diff --git a/vlib/compiler/main.v b/vlib/compiler/main.v
index bd051bc1a8..de27ccf425 100644
--- a/vlib/compiler/main.v
+++ b/vlib/compiler/main.v
@@ -8,11 +8,7 @@ import (
 	os.cmdline
 	strings
 	filepath
-	v.gen.x64
-	v.table
-	v.parser
-	v.gen
-	time
+	v.builder
 )
 
 pub const (
@@ -390,29 +386,15 @@ pub fn (v mut V) compile2() {
 		println('all .v files before:')
 		println(v.files)
 	}
-	v.add_v_files_to_compile()
+	// v.add_v_files_to_compile()
+	v.files << v.dir
 	if v.pref.is_verbose {
 		println('all .v files:')
 		println(v.files)
 	}
-	table := table.new_table()
-	files := parser.parse_files(v.files, table)
-	c := gen.cgen(files, table)
-	println('out: $v.out_name_c')
-	os.write_file(v.out_name_c, c)
-	/*
-		cgen.genln(c_builtin_types)
-
-		if !v.pref.is_bare {
-			cgen.genln(c_headers)
-		}
-		else {
-			cgen.genln(bare_c_headers)
-		}
-	}
-	*/
+	mut b := builder.new_builder()
+	b.build_c(v.files, v.out_name)
 	v.cc()
-
 }
 
 pub fn (v mut V) compile_x64() {
@@ -423,12 +405,8 @@ pub fn (v mut V) compile_x64() {
 	//v.files << v.v_files_from_dir(filepath.join(v.pref.vlib_path,'builtin','bare'))
 	v.files << v.dir
 
-	table := &table.new_table()
-	ticks := time.ticks()
-	files := parser.parse_files(v.files, table)
-	println('PARSE: ${time.ticks() - ticks}ms')
-	x64.gen(files, v.out_name)
-	println('x64 GEN: ${time.ticks() - ticks}ms')
+	mut b := builder.new_builder()
+	b.build_x64(v.files, v.out_name)
 }
 
 fn (v mut V) generate_init() {
diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 08a667106e..b55087f4b8 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -45,6 +45,7 @@ pub:
 // `foo.bar`
 pub struct SelectorExpr {
 pub:
+	pos   token.Position
 	expr  Expr
 	field string
 }
@@ -60,11 +61,13 @@ pub:
 pub struct Field {
 pub:
 	name string
+	// type_idx int
 	ti   types.TypeIdent
 }
 
 pub struct StructDecl {
 pub:
+	pos    token.Position
 	name   string
 	fields []Field
 	is_pub bool
@@ -72,7 +75,7 @@ pub:
 
 pub struct StructInit {
 pub:
-// typ    types.TypeIdent
+	pos    token.Position
 	ti     types.TypeIdent
 	fields []string
 	exprs  []Expr
@@ -81,7 +84,9 @@ pub:
 // import statement
 pub struct Import {
 pub:
-	mods map[string]string // alias -> module
+	pos   token.Position
+	mod   string
+	alias string
 	// expr Expr
 }
 
@@ -103,24 +108,27 @@ pub:
 
 pub struct CallExpr {
 pub:
-// func       Expr
+	// tok        token.Token
+	pos        token.Position
+mut:
+	// func       Expr
 	name       string
 	args       []Expr
-	is_unknown bool
-	tok        token.Token
 }
 
 pub struct MethodCallExpr {
 pub:
+	// tok        token.Token
+	pos        token.Position
 	expr       Expr
 	name       string
 	args       []Expr
-	is_unknown bool
-	tok        token.Token
 }
 
 pub struct Return {
 pub:
+	pos   token.Position
+	expected_ti types.TypeIdent // TODO: remove once checker updated
 	exprs []Expr
 }
 
@@ -144,12 +152,30 @@ pub struct VarDecl {
 pub:
 	name string
 	expr Expr
+	is_mut bool
+	mut:
 	ti   types.TypeIdent
+	pos  token.Position
 }
 
 pub struct File {
 pub:
-	stmts []Stmt
+	mod     Module
+	imports []Import
+	stmts   []Stmt
+}
+
+pub struct IdentVar {
+pub:
+	expr Expr
+	ti   types.TypeIdent
+}
+
+type IdentInfo = IdentVar
+
+pub enum IdentKind {
+	blank_ident
+	variable
 }
 
 // A single identifier
@@ -157,14 +183,18 @@ pub struct Ident {
 pub:
 	name     string
 	tok_kind token.Kind
+	pos      token.Position
 	value    string
+mut:
+	kind     IdentKind
+	info     IdentInfo
 }
 
 pub struct BinaryExpr {
 pub:
-// tok_kind token.Kind
 // op    BinaryOp
 	op    token.Kind
+	pos   token.Position
 	left  Expr
 	// left_ti types.TypeIdent
 	right Expr
@@ -231,6 +261,7 @@ pub:
 
 pub struct ReturnStmt {
 	tok_kind token.Kind // or pos
+	pos		 token.Position
 	results  []Expr
 }
 
@@ -246,9 +277,10 @@ pub:
 
 pub struct AssignExpr {
 pub:
+	op   token.Kind
+	pos  token.Position
 	left Expr
 	val  Expr
-	op   token.Kind
 }
 
