Reconstruct negative literal in parser

src/parser/DeclParser.cj

@@ -854,6 +854,11 @@ internal open class DeclParser {
         // the problem will be solved.
         if (helper.matches(TKH.PREFIX_UNARY_OPERATOR)) {
             let oper: Token = helper.previous()
+            if (oper.kind == TK.SUB && helper.matches(TK.INTEGER_LITERAL, TK.FLOAT_LITERAL)) {
+                let literal: Token = helper.previous()
+                return LitConstExpr(NodeIdManager.nextId(),
+                    Token(literal.kind, "-" + literal.value, oper.pos))
+            }
             let right: Expr = expectExpression(prefixUnaryExpression,
                 "Expected a postfixExpression after ${oper.value}, found '\u{001b}[31m${helper.peek().value}\u{001b}[0m'")
             return UnaryExpr(NodeIdManager.nextId(), oper, right)

src/test/Parser_test.cj

@@ -253,7 +253,7 @@ class ParserTests {
     func unaryExpr_test() {
         let test: String = """
             main(){
-                -134
+                -(134)
                 !134
             }"""
 
@@ -278,9 +278,11 @@ class ParserTests {
         let test: String = """
             main(){
                 1231
+                -1231
                 "string"
                 ()
                 1.2
+                -1.2
                 true
                 false
                 r'a'