[vala/wip/issue/987] vala: Don't rollback for possible member-access inside of type-argument-list

[Rico Tzschichholz <ricotz src gnome org>]

commit d2273e4bf1bd05d6615d1d8118e0b356529ede2e
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sun May 10 21:09:29 2020 +0200

    vala: Don't rollback for possible member-access inside of type-argument-list
    
    Fixes https://gitlab.gnome.org/GNOME/vala/issues/987

 vala/valaparser.vala | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/vala/valaparser.vala b/vala/valaparser.vala
index 9f0b976fc..7c528e157 100644
--- a/vala/valaparser.vala
+++ b/vala/valaparser.vala
@@ -108,6 +108,10 @@ public class Vala.Parser : CodeVisitor {
                return tokens[index].type;
        }
 
+       inline TokenType previous () {
+               return tokens[(index - 1 + BUFFER_SIZE) % BUFFER_SIZE].type;
+       }
+
        inline bool accept (TokenType type) {
                if (current () == type) {
                        next ();
@@ -1666,13 +1670,12 @@ public class Vala.Parser : CodeVisitor {
                var begin = get_location ();
 
                // decide between declaration and expression statement
+               bool maybe_type_argument_list = previous () == TokenType.OP_LT;
                try {
                        skip_type ();
                } catch (ParseError e) {
-                       prev ();
-                       var token = current ();
-                       next ();
-                       if (token == TokenType.DOT || token == TokenType.DOUBLE_COLON) {
+                       var token = previous ();
+                       if (!maybe_type_argument_list && (token == TokenType.DOT || token == 
TokenType.DOUBLE_COLON)) {
                                rollback (begin);
                                return true;
                        } else {