 pub struct ArrayInit {
diff --git a/vlib/v/builder/builder.v b/vlib/v/builder/builder.v
new file mode 100644
index 0000000000..7681bf5d71
--- /dev/null
+++ b/vlib/v/builder/builder.v
@@ -0,0 +1,45 @@
+module builder
+
+import (
+	os
+	time
+	v.table
+	v.checker
+	v.parser
+	v.gen
+	v.gen.x64
+)
+
+pub struct Builder {
+pub:
+	table   &table.Table
+	checker checker.Checker
+}
+
+pub fn new_builder() Builder {
+	table := table.new_table()
+	return Builder{
+		table: table
+		checker: checker.new_checker(table)
+	}
+}
+
+pub fn (b mut Builder) gen_c(v_files []string) string {
+	ast_files := parser.parse_files(v_files, b.table)
+	b.checker.check_files(v_files, ast_files)
+	return gen.cgen(ast_files, b.table)
+}
+
+pub fn (b mut Builder) build_c(v_files []string, out_file string) {
+	os.write_file(out_file, b.gen_c(v_files))
+}
+
+pub fn (b mut Builder) build_x64(v_files []string, out_file string) {
+	ticks := time.ticks()
+	ast_files := parser.parse_files(v_files, b.table)
+	println('PARSE: ${time.ticks() - ticks}ms')
+	b.checker.check_files(v_files, ast_files)
+	println('CHECK: ${time.ticks() - ticks}ms')
+	x64.gen(ast_files, out_file)
+	println('x64 GEN: ${time.ticks() - ticks}ms')
+}
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
new file mode 100644
index 0000000000..a513b61bd3
--- /dev/null
+++ b/vlib/v/checker/checker.v
@@ -0,0 +1,258 @@
+// 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 checker
+
+import (
+	v.ast
+	v.table
+	v.types
+	v.token
+)
+
+pub struct Checker {
+	table      &table.Table
+mut:
+	file_name  string
+	// TODO: resolved
+}
+
+pub fn new_checker(table &table.Table) Checker {
+	return Checker{
+		table: table
+	}
+}
+
+pub fn (c &Checker) check(ast_file ast.File) {
+	for stmt in ast_file.stmts {
+		c.stmt(stmt)
+	}
+}
+
+pub fn (c mut Checker) check_files(v_files []string, ast_files []ast.File) {
+	for i, file in ast_files {
+		c.file_name = v_files[i]
+		c.check(file)
+	}
+}
+
+pub fn (c &Checker) check_struct_init(struct_init ast.StructInit) {
+	typ := c.table.find_type(struct_init.ti.name) or {
+		c.error('unknown struct: $struct_init.ti.name', struct_init.pos)
+		panic('')
+	}
+	match typ.kind {
+		.placeholder {
+			c.error('unknown struct: $struct_init.ti.name', struct_init.pos)
+		}
+		.struct_ {
+			info := typ.info as types.Struct
+			for i, expr in struct_init.exprs {
+				field := info.fields[i]
+				expr_ti := c.table.get_expr_ti(expr)
+				if !c.table.check(expr_ti, field.ti) {
+					c.error('cannot assign $expr_ti.name as $field.ti.name for field $field.name', struct_init.pos)
+				}
+			}
+		}
+		else {}
+	}
+}
+
+pub fn (c &Checker) check_binary_expr(binary_expr ast.BinaryExpr) {
+	left_ti := c.table.get_expr_ti(binary_expr.left)
+	right_ti := c.table.get_expr_ti(binary_expr.right)
+	if !c.table.check(&right_ti, &left_ti) {
+		c.error('binary expr: cannot use $right_ti.name as $left_ti.name', binary_expr.pos)
+	}
+}
+
+fn (c &Checker) check_assign_expr(assign_expr ast.AssignExpr) {
+	left_ti := c.table.get_expr_ti(assign_expr.left)
+	right_ti := c.table.get_expr_ti(assign_expr.val)
+	if !c.table.check(right_ti, left_ti) {
+		c.error('cannot assign $right_ti.name to $left_ti.name', assign_expr.pos)
+	}
+}
+
+pub fn (c &Checker) check_call_expr(call_expr ast.CallExpr) {
+	fn_name := call_expr.name
+	if f := c.table.find_fn(fn_name) {
+		// return_ti := f.return_ti
+		if call_expr.args.len < f.args.len {
+			c.error('too few arguments in call to `$fn_name`', call_expr.pos)
+		} else if call_expr.args.len > f.args.len {
+			c.error('too many arguments in call to `$fn_name`', call_expr.pos)
+		}
+		for i, arg in f.args {
+			arg_expr := call_expr.args[i]
+			ti := c.table.get_expr_ti(arg_expr)
+			if !c.table.check(&ti, &arg.ti) {
+				c.error('cannot use type `$ti.name` as type `$arg.ti.name` in argument to `$fn_name`', call_expr.pos)
+			}
+		}
+	} else {
+		c.error('unknown fn: $fn_name', call_expr.pos)
+		// c.warn('unknown function `$fn_name`')
+	}
+}
+
+pub fn (c &Checker) check_method_call_expr(method_call_expr ast.MethodCallExpr) {
+	ti := c.table.get_expr_ti(method_call_expr.expr)
+	if !c.table.has_method(ti.idx, method_call_expr.name) {
+		c.error('type `$ti.name` has no method `$method_call_expr.name`', method_call_expr.pos)
+	}
+}
+
+pub fn (c &Checker) check_selector_expr(selector_expr ast.SelectorExpr) {
+	ti := c.table.get_expr_ti(selector_expr.expr)
+	field_name := selector_expr.field
+	// struct_ := c.table.types[ti.idx] as types.Struct
+	typ := c.table.types[ti.idx]
+	match typ.kind {
+		.struct_ {
+			// if !c.table.struct_has_field(it, field) {
+			// 	c.error('AAA unknown field `${it.name}.$field`')
+			// }
+			// TODO: fix bug
+			c.table.struct_find_field(typ, field_name) or {
+				c.error('unknown field `${typ.name}.$field_name`', selector_expr.pos)
+			}
+		}
+		else {
+			c.error('$ti.name is not a struct', selector_expr.pos)
+		}
+	}
+}
+
+// TODO: non deferred
+pub fn (c &Checker) check_return_stmt(return_stmt ast.Return) {
+	mut got_tis := []types.TypeIdent
+	for expr in return_stmt.exprs {
+		ti := c.table.get_expr_ti(expr)
+		got_tis << ti
+	}
+	expected_ti := return_stmt.expected_ti
+	mut expected_tis := [expected_ti]
+	if expected_ti.kind == .multi_return {
+		mr_type := c.table.types[expected_ti.idx]
+		mr_info := mr_type.info as types.MultiReturn
+		expected_tis = mr_info.tis
+	}
+	if expected_tis.len != got_tis.len {
+		c.error('wrong number of return arguments:\n\texpected: $expected_tis.str()\n\tgot: $got_tis.str()', return_stmt.pos)
+	}
+	for i, exp_ti in expected_tis {
+		got_ti := got_tis[i]
+		if !c.table.check(got_ti, exp_ti) {
+			c.error('cannot use `$got_ti.name` as type `$exp_ti.name` in return argument', return_stmt.pos)
+		}
+	}
+}
+
+fn (c &Checker) stmt(node ast.Stmt) {
+	match node {
+		ast.FnDecl {
+			for stmt in it.stmts {
+				c.stmt(stmt)
+			}
+		}
+		ast.Return {
+			c.check_return_stmt(it)
+		}
+		ast.VarDecl {
+			c.expr(it.expr)
+		}
+		ast.ForStmt {
+			c.expr(it.cond)
+			for stmt in it.stmts {
+				c.stmt(stmt)
+			}
+		}
+		ast.ForCStmt {
+			c.stmt(it.init)
+			c.expr(it.cond)
+			c.stmt(it.inc)
+			for stmt in it.stmts {
+				c.stmt(stmt)
+			}
+		}
+		// ast.StructDecl {}
+		ast.ExprStmt {
+			c.expr(it.expr)
+		}
+		else {}
+	}
+}
+
+fn (c &Checker) expr(node ast.Expr) {
+	match node {
+		ast.AssignExpr {
+			c.check_assign_expr(it)
+		}
+		// ast.IntegerLiteral {}
+		// ast.FloatLiteral {}
+		ast.PostfixExpr {
+			c.expr(it.expr)
+		}
+		ast.UnaryExpr {
+			c.expr(it.left)
+		}
+		// ast.StringLiteral {}
+		ast.PrefixExpr {
+			c.expr(it.right)
+		}
+		ast.BinaryExpr {
+			c.check_binary_expr(it)
+		}
+		ast.StructInit {
+			c.check_struct_init(it)
+		}
+		ast.CallExpr {
+			c.check_call_expr(it)
+		}
+		ast.MethodCallExpr {
+			c.check_method_call_expr(it)
+		}
+		ast.ArrayInit {
+			for expr in it.exprs {
+				c.expr(expr)
+			}
+		}
+		// ast.Ident {}
+		// ast.BoolLiteral {}
+		ast.SelectorExpr {
+			c.check_selector_expr(it)
+		}
+		ast.IndexExpr {
+			c.expr(it.left)
+			c.expr(it.index)
+		}
+		ast.IfExpr {
+			c.expr(it.cond)
+			for i, stmt in it.stmts {
+				c.stmt(stmt)
+			}
+			if it.else_stmts.len > 0 {
+				for stmt in it.else_stmts {
+					c.stmt(stmt)
+				}
+			}
+		}
+		else {}
+	}
+}
+
+pub fn (c &Checker) error(s string, pos token.Position) {
+	print_backtrace()
+	final_msg_line := '$c.file_name:$pos.line_nr: error: $s'
+	eprintln(final_msg_line)
+	/*
+	if colored_output {
+		eprintln(term.bold(term.red(final_msg_line)))
+	}else{
+		eprintln(final_msg_line)
+	}
+	*/
+	exit(1)
+}
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index d3186a35b9..82a78302f4 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -55,15 +55,18 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 				g.write('int ${it.name}(')
 			}
 			else {
-				g.write('$it.ti.name ${it.name}(')
-				g.definitions.write('$it.ti.name ${it.name}(')
+				ti := g.table.refresh_ti(it.ti)
+				g.write('$ti.name ${it.name}(')
+				g.definitions.write('$ti.name ${it.name}(')
 			}
 			for i, arg in it.args {
-				g.write(arg.ti.name + ' ' + arg.name)
+				// t := g.table.get_type(arg.ti.idx)
+				ti := g.table.refresh_ti(arg.ti)
+				g.write(ti.name + ' ' + arg.name)
 				if i < it.args.len - 1 {
 					g.write(', ')
 				}
-				g.definitions.write(arg.ti.name + ' ' + arg.name)
+				g.definitions.write(ti.name + ' ' + arg.name)
 			}
 			g.writeln(') { ')
 			if !is_main {
@@ -82,7 +85,9 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 			g.write('return ')
 			// multiple returns
 			if it.exprs.len > 1 {
-				g.write('($g.fn_decl.ti.name){')
+				// t := g.table.get_type(g.fn_decl.ti.idx)
+				ti := g.table.refresh_ti(g.fn_decl.ti)
+				g.write('($ti.name){')
 				for i, expr in it.exprs {
 					g.write('.arg$i=')
 					g.expr(expr)
@@ -99,7 +104,14 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 			g.writeln(';')
 		}
 		ast.VarDecl {
-			g.write('$it.ti.name $it.name = ')
+			mut ti := it.ti
+			if ti.kind == .unresolved {
+				ti = g.table.get_expr_ti(it.expr)
+				// println('A $it.ti.name')
+				// println('B $ti.name')
+				// panic("############# UNRESOLVED")
+			}
+			g.write('$ti.name $it.name = ')
 			g.expr(it.expr)
 			g.writeln(';')
 		}
@@ -128,7 +140,9 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 		ast.StructDecl {
 			g.writeln('typedef struct {')
 			for field in it.fields {
-				g.writeln('\t$field.ti.name $field.name;')
+				// t := g.table.get_type(field.ti.idx)
+				ti := g.table.refresh_ti(field.ti)
+				g.writeln('\t$ti.name $field.name;')
 			}
 			g.writeln('} $it.name;')
 		}
@@ -197,7 +211,9 @@ fn (g mut Gen) expr(node ast.Expr) {
 		}
 		// `user := User{name: 'Bob'}`
 		ast.StructInit {
-			g.writeln('($it.ti.name){')
+			// t := g.table.get_type(it.ti.idx)
+			ti := g.table.refresh_ti(it.ti)
+			g.writeln('($ti.name){')
 			for i, field in it.fields {
 				g.write('\t.$field = ')
 				g.expr(it.exprs[i])
@@ -215,8 +231,11 @@ fn (g mut Gen) expr(node ast.Expr) {
 			}
 			g.write(')')
 		}
+		ast.MethodCallExpr {}
 		ast.ArrayInit {
-			g.writeln('new_array_from_c_array($it.exprs.len, $it.exprs.len, sizeof($it.ti.name), {\t')
+			// t := g.table.get_type(it.ti.idx)
+			ti := g.table.refresh_ti(it.ti)
+			g.writeln('new_array_from_c_array($it.exprs.len, $it.exprs.len, sizeof($ti.name), {\t')
 			for expr in it.exprs {
 				g.expr(expr)
 				g.write(', ')
@@ -248,17 +267,18 @@ fn (g mut Gen) expr(node ast.Expr) {
 		ast.IfExpr {
 			// If expression? Assign the value to a temp var.
 			// Previously ?: was used, but it's too unreliable.
+			ti := g.table.refresh_ti(it.ti)
 			mut tmp := ''
-			if it.ti.kind != .void {
+			if ti.kind != .void {
 				tmp = g.table.new_tmp_var()
-				// g.writeln('$it.ti.name $tmp;')
+				// g.writeln('$ti.name $tmp;')
 			}
 			g.write('if (')
 			g.expr(it.cond)
 			g.writeln(') {')
 			for i, stmt in it.stmts {
 				// Assign ret value
-				if i == it.stmts.len - 1 && it.ti.kind != .void {
+				if i == it.stmts.len - 1 && ti.kind != .void {
 					// g.writeln('$tmp =')
 					println(1)
 				}
diff --git a/vlib/v/gen/cgen_test.v b/vlib/v/gen/cgen_test.v
index 5ac52d34ee..ef781d753f 100644
--- a/vlib/v/gen/cgen_test.v
+++ b/vlib/v/gen/cgen_test.v
@@ -1,10 +1,7 @@
 import (
 	os
 	filepath
-	v.parser
-	v.ast
-	v.gen
-	v.table
+	v.builder
 	term
 )
 
