[vala] parser: -val is now parsed as a literal instead of unary expression

[Luca Bruno <lucabru src gnome org>]

commit 3b9c095fa3018029818cf19b4c9fcbe8bec34c72
Author: Luca Bruno <lucabru src gnome org>
Date:   Sun Jun 21 15:07:23 2015 +0200

    parser: -val is now parsed as a literal instead of unary expression
    
    Fixes bug 643612

 tests/Makefile.am    |    1 +
 vala/valaparser.vala |    8 ++++++++
 2 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 343da51..03b228d 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -28,6 +28,7 @@ TESTS = \
        basic-types/bug596637.vala \
        basic-types/bug596785.vala \
        basic-types/bug632322.vala \
+       basic-types/bug643612.vala \
        basic-types/bug644046.vala \
        basic-types/bug647222.vala \
        basic-types/bug648364.vala \
diff --git a/vala/valaparser.vala b/vala/valaparser.vala
index 247a85c..e25eef8 100644
--- a/vala/valaparser.vala
+++ b/vala/valaparser.vala
@@ -1039,6 +1039,14 @@ public class Vala.Parser : CodeVisitor {
                if (operator != UnaryOperator.NONE) {
                        next ();
                        var op = parse_unary_expression ();
+                       var lit = op as IntegerLiteral;
+                       if (lit != null) {
+                               if (operator == UnaryOperator.PLUS) {
+                                       return lit;
+                               } else if (operator == UnaryOperator.MINUS) {
+                                       return new IntegerLiteral ("-"+lit.value, get_src (begin));
+                               }
+                       }
                        return new UnaryExpression (operator, op, get_src (begin));
                }
                switch (current ()) {