diff --git a/lexer/lexer.go b/lexer/lexer.go
index 5c33cde..b900f6f 100644
--- a/lexer/lexer.go
+++ b/lexer/lexer.go
@@ -250,7 +250,7 @@ func (l *Lexer) readNumber() string {
 
 func (l *Lexer) readString() string {
 	position := l.position + 1
-	for {
+	for l.ch != 0 {
 		l.readChar()
 		// check for quote escapes
 		if l.ch == '\\' && l.peekChar() == '"' {
diff --git a/plush_test.go b/plush_test.go
index 0ab8f01..9c9356f 100644
--- a/plush_test.go
+++ b/plush_test.go
@@ -448,6 +448,15 @@ func Test_LineNumberErrors_InsideForLoop(t *testing.T) {
 	r.Contains(err.Error(), "line 3:")
 }
 
+func Test_MissingQuote(t *testing.T) {
+	r := require.New(t)
+	input := `<%= foo("asdf) %>`
+	ctx := NewContext()
+	ctx.Set("foo", func(string) {})
+	_, err := Render(input, ctx)
+	r.Error(err)
+}
+
 func Test_RunScript(t *testing.T) {
 	r := require.New(t)
 	bb := &bytes.Buffer{}