@@ -26,9 +23,8 @@ fn test_c_files() {
 		ctext := os.read_file('$vroot/vlib/v/gen/tests/${i}.c') or {
 			panic(err)
 		}
-		table := &table.new_table()
-		program := parser.parse_file(path, table)
-		res := gen.cgen([program], table)
+		mut b := builder.new_builder()
+		res := b.gen_c([path])
 		if compare_texts(res, ctext) {
 			eprintln('${term_ok} ${i}')
 		}
diff --git a/vlib/v/gen/jsgen.v b/vlib/v/gen/jsgen.v
index 96dea1cbb6..ba3b790f93 100644
--- a/vlib/v/gen/jsgen.v
+++ b/vlib/v/gen/jsgen.v
@@ -3,16 +3,19 @@ module gen
 import (
 	strings
 	v.ast
+	v.table
 	term
 )
 
 struct JsGen {
 	out strings.Builder
+	table &table.Table
 }
 
-pub fn jsgen(program ast.File) string {
+pub fn jsgen(program ast.File, table &table.Table) string {
 	mut g := JsGen{
 		out: strings.new_builder(100)
+		table: table
 	}
 	for stmt in program.stmts {
 		g.stmt(stmt)
@@ -34,9 +37,11 @@ pub fn (g mut JsGen) writeln(s string) {
 fn (g mut JsGen) stmt(node ast.Stmt) {
 	match node {
 		ast.FnDecl {
-			g.write('/** @return { $it.ti.name } **/\nfunction ${it.name}(')
+			ti := g.table.refresh_ti(it.ti)
+			g.write('/** @return { $ti.name } **/\nfunction ${it.name}(')
 			for arg in it.args {
-				g.write(' /** @type { arg.ti.name } **/ $arg.name')
+				arg_ti := g.table.refresh_ti(arg.ti)
+				g.write(' /** @type { $arg_ti.name } **/ $arg.name')
 			}
 			g.writeln(') { ')
 			for stmt in it.stmts {
@@ -55,7 +60,8 @@ fn (g mut JsGen) stmt(node ast.Stmt) {
 			g.writeln(';')
 		}
 		ast.VarDecl {
-			g.write('var /* $it.ti.name */ $it.name = ')
+			ti := g.table.refresh_ti(it.ti)
+			g.write('var /* $ti.name */ $it.name = ')
 			g.expr(it.expr)
 			g.writeln(';')
 		}
@@ -114,7 +120,8 @@ fn (g mut JsGen) expr(node ast.Expr) {
 		}
 		// `user := User{name: 'Bob'}`
 		ast.StructInit {
-			g.writeln('/*$it.ti.name*/{')
+			ti := g.table.refresh_ti(it.ti)
+			g.writeln('/*$ti.name*/{')
 			for i, field in it.fields {
 				g.write('\t$field : ')
 				g.expr(it.exprs[i])
diff --git a/vlib/v/gen/tests/1.c b/vlib/v/gen/tests/1.c
index e28d4c91d1..16c2803c82 100644
--- a/vlib/v/gen/tests/1.c
+++ b/vlib/v/gen/tests/1.c
@@ -31,7 +31,7 @@ i < 10; i++;
 		1, 2, 3,
 	});
 	int number = nums[0];
-	void n = get_int2();
+	int n = get_int2();
 }
 
 int get_int(string a) {
diff --git a/vlib/v/parser/a_type.v b/vlib/v/parser/a_type.v
index d77ebef7da..40dfa92e8c 100644
--- a/vlib/v/parser/a_type.v
+++ b/vlib/v/parser/a_type.v
@@ -149,10 +149,11 @@ pub fn (p mut Parser) parse_ti() types.TypeIdent {
 				else {
 					// struct / enum
 					mut idx := p.table.find_type_idx(name)
-					// add placeholder
-					if idx == 0 {
-						idx = p.table.add_placeholder_type(name)
+					if idx > 0 {
+						return types.new_ti(p.table.types[idx].kind, name, idx, nr_muls)
 					}
+					// not found - add placeholder
+					idx = p.table.add_placeholder_type(name)
 					return types.new_ti(.placeholder, name, idx, nr_muls)
 				}
 	}
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index 5f899c471f..740b03c82e 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -13,50 +13,30 @@ pub fn (p mut Parser) call_expr() (ast.CallExpr,types.TypeIdent) {
 	tok := p.tok
 	fn_name := p.check_name()
 	p.check(.lpar)
-	mut is_unknown := false
-	is_unknown = false
 	mut args := []ast.Expr
-	mut return_ti := types.void_ti
-	if f := p.table.find_fn(fn_name) {
-		// println('found fn $fn_name')
-		return_ti = f.return_ti
-		for i, arg in f.args {
-			e,ti := p.expr(0)
-			if !types.check(&arg.ti, &ti) {
-				p.error('cannot use type `$ti.name` as type `$arg.ti.name` in argument to `$fn_name`')
-			}
-			args << e
-			if i < f.args.len - 1 {
-				p.check(.comma)
-			}
-		}
-		if p.tok.kind == .comma {
-			p.error('too many arguments in call to `$fn_name`')
-		}
-	}else{
-		is_unknown = true
-		p.warn('unknown function `$fn_name`')
-		for p.tok.kind != .rpar {
-			e,_ := p.expr(0)
-			args << e
-			if p.tok.kind != .rpar {
-				p.check(.comma)
-			}
+	// mut return_ti := types.void_ti
+	for p.tok.kind != .rpar {
+		e,_ := p.expr(0)
+		args << e
+		if p.tok.kind != .rpar {
+			p.check(.comma)
 		}
 	}
 	p.check(.rpar)
 	node := ast.CallExpr{
 		name: fn_name
 		args: args
-		is_unknown: is_unknown
-		tok: tok
-		// typ: return_ti
+		// tok: tok
+		pos: tok.position()
 		
