compiler: consider inlined types info on "append" handling

We need to search for "append" argument type info not only inside local
package type info map, but also inside the inlined type info map.
Close #2696.

pkg/compiler/codegen.go

@@ -1819,7 +1819,7 @@ func (c *codegen) convertBuiltin(expr *ast.CallExpr) {
 		emit.Opcodes(c.prog.BinWriter, opcode.DROP, opcode.PUSH0)
 	case "append":
 		arg := expr.Args[0]
-		typ := c.typeInfo.Types[arg].Type
+		typ := c.typeOf(arg)
 		ast.Walk(c, arg)
 		emit.Opcodes(c.prog.BinWriter, opcode.DUP, opcode.ISNULL)
 		if isByteSlice(typ) {

pkg/compiler/inline_test.go

@@ -432,3 +432,14 @@ func TestInlineDoubleConditionalReturn(t *testing.T) {
 		})
 	}
 }
+
+func TestInlineAppendStatement(t *testing.T) {
+	src := `package foo
+		import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline"
+
+		func Main() []byte {
+			val := []byte{4, 5, 6}
+			return inline.AppendInsideInline(val)
+		}`
+	eval(t, src, []byte{1, 2, 3, 4, 5, 6})
+}

pkg/compiler/testdata/inline/inline.go

@@ -64,3 +64,8 @@ func NewT() T {
 func (t T) GetN() int {
 	return t.N
 }
+
+func AppendInsideInline(val []byte) []byte {
+	inlinedType := []byte{1, 2, 3}
+	return append(inlinedType, val...)
+}