From bf904c2f823070ddda3adcf4b08a77eef29c6635 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kr=C3=BCger?=
 <45282134+UweKrueger@users.noreply.github.com>
Date: Mon, 4 Jan 2021 19:48:13 +0100
Subject: [PATCH] checker, cgen: allow using literals as `int` and `f64` for
 sum types (#7864)

---
 vlib/v/checker/check_types.v               |  2 +-
 vlib/v/checker/tests/is_type_not_exist.out |  7 --
 vlib/v/gen/cgen.v                          |  3 +-
 vlib/v/tests/sumtype_literal_test.v        | 84 ++++++++++++++++++++++
 4 files changed, 87 insertions(+), 9 deletions(-)
 create mode 100644 vlib/v/tests/sumtype_literal_test.v

diff --git a/vlib/v/checker/check_types.v b/vlib/v/checker/check_types.v
index c2653b38a2..7a1c06af51 100644
--- a/vlib/v/checker/check_types.v
+++ b/vlib/v/checker/check_types.v
@@ -123,7 +123,7 @@ pub fn (mut c Checker) check_basic(got table.Type, expected table.Type) bool {
 		return true
 	}
 	// sum type
-	if c.table.sumtype_has_variant(expected, got) {
+	if c.table.sumtype_has_variant(expected, c.table.mktyp(got)) {
 		return true
 	}
 	// fn type
diff --git a/vlib/v/checker/tests/is_type_not_exist.out b/vlib/v/checker/tests/is_type_not_exist.out
index 881050431a..1c52d7ac11 100644
--- a/vlib/v/checker/tests/is_type_not_exist.out
+++ b/vlib/v/checker/tests/is_type_not_exist.out
@@ -1,10 +1,3 @@
-vlib/v/checker/tests/is_type_not_exist.vv:4:25: error: cannot use `int literal` as `Integer` in argument 1 to `fn_with_sum_type_param`
-    2 | 
-    3 | fn main() {
-    4 |     fn_with_sum_type_param(1)
-      |                            ^
-    5 | }
-    6 |
 vlib/v/checker/tests/is_type_not_exist.vv:8:10: error: is: type `SomethingThatDontExist` does not exist
     6 | 
     7 | fn fn_with_sum_type_param(i Integer) {
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 83b49bf036..c980844e5e 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -1320,7 +1320,8 @@ fn (mut g Gen) for_in(it ast.ForInStmt) {
 }
 
 // use instead of expr() when you need to cast to union sum type (can add other casts also)
-fn (mut g Gen) expr_with_cast(expr ast.Expr, got_type table.Type, expected_type table.Type) {
+fn (mut g Gen) expr_with_cast(expr ast.Expr, got_type_raw table.Type, expected_type table.Type) {
+	got_type := g.table.mktyp(got_type_raw)
 	// cast to sum type
 	if expected_type != table.void_type {
 		expected_is_ptr := expected_type.is_ptr()
diff --git a/vlib/v/tests/sumtype_literal_test.v b/vlib/v/tests/sumtype_literal_test.v
new file mode 100644
index 0000000000..afcc9c29ce
--- /dev/null
+++ b/vlib/v/tests/sumtype_literal_test.v
@@ -0,0 +1,84 @@
+type Foo = f32 | f64 | i16 | int | u64
+
+fn test_assign_cast() {
+	a := Foo(3)
+	b := Foo(3.0)
+	c := Foo(-7.25)
+	d := Foo(i16(-4))
+	e := Foo(f32(-0.0625))
+	assert a is int
+	assert b is f64
+	assert b !is int
+	assert c is f64
+	assert d is i16
+	assert e is f32
+}
+
+fn test_assign_mut() {
+	mut a := Foo(0)
+	mut b := Foo(i16(3))
+	mut c := Foo(f32(1))
+	a = 12.3
+	b = -123456
+	c = 33.
+	assert a is f64
+	assert b is int
+	assert c is f64
+}
+
+fn test_call_arg() {
+	assert get_type_idx(0.25) == 1
+	assert get_type_idx(-7) == 3
+	assert get_type_idx(u64(0)) == 4
+	assert get_type_idx(f32(-0.125e-7)) == 0
+}
+
+fn get_type_idx(x Foo) int {
+	match x {
+		f32 {
+			return 0
+		}
+		f64 {
+			return 1
+		}
+		i16 {
+			return 2
+		}
+		int {
+			return 3
+		}
+		u64 {
+			return 4
+		}
+	}
+}
+
+fn test_sumtype_return() {
+	a := gen_foo(0)
+	b := gen_foo(1)
+	c := gen_foo(2)
+	d := gen_foo(3)
+	e := gen_foo(4)
+	assert a is f32
+	assert b is f64
+	assert c is f64
+	assert c !is int
+	assert d is i16
+	assert e is int
+}
+
+fn gen_foo(n int) Foo {
+	if n == 0 {
+		return f32(0.5)
+	}
+	if n == 1 {
+		return -17.3e23
+	}
+	if n == 2 {
+		return 32.
+	}
+	if n == 3 {
+		return i16(13)
+	}
+	return 1
+}