 	}
-	if is_unknown {
-		p.table.unknown_calls << node
+	mut ti := types.unresolved_ti
+	if f := p.table.find_fn(fn_name) {
+		ti = f.return_ti
 	}
-	return node,return_ti
+	println('adding call_expr check $fn_name')
+
+	return node, ti
 }
 
 pub fn (p mut Parser) call_args() []ast.Expr {
@@ -170,6 +150,7 @@ fn (p mut Parser) fn_decl() ast.FnDecl {
 
 pub fn (p &Parser) check_fn_calls() {
 	println('check fn calls2')
+	/*
 	for call in p.table.unknown_calls {
 		f := p.table.find_fn(call.name) or {
 			p.error_at_line('unknown function `$call.name`', call.tok.line_nr)
@@ -179,4 +160,5 @@ pub fn (p &Parser) check_fn_calls() {
 		// println(f.return_ti.name)
 		// println('IN AST typ=' + call.typ.name)
 	}
+	*/
 }
diff --git a/vlib/v/parser/module.v b/vlib/v/parser/module.v
new file mode 100644
index 0000000000..2ce4124e97
--- /dev/null
+++ b/vlib/v/parser/module.v
@@ -0,0 +1,4 @@
+// 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 parser
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index 494ec71af7..d6022e1a08 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -60,6 +60,22 @@ pub fn parse_file(path string, table &table.Table) ast.File {
 		file_name: path
 	}
 	p.read_first_token()
+
+	// module decl
+	module_decl := if p.tok.kind == .key_module {
+		p.module_decl()
+	} else {
+		ast.Module{
+			name: 'main'
+		}
+	}
+	// imports
+	mut imports := []ast.Import
+	for p.tok.kind == .key_import {
+		imports << p.import_stmt()
+	}
+	// TODO: import only mode
+
 	for {
 		// res := s.scan()
 		if p.tok.kind == .eof {
@@ -69,11 +85,12 @@ pub fn parse_file(path string, table &table.Table) ast.File {
 		// println('stmt at ' + p.tok.str())
 		stmts << p.top_stmt()
 	}
-	p.check_fn_calls()
 	// println('nr stmts = $stmts.len')
 	// println(stmts[0])
 	return ast.File{
-		stmts: stmts
+		mod:     module_decl
+		imports: imports
+		stmts:   stmts
 	}
 }
 
@@ -136,14 +153,11 @@ fn (p mut Parser) check_name() string {
 
 pub fn (p mut Parser) top_stmt() ast.Stmt {
 	match p.tok.kind {
-		.key_module {
-			return p.module_decl()
-		}
-		.key_import {
-			return p.import_stmt()
-		}
 		.key_pub {
 			match p.peek_tok.kind {
+				.key_const {
+					return p.const_decl()
+				}
 				.key_fn {
 					return p.fn_decl()
 				}
@@ -154,16 +168,16 @@ pub fn (p mut Parser) top_stmt() ast.Stmt {
 					p.error('wrong pub keyword usage')
 					return ast.Stmt{}
 				}
-	}
-			// .key_const {
-			// return p.const_decl()
-			// }
 			// .key_enum {
 			// return p.enum_decl()
 			// }
 			// .key_type {
 			// return p.type_decl()
 			// }
+			}
+		}
+		.key_const {
+			return p.const_decl()
 		}
 		.key_fn {
 			return p.fn_decl()
@@ -213,11 +227,12 @@ pub fn (p mut Parser) stmt() ast.Stmt {
 pub fn (p mut Parser) assign_expr(left ast.Expr) ast.AssignExpr {
 	op := p.tok.kind
 	p.next()
-	val,_ := p.expr(0)
+	val, _ := p.expr(0)
 	node := ast.AssignExpr{
 		left: left
-		op: op
 		val: val
+		op: op
+		pos: p.tok.position()
 	}
 	return node
 }
@@ -238,7 +253,7 @@ pub fn (p mut Parser) assign_stmt() ast.AssignStmt {
 	// println('assignn_stmt() ' + op.str())
 	p.next()
 	right_expr,right_type := p.expr(0)
-	if !types.check(left_type, right_type) {
+	if !p.table.check(left_type, right_type) {
 		p.error('oops')
 	}
 	return ast.AssignStmt{
@@ -282,7 +297,8 @@ pub fn (p &Parser) warn(s string) {
 
 pub fn (p mut Parser) name_expr() (ast.Expr,types.TypeIdent) {
 	mut node := ast.Expr{}
-	mut ti := types.void_ti
+	// mut ti := types.void_ti
+	mut ti := types.unresolved_ti
 	if p.tok.lit == 'C' {
 		p.next()
 		p.check(.dot)
@@ -293,7 +309,8 @@ pub fn (p mut Parser) name_expr() (ast.Expr,types.TypeIdent) {
 	}
 	// fn call
 	if p.peek_tok.kind == .lpar {
-		x,ti2 := p.call_expr() // TODO `node,typ :=` should work
+		println('calling $p.tok.lit')
+		x, ti2 := p.call_expr() // TODO `node,typ :=` should work
 		node = x
 		ti = ti2
 	}
@@ -308,22 +325,21 @@ pub fn (p mut Parser) name_expr() (ast.Expr,types.TypeIdent) {
 			field_name := p.check_name()
 			field_names << field_name
 			p.check(.colon)
-			// expr,field_type := p.expr(0)
 			expr,_ := p.expr(0)
-			// if !types.check(   ,field_type
 			exprs << expr
 		}
 		node = ast.StructInit{
 			ti: ti
 			exprs: exprs
 			fields: field_names
+			pos: p.tok.position()
 		}
 		p.check(.rcbr)
 	}
 	else {
 		// p.warn('name ')
 		// left := p.parse_ident()
-		node = ast.Ident{
+		mut ident := ast.Ident{
 			name: p.tok.lit
 		}
 		var := p.table.find_var(p.tok.lit) or {
@@ -331,6 +347,13 @@ pub fn (p mut Parser) name_expr() (ast.Expr,types.TypeIdent) {
 			exit(0)
 		}
 		ti = var.ti
+		ident.kind = .variable
+		ident.info = ast.IdentVar {
+			ti: ti
+			expr: var.expr
+		}
+		// ident.ti = ti
+		node = ident
 		p.next()
 	}
 	return node,ti
@@ -438,59 +461,33 @@ fn (p mut Parser) index_expr(left ast.Expr) (ast.Expr,types.TypeIdent) {
 	return node,ti
 }
 
-fn (p mut Parser) dot_expr(left ast.Expr, ti types.TypeIdent) (ast.Expr,types.TypeIdent) {
+fn (p mut Parser) dot_expr(left ast.Expr, left_ti &types.TypeIdent) (ast.Expr,types.TypeIdent) {
 	p.next()
 	field_name := p.check_name()
-	println('# $ti.name $ti.idx - $field_name')
-	if ti.kind != .void {
-		p.warn('#### void type in dot_expr - field: $field_name')
-	}
-	struc := p.table.types[ti.idx] as types.Struct
+	ti := types.unresolved_ti
 	// Method call
 	if p.tok.kind == .lpar {
-		if !p.table.struct_has_method(struc, field_name) {
-			p.error('type `$struc.name` has no method `$field_name`')
-		}
 		p.next()
 		args := p.call_args()
-		println('method call $field_name')
-		mut node := ast.Expr{}
-		node = ast.MethodCallExpr{
+		mcall_expr := ast.MethodCallExpr{
 			expr: left
 			name: field_name
 			args: args
+			pos: p.tok.position()
 		}
-		return node,types.int_ti
+		mut node := ast.Expr{}
+		node = mcall_expr
+		return node, ti
 	}
-	if !p.table.struct_has_field(struc, field_name) {
-		// t :=
-		p.error('type `$struc.name` has no field  `$field_name`')
-	}
-	/*
-				// p.next()
-				field := p.check_name()
-				if !ti.type_kind in  [.placeholder, .struct_] {
-					println('kind: $ti.str()')
-					p.error('cannot access field, `$ti.type_name` is not a struct')
-				}
-				typ := p.table.types[ti.type_idx] as types.Struct
-				mut ok := false
-				for f in typ.fields {
-					if f.name == field {
-						ok = true
-					}
-				}
-				if !ok {
-					p.error('unknown field `${typ.name}.$field`')
-				}
-				*/
 
