diff --git a/vlib/v/tests/if_smartcast_test.v b/vlib/v/tests/if_smartcast_test.v
index 625133fa7e..d9dd4625f7 100644
--- a/vlib/v/tests/if_smartcast_test.v
+++ b/vlib/v/tests/if_smartcast_test.v
@@ -38,6 +38,51 @@ fn test_nested_if_smartcast() {
 	}
 }
 
+type Bar = string | Test
+type Xya = int | string
+
+struct Test {
+	x string
+	xya Xya
+}
+
+struct BarWrapper {
+	y Bar
+}
+
+fn test_nested_selector_smartcast() {
+	f := BarWrapper{
+		y: Bar(Test{
+			x: 'Hi'
+			xya: Xya(int(5))
+		})
+	}
+
+	if f.y is Test {
+		z := f.y.x
+		assert f.y.x == 'Hi'
+		assert z == 'Hi'
+		if f.y.xya is int {
+			assert f.y.xya == 5
+		}
+	}
+}
+
+type Inner = int | string
+struct InnerStruct {
+	x Inner
+}
+type Outer = string | InnerStruct
+
+fn test_nested_if_is() {
+	b := Outer(InnerStruct{Inner(0)})
+	if b is InnerStruct {
+		if b.x is int {
+			assert b.x == 0
+		}
+	}
+}
+
 struct MutContainer {
 mut:
 	abc Alphabet
@@ -122,3 +167,89 @@ fn test_mutability() {
 		println('$cell.u')
 	}
 }
+
+type Expr = CallExpr | CTempVarExpr
+struct ExprWrapper {
+mut:
+	expr Expr
+}
+struct CallExpr {
+	y int
+	x string
+}
+
+struct CTempVarExpr {
+	x string
+}
+
+fn gen(_ Expr) CTempVarExpr {
+	return CTempVarExpr{}
+}
+
+fn test_reassign_from_function_with_parameter_selector() {
+	mut f := ExprWrapper{Expr(CallExpr{})}
+	if f.expr is CallExpr {
+		f.expr = gen(f.expr)
+	}
+}
+
+type Node = Expr | string
+
+fn test_nested_sumtype() {
+	c := Node(Expr(CallExpr{y: 1}))
+	if c is Expr {
+		if c is CallExpr {
+			assert c.y == 1
+		}
+		else {
+			assert false
+		}
+	}
+	else {
+		assert false
+	}
+}
+
+type Food = Milk | Eggs
+
+struct FoodWrapper {
+mut:
+	food Food
+}
+
+struct Milk {
+mut:
+	name string
+}
+
+struct Eggs {
+mut:
+	name string
+}
+
+fn test_if_mut_selector() {
+	mut f := FoodWrapper{Food(Milk{'test'})}
+	if mut f.food is Milk {
+		f.food.name = 'milk'
+		assert f.food.name == 'milk'
+	}
+}
+
+struct NodeWrapper {
+	node Node
+}
+
+fn test_nested_sumtype_selector() {
+	c := NodeWrapper{Node(Expr(CallExpr{y: 1}))}
+	if c.node is Expr {
+		if c.node is CallExpr {
+			assert c.node.y == 1
+		}
+		else {
+			assert false
+		}
+	}
+	else {
+		assert false
+	}
+}
diff --git a/vlib/v/tests/match_smartcast_test.v b/vlib/v/tests/match_smartcast_test.v
new file mode 100644
index 0000000000..a5194b9c54
--- /dev/null
+++ b/vlib/v/tests/match_smartcast_test.v
@@ -0,0 +1,94 @@
+type Node = Expr | string
+type Expr = IfExpr | IntegerLiteral
+
+struct IntegerLiteral {}
+struct IfExpr {
+	pos int
+}
+
+struct NodeWrapper {
+	node Node
+}
+
+fn test_nested_sumtype_match_selector() {
+	c := NodeWrapper{Node(Expr(IfExpr{pos: 1}))}
+	match c.node {
+		Expr {
+			match c.node {
+				IfExpr {
+					assert c.node.pos == 1
+				}
+				else {
+					assert false
+				}
+			}
+		}
+		else {
+			assert false
+		}
+	}
+}
+
+fn test_nested_sumtype_match() {
+	c := Node(Expr(IfExpr{pos: 1}))
+	match c {
+		Expr {
+			match c {
+				IfExpr {
+					assert c.pos == 1
+				}
+				else {
+					assert false
+				}
+			}
+		}
+		else {
+			assert false
+		}
+	}
+}
+
+struct Milk {
+mut:
+	name string
+}
+
+struct Eggs {
+mut:
+	name string
+}
+
+type Food = Milk | Eggs
+
+struct FoodWrapper {
+mut:
+	food Food
+}
+
+fn test_match_mut() {
+	mut f := Food(Milk{'test'})
+	match mut f {
+		Eggs {
+			f.name = 'eggs'
+			assert f.name == 'eggs'
+		}
+		Milk {
+			f.name = 'milk'
+			assert f.name == 'milk'
+		}
+	}
+}
+
+fn test_match_mut_selector() {
+	mut f := FoodWrapper{Food(Milk{'test'})}
+	match mut f.food {
+		Eggs {
+			f.food.name = 'eggs'
+			assert f.food.name == 'eggs'
+		}
+		Milk {
+			f.food.name = 'milk'
+			assert f.food.name == 'milk'
+		}
+	}
+}
diff --git a/vlib/v/tests/sum_type_test.v b/vlib/v/tests/sum_type_test.v
index 8316ec1ea9..96b98683b6 100644
--- a/vlib/v/tests/sum_type_test.v
+++ b/vlib/v/tests/sum_type_test.v
@@ -10,7 +10,6 @@ struct StructDecl {
 	pos int
 }
 
