retain recursive function names (#2667)

fixes #2665

lib/compress.js

@@ -4700,9 +4700,14 @@ merge(Compressor.prototype, {
                 if (d.recursive_refs > 0 && fixed.name instanceof AST_SymbolDefun) {
                     value = fixed.clone(true);
                     var defun_def = value.name.definition();
-                    value.name = make_node(AST_SymbolLambda, value.name, value.name);
-                    value.name.scope = value;
-                    var lambda_def = value.def_function(value.name);
+                    var lambda_def = value.variables.get(value.name.name);
+                    var name = lambda_def && lambda_def.orig[0];
+                    if (!(name instanceof AST_SymbolLambda)) {
+                        name = make_node(AST_SymbolLambda, value.name, value.name);
+                        name.scope = value;
+                        value.name = name;
+                        lambda_def = value.def_function(name);
+                    }
                     value.walk(new TreeWalker(function(node) {
                         if (node instanceof AST_SymbolRef && node.definition() === defun_def) {
                             node.thedef = lambda_def;

test/compress/drop-unused.js

@@ -1488,3 +1488,37 @@ issue_2660_2: {
     }
     expect_stdout: "0"
 }
+
+issue_2665: {
+    options = {
+        evaluate: true,
+        inline: true,
+        keep_fargs: false,
+        passes: 2,
+        reduce_funcs: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        typeofs: true,
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        function g() {
+            a-- && g();
+        }
+        typeof h == "function" && h();
+        function h() {
+            typeof g == "function" && g();
+        }
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        !function g() {
+            a-- && g();
+        }();
+        console.log(a);
+    }
+    expect_stdout: "-1"
+}