enhance inline (#5655)

- improve fix for #5653

lib/compress.js

@@ -189,6 +189,10 @@ Compressor.prototype = new TreeTransformer(function(node, descend, in_list) {
     if (node._squeezed) return node;
     var is_scope = node instanceof AST_Scope;
     if (is_scope) {
+        if (this.option("arrows") && is_arrow(node) && node.value) {
+            node.body = [ node.first_statement() ];
+            node.value = null;
+        }
         node.hoist_properties(this);
         node.hoist_declarations(this);
         node.process_returns(this);
@@ -8449,6 +8453,7 @@ Compressor.prototype.compress = function(node) {
     AST_Scope.DEFMETHOD("hoist_properties", function(compressor) {
         if (!compressor.option("hoist_props") || compressor.has_directive("use asm")) return;
         var self = this;
+        if (is_arrow(self) && self.value) return;
         var top_retain = self instanceof AST_Toplevel && compressor.top_retain || return_false;
         var defs_by_id = Object.create(null);
         var tt = new TreeTransformer(function(node, descend) {
@@ -8486,18 +8491,9 @@ Compressor.prototype.compress = function(node) {
                 return make_sequence(node, assignments);
             }
             if (node instanceof AST_Scope) {
-                var parent;
-                if (node === self || (parent = tt.parent()).TYPE == "Call" && parent.expression === node) {
-                    if (!(is_arrow(node) && node.value)) return;
-                    var stat = node.first_statement();
-                    node.body = [ stat ];
-                    node.value = null;
-                    descend(node, tt);
-                    if (node.body.length == 1 && node.body[0] === stat) {
-                        node.body.length = 0;
-                        node.value = stat.value;
-                    }
-                }
+                if (node === self) return;
+                var parent = tt.parent();
+                if (parent.TYPE == "Call" && parent.expression === node) return;
                 return node;
             }
             if (node instanceof AST_VarDef) {

test/compress/arrows.js

@@ -668,6 +668,28 @@ single_use_recursive: {
     node_version: ">=4"
 }
 
+inline_iife_within_arrow: {
+    options = {
+        arrows: true,
+        inline: true,
+    }
+    input: {
+        var f = () => console.log(function(a) {
+            return Math.ceil(a);
+        }(Math.random()));
+        f();
+    }
+    expect: {
+        var f = () => {
+            return console.log((a = Math.random(), Math.ceil(a)));
+            var a;
+        };
+        f();
+    }
+    expect_stdout: "1"
+    node_version: ">=4"
+}
+
 issue_4388: {
     options = {
         inline: true,