-
 struct IfExpr {
 	pos int
 }
@@ -19,49 +18,24 @@ struct IntegerLiteral {
 	val string
 }
 
-fn handle(e Expr) string {
-	is_literal := e is IntegerLiteral
-	assert is_literal
-	assert !(e !is IntegerLiteral)
-	if e is IntegerLiteral {
-		println('int')
-	}
-	match e {
-		IntegerLiteral {
-			assert e.val == '12'
-			return 'int'
-		}
-		IfExpr {
-			return 'if'
-		}
-	}
-	return ''
-}
-
-fn test_expr() {
-	expr := IntegerLiteral{
-		val: '12'
-	}
-	assert handle(expr) == 'int'
-	// assert expr is IntegerLiteral // TODO
-}
-
-fn test_assignment_and_push() {
-	mut expr1 := Expr{}
-	mut arr1 := []Expr{}
-	expr := IntegerLiteral{
-		val: '111'
-	}
-	arr1 << expr
-	match arr1[0] {
-		IntegerLiteral {
-			arr1 << arr1[0]
-			// should ref/dereference on assignent be made automatic?
-			// currently it is done for return stmt and fn args
-			expr1 = arr1[0]
-		}
-		else {}
-	}
+fn test_sum_type_match() {
+	// TODO: Remove these casts
+	assert is_gt_simple('3', int(2))
+	assert !is_gt_simple('3', int(5))
+	assert is_gt_simple('3', f64(1.2))
+	assert !is_gt_simple('3', f64(3.5))
+	assert is_gt_nested('3', int(2))
+	assert !is_gt_nested('3', int(5))
+	assert is_gt_nested('3', f64(1.2))
+	assert !is_gt_nested('3', f64(3.5))
+	assert concat('3', int(2)) == '3(int)2'
+	assert concat('3', int(5)) == '3(int)5'
+	assert concat('3', f64(1.2)) == '3(float)1.2'
+	assert concat('3', f64(3.5)) == '3(float)3.5'
+	assert get_sum('3', int(2)) == 5.0
+	assert get_sum('3', int(5)) == 8.0
+	assert get_sum('3', f64(1.2)) == 4.2
+	assert get_sum('3', f64(3.5)) == 6.5
 }
 
 // Test moving structs between master/sub arrays
@@ -105,18 +79,121 @@ fn test_converting_down() {
 	assert res[1].name == 'three'
 }
 
