compiler: emit byte constants properly

pkg/compiler/codegen.go

@@ -133,6 +133,7 @@ func (c *codegen) emitLoadConst(t types.TypeAndValue) {
 
 	switch typ.Kind() {
 	case types.Int, types.UntypedInt, types.Uint,
+		types.Int8, types.Uint8,
 		types.Int16, types.Uint16,
 		types.Int32, types.Uint32, types.Int64, types.Uint64:
 		val, _ := constant.Int64Val(t.Value)
@@ -143,10 +144,6 @@ func (c *codegen) emitLoadConst(t types.TypeAndValue) {
 	case types.Bool, types.UntypedBool:
 		val := constant.BoolVal(t.Value)
 		emit.Bool(c.prog.BinWriter, val)
-	case types.Byte:
-		val, _ := constant.Int64Val(t.Value)
-		b := byte(val)
-		emit.Bytes(c.prog.BinWriter, []byte{b})
 	default:
 		c.prog.Err = fmt.Errorf("compiler doesn't know how to convert this basic type: %v", t)
 		return

pkg/compiler/constant_test.go

@@ -36,6 +36,17 @@ func TestShortHandMultiConst(t *testing.T) {
 	eval(t, src, big.NewInt(6))
 }
 
+func TestByteConstant(t *testing.T) {
+	src := `package foo
+	import "github.com/nspcc-dev/neo-go/pkg/interop/convert"
+	const a byte = 0xFF
+	func Main() int64 {
+		x := convert.ToInteger(a)
+		return x+1
+	}`
+	eval(t, src, big.NewInt(0x100))
+}
+
 func TestGlobalsWithFunctionParams(t *testing.T) {
 	src := `
 		package foobar