fix corner case in evaluate (#4036)

fixes #4035

lib/compress.js

@@ -7436,6 +7436,7 @@ merge(Compressor.prototype, {
                 }
                 break;
             }
+            if (!(parent instanceof AST_UnaryPrefix && parent.operator == "delete")) {
                 if (self.left instanceof AST_Number && !self.right.is_constant()) switch (self.operator) {
                   // 0 + n => n
                   case "+":
@@ -7488,6 +7489,7 @@ merge(Compressor.prototype, {
                     break;
                 }
             }
+        }
         if (compressor.option("typeofs")) switch (self.operator) {
           case "&&":
             mark_locally_defined(self.left, self.right, null);

test/compress/evaluate.js

@@ -2833,3 +2833,39 @@ issue_3997: {
     }
     expect_stdout: "string"
 }
+
+issue_4035: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        var a = 0;
+        (function() {
+            var b = --a;
+            console.log(delete (0 + b));
+            console.log(delete (1 * b));
+            console.log(delete (b + 0));
+            console.log(delete (b - 0));
+            console.log(delete (b / 1));
+        })();
+    }
+    expect: {
+        var a = 0;
+        (function() {
+            var b = --a;
+            console.log((0 + b, true));
+            console.log((1 * b, true));
+            console.log((0 + b, true));
+            console.log((b - 0, true));
+            console.log((b / 1, true));
+        })();
+    }
+    expect_stdout: [
+        "true",
+        "true",
+        "true",
+        "true",
+        "true",
+    ]
+}