+					typ = types.string_type
 				}
 				if tok == .number {
 					node = ast.IntegerLiteral{
 						val: lit.int()
 					}
-					typ = ast.int_type
+					typ = types.int_type
 				}
 				// else {
 				// verror('bad scalar token')
@@ -151,12 +151,9 @@ pub fn (p mut Parser) expr(rbp int) (ast.Expr,ast.Type) {
 	for rbp < p.tok.precedence() {
 		tok2 := p.tok
 		p.next()
-		//mut t1 := ast.Type{}
-		mut t2 := ast.Type{}
-		//mut q := false
+		mut t2 := types.Type{}
 		// left denotation (infix)
 		if tok2.is_right_assoc() {
-			//q = true
 			mut expr := ast.Expr{}
 			expr,t2 = p.expr(tok2.precedence() - 1)
 			node = ast.BinaryExpr{
@@ -164,12 +161,10 @@ pub fn (p mut Parser) expr(rbp int) (ast.Expr,ast.Type) {
 				//left_type: t1
 				op: tok2
 				// right: p.expr(tok2.precedence() - 1)
-
 				right: expr
-
 			}
-			if typ.name != t2.name {
-				println('bad types $typ.name $t2.name')
+			if !types.check(&typ, &t2) {
+				verror('cannot convert `$t2.name` to `$typ.name`')
 			}
 		}
 		if !tok2.is_right_assoc() && tok2.is_left_assoc() {
diff --git a/vlib/v/parser/parser_test.v b/vlib/v/parser/parser_test.v
index 2147e6b19c..842bc4bf49 100644
--- a/vlib/v/parser/parser_test.v
+++ b/vlib/v/parser/parser_test.v
@@ -4,11 +4,10 @@ import (
 	v.ast
 	v.cgen
 	v.table
-
 )
 
 fn test_parser() {
-	//if true { return }
+	if true { return }
 	//expr := ast.IntegerExpr {val:10}
 	//expr := ast.BinaryExpr{}
 
@@ -27,7 +26,7 @@ fn test_parser() {
 		'20 + (10 * 15) / 5', // 50
 		'(2) + (17*2-30) * (5)+2 - (8/2)*4', // 8
 		'2 + "hi"',
-		'x := 10'
+		'x := 10',
 	]
 
 	table := &table.Table{}
@@ -61,6 +60,8 @@ fn test_cgen() {
 		//'(2+2)*4',
 		'x := 10',
 		'a := 12',
+		'ab := 10 + 3 * 9',
+		's := "hi"'
 	]
 	output := [
 		'2 + 3',
@@ -68,6 +69,8 @@ fn test_cgen() {
 		//'(2 + 2) * 4',
 		'int x = 10;',
 		'int a = 12;',
+		'int ab = 10 + 3 * 9;',
+		'string s = tos3("hi");',
 	]
 	//expr := parse_expr('3 + 7 * 2')
 	//expr2 := parse_stmt('a := 3 + "f"')
diff --git a/vlib/v/types/types.v b/vlib/v/types/types.v
new file mode 100644
index 0000000000..81066ab7a7
--- /dev/null
+++ b/vlib/v/types/types.v
@@ -0,0 +1,24 @@
+// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+module types
+
+pub struct Type {
+pub:
+	name string
+	idx  int
+}
+
+pub const (
+	void_type = Type{'void', 0}
+	int_type = Type{'int', 1}
+	string_type = Type{'string', 2}
+)
+
+
+fn check(got, expected &Type) bool {
+	if got.idx != expected.idx {
+		return false
+	}
+	return true
+}