fix block-scoped function for ES6

fixes #1903

lib/compress.js

@@ -1249,7 +1249,14 @@ merge(Compressor.prototype, {
                 return true;
             }
             if (node instanceof AST_Defun && (node === stat || !compressor.has_directive("use strict"))) {
-                target.push(node);
+                target.push(node === stat ? node : make_node(AST_Var, node, {
+                    definitions: [
+                        make_node(AST_VarDef, node, {
+                            name: make_node(AST_SymbolVar, node.name, node.name),
+                            value: null
+                        })
+                    ]
+                }));
                 return true;
             }
             if (node instanceof AST_Scope) {
@@ -2388,7 +2395,7 @@ merge(Compressor.prototype, {
                         }
                         if (hoist_funs && node instanceof AST_Defun
                             && !(tt.parent() instanceof AST_Export)
-                            && (tt.parent() === self || !compressor.has_directive("use strict"))) {
+                            && tt.parent() === self) {
                             hoisted.push(node);
                             return make_node(AST_EmptyStatement, node);
                         }

test/compress/dead-code.js

@@ -54,12 +54,12 @@ dead_code_2_should_warn: {
             x = 10;
             throw new Error("foo");
             var x;
-            function g(){};
+            var g;
         }
         f();
     }
     expect_stdout: true
-    node_version: "<=4"
+    node_version: ">=6"
 }
 
 dead_code_2_should_warn_strict: {
@@ -99,7 +99,7 @@ dead_code_2_should_warn_strict: {
         f();
     }
     expect_stdout: true
-    node_version: "=4"
+    node_version: ">=4"
 }
 
 dead_code_constant_boolean_should_warn_more: {
@@ -126,7 +126,7 @@ dead_code_constant_boolean_should_warn_more: {
     }
     expect: {
         var foo;
-        function bar() {}
+        var bar;
         // nothing for the while
         // as for the for, it should keep:
         var x = 10, y;
@@ -134,7 +134,7 @@ dead_code_constant_boolean_should_warn_more: {
         bar();
     }
     expect_stdout: true
-    node_version: "<=4"
+    node_version: ">=6"
 }
 
 dead_code_constant_boolean_should_warn_more_strict: {
@@ -217,7 +217,7 @@ dead_code_const_declaration: {
         var unused;
         const CONST_FOO = !1;
         var moo;
-        function bar() {}
+        var bar;
     }
     expect_stdout: true
 }
@@ -245,7 +245,7 @@ dead_code_const_annotation: {
         var unused;
         var CONST_FOO_ANN = !1;
         var moo;
-        function bar() {}
+        var bar;
     }
     expect_stdout: true
 }
@@ -312,7 +312,7 @@ dead_code_const_annotation_complex_scope: {
         var CONST_FOO_ANN = !1;
         var unused_var_2;
         var moo;
-        function bar() {}
+        var bar;
         var beef = 'good';
         var meat = 'beef';
         var pork = 'bad';

test/compress/functions.js

@@ -185,25 +185,25 @@ hoist_funs: {
         console.log(6, typeof f, typeof g);
     }
     expect: {
-        function f() {}
         function g() {}
         console.log(1, typeof f, typeof g);
         if (console.log(2, typeof f, typeof g))
             console.log(3, typeof f, typeof g);
         else {
             console.log(4, typeof f, typeof g);
+            function f() {}
             console.log(5, typeof f, typeof g);
         }
         console.log(6, typeof f, typeof g);
     }
     expect_stdout: [
-        "1 'function' 'function'",
-        "2 'function' 'function'",
+        "1 'undefined' 'function'",
+        "2 'undefined' 'function'",
         "4 'function' 'function'",
         "5 'function' 'function'",
         "6 'function' 'function'",
     ]
-    node_version: "<=4"
+    node_version: ">=6"
 }
 
 hoist_funs_strict: {
@@ -243,5 +243,5 @@ hoist_funs_strict: {
         "5 'function' 'function'",
         "6 'undefined' 'function'",
     ]
-    node_version: "=4"
+    node_version: ">=4"
 }

test/compress/issue-1052.js

@@ -134,9 +134,8 @@ defun_hoist_funs: {
     expect: {
         function e() {
             function f() {}
-            function g() {}
             function h() {}
-            !window;
+            if (window) function g() {}
         }
     }
 }