Catch small edge-case in parser

worldedit-core/src/test/java/com/sk89q/worldedit/internal/expression/ExpressionTest.java

@@ -74,6 +74,11 @@ public class ExpressionTest {
         assertEquals(8, compile("foo+bar", "foo", "bar").evaluate(5D, 3D), 0);
     }
 
+    @Test
+    void testTightTokenization() {
+        assertEquals(4, simpleEval("3+1"), 0);
+    }
+
     @Test
     public void testErrors() {
         // test lexer errors