-	mut node := ast.Expr{}
-	node = ast.SelectorExpr{
+	sel_expr := ast.SelectorExpr{
 		expr: left
 		field: field_name
+		pos: p.tok.position()
 	}
-	return node,types.int_ti
+	mut node := ast.Expr{}
+	node = sel_expr
+	return node, ti
 }
 
 fn (p mut Parser) infix_expr(left ast.Expr) (ast.Expr,types.TypeIdent) {
@@ -505,9 +502,10 @@ fn (p mut Parser) infix_expr(left ast.Expr) (ast.Expr,types.TypeIdent) {
 	}
 	mut expr := ast.Expr{}
 	expr = ast.BinaryExpr{
-		op: op
 		left: left
 		right: right
+		op: op
+		pos: p.tok.position()
 	}
 	return expr,ti
 }
@@ -587,7 +585,7 @@ fn (p mut Parser) for_statement() ast.Stmt {
 	}
 	// `for cond {`
 	cond,ti := p.expr(0)
-	if !types.check(types.bool_ti, ti) {
+	if !p.table.check(types.bool_ti, ti) {
 		p.error('non-bool used as for condition')
 	}
 	stmts := p.parse_block()
@@ -604,7 +602,7 @@ fn (p mut Parser) if_expr() (ast.Expr,types.TypeIdent) {
 	mut node := ast.Expr{}
 	p.check(.key_if)
 	cond,cond_ti := p.expr(0)
-	// if !types.check(types.bool_ti, cond_ti) {
+	// if !p.table.check(types.bool_ti, cond_ti) {
 	if cond_ti.kind != .bool {
 		p.error('non-bool used as if condition')
 	}
@@ -670,7 +668,7 @@ fn (p mut Parser) array_init() (ast.Expr,types.TypeIdent) {
 		if i == 0 {
 			val_ti = ti
 		}
-		else if !types.check(val_ti, ti) {
+		else if !p.table.check(val_ti, ti) {
 			p.error('expected array element with type `$val_ti.name`')
 		}
 		exprs << expr
@@ -714,25 +712,57 @@ fn (p mut Parser) parse_number_literal() (ast.Expr,types.TypeIdent) {
 
 fn (p mut Parser) module_decl() ast.Module {
 	p.check(.key_module)
-	p.next()
-	return ast.Module{}
+	name := p.check_name()
+	return ast.Module{
+		name: name
+	}
 }
 
-fn (p mut Parser) import_stmt() ast.Import {
-	p.check(.key_import)
-	name := p.check_name()
-	mut alias := name
+fn (p mut Parser) parse_import() ast.Import {
+	mod_name := p.check_name()
+	mut mod_alias := mod_name
 	if p.tok.kind == .key_as {
 		p.check(.key_as)
-		alias = p.check_name()
+		mod_alias = p.check_name()
 	}
-	mut mods := map[string]string
-	mods[alias] = name
 	return ast.Import{
-		mods: mods
+		mod: mod_name
+		alias: mod_alias
+		pos: p.tok.position()
 	}
 }
 
+fn (p mut Parser) import_stmt() []ast.Import {
+	p.check(.key_import)
+	mut imports := []ast.Import
+	if p.tok.kind == .lpar {
+		p.check(.lpar)
+		for p.tok.kind != .rpar {
+			imports << p.parse_import()
+		}
+		p.check(.rpar)
+	} else {
+		imports << p.parse_import()
+	}
+	return imports
+}
+
+// TODO
+//fn (p mut Parser) const_decl() ast... {
+fn (p mut Parser) const_decl() ast.Stmt {
+	p.check(.key_const)
+	p.check(.lpar)
+	for p.tok.kind != .rpar {
+		name := p.check_name()
+		println('const: $name')
+		p.check(.assign)
+		_, _ := p.expr(0)
+		// expr, ti := p.expr(0)
+	}
+	p.check(.rpar)
+	return ast.Stmt{}
+}
+
 fn (p mut Parser) struct_decl() ast.StructDecl {
 	is_pub := p.tok.kind == .key_pub
 	if is_pub {
@@ -756,18 +786,23 @@ fn (p mut Parser) struct_decl() ast.StructDecl {
 		}
 		fields << types.Field{
 			name: field_name
-			type_idx: ti.idx
+			// type_idx: ti.idx
+			ti: ti
 		}
 	}
 	p.check(.rcbr)
-	p.table.register_struct(types.Struct{
+	p.table.register_type(table.Type{
+		kind: .struct_
 		name: name
-		fields: fields
+		info: types.Struct{
+			fields: fields
+		}
 	})
 	return ast.StructDecl{
 		name: name
 		is_pub: is_pub
 		fields: ast_fields
+		pos: p.tok.position()
 	}
 }
 
@@ -776,11 +811,12 @@ fn (p mut Parser) return_stmt() ast.Return {
 	// return expressions
 	mut exprs := []ast.Expr
 	// return type idents
-	mut got_tis := []types.TypeIdent
+	// mut got_tis := []types.TypeIdent
 	for {
-		expr,ti := p.expr(0)
+		// expr,ti := p.expr(0)
+		expr, _ := p.expr(0)
 		exprs << expr
-		got_tis << ti
+		// got_tis << ti
 		if p.tok.kind == .comma {
 			p.check(.comma)
 		}
@@ -788,23 +824,13 @@ fn (p mut Parser) return_stmt() ast.Return {
 			break
 		}
 	}
-	mut expected_tis := [p.return_ti]
-	if p.return_ti.kind == .multi_return {
-		mr_type := p.table.types[p.return_ti.idx] as types.MultiReturn
-		expected_tis = mr_type.tis
-	}
-	if expected_tis.len != got_tis.len {
-		p.error('wrong number of return arguments:\n\texpected: $expected_tis.str()\n\tgot: $got_tis.str()')
-	}
-	for i, exp_ti in expected_tis {
-		got_ti := got_tis[i]
-		if !types.check(got_ti, exp_ti) {
-			p.error('cannot use `$got_ti.name` as type `$exp_ti.name` in return argument')
-		}
-	}
-	return ast.Return{
+	// TODO: consider non deferred
+	stmt := ast.Return{
+		expected_ti: p.return_ti
 		exprs: exprs
+		pos: p.tok.position()
 	}
+	return stmt
 }
 
 fn (p mut Parser) var_decl() ast.VarDecl {
@@ -820,25 +846,29 @@ fn (p mut Parser) var_decl() ast.VarDecl {
 	}
 	name := p.tok.lit
 	p.read_first_token()
-	expr,ti := p.expr(token.lowest_prec)
+	expr, ti := p.expr(token.lowest_prec)
 	if _ := p.table.find_var(name) {
 		p.error('redefinition of `$name`')
 	}
 	p.table.register_var(table.Var{
 		name: name
-		ti: ti
 		is_mut: is_mut
+		expr: expr
+		ti: ti
 	})
 	// println(p.table.names)
-	// println('added var `$name` with type $t.name')
-	return ast.VarDecl{
+	node := ast.VarDecl{
 		name: name
 		expr: expr // p.expr(token.lowest_prec)
-		
+		is_mut: is_mut
 		ti: ti
+		pos: p.tok.position()
 	}
+	return node
 }
 
+
+
 fn verror(s string) {
 	println(s)
 	exit(1)
diff --git a/vlib/v/parser/parser_test.v b/vlib/v/parser/parser_test.v
index 2a016ce975..8252a4ad2d 100644
--- a/vlib/v/parser/parser_test.v
+++ b/vlib/v/parser/parser_test.v
@@ -4,6 +4,7 @@ import (
 	v.ast
 	v.gen
 	v.table
+	v.checker
 	term
 )
 
@@ -37,7 +38,7 @@ fn test_one() {
 	//
 	]
 	expected := 'int a = 10;int b = -a;int c = 20;'
-	table := &table.Table{}
+	table := table.new_table()
 	mut e := []ast.Stmt
 	for line in input {
 		e << parse_stmt(line, table)
@@ -118,7 +119,8 @@ fn test_parse_expr() {
 	'-a;',
 	]
 	mut e := []ast.Stmt
-	table := &table.Table{}
+	table := table.new_table()
+	mut checker := checker.new_checker(table)
 	for s in input {
 		// println('\n\nst="$s"')
 		e << parse_stmt(s, table)
@@ -126,6 +128,7 @@ fn test_parse_expr() {
 	program := ast.File{
 		stmts: e
 	}
+	checker.check(program)
 	res := gen.cgen([program], table)
 	println('========')
 	println(res)
diff --git a/vlib/v/table/table.v b/vlib/v/table/table.v
index e5e7ff8c20..c9a44e5b2c 100644
--- a/vlib/v/table/table.v
+++ b/vlib/v/table/table.v
@@ -1,30 +1,21 @@
 module table
 
 import (
-	v.types
 	v.ast
+	v.types
 )
 