-fn test_nested_sumtype() {
-	c := Node(Expr(IfExpr{pos:1}))
-	if c is Expr {
-		if c is IfExpr {
-			assert true
+
+fn test_assignment_and_push() {
+	mut expr1 := Expr{}
+	mut arr1 := []Expr{}
+	expr := IntegerLiteral{
+		val: '111'
+	}
+	arr1 << expr
+	match arr1[0] {
+		IntegerLiteral {
+			arr1 << arr1[0]
+			expr1 = arr1[0]
 		}
-		else {
-			assert false
+		else {}
+	}
+}
+
+fn test_expr() {
+	expr := IntegerLiteral{
+		val: '12'
+	}
+	assert handle(expr) == 'int'
+	// assert expr is IntegerLiteral // TODO
+}
+
+struct Outer2 {
+	e Expr
+}
+
+fn test_zero_value_init() {
+	// no c compiler error then it's successful
+	_ := Outer2{}
+}
+
+type Bar = string | Test
+type Xyz = int | string
+
+struct Test {
+	x string
+	xyz Xyz
+}
+
+fn test_assignment() {
+	y := 5
+	mut x := Xyz(y)
+	x = 'test'
+
+	if x is string {
+		x2 := x as string
+		assert x2 == 'test'
+	}
+}
+
+struct Foo {
+	y Bar
+}
+
+fn test_as_cast() {
+	f := Foo{
+		y: Bar('test')
+	}
+	y := f.y as string
+	assert y == 'test'
+}
+
+fn test_typeof() {
+    x := Expr(IfExpr{})
+	assert typeof(x) == 'IfExpr'
+}
+
+type Food = Milk | Eggs
+
+struct FoodWrapper {
+mut:
+	food Food
+}
+
+struct Milk {
+mut:
+	name string
+}
+
+struct Eggs {
+mut:
+	name string
+}
+
+fn test_match_aggregate() {
+	f := Food(Milk{'test'})
+	match f {
+		Milk, Eggs {
+			assert f.name == 'test'
 		}
 	}
-	else {
-		assert false
+}
+
+fn test_if() {
+	mut f := Food(Milk{'test'})
+	if f is Milk {
+		// only works without smartcast
+		assert f is Milk
+	}
+}
+
+fn test_match() {
+	mut f := Food(Milk{'test'})
+	match f {
+		Eggs {
+			// only works without smartcast
+			assert f is Eggs
+		}
+		Milk {
+			// only works without smartcast
+			assert f is Milk
+		}
 	}
 }
 
@@ -158,15 +235,15 @@ fn test_int_cast_to_sumtype() {
 	}
 }
 
-// TODO: change definition once types other than any_int and any_float (int, f64, etc) are supported in sumtype
-type Number = any_int | any_float
+// TODO: change definition once types other than int and f64 (int, f64, etc) are supported in sumtype
+type Number = int | f64
 
 fn is_gt_simple(val string, dst Number) bool {
 	match dst {
-		any_int {
+		int {
 			return val.int() > dst
 		}
-		any_float {
+		f64 {
 			return dst < val.f64()
 		}
 	}
@@ -175,9 +252,9 @@ fn is_gt_simple(val string, dst Number) bool {
 fn is_gt_nested(val string, dst Number) bool {
 	dst2 := dst
 	match dst {
-		any_int {
+		int {
 			match dst2 {
-				any_int {
+				int {
 					return val.int() > dst
 				}
 				// this branch should never been hit
@@ -186,9 +263,9 @@ fn is_gt_nested(val string, dst Number) bool {
 				}
 			}
 		}
-		any_float {
+		f64 {
 			match dst2 {
-				any_float {
+				f64 {
 					return dst < val.f64()
 				}
 				// this branch should never been hit
@@ -202,12 +279,12 @@ fn is_gt_nested(val string, dst Number) bool {
 
 fn concat(val string, dst Number) string {
 	match dst {
-		any_int {
+		int {
 			mut res := val + '(int)'
 			res += dst.str()
 			return res
 		}
-		any_float {
+		f64 {
 			mut res := val + '(float)'
 			res += dst.str()
 			return res
@@ -217,12 +294,12 @@ fn concat(val string, dst Number) string {
 
 fn get_sum(val string, dst Number) f64 {
 	match dst {
-		any_int {
+		int {
 			mut res := val.int()
 			res += dst
 			return res
 		}
-		any_float {
+		f64 {
 			mut res := val.f64()
 			res += dst
 			return res
@@ -230,21 +307,22 @@ fn get_sum(val string, dst Number) f64 {
 	}
 }
 
