fix bugs on substituted AST_Defun (#2661)

fixes #2660

lib/compress.js

@@ -3685,8 +3685,9 @@ merge(Compressor.prototype, {
         if (compressor.option("reduce_vars") && fn instanceof AST_SymbolRef) {
             fn = fn.fixed_value();
         }
+        var is_func = fn instanceof AST_Lambda;
         if (compressor.option("unused")
-            && fn instanceof AST_Function
+            && is_func
             && !fn.uses_arguments
             && !fn.uses_eval) {
             var pos = 0, last = 0;
@@ -3855,7 +3856,7 @@ merge(Compressor.prototype, {
                 if (func instanceof AST_SymbolRef) {
                     func = func.fixed_value();
                 }
-                if (func instanceof AST_Function && !func.contains_this()) {
+                if (func instanceof AST_Lambda && !func.contains_this()) {
                     return make_sequence(this, [
                         self.args[0],
                         make_node(AST_Call, self, {
@@ -3925,7 +3926,7 @@ merge(Compressor.prototype, {
                 }
             }
         }
-        var stat = fn instanceof AST_Function && fn.body[0];
+        var stat = is_func && fn.body[0];
         if (compressor.option("inline") && stat instanceof AST_Return) {
             var value = stat.value;
             if (!value || value.is_constant_expression()) {
@@ -3933,7 +3934,7 @@ merge(Compressor.prototype, {
                 return make_sequence(self, args).optimize(compressor);
             }
         }
-        if (fn instanceof AST_Function) {
+        if (is_func) {
             var def, value, scope, level = -1;
             if (compressor.option("inline")
                 && !fn.uses_arguments
@@ -4670,11 +4671,8 @@ merge(Compressor.prototype, {
             && is_lhs(self, compressor.parent()) !== self) {
             var d = self.definition();
             var fixed = self.fixed_value();
-            if (fixed instanceof AST_Defun) {
-                d.fixed = fixed = make_node(AST_Function, fixed, fixed);
-            }
             var single_use = d.single_use;
-            if (single_use && fixed instanceof AST_Function) {
+            if (single_use && fixed instanceof AST_Lambda) {
                 if (d.scope !== self.scope
                     && (!compressor.option("reduce_funcs")
                         || d.escaped == 1
@@ -4695,6 +4693,9 @@ merge(Compressor.prototype, {
                 }
             }
             if (single_use && fixed) {
+                if (fixed instanceof AST_Defun) {
+                    fixed = make_node(AST_Function, fixed, fixed);
+                }
                 var value;
                 if (d.recursive_refs > 0 && fixed.name instanceof AST_SymbolDefun) {
                     value = fixed.clone(true);
@@ -4705,6 +4706,7 @@ merge(Compressor.prototype, {
                     value.walk(new TreeWalker(function(node) {
                         if (node instanceof AST_SymbolRef && node.definition() === defun_def) {
                             node.thedef = lambda_def;
+                            lambda_def.references.push(node);
                         }
                     }));
                 } else {

test/compress/drop-unused.js

@@ -1434,3 +1434,57 @@ defun_lambda_same_name: {
     }
     expect_stdout: "120"
 }
+
+issue_2660_1: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 2;
+        function f(b) {
+            return b && f() || a--;
+        }
+        f(1);
+        console.log(a);
+    }
+    expect: {
+        var a = 2;
+        (function f(b) {
+            return b && f() || a--;
+        })(1);
+        console.log(a);
+    }
+    expect_stdout: "1"
+}
+
+issue_2660_2: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        function f(b) {
+            b && f();
+            --a, a.toString();
+        }
+        f();
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        (function f(b) {
+            b && f(),
+            (--a).toString();
+        })(),
+        console.log(a);
+    }
+    expect_stdout: "0"
+}