 pub struct Table {
 	// struct_fields map[string][]string
 pub mut:
-	types         []types.Type
+	types         []Type
 	// type_idxs Hashmap
 	type_idxs     map[string]int
 	local_vars    []Var
 	// fns Hashmap
 	fns           map[string]Fn
-	methods       [][]Fn
-	//
-	unknown_calls []ast.CallExpr
 	tmp_cnt       int
-}
-
-pub struct Var {
-pub:
-	name   string
-	ti     types.TypeIdent
-	is_mut bool
+	imports       []string
 }
 
 pub struct Fn {
@@ -34,6 +25,29 @@ pub:
 	return_ti types.TypeIdent
 }
 
+pub struct Var {
+pub:
+	name   string
+	is_mut bool
+	expr   ast.Expr
+mut:
+	ti     types.TypeIdent
+}
+
+pub struct Type {
+pub:
+	parent_idx int
+mut:
+	info    types.TypeInfo
+	kind    types.Kind
+	name    string
+	methods []Fn
+}
+
+pub fn (t Type) str() string {
+	return t.name
+}
+
 pub fn new_table() &Table {
 	mut t := &Table{}
 	t.register_builtin_types()
@@ -41,55 +55,56 @@ pub fn new_table() &Table {
 }
 
 pub fn (t mut Table) register_builtin_types() {
-	// add dummy type at 0 so nothing can go there
+	// reserve index 0 so nothing can go there
 	// save index check, 0 will mean not found
-	t.register_type(types.Type{}, 'dymmy_type_at_idx_0', 0)
-	t.register_type(types.Primitive{
-		idx: types.void_type_idx
-		kind: .void
-	}, 'void', types.void_type_idx)
-	t.register_type(types.Primitive{
-		idx: types.voidptr_type_idx
-		kind: .voidptr
-	}, 'voidptr', types.voidptr_type_idx)
-	t.register_type(types.Primitive{
-		idx: types.charptr_type_idx
-		kind: .charptr
-	}, 'charptr', types.charptr_type_idx)
-	t.register_type(types.Primitive{
-		idx: types.byteptr_type_idx
-		kind: .byteptr
-	}, 'byteptr', types.byteptr_type_idx)
-	t.register_type(types.Int{
-		types.i8_type_idx,8,false}, 'i8', types.i8_type_idx)
-	t.register_type(types.Int{
-		types.i16_type_idx,16,false}, 'i16', types.i16_type_idx)
-	t.register_type(types.Int{
-		types.i64_type_idx,32,false}, 'int', types.int_type_idx)
-	t.register_type(types.Int{
-		types.i64_type_idx,64,false}, 'i64', types.i64_type_idx)
-	t.register_type(types.Int{
-		types.u16_type_idx,16,true}, 'u16', types.u16_type_idx)
-	t.register_type(types.Int{
-		types.u32_type_idx,32,true}, 'u32', types.u32_type_idx)
-	t.register_type(types.Int{
-		types.u64_type_idx,64,true}, 'u64', types.u64_type_idx)
-	t.register_type(types.Float{
-		types.f64_type_idx,32}, 'f32', types.f32_type_idx)
-	t.register_type(types.Float{
-		types.f64_type_idx,64}, 'f64', types.f64_type_idx)
-	t.register_type(types.String{
-		types.string_type_idx}, 'string', types.string_type_idx)
-	t.register_type(types.Primitive{
-		idx: types.char_type_idx
-		kind: .char
-	}, 'char', types.char_type_idx)
-	t.register_type(types.Primitive{
-		idx: types.byte_type_idx
-		kind: .byte
-	}, 'byte', types.byte_type_idx)
-	t.register_type(types.Bool{
-		types.bool_type_idx}, 'bool', types.bool_type_idx)
+	t.register_type(Type{kind: .placeholder, name: 'reserved_0'})
+	t.register_type(Type{kind: .void, name: 'void'})
+	t.register_type(Type{kind: .voidptr, name: 'voidptr'})
+	t.register_type(Type{kind: .charptr, name: 'charptr'})
+	t.register_type(Type{kind: .byteptr, name: 'byteptr'})
+	t.register_type(Type{kind: .i8, name: 'i8'})
+	t.register_type(Type{kind: .i16, name: 'i16'})
+	t.register_type(Type{kind: .int, name: 'int'})
+	t.register_type(Type{kind: .i64, name: 'i64'})
+	t.register_type(Type{kind: .u16, name: 'u16'})
+	t.register_type(Type{kind: .u32, name: 'u32'})
+	t.register_type(Type{kind: .u64, name: 'u64'})
+	t.register_type(Type{kind: .f32, name: 'f32'})
+	t.register_type(Type{kind: .f64, name: 'f64'})
+	t.register_type(Type{kind: .string, name: 'string'})
+	t.register_type(Type{kind: .char, name: 'char'})
+	t.register_type(Type{kind: .byte, name: 'byte'})
+	t.register_type(Type{kind: .bool, name: 'bool'})
+}
+
+pub fn (t &Table) refresh_ti(ti types.TypeIdent) types.TypeIdent {
+	if ti.idx == 0 {
+		return ti
+	}
+	if ti.kind in [.placeholder, .unresolved] {
+		typ := t.types[ti.idx]
+		return { ti| 
+			kind: typ.kind,
+			name: typ.name
+		}
+	}
+	return ti
+}
+
+pub fn (t &Table) get_type(idx int) Type {
+	if idx == 0 {
+		panic('get_type: idx 0')
+	}
+	return t.types[idx]
+}
+
+pub fn (t &Table) find_var_idx(name string) int {
+	for i,var in t.local_vars {
+		if var.name == name {
+			return i
+		}
+	}
+	return -1
 }
 
 pub fn (t &Table) find_var(name string) ?Var {
@@ -122,6 +137,7 @@ pub fn (t mut Table) clear_vars() {
 }
 
 pub fn (t mut Table) register_var(v Var) {
+	println('register_var: $v.name - $v.ti.name')
 	t.local_vars << v
 	/*
 	mut new_var := {
@@ -159,68 +175,66 @@ pub fn (t mut Table) register_fn(new_fn Fn) {
 	t.fns[new_fn.name] = new_fn
 }
 
-pub fn (t mut Table) register_method(ti types.TypeIdent, new_fn Fn) bool {
-	println('register method `$new_fn.name` tiname=$ti.name ')
-	/*
-	match t.types[ti.idx] {
-		types.Struct {
-			println('got struct')
-		}
-		else {
-			return false
-		}
-	}
-	mut struc := t.types[ti.idx] as types.Struct
-	if struc.methods.len == 0 {
-		struc.methods = make(0, 0, sizeof(types.Field))
-	}
-	println('register method `$new_fn.name` struct=$struc.name ')
-	struc.methods << types.Field{
-		name: new_fn.name
-	}
-	t.types[ti.idx] = struc
-	*/
-
-	println('register method `$new_fn.name` struct=$ti.name ')
-	println('##### $ti.idx - $t.methods.len')
-	t.methods[ti.idx] << new_fn
+pub fn (t mut Table) register_method(ti &types.TypeIdent, new_fn Fn) bool {
+	idx := ti.idx
+	println('register method `$new_fn.name` type=$ti.name idx=$ti.idx')
+	mut methods := t.types[idx].methods
+	methods << new_fn
+	t.types[idx].methods = methods
 	return true
 }
 
+pub fn (t &Table) has_method(type_idx int, name string) bool {
+	t.find_method(type_idx, name) or {
+		return false
+	}
+	return true
+}
+
+pub fn (t &Table) find_method(type_idx int, name string) ?Fn {
+	for method in t.types[type_idx].methods {
+		if method.name == name {
+			return method
+		}
+	}
+	return none
+}
+
 pub fn (t mut Table) new_tmp_var() string {
 	t.tmp_cnt++
 	return 'tmp$t.tmp_cnt'
 }
 
-pub fn (t &Table) struct_has_field(s &types.Struct, name string) bool {
-	println('struct_has_field($s.name, $name) s.idx=$s.idx types.len=$t.types.len s.parent_idx=$s.parent_idx')
+pub fn (t &Table) struct_has_field(s &Type, name string) bool {
+	println('struct_has_field($s.name, $name) types.len=$t.types.len s.parent_idx=$s.parent_idx')
 	// for typ in t.types {
 	// println('$typ.idx $typ.name')
 	// }
-	for field in s.fields {
-		if field.name == name {
-			return true
-		}
-	}
-	if s.parent_idx != 0 {
-		parent := t.types[s.parent_idx] as types.Struct
-		println('got parent $parent.name')
-		for field in parent.fields {
-			if field.name == name {
-				return true
-			}
-		}
+	if _ := t.struct_find_field(s, name) {
+		return true
 	}
 	return false
 }
 