-fn test_sum_type_match() {
-	assert is_gt_simple('3', 2)
-	assert !is_gt_simple('3', 5)
-	assert is_gt_simple('3', 1.2)
-	assert !is_gt_simple('3', 3.5)
-	assert is_gt_nested('3', 2)
-	assert !is_gt_nested('3', 5)
-	assert is_gt_nested('3', 1.2)
-	assert !is_gt_nested('3', 3.5)
-	assert concat('3', 2) == '3(int)2'
-	assert concat('3', 5) == '3(int)5'
-	assert concat('3', 1.2) == '3(float)1.2'
-	assert concat('3', 3.5) == '3(float)3.5'
-	assert get_sum('3', 2) == 5.0
-	assert get_sum('3', 5) == 8.0
-	assert get_sum('3', 1.2) == 4.2
-	assert get_sum('3', 3.5) == 6.5
+fn handle(e Expr) string {
+	is_literal := e is IntegerLiteral
+	assert is_literal
+	assert !(e !is IntegerLiteral)
+	if e is IntegerLiteral {
+		assert typeof(e.val) == 'string'
+	}
+	match e {
+		IntegerLiteral {
+			assert e.val == '12'
+			// assert e.val == '12' // TODO
+			return 'int'
+		}
+		IfExpr {
+			return 'if'
+		}
+	}
+	return ''
 }
diff --git a/vlib/v/tests/union_sum_type_test.v b/vlib/v/tests/union_sum_type_test.v
deleted file mode 100644
index f331ecd1c0..0000000000
--- a/vlib/v/tests/union_sum_type_test.v
+++ /dev/null
@@ -1,511 +0,0 @@
-type Expr = IfExpr | IntegerLiteral
-type Stmt = FnDecl | StructDecl
-type Node = Expr | Stmt
-
-struct FnDecl {
-	pos int
-}
-
-struct StructDecl {
-	pos int
-}
-
-
-struct IfExpr {
-	pos int
-}
-
-struct IntegerLiteral {
-	val string
-}
-
-fn handle(e Expr) string {
-	is_literal := e is IntegerLiteral
-	assert is_literal
-	assert !(e !is IntegerLiteral)
-	if e is IntegerLiteral {
-		assert typeof(e.val) == 'string'
-	}
-	match e {
-		IntegerLiteral {
-			assert e.val == '12'
-			// assert e.val == '12' // TODO
-			return 'int'
-		}
-		IfExpr {
-			return 'if'
-		}
-	}
-	return ''
-}
-
-fn test_expr() {
-	expr := IntegerLiteral{
-		val: '12'
-	}
-	assert handle(expr) == 'int'
-	// assert expr is IntegerLiteral // TODO
-}
-
-fn test_assignment_and_push() {
-	mut expr1 := Expr{}
-	mut arr1 := []Expr{}
-	expr := IntegerLiteral{
-		val: '111'
-	}
-	arr1 << expr
-	match arr1[0] {
-		IntegerLiteral {
-			arr1 << arr1[0]
-			// should ref/dereference on assignent be made automatic?
-			// currently it is done for return stmt and fn args
-			expr1 = arr1[0]
-		}
-		else {}
-	}
-}
-
-// Test moving structs between master/sub arrays
-type Master = Sub1 | Sub2
-
-struct Sub1 {
-mut:
-	val  int
-	name string
-}
-
-struct Sub2 {
-	name string
-	val  int
-}
-
-fn test_converting_down() {
-	mut out := []Master{}
-	out << Sub1{
-		val: 1
-		name: 'one'
-	}
-	out << Sub2{
-		val: 2
-		name: 'two'
-	}
-	out << Sub2{
-		val: 3
-		name: 'three'
-	}
-	mut res := []Sub2{cap: out.len}
-	for d in out {
-		match d {
-			Sub2 { res << d }
-			else {}
-		}
-	}
-	assert res[0].val == 2
-	assert res[0].name == 'two'
-	assert res[1].val == 3
-	assert res[1].name == 'three'
-}
-
-struct NodeWrapper {
-	node Node
-}
-
-fn test_nested_sumtype_selector() {
-	c := NodeWrapper{Node(Expr(IfExpr{pos: 1}))}
-	if c.node is Expr {
-		if c.node is IfExpr {
-			assert c.node.pos == 1
