Fix parsing of expression statements

Parser.Tests/MParserShould.cs

@@ -22,6 +22,17 @@ namespace Parser.Tests
             Assert.IsType<AssignmentExpressionSyntaxNode>(((ExpressionStatementSyntaxNode)assignment).Expression);
         }
 
+        [Fact]
+        public void ParseExpressionStatement()
+        {
+            var text = "2 + 3";
+            var sut = GetSut(text);
+            var actual = sut.Parse();
+            var statement = actual.Root.StatementList[0].AsNode();
+            Assert.IsType<ExpressionStatementSyntaxNode>(statement);
+            Assert.IsType<BinaryOperationExpressionSyntaxNode>(((ExpressionStatementSyntaxNode)statement).Expression);
+        }
+
         [Fact]
         public void ParseAssignmentExpression_Incomplete()
         {

Parser/Internal/MParserGreen.cs

@@ -1070,8 +1070,6 @@ namespace Parser.Internal
                     case "elseif":
                     case "end":
                         return null;
-                    default:
-                        return ParseExpressionStatement();
                 }
             }
 
@@ -1084,7 +1082,7 @@ namespace Parser.Internal
             {
                 return Factory.EmptyStatementSyntax(EatToken());
             }
-            throw new ParsingException($"Unexpected token \"{CurrentToken}\" at {CurrentPosition}.");
+            return ParseExpressionStatement();
         }
         
         private SyntaxList ParseStatementList()