remove extraneous ! before AST_Arrow (#2185)

lib/compress.js

@@ -561,8 +561,8 @@ merge(Compressor.prototype, {
         return orig.length == 1 && orig[0] instanceof AST_SymbolLambda;
     });
 
-    function is_func_expr(node, traditional) {
+    function is_func_expr(node) {
-        return node instanceof AST_Function || !traditional && node instanceof AST_Arrow;
+        return node instanceof AST_Arrow || node instanceof AST_Function;
     }
 
     function is_lhs_read_only(lhs) {
@@ -706,9 +706,9 @@ merge(Compressor.prototype, {
         return x;
     };
 
-    function is_iife_call(node, traditional) {
+    function is_iife_call(node) {
         if (node instanceof AST_Call && !(node instanceof AST_New)) {
-            return is_func_expr(node.expression, traditional) || is_iife_call(node.expression);
+            return node.expression instanceof AST_Function || is_iife_call(node.expression);
         }
         return false;
     }
@@ -3452,7 +3452,7 @@ merge(Compressor.prototype, {
         }
         if (compressor.option("negate_iife")
             && compressor.parent() instanceof AST_SimpleStatement
-            && is_iife_call(self, true)) {
+            && is_iife_call(self)) {
             return self.negate(compressor, true);
         }
         var ev = self.evaluate(compressor);

test/compress/arrow.js

@@ -312,7 +312,7 @@ issue_2105_1: {
         });
     }
     expect: {
-        !void (() => {
+        void (() => {
             var quux = () => {
                 console.log("PASS");
             };
@@ -357,7 +357,7 @@ issue_2105_2: {
         });
     }
     expect: {
-        !void (() => {
+        void (() => {
             var quux = () => {
                 console.log("PASS");
             };
@@ -528,7 +528,7 @@ issue_2084: {
     }
     expect: {
         var c = 0;
-        !((c) => {
+        ((c) => {
             c = 1 + c,
             c = 1 + (c = 0),
             0 !== 23..toString() && (c = 1 + c);