replace single-use recursive functions (#2659)

fixes #2628

test/compress/collapse_vars.js

@@ -3878,10 +3878,9 @@ recursive_function_replacement: {
         console.log(f(c));
     }
     expect: {
-        function f(n) {
-            return x(y(f(n)));
-        }
-        console.log(f(c));
+        console.log(function n(o) {
+            return x(y(n(o)));
+        }(c));
     }
 }
 

test/compress/functions.js

@@ -1345,11 +1345,10 @@ issue_2630_3: {
     expect: {
         var x = 2, a = 1;
         (function() {
-            function f1(a) {
+            (function f1(a) {
                 f2();
                 --x >= 0 && f1({});
-            }
-            f1(a++);
+            })(a++);
             function f2() {
                 a++;
             }
@@ -1424,7 +1423,7 @@ issue_2630_5: {
     expect_stdout: "155"
 }
 
-recursive_inline: {
+recursive_inline_1: {
     options = {
         inline: true,
         reduce_funcs: true,
@@ -1448,6 +1447,26 @@ recursive_inline: {
     expect: {}
 }
 
+recursive_inline_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f(n) {
+            return n ? n * f(n - 1) : 1;
+        }
+        console.log(f(5));
+    }
+    expect: {
+        console.log(function f(n) {
+            return n ? n * f(n - 1) : 1;
+        }(5));
+    }
+    expect_stdout: "120"
+}
+
 issue_2657: {
     options = {
         inline: true,

test/compress/reduce_vars.js

@@ -1355,10 +1355,9 @@ defun_inline_1: {
         function f() {
             return function(b) {
                 return b;
-            }(2) + h();
-            function h() {
+            }(2) + function h() {
                 return h();
-            }
+            }();
         }
     }
 }
@@ -1382,12 +1381,11 @@ defun_inline_2: {
     }
     expect: {
         function f() {
-            function h() {
-                return h();
-            }
             return function(b) {
                 return b;
-            }(2) + h();
+            }(2) + function h() {
+                return h();
+            }();
         }
     }
 }