-pub fn (t &Table) struct_has_method(s &types.Struct, name string) bool {
-	for field in t.methods[s.idx] {
+pub fn (t &Table) struct_find_field(s &Type, name string) ?types.Field {
+	println('struct_find_field($s.name, $name) types.len=$t.types.len s.parent_idx=$s.parent_idx')
+	info := s.info as types.Struct
+	for field in info.fields {
 		if field.name == name {
-			return true
+			return field
 		}
 	}
-	return false
+	if s.parent_idx != 0 {
+		parent := t.types[s.parent_idx]
+		parent_info := s.info as types.Struct
+		println('got parent $parent.name')
+		for field in parent_info.fields {
+			if field.name == name {
+				return field
+			}
+		}
+	}
+	return none
 }
 
 [inline]
@@ -229,7 +243,7 @@ pub fn (t &Table) find_type_idx(name string) int {
 }
 
 [inline]
-pub fn (t &Table) find_type(name string) ?types.Type {
+pub fn (t &Table) find_type(name string) ?Type {
 	idx := t.type_idxs[name]
 	if idx > 0 {
 		return t.types[idx]
@@ -238,52 +252,30 @@ pub fn (t &Table) find_type(name string) ?types.Type {
 }
 
 [inline]
-pub fn (t mut Table) register_type(typ types.Type, name string, idx int) {
-	// sanity check
-	if idx != t.types.len {
-		panic('error registering type $name, type.idx must = table.types.len (got `$idx` expected `$t.types.len`')
-	}
-	t.type_idxs[name] = idx
-	t.types << typ
-	e := []Fn
-	t.methods << e // TODO [] breaks V
-}
-
-pub fn (t mut Table) register_struct(typ types.Struct) int {
-	println('register_struct($typ.name)')
-	// existing
+pub fn (t mut Table) register_type(typ Type) int {
 	existing_idx := t.type_idxs[typ.name]
 	if existing_idx > 0 {
 		ex_type := t.types[existing_idx]
-		match ex_type {
-			types.Placeholder {
+		match ex_type.kind {
+			.placeholder {
 				// override placeholder
-				println('overriding type placeholder `$it.name` with struct')
-				mut struct_type := types.Type{}
-				struct_type = {
-					typ |
-					idx:existing_idx
+				println('overriding type placeholder `$typ.name`')
+				t.types[existing_idx] = {typ|
+					methods: ex_type.methods
 				}
-				t.types[existing_idx] = struct_type
-				return existing_idx
-			}
-			types.Struct {
 				return existing_idx
 			}
 			else {
+				if ex_type.kind == typ.kind {
+					return existing_idx
+				}
 				panic('cannot register type `$typ.name`, another type with this name exists')
 			}
+		}
 	}
-	}
-	// register
-	println('registering: $typ.name')
 	idx := t.types.len
-	struct_type := {
-		typ |
-		idx:idx,
-		parent_idx:0,
-	}
-	t.register_type(struct_type, typ.name, idx)
+	t.types << typ
+	t.type_idxs[typ.name] = idx
 	return idx
 }
 
@@ -295,13 +287,15 @@ pub fn (t mut Table) find_or_register_map(key_ti &types.TypeIdent, value_ti &typ
 		return existing_idx,name
 	}
 	// register
-	idx := t.types.len
-	map_type := types.Map{
+	map_type := Type{
+		kind: .map
 		name: name
-		key_type_idx: key_ti.idx
-		value_type_idx: value_ti.idx
+		info: types.Map{
+			key_type_idx: key_ti.idx
+			value_type_idx: value_ti.idx
+		}
 	}
-	t.register_type(map_type, name, idx)
+	idx := t.register_type(map_type)
 	return idx,name
 }
 
@@ -314,16 +308,17 @@ pub fn (t mut Table) find_or_register_array(elem_ti &types.TypeIdent, nr_dims in
 	}
 	// register
 	parent_idx := t.type_idxs['array']
-	idx := t.types.len
-	array_type := types.Array{
-		idx: idx
+	array_type := Type{
 		parent_idx: parent_idx
+		kind: .array
 		name: name
-		elem_type_idx: elem_ti.idx
-		elem_is_ptr: elem_ti.is_ptr()
-		nr_dims: nr_dims
+		info: types.Array{
+			elem_type_idx: elem_ti.idx
+			elem_is_ptr: elem_ti.is_ptr()
+			nr_dims: nr_dims
+		}
 	}
-	t.register_type(array_type, name, idx)
+	idx := t.register_type(array_type)
 	return idx,name
 }
 
@@ -335,16 +330,17 @@ pub fn (t mut Table) find_or_register_array_fixed(elem_ti &types.TypeIdent, size
 		return existing_idx,name
 	}
 	// register
-	idx := t.types.len
-	array_fixed_type := types.ArrayFixed{
-		idx: idx
+	array_fixed_type := Type{
+		kind: .array_fixed
 		name: name
-		elem_type_idx: elem_ti.idx
-		elem_is_ptr: elem_ti.is_ptr()
-		size: size
-		nr_dims: nr_dims
+		info: types.ArrayFixed{
+			elem_type_idx: elem_ti.idx
+			elem_is_ptr: elem_ti.is_ptr()
+			size: size
+			nr_dims: nr_dims
+		}
 	}
-	t.register_type(array_fixed_type, name, idx)
+	idx := t.register_type(array_fixed_type)
 	return idx,name
 }
 
@@ -359,13 +355,14 @@ pub fn (t mut Table) find_or_register_multi_return(mr_tis []types.TypeIdent) (in
 		return existing_idx,name
 	}
 	// register
-	idx := t.types.len
-	mr_type := types.MultiReturn{
-		idx: idx
+	mr_type := Type{
+		kind: .multi_return
 		name: name
-		tis: mr_tis
+		info: types.MultiReturn{
+			tis: mr_tis
+		}
 	}
-	t.register_type(mr_type, name, idx)
+	idx := t.register_type(mr_type)
 	return idx,name
 }
 
@@ -377,22 +374,121 @@ pub fn (t mut Table) find_or_register_variadic(variadic_ti &types.TypeIdent) (in
 		return existing_idx,name
 	}
 	// register
-	idx := t.types.len
-	variadic_type := types.Variadic{
-		idx: idx
-		ti: variadic_ti
+	variadic_type := Type{
+		kind: .variadic
+		name: name
+		info: types.Variadic{
+			ti: variadic_ti
+		}
 	}
-	t.register_type(variadic_type, name, idx)
+	idx := t.register_type(variadic_type)
 	return idx,name
 }
 
