lang: lex: only read linefeeds up to the end of the current line buffer

lang/lex.c

@@ -482,6 +482,11 @@ static int advance(struct ivy_lexer *lex)
 	return c;
 }
 
+static bool input_available(struct ivy_lexer* lex)
+{
+	return lex->lex_linebuf_ptr < lex->lex_linebuf_len;
+}
+
 static bool char_can_begin_symbol(char c)
 {
 	for (size_t i = 0; i < nr_symbols; i++) {
@@ -999,6 +1004,11 @@ static enum ivy_status pump_tokens(struct ivy_lexer *lex)
 	if (c == '\n') {
 		while (c == '\n') {
 			advance(lex);
+
+			if (!input_available(lex)) {
+				break;
+			}
+
 			c = peek(lex);
 		}