-		}
-		else {
-			assert false
-		}
-	}
-	else {
-		assert false
-	}
-}
-
-fn test_nested_sumtype_match_selector() {
-	c := NodeWrapper{Node(Expr(IfExpr{pos: 1}))}
-	match c.node {
-		Expr {
-			match c.node {
-				IfExpr {
-					assert c.node.pos == 1
-				}
-				else {
-					assert false
-				}
-			}
-		}
-		else {
-			assert false
-		}
-	}
-}
-
-fn test_nested_sumtype() {
-	c := Node(Expr(IfExpr{pos:1}))
-	if c is Expr {
-		if c is IfExpr {
-			assert c.pos == 1
-		}
-		else {
-			assert false
-		}
-	}
-	else {
-		assert false
-	}
-}
-
-fn test_nested_sumtype_match() {
-	c := Node(Expr(IfExpr{pos: 1}))
-	match c {
-		Expr {
-			match c {
-				IfExpr {
-					assert c.pos == 1
-				}
-				else {
-					assert false
-				}
-			}
-		}
-		else {
-			assert false
-		}
-	}
-}
-
-type Abc = int | string
-
-fn test_string_cast_to_sumtype() {
-	a := Abc('test')
-	match a {
-		int {
-			assert false
-		}
-		string {
-			assert true
-		}
-	}
-}
-
-fn test_int_cast_to_sumtype() {
-	// literal
-	a := Abc(111)
-	match a {
-		int {
-			assert true
-		}
-		string {
-			assert false
-		}
-	}
-	// var
-	i := 111
-	b := Abc(i)
-	match b {
-		int {
-			assert true
-		}
-		string {
-			assert false
-		}
-	}
-}
-
-// TODO: change definition once types other than int and f64 (int, f64, etc) are supported in sumtype
-type Number = int | f64
-
-fn is_gt_simple(val string, dst Number) bool {
-	match dst {
-		int {
-			return val.int() > dst
-		}
-		f64 {
-			return dst < val.f64()
-		}
-	}
-}
-
-fn is_gt_nested(val string, dst Number) bool {
-	dst2 := dst
-	match dst {
-		int {
-			match dst2 {
-				int {
-					return val.int() > dst
-				}
-				// this branch should never been hit
-				else {
-					return val.int() < dst
-				}
-			}
-		}
-		f64 {
-			match dst2 {
-				f64 {
-					return dst < val.f64()
-				}
-				// this branch should never been hit
-				else {
-					return dst > val.f64()
-				}
-			}
-		}
-	}
-}
-
-fn concat(val string, dst Number) string {
-	match dst {
-		int {
-			mut res := val + '(int)'
-			res += dst.str()
-			return res
-		}
-		f64 {
-			mut res := val + '(float)'
-			res += dst.str()
-			return res
-		}
-	}
-}
-
-fn get_sum(val string, dst Number) f64 {
-	match dst {
-		int {
-			mut res := val.int()
-			res += dst
-			return res
-		}
-		f64 {
-			mut res := val.f64()
-			res += dst
-			return res
-		}
-	}
-}
-
-type Bar = string | Test
-type Xyz = int | string
-
-struct Test {
-	x string
-	xyz Xyz
-}
-
-struct Foo {
-	y Bar
-}
-
-fn test_nested_selector_smartcast() {
-	f := Foo{
-		y: Bar(Test{
-			x: 'Hi'
-			xyz: Xyz(5)
-		})
-	}
-
-	if f.y is Test {
-		z := f.y.x
-		assert f.y.x == 'Hi'
-		assert z == 'Hi'
-		if f.y.xyz is int {
-			assert f.y.xyz == 5
-		}
-	}
-}
-
-fn test_as_cast() {
-	f := Foo{
-		y: Bar('test')
-	}
-	y := f.y as string
-	assert y == 'test'
-}
-
-fn test_assignment() {
-	y := 5
-	mut x := Xyz(y)
-	x = 'test'
-
-	if x is string {
-		x2 := x as string
-		assert x2 == 'test'
-	}
-}
-
-type Inner = int | string