 pub fn (t mut Table) add_placeholder_type(name string) int {
-	idx := t.types.len
-	ph_type := types.Placeholder{
-		idx: idx
+	ph_type := Type{
+		kind: .placeholder
 		name: name
 	}
-	println('added placeholder: $name - $idx ')
-	t.register_type(ph_type, name, idx)
+	idx := t.register_type(ph_type)
+	println('added placeholder: $name - $idx')
 	return idx
 }
+
+// [inline]
+// pub fn (t &Table) update_ti(ti &types.TypeIdent) types.TypeIdent {
+// 	if ti.kind == .unresolved {
+		
+// 	}
+// }
+
+pub fn (t &Table) check(got, expected &types.TypeIdent) bool {
+	println('check: $got.name, $expected.name')
+	if expected.kind == .voidptr {
+		return true
+	}
+	//if expected.name == 'array' {
+	//	return true
+	//}
+	if got.idx != expected.idx {
+		return false
+	}
+	return true
+}
+
+[inline]
+pub fn (t &Table) get_expr_ti(expr ast.Expr) types.TypeIdent {
+	match expr {
+		ast.ArrayInit{
+			return it.ti
+		}
+		ast.IndexExpr{
+			return t.get_expr_ti(it.left)
+		}
+		ast.CallExpr {
+			func := t.find_fn(it.name) or {
+				return types.void_ti
+			}
+			return func.return_ti
+		}
+		ast.MethodCallExpr {
+			ti := t.get_expr_ti(it.expr)
+			func := t.find_method(ti.idx, it.name) or {
+				return types.void_ti
+			}
+			return func.return_ti
+		}
+		ast.Ident {
+			if it.kind == .variable {
+				info := it.info as ast.IdentVar
+				if info.ti.kind != .unresolved {
+					return info.ti
+				}
+				return t.get_expr_ti(info.expr)
+			}
+			return types.void_ti
+		}
+		ast.StructInit {
+			return it.ti
+		}
+		ast.StringLiteral {
+			return types.string_ti
+		}
+		ast.IntegerLiteral {
+			return types.int_ti
+		}
+		ast.SelectorExpr {
+			ti := t.get_expr_ti(it.expr)
+			kind := t.types[ti.idx].kind
+			if ti.kind == .placeholder {
+				println(' ##### PH $ti.name')
+			}
+			if !(kind in [.placeholder, .struct_]) {
+				return types.void_ti
+			}
+			struct_ := t.types[ti.idx]
+			struct_info := struct_.info as types.Struct
+			for field in struct_info.fields {
+				if field.name == it.field {
+					return field.ti
+				}
+			}
+			if struct_.parent_idx != 0 {
+				parent := t.types[struct_.parent_idx]
+				parent_info := parent.info as types.Struct
+				for field in parent_info.fields {
+					if field.name == it.field {
+						return field.ti
+					}
+				}
+			}
+			return types.void_ti
+		}
+		ast.BinaryExpr {
+			return t.get_expr_ti(it.left)
+		}
+		else {
+			return types.void_ti
+		}
+	}
+}
diff --git a/vlib/v/token/position.v b/vlib/v/token/position.v
new file mode 100644
index 0000000000..39e8abb4c2
--- /dev/null
+++ b/vlib/v/token/position.v
@@ -0,0 +1,18 @@
+// 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 token
+
+pub struct Position {
+pub:
+	line_nr int // the line number in the source where the token occured
+	// pos      int // the position of the token in scanner text
+}
+
+[inline]
+pub fn (tok &Token) position() Position {
+	return Position{
+		line_nr: tok.line_nr
+		// pos: tok.pos
+	}
+}
diff --git a/vlib/v/types/types.v b/vlib/v/types/types.v
index 894acaf79c..57a186f5aa 100644
--- a/vlib/v/types/types.v
+++ b/vlib/v/types/types.v
@@ -29,14 +29,10 @@ pub enum Kind {
 	voidptr
 	charptr
 	byteptr
-	const_
-	enum_
-	struct_
-	int
 	i8
 	i16
+	int
 	i64
-	byte
 	u16
 	u32
 	u64
@@ -44,20 +40,25 @@ pub enum Kind {
 	f64
 	string
 	char
+	byte
 	bool
+	const_
+	enum_
+	struct_
 	array
 	array_fixed
 	map
 	multi_return
 	variadic
+	unresolved	
 }
 
-pub type Type = Placeholder | Primitive | Const | Enum | Struct | Int | Float | 	
-String | Bool | Array | ArrayFixed | Map | MultiReturn | Variadic
+pub type TypeInfo = Array | ArrayFixed | Map | Struct | MultiReturn | Variadic
 
 pub struct TypeIdent {
 pub:
 	idx     int
+mut:
 	kind    Kind
 	name    string
 	nr_muls int
@@ -73,17 +74,18 @@ pub fn new_ti(kind Kind, name string, idx int, nr_muls int) TypeIdent {
 	}
 }
 
-[inline]
-pub fn new_builtin_ti(kind Kind, nr_muls int) TypeIdent {
-	return TypeIdent{
-		idx: -int(kind) - 1
-		kind: kind
-		name: kind.str()
-		nr_muls: nr_muls
-	}
-}
+// [inline]
+// pub fn new_builtin_ti(kind Kind, nr_muls int) TypeIdent {
+// 	return TypeIdent{
+// 		idx: -int(kind) - 1
+// 		kind: kind
+// 		name: kind.str()
+// 		nr_muls: nr_muls
+// 	}
+// }
 
 pub const (
+	unresolved_ti = new_ti(.unresolved, 'unresolved', 0, 0)
 	void_ti = new_ti(.void, 'void', void_type_idx, 0)
 	int_ti = new_ti(.int, 'int', int_type_idx, 0)
 	string_ti = new_ti(.string, 'string', string_type_idx, 0)
@@ -115,24 +117,15 @@ pub fn (ti &TypeIdent) str() string {
 	for _ in 0 .. ti.nr_muls {
 		muls += '&'
 	}
-	return '$muls$ti.name'
-}
-
-pub fn check(got, expected &TypeIdent) bool {
-	if expected.kind == .voidptr {
-		return true
-	}
-	if expected.name == 'array' {
-		return true
-	}
-	if got.idx != expected.idx {
-		return false
-	}
-	return true
+	// return '$muls$ti.name'
+	return '$muls$ti.idx'
 }
 
 pub fn (k Kind) str() string {
 	k_str := match k {
+		.unresolved{
+			'unresolved'
+		}
 		.placeholder{
 			'placeholder'
 		}
@@ -148,12 +141,12 @@ pub fn (k Kind) str() string {
 		.byteptr{
 			'byteptr'
 		}
-		.const_{
-			'const'
-		}
-		.enum_{
-			'enum'
-		}
+		// .const_{
+		// 	'const'
+		// }
+		// .enum_{
+		// 	'enum'
+		// }
 		.struct_{
 			'struct'
 		}
@@ -222,75 +215,42 @@ pub fn (kinds []Kind) str() string {
 	return kinds_str
 }
 
-pub struct Placeholder {
-pub:
-	idx  int
-	name string
-	// kind Kind
-}
-// Void | Voidptr | Charptr | Byteptr
-pub struct Primitive {
-pub:
-	idx  int
-	kind Kind
-}
+// pub struct Const {
+// pub:
+// 	name string
+// }
 
-pub struct Const {
-pub:
-	idx  int
-	name string
-}
-
-pub struct Enum {
-pub:
-	idx  int
-	name string
-}
+// pub struct Enum {
+// pub:
+// 	name string
+// }
 
 pub struct Struct {
-pub:
-	idx        int
-	parent_idx int
-	name       string
 pub mut:
 	fields     []Field
-	methods    []Field // TODO Method
 }
 
 pub struct Field {
 pub:
 	name     string
-	type_idx int
+	ti       TypeIdent
+	// type_idx int
 }
 
-pub struct Int {
-pub:
-	idx         int
-	bit_size    u32
-	is_unsigned bool
-}
+// pub struct Int {
+// pub:
+// 	bit_size    u32
+// 	is_unsigned bool
+// }
 
-pub struct Float {
-pub:
-	idx      int
-	bit_size u32
-}
+// pub struct Float {
+// pub:
+// 	bit_size u32
+// }
 
-pub struct String {
-pub:
-	idx int
-}
-
-pub struct Bool {
-pub:
-	idx int
-}
 
 pub struct Array {
 pub:
-	idx            int
-	parent_idx     int
-	name           string
 	elem_type_kind Kind
 	elem_type_idx  int
 	elem_is_ptr    bool
@@ -299,9 +259,6 @@ pub:
 
 pub struct ArrayFixed {
 pub:
-	idx            int
-	parent_idx     int
-	name           string
 	elem_type_kind Kind
 	elem_type_idx  int
 	elem_is_ptr    bool
@@ -311,8 +268,6 @@ pub:
 
 pub struct Map {
 pub:
-	idx             int
-	name            string
 	key_type_kind   Kind
 	key_type_idx    int
 	value_type_kind Kind
@@ -321,89 +276,11 @@ pub:
 
 pub struct MultiReturn {
 pub:
-	idx  int
 	name string
 	tis  []TypeIdent
 }
 
 pub struct Variadic {
 pub:
-	idx int
 	ti  TypeIdent
 }
-
-pub fn (t Primitive) str() string {
-	s := match t.kind {
-		.void{
-			'void'
-		}
-		.voidptr{
-			'voidptr'
-		}
-		.charptr{
-			'charptr'
-		}
-		.byteptr{
-			'byteptr'
-		}
-		.char{
-			'char'
-		}
-		.byte{
-			'byte'
-		}
-		else {
-			'unknown'}
-	}
-	return s
-}
-
-pub fn (t Const) str() string {
-	return t.name
-}
-
-pub fn (t Enum) str() string {
-	return t.name
-}
-
-pub fn (t Struct) str() string {
-	return t.name
-}
-
-pub fn (t Int) str() string {
-	return if t.is_unsigned { 'u$t.bit_size' } else { 'i$t.bit_size' }
-}
-
-pub fn (t Float) str() string {
-	return 'f$t.bit_size'
-}
-
-pub fn (t String) str() string {
-	return 'string'
-}
-
-pub fn (t Array) str() string {
-	return t.name
-}
-
-pub fn (t ArrayFixed) str() string {
-	return t.name
-}
-
-pub fn (t Map) str() string {
-	return t.name
-}
-
-pub fn (t MultiReturn) str() string {
-	return t.name
-}
-
-pub fn (t Variadic) str() string {
-	return 'variadic_$t.ti.kind.str()'
-}
-
-/*
-pub fn (s &Struct) has_field(name string) bool {
-
-}
-*/