-struct InnerStruct {
-	x Inner
-}
-type Outer = string | InnerStruct
-
-fn test_nested_if_is() {
-	b := Outer(InnerStruct{Inner(0)})
-	if b is InnerStruct {
-		if b.x is int {
-			assert b.x == 0
-		}
-	}
-}
-
-type Expr3 = CallExpr | CTempVarExpr
-struct Expr3Wrapper {
-mut:
-	expr Expr3
-}
-struct CallExpr {
-	y int
-	x string
-}
-
-struct CTempVarExpr {
-	x string
-}
-
-fn gen(_ Expr3) CTempVarExpr {
-	return CTempVarExpr{}
-}
-
-fn test_reassign_from_function_with_parameter() {
-	mut f := Expr3(CallExpr{})
-	if f is CallExpr {
-		f = gen(f)
-	}
-}
-
-fn test_reassign_from_function_with_parameter_selector() {
-	mut f := Expr3Wrapper{Expr3(CallExpr{})}
-	if f.expr is CallExpr {
-		f.expr = gen(f.expr)
-	}
-}
-
-fn test_typeof() {
-    x := Expr3(CTempVarExpr{})
-	assert typeof(x) == 'CTempVarExpr'
-}
-
-struct Outer2 {
-	e Expr3
-}
-
-fn test_zero_value_init() {
-	// no c compiler error then it's successful
-	_ := Outer2{}
-}
-
-struct Milk {
-mut:
-	name string
-}
-
-struct Eggs {
-mut:
-	name string
-}
-
-type Food = Milk | Eggs
-
-struct FoodWrapper {
-mut:
-	food Food
-}
-
-fn test_match_aggregate() {
-	f := Food(Milk{'test'})
-	match f {
-		Milk, Eggs {
-			assert f.name == 'test'
-		}
-	}
-}
-
-fn test_match_mut() {
-	mut f := Food(Milk{'test'})
-	match mut f {
-		Eggs {
-			f.name = 'eggs'
-			assert f.name == 'eggs'
-		}
-		Milk {
-			f.name = 'milk'
-			assert f.name == 'milk'
-		}
-	}
-}
-
-fn test_match_not_mut() {
-	mut f := Food(Milk{'test'})
-	match f {
-		Eggs {
-			// only works without smartcast
-			assert f is Eggs
-		}
-		Milk {
-			// only works without smartcast
-			assert f is Milk
-		}
-	}
-}
-
-fn test_if_mut() {
-	mut f := Food(Milk{'test'})
-	if mut f is Milk {
-		f.name = 'milk'
-		assert f.name == 'milk'
-	}
-}
-
-fn test_if_not_mut() {
-	mut f := Food(Milk{'test'})
-	if f is Milk {
-		// only works without smartcast
-		assert f is Milk
-	}
-}
-
-fn test_match_mut_selector() {
-	mut f := FoodWrapper{Food(Milk{'test'})}
-	match mut f.food {
-		Eggs {
-			f.food.name = 'eggs'
-			assert f.food.name == 'eggs'
-		}
-		Milk {
-			f.food.name = 'milk'
-			assert f.food.name == 'milk'
-		}
-	}
-}
-
-fn test_if_mut_selector() {
-	mut f := FoodWrapper{Food(Milk{'test'})}
-	if mut f.food is Milk {
-		f.food.name = 'milk'
-		assert f.food.name == 'milk'
-	}
-}
-
-fn test_sum_type_match() {
-	// TODO: Remove these casts
-	assert is_gt_simple('3', int(2))
-	assert !is_gt_simple('3', int(5))
-	assert is_gt_simple('3', f64(1.2))
-	assert !is_gt_simple('3', f64(3.5))
-	assert is_gt_nested('3', int(2))
-	assert !is_gt_nested('3', int(5))
-	assert is_gt_nested('3', f64(1.2))
-	assert !is_gt_nested('3', f64(3.5))
-	assert concat('3', int(2)) == '3(int)2'
-	assert concat('3', int(5)) == '3(int)5'
-	assert concat('3', f64(1.2)) == '3(float)1.2'
-	assert concat('3', f64(3.5)) == '3(float)3.5'
-	assert get_sum('3', int(2)) == 5.0
-	assert get_sum('3', int(5)) == 8.0
-	assert get_sum('3', f64(1.2)) == 4.2
-	assert get_sum('3', f64(3.5)) == 6.5
-}